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Diffstat (limited to 'doc')
107 files changed, 6191 insertions, 5751 deletions
diff --git a/doc/manual/bugs.xml b/doc/manual/bugs/bugs.xml index aa87e4b57048..aa87e4b57048 100644 --- a/doc/manual/bugs.xml +++ b/doc/manual/bugs/bugs.xml diff --git a/doc/manual/builds/build-farm.xml b/doc/manual/builds/build-farm.xml new file mode 100644 index 000000000000..e0e9f10f1173 --- /dev/null +++ b/doc/manual/builds/build-farm.xml @@ -0,0 +1,22 @@ +<part xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='chap-distributed-builds'> + +<title>Distributed Builds</title> + +<partintro> +<para>Nix supports distributed builds, where a local Nix installation can +forward Nix builds to other machines over the network. This allows +multiple builds to be performed in parallel (thus improving +performance) and allows Nix to perform multi-platform builds in a +semi-transparent way. For instance, if you perform a build for a +<literal>powerpc-darwin</literal> on an <literal>i686-linux</literal> +machine, Nix can automatically forward the build to a +<literal>powerpc-darwin</literal> machine, if available.</para> +</partintro> + +<xi:include href="enabling-builds.xml" /> + +</part> diff --git a/doc/manual/build-farm.xml b/doc/manual/builds/enabling-builds.xml index 2e0d86b89f09..4b45812ee918 100644 --- a/doc/manual/build-farm.xml +++ b/doc/manual/builds/enabling-builds.xml @@ -1,17 +1,10 @@ <chapter xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xml:id='chap-distributed-builds'> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-enabling-builds"> -<title>Setting Up Distributed Builds</title> - -<para>Nix supports distributed builds: a local Nix installation can -forward Nix builds to other machines over the network. This allows -multiple builds to be performed in parallel (thus improving -performance) and allows Nix to perform multi-platform builds in a -semi-transparent way. For instance, if you perform a build for a -<literal>powerpc-darwin</literal> on an <literal>i686-linux</literal> -machine, Nix can automatically forward the build to a -<literal>powerpc-darwin</literal> machine, if available.</para> +<title>Enabling Distributed Builds</title> <para>You can enable distributed builds by setting the environment variable <envar>NIX_BUILD_HOOK</envar> to point to a program that Nix @@ -109,5 +102,5 @@ load on the remote machine, so if you have multiple instances of Nix running, they should use the same <envar>NIX_CURRENT_LOAD</envar> file. Maybe in the future <filename>build-remote.pl</filename> will look at the actual remote load.</para> - -</chapter> + +</chapter> \ No newline at end of file diff --git a/doc/manual/command-ref/command-ref.xml b/doc/manual/command-ref/command-ref.xml new file mode 100644 index 000000000000..cfad9b7d7966 --- /dev/null +++ b/doc/manual/command-ref/command-ref.xml @@ -0,0 +1,20 @@ +<part xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='part-command-ref'> + +<title>Command Reference</title> + +<partintro> +<para>This section lists commands and options that you can use when you +work with Nix.</para> +</partintro> + +<xi:include href="opt-common.xml" /> +<xi:include href="env-common.xml" /> +<xi:include href="main-commands.xml" /> +<xi:include href="utilities.xml" /> +<xi:include href="files.xml" /> + +</part> diff --git a/doc/manual/conf-file.xml b/doc/manual/command-ref/conf-file.xml index e420d1ed6c34..e420d1ed6c34 100644 --- a/doc/manual/conf-file.xml +++ b/doc/manual/command-ref/conf-file.xml diff --git a/doc/manual/env-common.xml b/doc/manual/command-ref/env-common.xml index 3d0b35f3ef6b..b52e450309f4 100644 --- a/doc/manual/env-common.xml +++ b/doc/manual/command-ref/env-common.xml @@ -1,8 +1,10 @@ -<section xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xml:id="sec-common-env"> +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-common-env"> -<title>Common environment variables</title> +<title>Common Environment Variables</title> <para>Most Nix commands interpret the following environment variables:</para> @@ -335,4 +337,4 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen> </variablelist> -</section> +</chapter> diff --git a/doc/manual/command-ref/files.xml b/doc/manual/command-ref/files.xml new file mode 100644 index 000000000000..7bbc96e89982 --- /dev/null +++ b/doc/manual/command-ref/files.xml @@ -0,0 +1,14 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='ch-files'> + +<title>Files</title> + +<para>This section lists configuration files that you can use when you +work with Nix.</para> + +<xi:include href="conf-file.xml" /> + +</chapter> \ No newline at end of file diff --git a/doc/manual/command-ref/main-commands.xml b/doc/manual/command-ref/main-commands.xml new file mode 100644 index 000000000000..0f4169243ca9 --- /dev/null +++ b/doc/manual/command-ref/main-commands.xml @@ -0,0 +1,17 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='ch-main-commands'> + +<title>Main Commands</title> + +<para>This section lists commands and options that you can use when you +work with Nix.</para> + +<xi:include href="nix-env.xml" /> +<xi:include href="nix-build.xml" /> +<xi:include href="nix-shell.xml" /> +<xi:include href="nix-store.xml" /> + +</chapter> \ No newline at end of file diff --git a/doc/manual/nix-build.xml b/doc/manual/command-ref/nix-build.xml index 3832f5fc3450..669a48f8c3ee 100644 --- a/doc/manual/nix-build.xml +++ b/doc/manual/command-ref/nix-build.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-build"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-build"> <refmeta> <refentrytitle>nix-build</refentrytitle> diff --git a/doc/manual/nix-channel.xml b/doc/manual/command-ref/nix-channel.xml index 2c4e1151b0d4..e13394c7d9fd 100644 --- a/doc/manual/nix-channel.xml +++ b/doc/manual/command-ref/nix-channel.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-channel"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-channel"> <refmeta> <refentrytitle>nix-channel</refentrytitle> diff --git a/doc/manual/nix-collect-garbage.xml b/doc/manual/command-ref/nix-collect-garbage.xml index cf870740f4ab..f2009dcbd767 100644 --- a/doc/manual/nix-collect-garbage.xml +++ b/doc/manual/command-ref/nix-collect-garbage.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-collect-garbage"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-collect-garbage"> <refmeta> <refentrytitle>nix-collect-garbage</refentrytitle> diff --git a/doc/manual/nix-copy-closure.xml b/doc/manual/command-ref/nix-copy-closure.xml index 3f8fd8017089..3f8fd8017089 100644 --- a/doc/manual/nix-copy-closure.xml +++ b/doc/manual/command-ref/nix-copy-closure.xml diff --git a/doc/manual/nix-daemon.xml b/doc/manual/command-ref/nix-daemon.xml index c68605fd6566..4311664ed70c 100644 --- a/doc/manual/nix-daemon.xml +++ b/doc/manual/command-ref/nix-daemon.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-daemon"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-daemon"> <refmeta> <refentrytitle>nix-daemon</refentrytitle> diff --git a/doc/manual/nix-env.xml b/doc/manual/command-ref/nix-env.xml index c44020803451..494edc3e502c 100644 --- a/doc/manual/nix-env.xml +++ b/doc/manual/command-ref/nix-env.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-env"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-env"> <refmeta> <refentrytitle>nix-env</refentrytitle> diff --git a/doc/manual/nix-hash.xml b/doc/manual/command-ref/nix-hash.xml index af4e361ff8d4..897d92e2c746 100644 --- a/doc/manual/nix-hash.xml +++ b/doc/manual/command-ref/nix-hash.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-hash"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-hash"> <refmeta> <refentrytitle>nix-hash</refentrytitle> diff --git a/doc/manual/nix-install-package.xml b/doc/manual/command-ref/nix-install-package.xml index 54a66348f013..fa3b46e22c19 100644 --- a/doc/manual/nix-install-package.xml +++ b/doc/manual/command-ref/nix-install-package.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-install-package"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-install-package"> <refmeta> <refentrytitle>nix-install-package</refentrytitle> diff --git a/doc/manual/nix-instantiate.xml b/doc/manual/command-ref/nix-instantiate.xml index 6a4348f002ed..8649cd58cc60 100644 --- a/doc/manual/nix-instantiate.xml +++ b/doc/manual/command-ref/nix-instantiate.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-instantiate"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-instantiate"> <refmeta> <refentrytitle>nix-instantiate</refentrytitle> diff --git a/doc/manual/nix-prefetch-url.xml b/doc/manual/command-ref/nix-prefetch-url.xml index c416e675b05c..885c958ce60a 100644 --- a/doc/manual/nix-prefetch-url.xml +++ b/doc/manual/command-ref/nix-prefetch-url.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-prefetch-url"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-prefetch-url"> <refmeta> <refentrytitle>nix-prefetch-url</refentrytitle> diff --git a/doc/manual/nix-pull.xml b/doc/manual/command-ref/nix-pull.xml index 8e4a505e1d25..43d5a6c56b2f 100644 --- a/doc/manual/nix-pull.xml +++ b/doc/manual/command-ref/nix-pull.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-pull"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-pull"> <refmeta> <refentrytitle>nix-pull</refentrytitle> diff --git a/doc/manual/nix-push.xml b/doc/manual/command-ref/nix-push.xml index e789bbf7d352..9c6cdfa2f268 100644 --- a/doc/manual/nix-push.xml +++ b/doc/manual/command-ref/nix-push.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-push"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-push"> <refmeta> <refentrytitle>nix-push</refentrytitle> diff --git a/doc/manual/nix-shell.xml b/doc/manual/command-ref/nix-shell.xml index d5f70a9e66a2..1cb2ebfdd285 100644 --- a/doc/manual/nix-shell.xml +++ b/doc/manual/command-ref/nix-shell.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-shell"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-shell"> <refmeta> <refentrytitle>nix-shell</refentrytitle> diff --git a/doc/manual/nix-store.xml b/doc/manual/command-ref/nix-store.xml index c9a912ff0ee4..ae0f683f2c16 100644 --- a/doc/manual/nix-store.xml +++ b/doc/manual/command-ref/nix-store.xml @@ -1,7 +1,8 @@ <refentry xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xmlns:xi="http://www.w3.org/2001/XInclude" - xml:id="sec-nix-store"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-nix-store"> <refmeta> <refentrytitle>nix-store</refentrytitle> diff --git a/doc/manual/opt-common-syn.xml b/doc/manual/command-ref/opt-common-syn.xml index d65f4009ee6e..d65f4009ee6e 100644 --- a/doc/manual/opt-common-syn.xml +++ b/doc/manual/command-ref/opt-common-syn.xml diff --git a/doc/manual/opt-common.xml b/doc/manual/command-ref/opt-common.xml index 7cef96b1b2f0..c7e8ae1ed05f 100644 --- a/doc/manual/opt-common.xml +++ b/doc/manual/command-ref/opt-common.xml @@ -1,6 +1,6 @@ -<section xmlns="http://docbook.org/ns/docbook" xml:id="sec-common-options"> +<chapter xmlns="http://docbook.org/ns/docbook" xml:id="sec-common-options"> -<title>Common options</title> +<title>Common Options</title> <para>Most Nix commands accept the following command-line options:</para> @@ -387,4 +387,4 @@ </variablelist> -</section> +</chapter> diff --git a/doc/manual/opt-inst-syn.xml b/doc/manual/command-ref/opt-inst-syn.xml index e8c3f1ec6f04..e8c3f1ec6f04 100644 --- a/doc/manual/opt-inst-syn.xml +++ b/doc/manual/command-ref/opt-inst-syn.xml diff --git a/doc/manual/command-ref/utilities.xml b/doc/manual/command-ref/utilities.xml new file mode 100644 index 000000000000..190962ceae74 --- /dev/null +++ b/doc/manual/command-ref/utilities.xml @@ -0,0 +1,23 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='ch-utilities'> + +<title>Utilities</title> + +<para>This section lists utilities that you can use when you +work with Nix.</para> + +<xi:include href="nix-channel.xml" /> +<xi:include href="nix-collect-garbage.xml" /> +<xi:include href="nix-copy-closure.xml" /> +<xi:include href="nix-daemon.xml" /> +<xi:include href="nix-hash.xml" /> +<xi:include href="nix-install-package.xml" /> +<xi:include href="nix-instantiate.xml" /> +<xi:include href="nix-prefetch-url.xml" /> +<xi:include href="nix-pull.xml" /> +<xi:include href="nix-push.xml" /> + +</chapter> \ No newline at end of file diff --git a/doc/manual/expressions/advanced-attributes.xml b/doc/manual/expressions/advanced-attributes.xml new file mode 100644 index 000000000000..f8b84b98cb82 --- /dev/null +++ b/doc/manual/expressions/advanced-attributes.xml @@ -0,0 +1,262 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-advanced-attributes"> + +<title>Advanced Attributes</title> + +<para>Derivations can declare some infrequently used optional +attributes.</para> + +<variablelist> + + <varlistentry><term><varname>allowedReferences</varname></term> + + <listitem><para>The optional attribute + <varname>allowedReferences</varname> specifies a list of legal + references (dependencies) of the output of the builder. For + example, + +<programlisting> +allowedReferences = []; +</programlisting> + + enforces that the output of a derivation cannot have any runtime + dependencies on its inputs. To allow an output to have a runtime + dependency on itself, use <literal>"out"</literal> as a list item. + This is used in NixOS to check that generated files such as + initial ramdisks for booting Linux don’t have accidental + dependencies on other paths in the Nix store.</para></listitem> + + </varlistentry> + + + <varlistentry><term><varname>allowedRequisites</varname></term> + + <listitem><para>This attribute is similar to + <varname>allowedReferences</varname>, but it specifies the legal + requisites of the whole closure, so all the dependencies + recursively. For example, + +<programlisting> +allowedReferences = [ foobar ]; +</programlisting> + + enforces that the output of a derivation cannot have any other + runtime dependency than <varname>foobar</varname>, and in addition + it enforces that <varname>foobar</varname> itself doesn't + introduce any other dependency itself.</para></listitem> + + </varlistentry> + + + <varlistentry><term><varname>exportReferencesGraph</varname></term> + + <listitem><para>This attribute allows builders access to the + references graph of their inputs. The attribute is a list of + inputs in the Nix store whose references graph the builder needs + to know. The value of this attribute should be a list of pairs + <literal>[ <replaceable>name1</replaceable> + <replaceable>path1</replaceable> <replaceable>name2</replaceable> + <replaceable>path2</replaceable> <replaceable>...</replaceable> + ]</literal>. The references graph of each + <replaceable>pathN</replaceable> will be stored in a text file + <replaceable>nameN</replaceable> in the temporary build directory. + The text files have the format used by <command>nix-store + --register-validity</command> (with the deriver fields left + empty). For example, when the following derivation is built: + +<programlisting> +derivation { + ... + exportReferencesGraph = [ "libfoo-graph" libfoo ]; +}; +</programlisting> + + the references graph of <literal>libfoo</literal> is placed in the + file <filename>libfoo-graph</filename> in the temporary build + directory.</para> + + <para><varname>exportReferencesGraph</varname> is useful for + builders that want to do something with the closure of a store + path. Examples include the builders in NixOS that generate the + initial ramdisk for booting Linux (a <command>cpio</command> + archive containing the closure of the boot script) and the + ISO-9660 image for the installation CD (which is populated with a + Nix store containing the closure of a bootable NixOS + configuration).</para></listitem> + + </varlistentry> + + + <varlistentry xml:id="fixed-output-drvs"> + <term><varname>outputHash</varname></term> + <term><varname>outputHashAlgo</varname></term> + <term><varname>outputHashMode</varname></term> + + <listitem><para>These attributes declare that the derivation is a + so-called <emphasis>fixed-output derivation</emphasis>, which + means that a cryptographic hash of the output is already known in + advance. When the build of a fixed-output derivation finishes, + Nix computes the cryptographic hash of the output and compares it + to the hash declared with these attributes. If there is a + mismatch, the build fails.</para> + + <para>The rationale for fixed-output derivations is derivations + such as those produced by the <function>fetchurl</function> + function. This function downloads a file from a given URL. To + ensure that the downloaded file has not been modified, the caller + must also specify a cryptographic hash of the file. For example, + +<programlisting> +fetchurl { + url = http://ftp.gnu.org/pub/gnu/hello/hello-2.1.1.tar.gz; + md5 = "70c9ccf9fac07f762c24f2df2290784d"; +} +</programlisting> + + It sometimes happens that the URL of the file changes, e.g., + because servers are reorganised or no longer available. We then + must update the call to <function>fetchurl</function>, e.g., + +<programlisting> +fetchurl { + url = ftp://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz; + md5 = "70c9ccf9fac07f762c24f2df2290784d"; +} +</programlisting> + + If a <function>fetchurl</function> derivation was treated like a + normal derivation, the output paths of the derivation and + <emphasis>all derivations depending on it</emphasis> would change. + For instance, if we were to change the URL of the Glibc source + distribution in Nixpkgs (a package on which almost all other + packages depend) massive rebuilds would be needed. This is + unfortunate for a change which we know cannot have a real effect + as it propagates upwards through the dependency graph.</para> + + <para>For fixed-output derivations, on the other hand, the name of + the output path only depends on the <varname>outputHash*</varname> + and <varname>name</varname> attributes, while all other attributes + are ignored for the purpose of computing the output path. (The + <varname>name</varname> attribute is included because it is part + of the path.)</para> + + <para>As an example, here is the (simplified) Nix expression for + <varname>fetchurl</varname>: + +<programlisting> +{ stdenv, curl }: # The <command>curl</command> program is used for downloading. + +{ url, md5 }: + +stdenv.mkDerivation { + name = baseNameOf (toString url); + builder = ./builder.sh; + buildInputs = [ curl ]; + + # This is a fixed-output derivation; the output must be a regular + # file with MD5 hash <varname>md5</varname>. + outputHashMode = "flat"; + outputHashAlgo = "md5"; + outputHash = md5; + + inherit url; +} +</programlisting> + + </para> + + <para>The <varname>outputHashAlgo</varname> attribute specifies + the hash algorithm used to compute the hash. It can currently be + <literal>"md5"</literal>, <literal>"sha1"</literal> or + <literal>"sha256"</literal>.</para> + + <para>The <varname>outputHashMode</varname> attribute determines + how the hash is computed. It must be one of the following two + values: + + <variablelist> + + <varlistentry><term><literal>"flat"</literal></term> + + <listitem><para>The output must be a non-executable regular + file. If it isn’t, the build fails. The hash is simply + computed over the contents of that file (so it’s equal to what + Unix commands like <command>md5sum</command> or + <command>sha1sum</command> produce).</para> + + <para>This is the default.</para></listitem> + + </varlistentry> + + <varlistentry><term><literal>"recursive"</literal></term> + + <listitem><para>The hash is computed over the NAR archive dump + of the output (i.e., the result of <link + linkend="refsec-nix-store-dump"><command>nix-store + --dump</command></link>). In this case, the output can be + anything, including a directory tree.</para></listitem> + + </varlistentry> + + </variablelist> + + </para> + + <para>The <varname>outputHash</varname> attribute, finally, must + be a string containing the hash in either hexadecimal or base-32 + notation. (See the <link + linkend="sec-nix-hash"><command>nix-hash</command> command</link> + for information about converting to and from base-32 + notation.)</para></listitem> + + </varlistentry> + + + <varlistentry><term><varname>impureEnvVars</varname></term> + + <listitem><para>This attribute allows you to specify a list of + environment variables that should be passed from the environment + of the calling user to the builder. Usually, the environment is + cleared completely when the builder is executed, but with this + attribute you can allow specific environment variables to be + passed unmodified. For example, <function>fetchurl</function> in + Nixpkgs has the line + +<programlisting> +impureEnvVars = [ "http_proxy" "https_proxy" <replaceable>...</replaceable> ]; +</programlisting> + + to make it use the proxy server configuration specified by the + user in the environment variables <envar>http_proxy</envar> and + friends.</para> + + <para>This attribute is only allowed in <link + linkend="fixed-output-drvs">fixed-output derivations</link>, where + impurities such as these are okay since (the hash of) the output + is known in advance. It is ignored for all other + derivations.</para></listitem> + + </varlistentry> + + + <varlistentry><term><varname>preferLocalBuild</varname></term> + + <listitem><para>If this attribute is set to + <literal>true</literal>, it has two effects. First, the + derivation will always be built, not substituted, even if a + substitute is available. Second, if <link + linkend="chap-distributed-builds">distributed building is + enabled</link>, then, if possible, the derivaton will be built + locally instead of forwarded to a remote machine. This is + appropriate for trivial builders where the cost of doing a + download or remote build would exceed the cost of building + locally.</para></listitem> + + </varlistentry> + +</variablelist> + +</section> diff --git a/doc/manual/expressions/arguments-variables.xml b/doc/manual/expressions/arguments-variables.xml new file mode 100644 index 000000000000..bf60cb7eef8a --- /dev/null +++ b/doc/manual/expressions/arguments-variables.xml @@ -0,0 +1,121 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='sec-arguments'> + +<title>Arguments and Variables</title> + +<example xml:id='ex-hello-composition'> + +<title>Composing GNU Hello +(<filename>all-packages.nix</filename>)</title> +<programlisting> +... + +rec { <co xml:id='ex-hello-composition-co-1' /> + + hello = import ../applications/misc/hello/ex-1 <co xml:id='ex-hello-composition-co-2' /> { <co xml:id='ex-hello-composition-co-3' /> + inherit fetchurl stdenv perl; + }; + + perl = import ../development/interpreters/perl { <co xml:id='ex-hello-composition-co-4' /> + inherit fetchurl stdenv; + }; + + fetchurl = import ../build-support/fetchurl { + inherit stdenv; ... + }; + + stdenv = ...; + +} +</programlisting> +</example> + +<para>The Nix expression in <xref linkend='ex-hello-nix' /> is a +function; it is missing some arguments that have to be filled in +somewhere. In the Nix Packages collection this is done in the file +<filename>pkgs/top-level/all-packages.nix</filename>, where all +Nix expressions for packages are imported and called with the +appropriate arguments. <xref linkend='ex-hello-composition' /> shows +some fragments of +<filename>all-packages.nix</filename>.</para> + +<calloutlist> + + <callout arearefs='ex-hello-composition-co-1'> + + <para>This file defines a set of attributes, all of which are + concrete derivations (i.e., not functions). In fact, we define a + <emphasis>mutually recursive</emphasis> set of attributes. That + is, the attributes can refer to each other. This is precisely + what we want since we want to <quote>plug</quote> the + various packages into each other.</para> + + </callout> + + <callout arearefs='ex-hello-composition-co-2'> + + <para>Here we <emphasis>import</emphasis> the Nix expression for + GNU Hello. The import operation just loads and returns the + specified Nix expression. In fact, we could just have put the + contents of <xref linkend='ex-hello-nix' /> in + <filename>all-packages.nix</filename> at this point. That + would be completely equivalent, but it would make the file rather + bulky.</para> + + <para>Note that we refer to + <filename>../applications/misc/hello/ex-1</filename>, not + <filename>../applications/misc/hello/ex-1/default.nix</filename>. + When you try to import a directory, Nix automatically appends + <filename>/default.nix</filename> to the file name.</para> + + </callout> + + <callout arearefs='ex-hello-composition-co-3'> + + <para>This is where the actual composition takes place. Here we + <emphasis>call</emphasis> the function imported from + <filename>../applications/misc/hello/ex-1</filename> with a set + containing the things that the function expects, namely + <varname>fetchurl</varname>, <varname>stdenv</varname>, and + <varname>perl</varname>. We use inherit again to use the + attributes defined in the surrounding scope (we could also have + written <literal>fetchurl = fetchurl;</literal>, etc.).</para> + + <para>The result of this function call is an actual derivation + that can be built by Nix (since when we fill in the arguments of + the function, what we get is its body, which is the call to + <varname>stdenv.mkDerivation</varname> in <xref + linkend='ex-hello-nix' />).</para> + + <note><para>Nixpkgs has a convenience function + <function>callPackage</function> that imports and calls a + function, filling in any missing arguments by passing the + corresponding attribute from the Nixpkgs set, like this: + +<programlisting> +hello = callPackage ../applications/misc/hello/ex-1 { }; +</programlisting> + + If necessary, you can set or override arguments: + +<programlisting> +hello = callPackage ../applications/misc/hello/ex-1 { stdenv = myStdenv; }; +</programlisting> + + </para></note> + + </callout> + + <callout arearefs='ex-hello-composition-co-4'> + + <para>Likewise, we have to instantiate Perl, + <varname>fetchurl</varname>, and the standard environment.</para> + + </callout> + +</calloutlist> + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/build-script.xml b/doc/manual/expressions/build-script.xml new file mode 100644 index 000000000000..7bad8f808d58 --- /dev/null +++ b/doc/manual/expressions/build-script.xml @@ -0,0 +1,119 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='sec-build-script'> + +<title>Build Script</title> + +<example xml:id='ex-hello-builder'><title>Build script for GNU Hello +(<filename>builder.sh</filename>)</title> +<programlisting> +source $stdenv/setup <co xml:id='ex-hello-builder-co-1' /> + +PATH=$perl/bin:$PATH <co xml:id='ex-hello-builder-co-2' /> + +tar xvfz $src <co xml:id='ex-hello-builder-co-3' /> +cd hello-* +./configure --prefix=$out <co xml:id='ex-hello-builder-co-4' /> +make <co xml:id='ex-hello-builder-co-5' /> +make install</programlisting> +</example> + +<para><xref linkend='ex-hello-builder' /> shows the builder referenced +from Hello's Nix expression (stored in +<filename>pkgs/applications/misc/hello/ex-1/builder.sh</filename>). +The builder can actually be made a lot shorter by using the +<emphasis>generic builder</emphasis> functions provided by +<varname>stdenv</varname>, but here we write out the build steps to +elucidate what a builder does. It performs the following +steps:</para> + +<calloutlist> + + <callout arearefs='ex-hello-builder-co-1'> + + <para>When Nix runs a builder, it initially completely clears the + environment (except for the attributes declared in the + derivation). For instance, the <envar>PATH</envar> variable is + empty<footnote><para>Actually, it's initialised to + <filename>/path-not-set</filename> to prevent Bash from setting it + to a default value.</para></footnote>. This is done to prevent + undeclared inputs from being used in the build process. If for + example the <envar>PATH</envar> contained + <filename>/usr/bin</filename>, then you might accidentally use + <filename>/usr/bin/gcc</filename>.</para> + + <para>So the first step is to set up the environment. This is + done by calling the <filename>setup</filename> script of the + standard environment. The environment variable + <envar>stdenv</envar> points to the location of the standard + environment being used. (It wasn't specified explicitly as an + attribute in <xref linkend='ex-hello-nix' />, but + <varname>mkDerivation</varname> adds it automatically.)</para> + + </callout> + + <callout arearefs='ex-hello-builder-co-2'> + + <para>Since Hello needs Perl, we have to make sure that Perl is in + the <envar>PATH</envar>. The <envar>perl</envar> environment + variable points to the location of the Perl package (since it + was passed in as an attribute to the derivation), so + <filename><replaceable>$perl</replaceable>/bin</filename> is the + directory containing the Perl interpreter.</para> + + </callout> + + <callout arearefs='ex-hello-builder-co-3'> + + <para>Now we have to unpack the sources. The + <varname>src</varname> attribute was bound to the result of + fetching the Hello source tarball from the network, so the + <envar>src</envar> environment variable points to the location in + the Nix store to which the tarball was downloaded. After + unpacking, we <command>cd</command> to the resulting source + directory.</para> + + <para>The whole build is performed in a temporary directory + created in <varname>/tmp</varname>, by the way. This directory is + removed after the builder finishes, so there is no need to clean + up the sources afterwards. Also, the temporary directory is + always newly created, so you don't have to worry about files from + previous builds interfering with the current build.</para> + + </callout> + + <callout arearefs='ex-hello-builder-co-4'> + + <para>GNU Hello is a typical Autoconf-based package, so we first + have to run its <filename>configure</filename> script. In Nix + every package is stored in a separate location in the Nix store, + for instance + <filename>/nix/store/9a54ba97fb71b65fda531012d0443ce2-hello-2.1.1</filename>. + Nix computes this path by cryptographically hashing all attributes + of the derivation. The path is passed to the builder through the + <envar>out</envar> environment variable. So here we give + <filename>configure</filename> the parameter + <literal>--prefix=$out</literal> to cause Hello to be installed in + the expected location.</para> + + </callout> + + <callout arearefs='ex-hello-builder-co-5'> + + <para>Finally we build Hello (<literal>make</literal>) and install + it into the location specified by <envar>out</envar> + (<literal>make install</literal>).</para> + + </callout> + +</calloutlist> + +<para>If you are wondering about the absence of error checking on the +result of various commands called in the builder: this is because the +shell script is evaluated with Bash's <option>-e</option> option, +which causes the script to be aborted if any command fails without an +error check.</para> + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/builder-syntax.xml b/doc/manual/expressions/builder-syntax.xml new file mode 100644 index 000000000000..e51bade44e59 --- /dev/null +++ b/doc/manual/expressions/builder-syntax.xml @@ -0,0 +1,119 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='sec-builder-syntax'> + +<title>Builder Syntax</title> + +<example xml:id='ex-hello-builder'><title>Build script for GNU Hello +(<filename>builder.sh</filename>)</title> +<programlisting> +source $stdenv/setup <co xml:id='ex-hello-builder-co-1' /> + +PATH=$perl/bin:$PATH <co xml:id='ex-hello-builder-co-2' /> + +tar xvfz $src <co xml:id='ex-hello-builder-co-3' /> +cd hello-* +./configure --prefix=$out <co xml:id='ex-hello-builder-co-4' /> +make <co xml:id='ex-hello-builder-co-5' /> +make install</programlisting> +</example> + +<para><xref linkend='ex-hello-builder' /> shows the builder referenced +from Hello's Nix expression (stored in +<filename>pkgs/applications/misc/hello/ex-1/builder.sh</filename>). +The builder can actually be made a lot shorter by using the +<emphasis>generic builder</emphasis> functions provided by +<varname>stdenv</varname>, but here we write out the build steps to +elucidate what a builder does. It performs the following +steps:</para> + +<calloutlist> + + <callout arearefs='ex-hello-builder-co-1'> + + <para>When Nix runs a builder, it initially completely clears the + environment (except for the attributes declared in the + derivation). For instance, the <envar>PATH</envar> variable is + empty<footnote><para>Actually, it's initialised to + <filename>/path-not-set</filename> to prevent Bash from setting it + to a default value.</para></footnote>. This is done to prevent + undeclared inputs from being used in the build process. If for + example the <envar>PATH</envar> contained + <filename>/usr/bin</filename>, then you might accidentally use + <filename>/usr/bin/gcc</filename>.</para> + + <para>So the first step is to set up the environment. This is + done by calling the <filename>setup</filename> script of the + standard environment. The environment variable + <envar>stdenv</envar> points to the location of the standard + environment being used. (It wasn't specified explicitly as an + attribute in <xref linkend='ex-hello-nix' />, but + <varname>mkDerivation</varname> adds it automatically.)</para> + + </callout> + + <callout arearefs='ex-hello-builder-co-2'> + + <para>Since Hello needs Perl, we have to make sure that Perl is in + the <envar>PATH</envar>. The <envar>perl</envar> environment + variable points to the location of the Perl package (since it + was passed in as an attribute to the derivation), so + <filename><replaceable>$perl</replaceable>/bin</filename> is the + directory containing the Perl interpreter.</para> + + </callout> + + <callout arearefs='ex-hello-builder-co-3'> + + <para>Now we have to unpack the sources. The + <varname>src</varname> attribute was bound to the result of + fetching the Hello source tarball from the network, so the + <envar>src</envar> environment variable points to the location in + the Nix store to which the tarball was downloaded. After + unpacking, we <command>cd</command> to the resulting source + directory.</para> + + <para>The whole build is performed in a temporary directory + created in <varname>/tmp</varname>, by the way. This directory is + removed after the builder finishes, so there is no need to clean + up the sources afterwards. Also, the temporary directory is + always newly created, so you don't have to worry about files from + previous builds interfering with the current build.</para> + + </callout> + + <callout arearefs='ex-hello-builder-co-4'> + + <para>GNU Hello is a typical Autoconf-based package, so we first + have to run its <filename>configure</filename> script. In Nix + every package is stored in a separate location in the Nix store, + for instance + <filename>/nix/store/9a54ba97fb71b65fda531012d0443ce2-hello-2.1.1</filename>. + Nix computes this path by cryptographically hashing all attributes + of the derivation. The path is passed to the builder through the + <envar>out</envar> environment variable. So here we give + <filename>configure</filename> the parameter + <literal>--prefix=$out</literal> to cause Hello to be installed in + the expected location.</para> + + </callout> + + <callout arearefs='ex-hello-builder-co-5'> + + <para>Finally we build Hello (<literal>make</literal>) and install + it into the location specified by <envar>out</envar> + (<literal>make install</literal>).</para> + + </callout> + +</calloutlist> + +<para>If you are wondering about the absence of error checking on the +result of various commands called in the builder: this is because the +shell script is evaluated with Bash's <option>-e</option> option, +which causes the script to be aborted if any command fails without an +error check.</para> + +</section> \ No newline at end of file diff --git a/doc/manual/builtins.xml b/doc/manual/expressions/builtins.xml index b289c6f0ed4b..4edb3a1a76fb 100644 --- a/doc/manual/builtins.xml +++ b/doc/manual/expressions/builtins.xml @@ -1,9 +1,10 @@ <section xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xml:id='ssec-builtins'> - -<title>Built-in functions</title> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='ssec-builtins'> +<title>Built-in Functions</title> <para>This section lists the functions and constants built into the Nix expression evaluator. (The built-in function diff --git a/doc/manual/expressions/custom-builder.xml b/doc/manual/expressions/custom-builder.xml new file mode 100644 index 000000000000..c26deac40f4a --- /dev/null +++ b/doc/manual/expressions/custom-builder.xml @@ -0,0 +1,26 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-custom-builder"> + +<title>Customizing the Generic Builder</title> + +<para>The operation of the generic builder can be modified in many +places by setting certain variables. These <emphasis>hook +variables</emphasis> are typically set to the name of some shell +function defined by you. For instance, to perform some additional +steps after <command>make install</command> you would set the +<varname>postInstall</varname> variable: + +<programlisting> +postInstall=myPostInstall + +myPostInstall() { + mkdir $out/share/extra + cp extrafiles/* $out/share/extra +}</programlisting> + +</para> + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/debug-build.xml b/doc/manual/expressions/debug-build.xml new file mode 100644 index 000000000000..508cb2c1930e --- /dev/null +++ b/doc/manual/expressions/debug-build.xml @@ -0,0 +1,33 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-debug-build"> + +<title>Debugging Build Failures</title> + +<para>At the beginning of each phase, the set of all shell variables +is written to the file <filename>env-vars</filename> at the top-level +build directory. This is useful for debugging: it allows you to +recreate the environment in which a build was performed. For +instance, if a build fails, then assuming you used the +<option>-K</option> flag, you can go to the output directory and +<quote>switch</quote> to the environment of the builder: + +<screen> +$ nix-build -K ./foo.nix +... fails, keeping build directory `/tmp/nix-1234-0' + +$ cd /tmp/nix-1234-0 + +$ source env-vars + +<lineannotation>(edit some files...)</lineannotation> + +$ make + +<lineannotation>(execution continues with the same GCC, make, etc.)</lineannotation></screen> + +</para> + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/derivations.xml b/doc/manual/expressions/derivations.xml new file mode 100644 index 000000000000..b57c33f4e3a9 --- /dev/null +++ b/doc/manual/expressions/derivations.xml @@ -0,0 +1,211 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-derivation"> + +<title>Derivations</title> + +<para>The most important built-in function is +<function>derivation</function>, which is used to describe a single +derivation (a build action). It takes as input a set, the attributes +of which specify the inputs of the build.</para> + +<itemizedlist> + + <listitem xml:id="attr-system"><para>There must be an attribute named + <varname>system</varname> whose value must be a string specifying a + Nix platform identifier, such as <literal>"i686-linux"</literal> or + <literal>"powerpc-darwin"</literal><footnote><para>To figure out + your platform identifier, look at the line <quote>Checking for the + canonical Nix system name</quote> in the output of Nix's + <filename>configure</filename> script.</para></footnote> The build + can only be performed on a machine and operating system matching the + platform identifier. (Nix can automatically forward builds for + other platforms by forwarding them to other machines; see <xref + linkend='chap-distributed-builds' />.)</para></listitem> + + <listitem><para>There must be an attribute named + <varname>name</varname> whose value must be a string. This is used + as a symbolic name for the package by <command>nix-env</command>, + and it is appended to the output paths of the + derivation.</para></listitem> + + <listitem><para>There must be an attribute named + <varname>builder</varname> that identifies the program that is + executed to perform the build. It can be either a derivation or a + source (a local file reference, e.g., + <filename>./builder.sh</filename>).</para></listitem> + + <listitem><para>Every attribute is passed as an environment variable + to the builder. Attribute values are translated to environment + variables as follows: + + <itemizedlist> + + <listitem><para>Strings and integers are just passed + verbatim.</para></listitem> + + <listitem><para>A <emphasis>path</emphasis> (e.g., + <filename>../foo/sources.tar</filename>) causes the referenced + file to be copied to the store; its location in the store is put + in the environment variable. The idea is that all sources + should reside in the Nix store, since all inputs to a derivation + should reside in the Nix store.</para></listitem> + + <listitem><para>A <emphasis>derivation</emphasis> causes that + derivation to be built prior to the present derivation; its + default output path is put in the environment + variable.</para></listitem> + + <listitem><para>Lists of the previous types are also allowed. + They are simply concatenated, separated by + spaces.</para></listitem> + + <listitem><para><literal>true</literal> is passed as the string + <literal>1</literal>, <literal>false</literal> and + <literal>null</literal> are passed as an empty string. + </para></listitem> + </itemizedlist> + + </para></listitem> + + <listitem><para>The optional attribute <varname>args</varname> + specifies command-line arguments to be passed to the builder. It + should be a list.</para></listitem> + + <listitem><para>The optional attribute <varname>outputs</varname> + specifies a list of symbolic outputs of the derivation. By default, + a derivation produces a single output path, denoted as + <literal>out</literal>. However, derivations can produce multiple + output paths. This is useful because it allows outputs to be + downloaded or garbage-collected separately. For instance, imagine a + library package that provides a dynamic library, header files, and + documentation. A program that links against the library doesn’t + need the header files and documentation at runtime, and it doesn’t + need the documentation at build time. Thus, the library package + could specify: +<programlisting> +outputs = [ "lib" "headers" "doc" ]; +</programlisting> + This will cause Nix to pass environment variables + <literal>lib</literal>, <literal>headers</literal> and + <literal>doc</literal> to the builder containing the intended store + paths of each output. The builder would typically do something like +<programlisting> +./configure --libdir=$lib/lib --includedir=$headers/include --docdir=$doc/share/doc +</programlisting> + for an Autoconf-style package. You can refer to each output of a + derivation by selecting it as an attribute, e.g. +<programlisting> +buildInputs = [ pkg.lib pkg.headers ]; +</programlisting> + The first element of <varname>output</varname> determines the + <emphasis>default output</emphasis>. Thus, you could also write +<programlisting> +buildInputs = [ pkg pkg.headers ]; +</programlisting> + since <literal>pkg</literal> is equivalent to + <literal>pkg.lib</literal>.</para></listitem> + +</itemizedlist> + +<para>The function <function>mkDerivation</function> in the standard +environment is a wrapper around <function>derivation</function> that +adds a default value for <varname>system</varname> and always uses +Bash as the builder, to which the supplied builder is passed as a +command-line argument. See <xref linkend='sec-standard-environment' +/>.</para> + +<para>The builder is executed as follows: + +<itemizedlist> + + <listitem><para>A temporary directory is created under the directory + specified by <envar>TMPDIR</envar> (default + <filename>/tmp</filename>) where the build will take place. The + current directory is changed to this directory.</para></listitem> + + <listitem><para>The environment is cleared and set to the derivation + attributes, as specified above.</para></listitem> + + <listitem><para>In addition, the following variables are set: + + <itemizedlist> + + <listitem><para><envar>NIX_BUILD_TOP</envar> contains the path of + the temporary directory for this build.</para></listitem> + + <listitem><para>Also, <envar>TMPDIR</envar>, + <envar>TEMPDIR</envar>, <envar>TMP</envar>, <envar>TEMP</envar> + are set to point to the temporary directory. This is to prevent + the builder from accidentally writing temporary files anywhere + else. Doing so might cause interference by other + processes.</para></listitem> + + <listitem><para><envar>PATH</envar> is set to + <filename>/path-not-set</filename> to prevent shells from + initialising it to their built-in default value.</para></listitem> + + <listitem><para><envar>HOME</envar> is set to + <filename>/homeless-shelter</filename> to prevent programs from + using <filename>/etc/passwd</filename> or the like to find the + user's home directory, which could cause impurity. Usually, when + <envar>HOME</envar> is set, it is used as the location of the home + directory, even if it points to a non-existent + path.</para></listitem> + + <listitem><para><envar>NIX_STORE</envar> is set to the path of the + top-level Nix store directory (typically, + <filename>/nix/store</filename>).</para></listitem> + + <listitem><para>For each output declared in + <varname>outputs</varname>, the corresponding environment variable + is set to point to the intended path in the Nix store for that + output. Each output path is a concatenation of the cryptographic + hash of all build inputs, the <varname>name</varname> attribute + and the output name. (The output name is omitted if it’s + <literal>out</literal>.)</para></listitem> + + </itemizedlist> + + </para></listitem> + + <listitem><para>If an output path already exists, it is removed. + Also, locks are acquired to prevent multiple Nix instances from + performing the same build at the same time.</para></listitem> + + <listitem><para>A log of the combined standard output and error is + written to <filename>/nix/var/log/nix</filename>.</para></listitem> + + <listitem><para>The builder is executed with the arguments specified + by the attribute <varname>args</varname>. If it exits with exit + code 0, it is considered to have succeeded.</para></listitem> + + <listitem><para>The temporary directory is removed (unless the + <option>-K</option> option was specified).</para></listitem> + + <listitem><para>If the build was successful, Nix scans each output + path for references to input paths by looking for the hash parts of + the input paths. Since these are potential runtime dependencies, + Nix registers them as dependencies of the output + paths.</para></listitem> + + <listitem><para>After the build, Nix sets the last-modified + timestamp on all files in the build result to 1 (00:00:01 1/1/1970 + UTC), sets the group to the default group, and sets the mode of the + file to 0444 or 0555 (i.e., read-only, with execute permission + enabled if the file was originally executable). Note that possible + <literal>setuid</literal> and <literal>setgid</literal> bits are + cleared. Setuid and setgid programs are not currently supported by + Nix. This is because the Nix archives used in deployment have no + concept of ownership information, and because it makes the build + result dependent on the user performing the build.</para></listitem> + +</itemizedlist> + +</para> + +<xi:include href="advanced-attributes.xml" /> + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/expression-language.xml b/doc/manual/expressions/expression-language.xml new file mode 100644 index 000000000000..240ef80f1463 --- /dev/null +++ b/doc/manual/expressions/expression-language.xml @@ -0,0 +1,30 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-expression-language"> + +<title>Nix Expression Language</title> + +<para>The Nix expression language is a pure, lazy, functional +language. Purity means that operations in the language don't have +side-effects (for instance, there is no variable assignment). +Laziness means that arguments to functions are evaluated only when +they are needed. Functional means that functions are +<quote>normal</quote> values that can be passed around and manipulated +in interesting ways. The language is not a full-featured, general +purpose language. Its main job is to describe packages, +compositions of packages, and the variability within +packages.</para> + +<para>This section presents the various features of the +language.</para> + +<xi:include href="language-values.xml" /> +<xi:include href="language-constructs.xml" /> +<xi:include href="language-operators.xml" /> +<xi:include href="derivations.xml" /> +<xi:include href="builtins.xml" /> + + +</chapter> diff --git a/doc/manual/expressions/expression-syntax.xml b/doc/manual/expressions/expression-syntax.xml new file mode 100644 index 000000000000..6f1a3a10c4e4 --- /dev/null +++ b/doc/manual/expressions/expression-syntax.xml @@ -0,0 +1,148 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='sec-expression-syntax'> + +<title>Expression Syntax</title> + +<example xml:id='ex-hello-nix'><title>Nix expression for GNU Hello +(<filename>default.nix</filename>)</title> +<programlisting> +{ stdenv, fetchurl, perl }: <co xml:id='ex-hello-nix-co-1' /> + +stdenv.mkDerivation { <co xml:id='ex-hello-nix-co-2' /> + name = "hello-2.1.1"; <co xml:id='ex-hello-nix-co-3' /> + builder = ./builder.sh; <co xml:id='ex-hello-nix-co-4' /> + src = fetchurl { <co xml:id='ex-hello-nix-co-5' /> + url = ftp://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz; + md5 = "70c9ccf9fac07f762c24f2df2290784d"; + }; + inherit perl; <co xml:id='ex-hello-nix-co-6' /> +}</programlisting> +</example> + +<para><xref linkend='ex-hello-nix' /> shows a Nix expression for GNU +Hello. It's actually already in the Nix Packages collection in +<filename>pkgs/applications/misc/hello/ex-1/default.nix</filename>. +It is customary to place each package in a separate directory and call +the single Nix expression in that directory +<filename>default.nix</filename>. The file has the following elements +(referenced from the figure by number): + +<calloutlist> + + <callout arearefs='ex-hello-nix-co-1'> + + <para>This states that the expression is a + <emphasis>function</emphasis> that expects to be called with three + arguments: <varname>stdenv</varname>, <varname>fetchurl</varname>, + and <varname>perl</varname>. They are needed to build Hello, but + we don't know how to build them here; that's why they are function + arguments. <varname>stdenv</varname> is a package that is used + by almost all Nix Packages packages; it provides a + <quote>standard</quote> environment consisting of the things you + would expect in a basic Unix environment: a C/C++ compiler (GCC, + to be precise), the Bash shell, fundamental Unix tools such as + <command>cp</command>, <command>grep</command>, + <command>tar</command>, etc. <varname>fetchurl</varname> is a + function that downloads files. <varname>perl</varname> is the + Perl interpreter.</para> + + <para>Nix functions generally have the form <literal>{ x, y, ..., + z }: e</literal> where <varname>x</varname>, <varname>y</varname>, + etc. are the names of the expected arguments, and where + <replaceable>e</replaceable> is the body of the function. So + here, the entire remainder of the file is the body of the + function; when given the required arguments, the body should + describe how to build an instance of the Hello package.</para> + + </callout> + + <callout arearefs='ex-hello-nix-co-2'> + + <para>So we have to build a package. Building something from + other stuff is called a <emphasis>derivation</emphasis> in Nix (as + opposed to sources, which are built by humans instead of + computers). We perform a derivation by calling + <varname>stdenv.mkDerivation</varname>. + <varname>mkDerivation</varname> is a function provided by + <varname>stdenv</varname> that builds a package from a set of + <emphasis>attributes</emphasis>. A set is just a list of + key/value pairs where each key is a string and each value is an + arbitrary Nix expression. They take the general form <literal>{ + <replaceable>name1</replaceable> = + <replaceable>expr1</replaceable>; <replaceable>...</replaceable> + <replaceable>nameN</replaceable> = + <replaceable>exprN</replaceable>; }</literal>.</para> + + </callout> + + <callout arearefs='ex-hello-nix-co-3'> + + <para>The attribute <varname>name</varname> specifies the symbolic + name and version of the package. Nix doesn't really care about + these things, but they are used by for instance <command>nix-env + -q</command> to show a <quote>human-readable</quote> name for + packages. This attribute is required by + <varname>mkDerivation</varname>.</para> + + </callout> + + <callout arearefs='ex-hello-nix-co-4'> + + <para>The attribute <varname>builder</varname> specifies the + builder. This attribute can sometimes be omitted, in which case + <varname>mkDerivation</varname> will fill in a default builder + (which does a <literal>configure; make; make install</literal>, in + essence). Hello is sufficiently simple that the default builder + would suffice, but in this case, we will show an actual builder + for educational purposes. The value + <command>./builder.sh</command> refers to the shell script shown + in <xref linkend='ex-hello-builder' />, discussed below.</para> + + </callout> + + <callout arearefs='ex-hello-nix-co-5'> + + <para>The builder has to know what the sources of the package + are. Here, the attribute <varname>src</varname> is bound to the + result of a call to the <command>fetchurl</command> function. + Given a URL and an MD5 hash of the expected contents of the file + at that URL, this function builds a derivation that downloads the + file and checks its hash. So the sources are a dependency that + like all other dependencies is built before Hello itself is + built.</para> + + <para>Instead of <varname>src</varname> any other name could have + been used, and in fact there can be any number of sources (bound + to different attributes). However, <varname>src</varname> is + customary, and it's also expected by the default builder (which we + don't use in this example).</para> + + </callout> + + <callout arearefs='ex-hello-nix-co-6'> + + <para>Since the derivation requires Perl, we have to pass the + value of the <varname>perl</varname> function argument to the + builder. All attributes in the set are actually passed as + environment variables to the builder, so declaring an attribute + + <programlisting> +perl = perl;</programlisting> + + will do the trick: it binds an attribute <varname>perl</varname> + to the function argument which also happens to be called + <varname>perl</varname>. However, it looks a bit silly, so there + is a shorter syntax. The <literal>inherit</literal> keyword + causes the specified attributes to be bound to whatever variables + with the same name happen to be in scope.</para> + + </callout> + +</calloutlist> + +</para> + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/generic-builder.xml b/doc/manual/expressions/generic-builder.xml new file mode 100644 index 000000000000..f8567a042d47 --- /dev/null +++ b/doc/manual/expressions/generic-builder.xml @@ -0,0 +1,98 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='sec-generic-builder'> + +<title>Generic Builder Syntax</title> + +<para>Recall from <xref linkend='ex-hello-builder' /> that the builder +looked something like this: + +<programlisting> +PATH=$perl/bin:$PATH +tar xvfz $src +cd hello-* +./configure --prefix=$out +make +make install</programlisting> + +The builders for almost all Unix packages look like this — set up some +environment variables, unpack the sources, configure, build, and +install. For this reason the standard environment provides some Bash +functions that automate the build process. A builder using the +generic build facilities in shown in <xref linkend='ex-hello-builder2' +/>.</para> + +<example xml:id='ex-hello-builder2'><title>Build script using the generic +build functions</title> +<programlisting> +buildInputs="$perl" <co xml:id='ex-hello-builder2-co-1' /> + +source $stdenv/setup <co xml:id='ex-hello-builder2-co-2' /> + +genericBuild <co xml:id='ex-hello-builder2-co-3' /></programlisting> +</example> + +<calloutlist> + + <callout arearefs='ex-hello-builder2-co-1'> + + <para>The <envar>buildInputs</envar> variable tells + <filename>setup</filename> to use the indicated packages as + <quote>inputs</quote>. This means that if a package provides a + <filename>bin</filename> subdirectory, it's added to + <envar>PATH</envar>; if it has a <filename>include</filename> + subdirectory, it's added to GCC's header search path; and so + on.<footnote><para>How does it work? <filename>setup</filename> + tries to source the file + <filename><replaceable>pkg</replaceable>/nix-support/setup-hook</filename> + of all dependencies. These “setup hooks” can then set up whatever + environment variables they want; for instance, the setup hook for + Perl sets the <envar>PERL5LIB</envar> environment variable to + contain the <filename>lib/site_perl</filename> directories of all + inputs.</para></footnote> + </para> + + </callout> + + <callout arearefs='ex-hello-builder2-co-2'> + + <para>The function <function>genericBuild</function> is defined in + the file <literal>$stdenv/setup</literal>.</para> + + </callout> + + <callout arearefs='ex-hello-builder2-co-3'> + + <para>The final step calls the shell function + <function>genericBuild</function>, which performs the steps that + were done explicitly in <xref linkend='ex-hello-builder' />. The + generic builder is smart enough to figure out whether to unpack + the sources using <command>gzip</command>, + <command>bzip2</command>, etc. It can be customised in many ways; + see <xref linkend='sec-standard-environment' />.</para> + + </callout> + +</calloutlist> + +<para>Discerning readers will note that the +<envar>buildInputs</envar> could just as well have been set in the Nix +expression, like this: + +<programlisting> + buildInputs = [ perl ];</programlisting> + +The <varname>perl</varname> attribute can then be removed, and the +builder becomes even shorter: + +<programlisting> +source $stdenv/setup +genericBuild</programlisting> + +In fact, <varname>mkDerivation</varname> provides a default builder +that looks exactly like that, so it is actually possible to omit the +builder for Hello entirely.</para> + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/language-constructs.xml b/doc/manual/expressions/language-constructs.xml new file mode 100644 index 000000000000..ddb3498946b7 --- /dev/null +++ b/doc/manual/expressions/language-constructs.xml @@ -0,0 +1,344 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-constructs"> + +<title>Language Constructs</title> + +<simplesect><title>Recursive sets</title> + +<para>Recursive sets are just normal sets, but the attributes can +refer to each other. For example, + +<programlisting> +rec { + x = y; + y = 123; +}.x +</programlisting> + +evaluates to <literal>123</literal>. Note that without +<literal>rec</literal> the binding <literal>x = y;</literal> would +refer to the variable <varname>y</varname> in the surrounding scope, +if one exists, and would be invalid if no such variable exists. That +is, in a normal (non-recursive) set, attributes are not added to the +lexical scope; in a recursive set, they are.</para> + +<para>Recursive sets of course introduce the danger of infinite +recursion. For example, + +<programlisting> +rec { + x = y; + y = x; +}.x</programlisting> + +does not terminate<footnote><para>Actually, Nix detects infinite +recursion in this case and aborts (<quote>infinite recursion +encountered</quote>).</para></footnote>.</para> + +</simplesect> + + +<simplesect><title>Let-expressions</title> + +<para>A let-expression allows you define local variables for an +expression. For instance, + +<programlisting> +let + x = "foo"; + y = "bar"; +in x + y</programlisting> + +evaluates to <literal>"foobar"</literal>. + +</para> + +</simplesect> + + +<simplesect><title>Inheriting attributes</title> + +<para>When defining a set it is often convenient to copy variables +from the surrounding lexical scope (e.g., when you want to propagate +attributes). This can be shortened using the +<literal>inherit</literal> keyword. For instance, + +<programlisting> +let x = 123; in +{ inherit x; + y = 456; +}</programlisting> + +evaluates to <literal>{ x = 123; y = 456; }</literal>. (Note that +this works because <varname>x</varname> is added to the lexical scope +by the <literal>let</literal> construct.) It is also possible to +inherit attributes from another set. For instance, in this fragment +from <filename>all-packages.nix</filename>, + +<programlisting> + graphviz = (import ../tools/graphics/graphviz) { + inherit fetchurl stdenv libpng libjpeg expat x11 yacc; + inherit (xlibs) libXaw; + }; + + xlibs = { + libX11 = ...; + libXaw = ...; + ... + } + + libpng = ...; + libjpg = ...; + ...</programlisting> + +the set used in the function call to the function defined in +<filename>../tools/graphics/graphviz</filename> inherits a number of +variables from the surrounding scope (<varname>fetchurl</varname> +... <varname>yacc</varname>), but also inherits +<varname>libXaw</varname> (the X Athena Widgets) from the +<varname>xlibs</varname> (X11 client-side libraries) set.</para> + +</simplesect> + + +<simplesect xml:id="ss-functions"><title>Functions</title> + +<para>Functions have the following form: + +<programlisting> +<replaceable>pattern</replaceable>: <replaceable>body</replaceable></programlisting> + +The pattern specifies what the argument of the function must look +like, and binds variables in the body to (parts of) the +argument. There are three kinds of patterns:</para> + +<itemizedlist> + + + <listitem><para>If a pattern is a single identifier, then the + function matches any argument. Example: + + <programlisting> +let negate = x: !x; + concat = x: y: x + y; +in if negate true then concat "foo" "bar" else ""</programlisting> + + Note that <function>concat</function> is a function that takes one + argument and returns a function that takes another argument. This + allows partial parameterisation (i.e., only filling some of the + arguments of a function); e.g., + + <programlisting> +map (concat "foo") [ "bar" "bla" "abc" ]</programlisting> + + evaluates to <literal>[ "foobar" "foobla" + "fooabc" ]</literal>.</para></listitem> + + + <listitem><para>A <emphasis>set pattern</emphasis> of the form + <literal>{ name1, name2, …, nameN }</literal> matches a set + containing the listed attributes, and binds the values of those + attributes to variables in the function body. For example, the + function + +<programlisting> +{ x, y, z }: z + y + x</programlisting> + + can only be called with a set containing exactly the attributes + <varname>x</varname>, <varname>y</varname> and + <varname>z</varname>. No other attributes are allowed. If you want + to allow additional arguments, you can use an ellipsis + (<literal>...</literal>): + +<programlisting> +{ x, y, z, ... }: z + y + x</programlisting> + + This works on any set that contains at least the three named + attributes.</para> + + <para>It is possible to provide <emphasis>default values</emphasis> + for attributes, in which case they are allowed to be missing. A + default value is specified by writing + <literal><replaceable>name</replaceable> ? + <replaceable>e</replaceable></literal>, where + <replaceable>e</replaceable> is an arbitrary expression. For example, + +<programlisting> +{ x, y ? "foo", z ? "bar" }: z + y + x</programlisting> + + specifies a function that only requires an attribute named + <varname>x</varname>, but optionally accepts <varname>y</varname> + and <varname>z</varname>.</para></listitem> + + + <listitem><para>An <literal>@</literal>-pattern provides a means of referring + to the whole value being matched: + +<programlisting> +args@{ x, y, z, ... }: z + y + x + args.a</programlisting> + + Here <varname>args</varname> is bound to the entire argument, which + is further matched against the pattern <literal>{ x, y, z, + ... }</literal>.</para></listitem> + + +</itemizedlist> + +<para>Note that functions do not have names. If you want to give them +a name, you can bind them to an attribute, e.g., + +<programlisting> +let concat = { x, y }: x + y; +in concat { x = "foo"; y = "bar"; }</programlisting> + +</para> + +</simplesect> + + +<simplesect><title>Conditionals</title> + +<para>Conditionals look like this: + +<programlisting> +if <replaceable>e1</replaceable> then <replaceable>e2</replaceable> else <replaceable>e3</replaceable></programlisting> + +where <replaceable>e1</replaceable> is an expression that should +evaluate to a Boolean value (<literal>true</literal> or +<literal>false</literal>).</para> + +</simplesect> + + +<simplesect><title>Assertions</title> + +<para>Assertions are generally used to check that certain requirements +on or between features and dependencies hold. They look like this: + +<programlisting> +assert <replaceable>e1</replaceable>; <replaceable>e2</replaceable></programlisting> + +where <replaceable>e1</replaceable> is an expression that should +evaluate to a Boolean value. If it evaluates to +<literal>true</literal>, <replaceable>e2</replaceable> is returned; +otherwise expression evaluation is aborted and a backtrace is printed.</para> + +<example xml:id='ex-subversion-nix'><title>Nix expression for Subversion</title> +<programlisting> +{ localServer ? false +, httpServer ? false +, sslSupport ? false +, pythonBindings ? false +, javaSwigBindings ? false +, javahlBindings ? false +, stdenv, fetchurl +, openssl ? null, httpd ? null, db4 ? null, expat, swig ? null, j2sdk ? null +}: + +assert localServer -> db4 != null; <co xml:id='ex-subversion-nix-co-1' /> +assert httpServer -> httpd != null && httpd.expat == expat; <co xml:id='ex-subversion-nix-co-2' /> +assert sslSupport -> openssl != null && (httpServer -> httpd.openssl == openssl); <co xml:id='ex-subversion-nix-co-3' /> +assert pythonBindings -> swig != null && swig.pythonSupport; +assert javaSwigBindings -> swig != null && swig.javaSupport; +assert javahlBindings -> j2sdk != null; + +stdenv.mkDerivation { + name = "subversion-1.1.1"; + ... + openssl = if sslSupport then openssl else null; <co xml:id='ex-subversion-nix-co-4' /> + ... +}</programlisting> +</example> + +<para><xref linkend='ex-subversion-nix' /> show how assertions are +used in the Nix expression for Subversion.</para> + +<calloutlist> + + <callout arearefs='ex-subversion-nix-co-1'> + <para>This assertion states that if Subversion is to have support + for local repositories, then Berkeley DB is needed. So if the + Subversion function is called with the + <varname>localServer</varname> argument set to + <literal>true</literal> but the <varname>db4</varname> argument + set to <literal>null</literal>, then the evaluation fails.</para> + </callout> + + <callout arearefs='ex-subversion-nix-co-2'> + <para>This is a more subtle condition: if Subversion is built with + Apache (<literal>httpServer</literal>) support, then the Expat + library (an XML library) used by Subversion should be same as the + one used by Apache. This is because in this configuration + Subversion code ends up being linked with Apache code, and if the + Expat libraries do not match, a build- or runtime link error or + incompatibility might occur.</para> + </callout> + + <callout arearefs='ex-subversion-nix-co-3'> + <para>This assertion says that in order for Subversion to have SSL + support (so that it can access <literal>https</literal> URLs), an + OpenSSL library must be passed. Additionally, it says that + <emphasis>if</emphasis> Apache support is enabled, then Apache's + OpenSSL should match Subversion's. (Note that if Apache support + is not enabled, we don't care about Apache's OpenSSL.)</para> + </callout> + + <callout arearefs='ex-subversion-nix-co-4'> + <para>The conditional here is not really related to assertions, + but is worth pointing out: it ensures that if SSL support is + disabled, then the Subversion derivation is not dependent on + OpenSSL, even if a non-<literal>null</literal> value was passed. + This prevents an unnecessary rebuild of Subversion if OpenSSL + changes.</para> + </callout> + +</calloutlist> + +</simplesect> + + + +<simplesect><title>With-expressions</title> + +<para>A <emphasis>with-expression</emphasis>, + +<programlisting> +with <replaceable>e1</replaceable>; <replaceable>e2</replaceable></programlisting> + +introduces the set <replaceable>e1</replaceable> into the lexical +scope of the expression <replaceable>e2</replaceable>. For instance, + +<programlisting> +let as = { x = "foo"; y = "bar"; }; +in with as; x + y</programlisting> + +evaluates to <literal>"foobar"</literal> since the +<literal>with</literal> adds the <varname>x</varname> and +<varname>y</varname> attributes of <varname>as</varname> to the +lexical scope in the expression <literal>x + y</literal>. The most +common use of <literal>with</literal> is in conjunction with the +<function>import</function> function. E.g., + +<programlisting> +with (import ./definitions.nix); ...</programlisting> + +makes all attributes defined in the file +<filename>definitions.nix</filename> available as if they were defined +locally in a <literal>rec</literal>-expression.</para> + +</simplesect> + + +<simplesect><title>Comments</title> + +<para>Comments can be single-line, started with a <literal>#</literal> +character, or inline/multi-line, enclosed within <literal>/* +... */</literal>.</para> + +</simplesect> + + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/language-operators.xml b/doc/manual/expressions/language-operators.xml new file mode 100644 index 000000000000..a3323ced4c50 --- /dev/null +++ b/doc/manual/expressions/language-operators.xml @@ -0,0 +1,113 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-language-operators"> + +<title>Operators</title> + +<para><xref linkend='table-operators' /> lists the operators in the +Nix expression language, in order of precedence (from strongest to +weakest binding).</para> + +<table xml:id='table-operators'> + <title>Operators</title> + <tgroup cols='3'> + <thead> + <row> + <entry>Syntax</entry> + <entry>Associativity</entry> + <entry>Description</entry> + </row> + </thead> + <tbody> + <row> + <entry><replaceable>e</replaceable> <literal>.</literal> + <replaceable>attrpath</replaceable> + [ <literal>or</literal> <replaceable>def</replaceable> ] + </entry> + <entry>none</entry> + <entry>Select attribute denoted by the attribute path + <replaceable>attrpath</replaceable> from set + <replaceable>e</replaceable>. (An attribute path is a + dot-separated list of attribute names.) If the attribute + doesn’t exist, return <replaceable>def</replaceable> if + provided, otherwise abort evaluation.</entry> + </row> + <row> + <entry><replaceable>e1</replaceable> <replaceable>e2</replaceable></entry> + <entry>left</entry> + <entry>Call function <replaceable>e1</replaceable> with + argument <replaceable>e2</replaceable>.</entry> + </row> + <row> + <entry><replaceable>e</replaceable> <literal>?</literal> + <replaceable>attrpath</replaceable></entry> + <entry>none</entry> + <entry>Test whether set <replaceable>e</replaceable> contains + the attribute denoted by <replaceable>attrpath</replaceable>; + return <literal>true</literal> or + <literal>false</literal>.</entry> + </row> + <row> + <entry><replaceable>e1</replaceable> <literal>++</literal> <replaceable>e2</replaceable></entry> + <entry>right</entry> + <entry>List concatenation.</entry> + </row> + <row> + <entry><replaceable>e1</replaceable> <literal>+</literal> <replaceable>e2</replaceable></entry> + <entry>left</entry> + <entry>String or path concatenation.</entry> + </row> + <row> + <entry><literal>!</literal> <replaceable>e</replaceable></entry> + <entry>left</entry> + <entry>Boolean negation.</entry> + </row> + <row> + <entry><replaceable>e1</replaceable> <literal>//</literal> + <replaceable>e2</replaceable></entry> + <entry>right</entry> + <entry>Return a set consisting of the attributes in + <replaceable>e1</replaceable> and + <replaceable>e2</replaceable> (with the latter taking + precedence over the former in case of equally named + attributes).</entry> + </row> + <row> + <entry><replaceable>e1</replaceable> <literal>==</literal> + <replaceable>e2</replaceable></entry> + <entry>none</entry> + <entry>Equality.</entry> + </row> + <row> + <entry><replaceable>e1</replaceable> <literal>!=</literal> + <replaceable>e2</replaceable></entry> + <entry>none</entry> + <entry>Inequality.</entry> + </row> + <row> + <entry><replaceable>e1</replaceable> <literal>&&</literal> + <replaceable>e2</replaceable></entry> + <entry>left</entry> + <entry>Logical AND.</entry> + </row> + <row> + <entry><replaceable>e1</replaceable> <literal>||</literal> + <replaceable>e2</replaceable></entry> + <entry>left</entry> + <entry>Logical OR.</entry> + </row> + <row> + <entry><replaceable>e1</replaceable> <literal>-></literal> + <replaceable>e2</replaceable></entry> + <entry>none</entry> + <entry>Logical implication (equivalent to + <literal>!<replaceable>e1</replaceable> || + <replaceable>e2</replaceable></literal>).</entry> + </row> + </tbody> + </tgroup> +</table> + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/language-values.xml b/doc/manual/expressions/language-values.xml new file mode 100644 index 000000000000..519657f1563a --- /dev/null +++ b/doc/manual/expressions/language-values.xml @@ -0,0 +1,268 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='ssec-values'> + +<title>Values</title> + + +<simplesect><title>Simple Values</title> + +<para>Nix has the following basic data types: + +<itemizedlist> + + <listitem> + + <para><emphasis>Strings</emphasis> can be written in three + ways.</para> + + <para>The most common way is to enclose the string between double + quotes, e.g., <literal>"foo bar"</literal>. Strings can span + multiple lines. The special characters <literal>"</literal> and + <literal>\</literal> and the character sequence + <literal>${</literal> must be escaped by prefixing them with a + backslash (<literal>\</literal>). Newlines, carriage returns and + tabs can be written as <literal>\n</literal>, + <literal>\r</literal> and <literal>\t</literal>, + respectively.</para> + + <para>You can include the result of an expression into a string by + enclosing it in + <literal>${<replaceable>...</replaceable>}</literal>, a feature + known as <emphasis>antiquotation</emphasis>. The enclosed + expression must evaluate to something that can be coerced into a + string (meaning that it must be a string, a path, or a + derivation). For instance, rather than writing + +<programlisting> +"--with-freetype2-library=" + freetype + "/lib"</programlisting> + + (where <varname>freetype</varname> is a derivation), you can + instead write the more natural + +<programlisting> +"--with-freetype2-library=${freetype}/lib"</programlisting> + + The latter is automatically translated to the former. A more + complicated example (from the Nix expression for <link + xlink:href='http://www.trolltech.com/products/qt'>Qt</link>): + +<programlisting> +configureFlags = " + -system-zlib -system-libpng -system-libjpeg + ${if openglSupport then "-dlopen-opengl + -L${mesa}/lib -I${mesa}/include + -L${libXmu}/lib -I${libXmu}/include" else ""} + ${if threadSupport then "-thread" else "-no-thread"} +";</programlisting> + + Note that Nix expressions and strings can be arbitrarily nested; + in this case the outer string contains various antiquotations that + themselves contain strings (e.g., <literal>"-thread"</literal>), + some of which in turn contain expressions (e.g., + <literal>${mesa}</literal>).</para> + + <para>The second way to write string literals is as an + <emphasis>indented string</emphasis>, which is enclosed between + pairs of <emphasis>double single-quotes</emphasis>, like so: + +<programlisting> +'' + This is the first line. + This is the second line. + This is the third line. +''</programlisting> + + This kind of string literal intelligently strips indentation from + the start of each line. To be precise, it strips from each line a + number of spaces equal to the minimal indentation of the string as + a whole (disregarding the indentation of empty lines). For + instance, the first and second line are indented two space, while + the third line is indented four spaces. Thus, two spaces are + stripped from each line, so the resulting string is + +<programlisting> +"This is the first line.\nThis is the second line.\n This is the third line.\n"</programlisting> + + </para> + + <para>Note that the whitespace and newline following the opening + <literal>''</literal> is ignored if there is no non-whitespace + text on the initial line.</para> + + <para>Antiquotation + (<literal>${<replaceable>expr</replaceable>}</literal>) is + supported in indented strings.</para> + + <para>Since <literal>${</literal> and <literal>''</literal> have + special meaning in indented strings, you need a way to quote them. + <literal>${</literal> can be escaped by prefixing it with + <literal>''</literal> (that is, two single quotes), i.e., + <literal>''${</literal>. <literal>''</literal> can be escaped by + prefixing it with <literal>'</literal>, i.e., + <literal>'''</literal>. Finally, linefeed, carriage-return and + tab characters can be written as <literal>''\n</literal>, + <literal>''\r</literal>, <literal>''\t</literal>.</para> + + <para>Indented strings are primarily useful in that they allow + multi-line string literals to follow the indentation of the + enclosing Nix expression, and that less escaping is typically + necessary for strings representing languages such as shell scripts + and configuration files because <literal>''</literal> is much less + common than <literal>"</literal>. Example: + +<programlisting> +stdenv.mkDerivation { + <replaceable>...</replaceable> + postInstall = + '' + mkdir $out/bin $out/etc + cp foo $out/bin + echo "Hello World" > $out/etc/foo.conf + ${if enableBar then "cp bar $out/bin" else ""} + ''; + <replaceable>...</replaceable> +} +</programlisting> + + </para> + + <para>Finally, as a convenience, <emphasis>URIs</emphasis> as + defined in appendix B of <link + xlink:href='http://www.ietf.org/rfc/rfc2396.txt'>RFC 2396</link> + can be written <emphasis>as is</emphasis>, without quotes. For + instance, the string + <literal>"http://example.org/foo.tar.bz2"</literal> + can also be written as + <literal>http://example.org/foo.tar.bz2</literal>.</para> + + </listitem> + + <listitem><para><emphasis>Integers</emphasis>, e.g., + <literal>123</literal>.</para></listitem> + + <listitem><para><emphasis>Paths</emphasis>, e.g., + <filename>/bin/sh</filename> or <filename>./builder.sh</filename>. + A path must contain at least one slash to be recognised as such; for + instance, <filename>builder.sh</filename> is not a + path<footnote><para>It's parsed as an expression that selects the + attribute <varname>sh</varname> from the variable + <varname>builder</varname>.</para></footnote>. If the file name is + relative, i.e., if it does not begin with a slash, it is made + absolute at parse time relative to the directory of the Nix + expression that contained it. For instance, if a Nix expression in + <filename>/foo/bar/bla.nix</filename> refers to + <filename>../xyzzy/fnord.nix</filename>, the absolute path is + <filename>/foo/xyzzy/fnord.nix</filename>.</para></listitem> + + <listitem><para><emphasis>Booleans</emphasis> with values + <literal>true</literal> and + <literal>false</literal>.</para></listitem> + + <listitem><para>The null value, denoted as + <literal>null</literal>.</para></listitem> + +</itemizedlist> + +</para> + +</simplesect> + + +<simplesect><title>Lists</title> + +<para>Lists are formed by enclosing a whitespace-separated list of +values between square brackets. For example, + +<programlisting> +[ 123 ./foo.nix "abc" (f { x = y; }) ]</programlisting> + +defines a list of four elements, the last being the result of a call +to the function <varname>f</varname>. Note that function calls have +to be enclosed in parentheses. If they had been omitted, e.g., + +<programlisting> +[ 123 ./foo.nix "abc" f { x = y; } ]</programlisting> + +the result would be a list of five elements, the fourth one being a +function and the fifth being a set.</para> + +</simplesect> + + +<simplesect><title>Sets</title> + +<para>Sets are really the core of the language, since ultimately the +Nix language is all about creating derivations, which are really just +sets of attributes to be passed to build scripts.</para> + +<para>Sets are just a list of name/value pairs (called +<emphasis>attributes</emphasis>) enclosed in curly brackets, where +each value is an arbitrary expression terminated by a semicolon. For +example: + +<programlisting> +{ x = 123; + text = "Hello"; + y = f { bla = 456; }; +}</programlisting> + +This defines a set with attributes named <varname>x</varname>, +<varname>text</varname>, <varname>y</varname>. The order of the +attributes is irrelevant. An attribute name may only occur +once.</para> + +<para>Attributes can be selected from a set using the +<literal>.</literal> operator. For instance, + +<programlisting> +{ a = "Foo"; b = "Bar"; }.a</programlisting> + +evaluates to <literal>"Foo"</literal>. It is possible to provide a +default value in an attribute selection using the +<literal>or</literal> keyword. For example, + +<programlisting> +{ a = "Foo"; b = "Bar"; }.c or "Xyzzy"</programlisting> + +will evaluate to <literal>"Xyzzy"</literal> because there is no +<varname>c</varname> attribute in the set.</para> + +<para>You can use arbitrary double-quoted strings as attribute +names: + +<programlisting> +{ "foo ${bar}" = 123; "nix-1.0" = 456; }."foo ${bar}" +</programlisting> + +This will evaluate to <literal>123</literal> (Assuming +<literal>bar</literal> is antiquotable). In the case where an +attribute name is just a single antiquotation, the quotes can be +dropped: + +<programlisting> +{ foo = 123; }.${bar} or 456 </programlisting> + +This will evaluate to <literal>123</literal> if +<literal>bar</literal> evaluates to <literal>"foo"</literal> when +coerced to a string and <literal>456</literal> otherwise (again +assuming <literal>bar</literal> is antiquotable).</para> + +<para>In the special case where an attribute name inside of a set declaration +evaluates to <literal>null</literal> (which is normally an error, as +<literal>null</literal> is not antiquotable), that attribute is simply not +added to the set: + +<programlisting> +{ ${if foo then "bar" else null} = true; }</programlisting> + +This will evaluate to <literal>{}</literal> if <literal>foo</literal> +evaluates to <literal>false</literal>.</para> + + +</simplesect> + + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/simple-building-testing.xml b/doc/manual/expressions/simple-building-testing.xml new file mode 100644 index 000000000000..cc90409b5e93 --- /dev/null +++ b/doc/manual/expressions/simple-building-testing.xml @@ -0,0 +1,86 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='sec-building-simple'> + +<title>Building and Testing</title> + +<para>You can now try to build Hello. Of course, you could do +<literal>nix-env -f pkgs/top-level/all-packages.nix -i hello</literal>, +but you may not want to install a possibly broken package just yet. +The best way to test the package is by using the command <command +linkend="sec-nix-build">nix-build</command>, which builds a Nix +expression and creates a symlink named <filename>result</filename> in +the current directory: + +<screen> +$ nix-build pkgs/top-level/all-packages.nix -A hello +building path `/nix/store/632d2b22514d...-hello-2.1.1' +hello-2.1.1/ +hello-2.1.1/intl/ +hello-2.1.1/intl/ChangeLog +<replaceable>...</replaceable> + +$ ls -l result +lrwxrwxrwx ... 2006-09-29 10:43 result -> /nix/store/632d2b22514d...-hello-2.1.1 + +$ ./result/bin/hello +Hello, world!</screen> + +The <link linkend='opt-attr'><option>-A</option></link> option selects +the <literal>hello</literal> attribute from +<filename>all-packages.nix</filename>. This is faster than using the +symbolic package name specified by the <literal>name</literal> +attribute (which also happens to be <literal>hello</literal>) and is +unambiguous (there can be multiple packages with the symbolic name +<literal>hello</literal>, but there can be only one attribute in a set +named <literal>hello</literal>).</para> + +<para><command>nix-build</command> registers the +<filename>./result</filename> symlink as a garbage collection root, so +unless and until you delete the <filename>./result</filename> symlink, +the output of the build will be safely kept on your system. You can +use <command>nix-build</command>’s <option +linkend='opt-out-link'>-o</option> switch to give the symlink another +name.</para> + +<para>Nix has a transactional semantics. Once a build finishes +successfully, Nix makes a note of this in its database: it registers +that the path denoted by <envar>out</envar> is now +<quote>valid</quote>. If you try to build the derivation again, Nix +will see that the path is already valid and finish immediately. If a +build fails, either because it returns a non-zero exit code, because +Nix or the builder are killed, or because the machine crashes, then +the output paths will not be registered as valid. If you try to build +the derivation again, Nix will remove the output paths if they exist +(e.g., because the builder died half-way through <literal>make +install</literal>) and try again. Note that there is no +<quote>negative caching</quote>: Nix doesn't remember that a build +failed, and so a failed build can always be repeated. This is because +Nix cannot distinguish between permanent failures (e.g., a compiler +error due to a syntax error in the source) and transient failures +(e.g., a disk full condition).</para> + +<para>Nix also performs locking. If you run multiple Nix builds +simultaneously, and they try to build the same derivation, the first +Nix instance that gets there will perform the build, while the others +block (or perform other derivations if available) until the build +finishes: + +<screen> +$ nix-build pkgs/top-level/all-packages.nix -A hello +waiting for lock on `/nix/store/0h5b7hp8d4hqfrw8igvx97x1xawrjnac-hello-2.1.1x'</screen> + +So it is always safe to run multiple instances of Nix in parallel +(which isn’t the case with, say, <command>make</command>).</para> + +<para>If you have a system with multiple CPUs, you may want to have +Nix build different derivations in parallel (insofar as possible). +Just pass the option <link linkend='opt-max-jobs'><option>-j +<replaceable>N</replaceable></option></link>, where +<replaceable>N</replaceable> is the maximum number of jobs to be run +in parallel, or set. Typically this should be the number of +CPUs.</para> + +</section> \ No newline at end of file diff --git a/doc/manual/expressions/simple-expression.xml b/doc/manual/expressions/simple-expression.xml new file mode 100644 index 000000000000..a8eb96f5a8e2 --- /dev/null +++ b/doc/manual/expressions/simple-expression.xml @@ -0,0 +1,47 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-simple-expression"> + +<title>Simple Nix Expression Use-Case</title> + +<para>This section shows how to add and test the <link +xlink:href='http://www.gnu.org/software/hello/hello.html'>GNU Hello +package</link> to the Nix Packages collection. Hello is a program +that prints out the text <quote>Hello, world!</quote>.</para> + +<para>To add a package to the Nix Packages collection, you generally +need to do three things: + +<orderedlist> + + <listitem><para>Write a Nix expression for the package. This is a + file that describes all the inputs involved in building the package, + such as dependencies, sources, and so on.</para></listitem> + + <listitem><para>Write a <emphasis>builder</emphasis>. This is a + shell script<footnote><para>In fact, it can be written in any + language, but typically it's a <command>bash</command> shell + script.</para></footnote> that actually builds the package from + the inputs.</para></listitem> + + <listitem><para>Add the package to the file + <filename>pkgs/top-level/all-packages.nix</filename>. The Nix + expression written in the first step is a + <emphasis>function</emphasis>; it requires other packages in order + to build it. In this step you put it all together, i.e., you call + the function with the right arguments to build the actual + package.</para></listitem> + +</orderedlist> + +</para> + +<xi:include href="expression-syntax.xml" /> +<xi:include href="build-script.xml" /> +<xi:include href="arguments-variables.xml" /> +<xi:include href="simple-building-testing.xml" /> +<xi:include href="generic-builder.xml" /> + +</chapter> \ No newline at end of file diff --git a/doc/manual/expressions/standard-env.xml b/doc/manual/expressions/standard-env.xml new file mode 100644 index 000000000000..2571f43fccba --- /dev/null +++ b/doc/manual/expressions/standard-env.xml @@ -0,0 +1,60 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='sec-standard-environment'> + +<title>The Standard Environment</title> + + +<para>The standard environment is used by passing it as an input +called <envar>stdenv</envar> to the derivation, and then doing + +<programlisting> +source $stdenv/setup</programlisting> + +at the top of the builder.</para> + +<para>Apart from adding the aforementioned commands to the +<envar>PATH</envar>, <filename>setup</filename> also does the +following: + +<itemizedlist> + + <listitem><para>All input packages specified in the + <envar>buildInputs</envar> environment variable have their + <filename>/bin</filename> subdirectory added to <envar>PATH</envar>, + their <filename>/include</filename> subdirectory added to the C/C++ + header file search path, and their <filename>/lib</filename> + subdirectory added to the linker search path. This can be extended. + For instance, when the <command>pkgconfig</command> package is + used, the subdirectory <filename>/lib/pkgconfig</filename> of each + input is added to the <envar>PKG_CONFIG_PATH</envar> environment + variable.</para></listitem> + + <listitem><para>The environment variable + <envar>NIX_CFLAGS_STRIP</envar> is set so that the compiler strips + debug information from object files. This can be disabled by + setting <envar>NIX_STRIP_DEBUG</envar> to + <literal>0</literal>.</para></listitem> + +</itemizedlist> + +</para> + +<para>The <filename>setup</filename> script also exports a function +called <function>genericBuild</function> that knows how to build +typical Autoconf-style packages. It can be customised to perform +builds for any type of package. It is advisable to use +<function>genericBuild</function> since it provides facilities that +are almost always useful such as unpacking of sources, patching of +sources, nested logging, etc.</para> + +<para>The definitive, up-to-date documentation of the generic builder +is the source itself, which resides in +<filename>pkgs/stdenv/generic/setup.sh</filename>.</para> + +<xi:include href="custom-builder.xml" /> +<xi:include href="debug-build.xml" /> + +</chapter> \ No newline at end of file diff --git a/doc/manual/expressions/writing-nix-expressions.xml b/doc/manual/expressions/writing-nix-expressions.xml new file mode 100644 index 000000000000..6d64f24cd32a --- /dev/null +++ b/doc/manual/expressions/writing-nix-expressions.xml @@ -0,0 +1,27 @@ +<part xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='chap-writing-nix-expressions'> + +<title>Nix Expressions</title> + +<partintro> +<para>This chapter shows you how to write Nix expressions, which +instruct Nix how to build packages. It starts with a +simple example (a Nix expression for GNU Hello), and then moves +on to a more in-depth look at the Nix expression language.</para> + +<note><para>This chapter is mostly about the Nix expression language. +For more extensive information on adding packages to the Nix Packages +collection (such as functions in the standard environment and coding +conventions), please consult <link +xlink:href="http://nixos.org/nixpkgs/manual/">its +manual</link>.</para></note> +</partintro> + +<xi:include href="simple-expression.xml" /> +<xi:include href="expression-language.xml" /> +<xi:include href="standard-env.xml" /> + +</part> diff --git a/doc/manual/glossary.xml b/doc/manual/glossary/glossary.xml index d74940c90b30..d74940c90b30 100644 --- a/doc/manual/glossary.xml +++ b/doc/manual/glossary/glossary.xml diff --git a/doc/manual/installation.xml b/doc/manual/installation.xml deleted file mode 100644 index 423bef5e22a8..000000000000 --- a/doc/manual/installation.xml +++ /dev/null @@ -1,447 +0,0 @@ -<?xml version="1.0" encoding="utf-8"?> -<chapter xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xml:id="chap-installation"> - -<title>Installation</title> - - -<section><title>Supported platforms</title> - -<para>Nix is currently supported on the following platforms: - -<itemizedlist> - - <listitem><para>Linux (particularly on x86, x86_64, and - PowerPC).</para></listitem> - - <listitem><para>Mac OS X.</para></listitem> - - <listitem><para>FreeBSD (only tested on Intel).</para></listitem> - - <!-- - <listitem><para>Windows through <link - xlink:href="http://www.cygwin.com/">Cygwin</link>.</para> - - <warning><para>On Cygwin, Nix <emphasis>must</emphasis> be installed - on an NTFS partition. It will not work correctly on a FAT - partition.</para></warning> - - </listitem> - --> - -</itemizedlist> - -</para> - -<para>Nix is pretty portable, so it should work on most other Unix -platforms as well.</para> - -</section> - - -<section><title>Installing a binary distribution</title> - -<para>The easiest way to install Nix is to run the following: - -<screen> -$ bash <(curl https://nixos.org/nix/install) -</screen> - -This will perform a single-user installation of Nix, meaning that -<filename>/nix</filename> is owned by the invoking user. You should -run this under your usual user account, <emphasis>not</emphasis> as -root. The script will invoke <command>sudo</command> to create -<filename>/nix</filename> if it doesn’t already exist. If you don’t -have <command>sudo</command>, you should manually create -<command>/nix</command> first as root: - -<screen> -$ mkdir /nix -$ chown alice /nix -</screen> - -</para> - -<para>You can also manually download and install a binary package. -Binary packages of the latest stable release are available for Fedora, -Debian, Ubuntu, Mac OS X and various other systems from the <link -xlink:href="http://nixos.org/nix/download.html">Nix homepage</link>. -You can also get builds of the latest development release from our -<link -xlink:href="http://hydra.nixos.org/job/nix/master/release/latest-finished#tabs-constituents">continuous -build system</link>.</para> - -<para>For Fedora, RPM packages are available. These can be installed -or upgraded using <command>rpm -U</command>. For example, - -<screen> -$ rpm -U nix-1.7-1.i386.rpm</screen> - -</para> - -<para>For Debian and Ubuntu, you can download a Deb package and -install it like this: - -<screen> -$ dpkg -i nix_1.7-1_amd64.deb</screen> - -</para> - -<para>For other platforms, including Mac OS X (Darwin), FreeBSD and -other Linux distributions, you can download a binary tarball that -contains Nix and all its dependencies. (This is what the install -script at <uri>https://nixos.org/nix/install</uri> uses.) You should -unpack it somewhere (e.g. in <filename>/tmp</filename>), and then run -the script named <command>install</command> inside the binary tarball: - -<screen> -alice$ cd /tmp -alice$ tar xfj nix-1.7-x86_64-darwin.tar.bz2 -alice$ cd nix-1.7-x86_64-darwin -alice$ ./install -</screen> - -</para> - -<para>Nix can be uninstalled using <command>rpm -e nix</command> or -<command>dpkg -r nix</command> on RPM- and Dpkg-based systems, -respectively. After this you should manually remove the Nix store and -other auxiliary data, if desired: - -<screen> -$ rm -rf /nix</screen> - -</para> - -</section> - - -<section><title>Installing Nix from source</title> - -<para>If no binary package is available, you can download and compile -a source distribution.</para> - -<section><title>Prerequisites</title> - -<itemizedlist> - - <listitem><para>GNU Make.</para></listitem> - - <listitem><para>A version of GCC or Clang that supports C++11.</para></listitem> - - <listitem><para>Perl 5.8 or higher.</para></listitem> - - <listitem><para><command>pkg-config</command> to locate - dependencies. If your distribution does not provide it, you can get - it from <link - xlink:href="http://www.freedesktop.org/wiki/Software/pkg-config" - />.</para></listitem> - - <listitem><para>The bzip2 compressor program and the - <literal>libbz2</literal> library. Thus you must have bzip2 - installed, including development headers and libraries. If your - distribution does not provide these, you can obtain bzip2 from <link - xlink:href="http://www.bzip.org/"/>.</para></listitem> - - <listitem><para>The SQLite embedded database library, version 3.6.19 - or higher. If your distribution does not provide it, please install - it from <link xlink:href="http://www.sqlite.org/" />.</para></listitem> - - <listitem><para>The Perl DBI and DBD::SQLite libraries, which are - available from <link - xlink:href="http://search.cpan.org/">CPAN</link> if your - distribution does not provide them.</para></listitem> - - <listitem><para>The <link - xlink:href="http://www.hpl.hp.com/personal/Hans_Boehm/gc/">Boehm - garbage collector</link> to reduce the evaluator’s memory - consumption (optional). To enable it, install - <literal>pkgconfig</literal> and the Boehm garbage collector, and - pass the flag <option>--enable-gc</option> to - <command>configure</command>.</para></listitem> - - <listitem><para>The <command>xmllint</command> and - <command>xsltproc</command> programs to build this manual and the - man-pages. These are part of the <literal>libxml2</literal> and - <literal>libxslt</literal> packages, respectively. You also need - the <link - xlink:href="http://docbook.sourceforge.net/projects/xsl/">DocBook - XSL stylesheets</link> and optionally the <link - xlink:href="http://www.docbook.org/schemas/5x"> DocBook 5.0 RELAX NG - schemas</link>. Note that these are only required if you modify the - manual sources or when you are building from the Git - repository.</para></listitem> - - <listitem><para>Recent versions of Bison and Flex to build the - parser. (This is because Nix needs GLR support in Bison and - reentrancy support in Flex.) For Bison, you need version 2.6, which - can be obtained from the <link - xlink:href="ftp://alpha.gnu.org/pub/gnu/bison">GNU FTP - server</link>. For Flex, you need version 2.5.35, which is - available on <link - xlink:href="http://lex.sourceforge.net/">SourceForge</link>. - Slightly older versions may also work, but ancient versions like the - ubiquitous 2.5.4a won't. Note that these are only required if you - modify the parser or when you are building from the Git - repository.</para></listitem> - -</itemizedlist> - -</section> - - -<section><title>Obtaining a source distribution</title> - -<para>The source tarball of the most recent stable release can be -downloaded from the <link -xlink:href="http://nixos.org/nix/download.html">Nix homepage</link>. -You can also grab the <link -xlink:href="http://hydra.nixos.org/job/nix/master/release/latest-finished#tabs-constituents">most -recent development release</link>.</para> - -<para>Alternatively, the most recent sources of Nix can be obtained -from its <link -xlink:href="https://github.com/NixOS/nix">Git -repository</link>. For example, the following command will check out -the latest revision into a directory called -<filename>nix</filename>:</para> - -<screen> -$ git clone https://github.com/NixOS/nix</screen> - -<para>Likewise, specific releases can be obtained from the <link -xlink:href="https://github.com/NixOS/nix/tags">tags</link> of the -repository.</para> - -</section> - - -<section><title>Building Nix from source</title> - -<para>After unpacking or checking out the Nix sources, issue the -following commands: - -<screen> -$ ./configure <replaceable>options...</replaceable> -$ make -$ make install</screen> - -Nix requires GNU Make so you may need to invoke -<command>gmake</command> instead.</para> - -<para>When building from the Git repository, these should be preceded -by the command: - -<screen> -$ ./bootstrap.sh</screen> - -</para> - -<para>The installation path can be specified by passing the -<option>--prefix=<replaceable>prefix</replaceable></option> to -<command>configure</command>. The default installation directory is -<filename>/usr/local</filename>. You can change this to any location -you like. You must have write permission to the -<replaceable>prefix</replaceable> path.</para> - -<para>Nix keeps its <emphasis>store</emphasis> (the place where -packages are stored) in <filename>/nix/store</filename> by default. -This can be changed using -<option>--with-store-dir=<replaceable>path</replaceable></option>.</para> - -<warning><para>It is best <emphasis>not</emphasis> to change the Nix -store from its default, since doing so makes it impossible to use -pre-built binaries from the standard Nixpkgs channels — that is, all -packages will need to be built from source.</para></warning> - -<para>Nix keeps state (such as its database and log files) in -<filename>/nix/var</filename> by default. This can be changed using -<option>--localstatedir=<replaceable>path</replaceable></option>.</para> - -<para>If you want to rebuild the documentation, pass the full path to -the DocBook RELAX NG schemas and to the DocBook XSL stylesheets using -the -<option>--with-docbook-rng=<replaceable>path</replaceable></option> -and -<option>--with-docbook-xsl=<replaceable>path</replaceable></option> -options.</para> - -</section> - - -</section> - - -<!-- TODO: should be updated -<section><title>Upgrading Nix through Nix</title> - -<para>You can install the latest stable version of Nix through Nix -itself by subscribing to the channel <link -xlink:href="http://nixos.org/releases/nix/channels/nix-stable" />, -or the latest unstable version by subscribing to the channel <link -xlink:href="http://nixos.org/releases/nix/channels/nix-unstable" />. -You can also do a <link linkend="sec-one-click">one-click -installation</link> by clicking on the package links at <link -xlink:href="http://nixos.org/releases/full-index-nix.html" />.</para> - -</section> ---> - - -<section><title>Security</title> - -<para>Nix has two basic security models. First, it can be used in -“single-user mode”, which is similar to what most other package -management tools do: there is a single user (typically <systemitem -class="username">root</systemitem>) who performs all package -management operations. All other users can then use the installed -packages, but they cannot perform package management operations -themselves.</para> - -<para>Alternatively, you can configure Nix in “multi-user mode”. In -this model, all users can perform package management operations — for -instance, every user can install software without requiring root -privileges. Nix ensures that this is secure. For instance, it’s not -possible for one user to overwrite a package used by another user with -a Trojan horse.</para> - - -<section><title>Single-user mode</title> - -<para>In single-user mode, all Nix operations that access the database -in <filename><replaceable>prefix</replaceable>/var/nix/db</filename> -or modify the Nix store in -<filename><replaceable>prefix</replaceable>/store</filename> must be -performed under the user ID that owns those directories. This is -typically <systemitem class="username">root</systemitem>. (If you -install from RPM packages, that’s in fact the default ownership.) -However, on single-user machines, it is often convenient to -<command>chown</command> those directories to your normal user account -so that you don’t have to <command>su</command> to <systemitem -class="username">root</systemitem> all the time.</para> - -</section> - - -<section xml:id="ssec-multi-user"><title>Multi-user mode</title> - -<para>To allow a Nix store to be shared safely among multiple users, -it is important that users are not able to run builders that modify -the Nix store or database in arbitrary ways, or that interfere with -builds started by other users. If they could do so, they could -install a Trojan horse in some package and compromise the accounts of -other users.</para> - -<para>To prevent this, the Nix store and database are owned by some -privileged user (usually <literal>root</literal>) and builders are -executed under special user accounts (usually named -<literal>nixbld1</literal>, <literal>nixbld2</literal>, etc.). When a -unprivileged user runs a Nix command, actions that operate on the Nix -store (such as builds) are forwarded to a <emphasis>Nix -daemon</emphasis> running under the owner of the Nix store/database -that performs the operation.</para> - -<note><para>Multi-user mode has one important limitation: only -<systemitem class="username">root</systemitem> can run <command -linkend="sec-nix-pull">nix-pull</command> to register the availability -of pre-built binaries. However, those registrations are shared by all -users, so they still get the benefit from <command>nix-pull</command>s -done by <systemitem class="username">root</systemitem>.</para></note> - - -<section><title>Setting up the build users</title> - -<para>The <emphasis>build users</emphasis> are the special UIDs under -which builds are performed. They should all be members of the -<emphasis>build users group</emphasis> <literal>nixbld</literal>. -This group should have no other members. The build users should not -be members of any other group. On Linux, you can create the group and -users as follows: - -<screen> -$ groupadd -r nixbld -$ for n in $(seq 1 10); do useradd -c "Nix build user $n" \ - -d /var/empty -g nixbld -G nixbld -M -N -r -s "$(which nologin)" \ - nixbld$n; done -</screen> - -This creates 10 build users. There can never be more concurrent builds -than the number of build users, so you may want to increase this if -you expect to do many builds at the same time.</para> - -</section> - - -<section><title>Running the daemon</title> - -<para>The <link linkend="sec-nix-daemon">Nix daemon</link> should be -started as follows (as <literal>root</literal>): - -<screen> -$ nix-daemon</screen> - -You’ll want to put that line somewhere in your system’s boot -scripts.</para> - -<para>To let unprivileged users use the daemon, they should set the -<link linkend="envar-remote"><envar>NIX_REMOTE</envar> environment -variable</link> to <literal>daemon</literal>. So you should put a -line like - -<programlisting> -export NIX_REMOTE=daemon</programlisting> - -into the users’ login scripts.</para> - -</section> - - -<section><title>Restricting access</title> - -<para>To limit which users can perform Nix operations, you can use the -permissions on the directory -<filename>/nix/var/nix/daemon-socket</filename>. For instance, if you -want to restrict the use of Nix to the members of a group called -<literal>nix-users</literal>, do - -<screen> -$ chgrp nix-users /nix/var/nix/daemon-socket -$ chmod ug=rwx,o= /nix/var/nix/daemon-socket -</screen> - -This way, users who are not in the <literal>nix-users</literal> group -cannot connect to the Unix domain socket -<filename>/nix/var/nix/daemon-socket/socket</filename>, so they cannot -perform Nix operations.</para> - -</section> - - -</section> <!-- end of multi-user --> - - -</section> <!-- end of security --> - - -<section><title>Using Nix</title> - -<para>To use Nix, some environment variables should be set. In -particular, <envar>PATH</envar> should contain the directories -<filename><replaceable>prefix</replaceable>/bin</filename> and -<filename>~/.nix-profile/bin</filename>. The first directory contains -the Nix tools themselves, while <filename>~/.nix-profile</filename> is -a symbolic link to the current <emphasis>user environment</emphasis> -(an automatically generated package consisting of symlinks to -installed packages). The simplest way to set the required environment -variables is to include the file -<filename><replaceable>prefix</replaceable>/etc/profile.d/nix.sh</filename> -in your <filename>~/.profile</filename> (or similar), like this:</para> - -<screen> -source <replaceable>prefix</replaceable>/etc/profile.d/nix.sh</screen> - -</section> - - -</chapter> diff --git a/doc/manual/installation/building-source.xml b/doc/manual/installation/building-source.xml new file mode 100644 index 000000000000..2202ec73febe --- /dev/null +++ b/doc/manual/installation/building-source.xml @@ -0,0 +1,57 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-building-source"> + +<title>Building Nix from Source</title> + +<para>After unpacking or checking out the Nix sources, issue the +following commands: + +<screen> +$ ./configure <replaceable>options...</replaceable> +$ make +$ make install</screen> + +Nix requires GNU Make so you may need to invoke +<command>gmake</command> instead.</para> + +<para>When building from the Git repository, these should be preceded +by the command: + +<screen> +$ ./bootstrap.sh</screen> + +</para> + +<para>The installation path can be specified by passing the +<option>--prefix=<replaceable>prefix</replaceable></option> to +<command>configure</command>. The default installation directory is +<filename>/usr/local</filename>. You can change this to any location +you like. You must have write permission to the +<replaceable>prefix</replaceable> path.</para> + +<para>Nix keeps its <emphasis>store</emphasis> (the place where +packages are stored) in <filename>/nix/store</filename> by default. +This can be changed using +<option>--with-store-dir=<replaceable>path</replaceable></option>.</para> + +<warning><para>It is best <emphasis>not</emphasis> to change the Nix +store from its default, since doing so makes it impossible to use +pre-built binaries from the standard Nixpkgs channels — that is, all +packages will need to be built from source.</para></warning> + +<para>Nix keeps state (such as its database and log files) in +<filename>/nix/var</filename> by default. This can be changed using +<option>--localstatedir=<replaceable>path</replaceable></option>.</para> + +<para>If you want to rebuild the documentation, pass the full path to +the DocBook RELAX NG schemas and to the DocBook XSL stylesheets using +the +<option>--with-docbook-rng=<replaceable>path</replaceable></option> +and +<option>--with-docbook-xsl=<replaceable>path</replaceable></option> +options.</para> + +</section> \ No newline at end of file diff --git a/doc/manual/installation/env-variables.xml b/doc/manual/installation/env-variables.xml new file mode 100644 index 000000000000..fc39cdd9dfef --- /dev/null +++ b/doc/manual/installation/env-variables.xml @@ -0,0 +1,24 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-env-variables"> + +<title>Environment Variables</title> + +<para>To use Nix, some environment variables should be set. In +particular, <envar>PATH</envar> should contain the directories +<filename><replaceable>prefix</replaceable>/bin</filename> and +<filename>~/.nix-profile/bin</filename>. The first directory contains +the Nix tools themselves, while <filename>~/.nix-profile</filename> is +a symbolic link to the current <emphasis>user environment</emphasis> +(an automatically generated package consisting of symlinks to +installed packages). The simplest way to set the required environment +variables is to include the file +<filename><replaceable>prefix</replaceable>/etc/profile.d/nix.sh</filename> +in your <filename>~/.profile</filename> (or similar), like this:</para> + +<screen> +source <replaceable>prefix</replaceable>/etc/profile.d/nix.sh</screen> + +</chapter> \ No newline at end of file diff --git a/doc/manual/installation/installation.xml b/doc/manual/installation/installation.xml new file mode 100644 index 000000000000..87895935288d --- /dev/null +++ b/doc/manual/installation/installation.xml @@ -0,0 +1,34 @@ +<part xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="chap-installation"> + +<title>Installation</title> + +<partintro> +<para>This section describes how to install and configure Nix for first-time use.</para> +</partintro> + +<xi:include href="supported-platforms.xml" /> +<xi:include href="installing-binary.xml" /> +<xi:include href="installing-source.xml" /> +<xi:include href="nix-security.xml" /> +<xi:include href="env-variables.xml" /> + +<!-- TODO: should be updated +<section><title>Upgrading Nix through Nix</title> + +<para>You can install the latest stable version of Nix through Nix +itself by subscribing to the channel <link +xlink:href="http://nixos.org/releases/nix/channels/nix-stable" />, +or the latest unstable version by subscribing to the channel <link +xlink:href="http://nixos.org/releases/nix/channels/nix-unstable" />. +You can also do a <link linkend="sec-one-click">one-click +installation</link> by clicking on the package links at <link +xlink:href="http://nixos.org/releases/full-index-nix.html" />.</para> + +</section> +--> + +</part> diff --git a/doc/manual/installation/installing-binary.xml b/doc/manual/installation/installing-binary.xml new file mode 100644 index 000000000000..a5f9ac844e09 --- /dev/null +++ b/doc/manual/installation/installing-binary.xml @@ -0,0 +1,81 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-installing-binary"> + +<title>Installing a Binary Distribution</title> + +<para>The easiest way to install Nix is to run the following command: + +<screen> +$ bash <(curl https://nixos.org/nix/install) +</screen> + +This will perform a single-user installation of Nix, meaning that +<filename>/nix</filename> is owned by the invoking user. You should +run this under your usual user account, <emphasis>not</emphasis> as +root. The script will invoke <command>sudo</command> to create +<filename>/nix</filename> if it doesn’t already exist. If you don’t +have <command>sudo</command>, you should manually create +<command>/nix</command> first as root: + +<screen> +$ mkdir /nix +$ chown alice /nix +</screen> + +</para> + +<para>You can also manually download and install a binary package. +Binary packages of the latest stable release are available for Fedora, +Debian, Ubuntu, Mac OS X and various other systems from the <link +xlink:href="http://nixos.org/nix/download.html">Nix homepage</link>. +You can also get builds of the latest development release from our +<link +xlink:href="http://hydra.nixos.org/job/nix/master/release/latest-finished#tabs-constituents">continuous +build system</link>.</para> + +<para>For Fedora, RPM packages are available. These can be installed +or upgraded using <command>rpm -U</command>. For example, + +<screen> +$ rpm -U nix-1.7-1.i386.rpm</screen> + +</para> + +<para>For Debian and Ubuntu, you can download a Deb package and +install it like this: + +<screen> +$ dpkg -i nix_1.7-1_amd64.deb</screen> + +</para> + +<para>For other platforms, including Mac OS X (Darwin), FreeBSD and +other Linux distributions, you can download a binary tarball that +contains Nix and all its dependencies. (This is what the install +script at <uri>https://nixos.org/nix/install</uri> uses.) You should +unpack it somewhere (e.g. in <filename>/tmp</filename>), and then run +the script named <command>install</command> inside the binary tarball: + +<screen> +alice$ cd /tmp +alice$ tar xfj nix-1.7-x86_64-darwin.tar.bz2 +alice$ cd nix-1.7-x86_64-darwin +alice$ ./install +</screen> + +</para> + +<para>Nix can be uninstalled using <command>rpm -e nix</command> or +<command>dpkg -r nix</command> on RPM- and Dpkg-based systems, +respectively. After this you should manually remove the Nix store and +other auxiliary data, if desired: + +<screen> +$ rm -rf /nix</screen> + +</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/installation/installing-source.xml b/doc/manual/installation/installing-source.xml new file mode 100644 index 000000000000..77beff1bcc78 --- /dev/null +++ b/doc/manual/installation/installing-source.xml @@ -0,0 +1,17 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-installing-source"> + +<title>Installing Nix from Source</title> + +<para>If no binary package is available, you can download and compile +a source distribution.</para> + +<xi:include href="prerequisites-source.xml" /> +<xi:include href="obtaining-source.xml" /> +<xi:include href="installing-source.xml" /> +<xi:include href="building-source.xml" /> + +</chapter> \ No newline at end of file diff --git a/doc/manual/installation/multi-user.xml b/doc/manual/installation/multi-user.xml new file mode 100644 index 000000000000..2eb4c258fcf7 --- /dev/null +++ b/doc/manual/installation/multi-user.xml @@ -0,0 +1,106 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-multi-user"> + +<title>Multi-User Mode</title> + +<para>To allow a Nix store to be shared safely among multiple users, +it is important that users are not able to run builders that modify +the Nix store or database in arbitrary ways, or that interfere with +builds started by other users. If they could do so, they could +install a Trojan horse in some package and compromise the accounts of +other users.</para> + +<para>To prevent this, the Nix store and database are owned by some +privileged user (usually <literal>root</literal>) and builders are +executed under special user accounts (usually named +<literal>nixbld1</literal>, <literal>nixbld2</literal>, etc.). When a +unprivileged user runs a Nix command, actions that operate on the Nix +store (such as builds) are forwarded to a <emphasis>Nix +daemon</emphasis> running under the owner of the Nix store/database +that performs the operation.</para> + +<note>Multi-user mode has one important limitation: only +<systemitem class="username">root</systemitem> can run <command +linkend="sec-nix-pull">nix-pull</command> to register the availability +of pre-built binaries. However, those registrations are shared by all +users, so they still get the benefit from <command>nix-pull</command>s +done by <systemitem class="username">root</systemitem>.</note> + + +<simplesect> + +<title>Setting up the build users</title> + +<para>The <emphasis>build users</emphasis> are the special UIDs under +which builds are performed. They should all be members of the +<emphasis>build users group</emphasis> <literal>nixbld</literal>. +This group should have no other members. The build users should not +be members of any other group. On Linux, you can create the group and +users as follows: + +<screen> +$ groupadd -r nixbld +$ for n in $(seq 1 10); do useradd -c "Nix build user $n" \ + -d /var/empty -g nixbld -G nixbld -M -N -r -s "$(which nologin)" \ + nixbld$n; done +</screen> + +This creates 10 build users. There can never be more concurrent builds +than the number of build users, so you may want to increase this if +you expect to do many builds at the same time.</para> + +</simplesect> + + +<simplesect> + +<title>Running the daemon</title> + +<para>The <link linkend="sec-nix-daemon">Nix daemon</link> should be +started as follows (as <literal>root</literal>): + +<screen> +$ nix-daemon</screen> + +You’ll want to put that line somewhere in your system’s boot +scripts.</para> + +<para>To let unprivileged users use the daemon, they should set the +<link linkend="envar-remote"><envar>NIX_REMOTE</envar> environment +variable</link> to <literal>daemon</literal>. So you should put a +line like + +<programlisting> +export NIX_REMOTE=daemon</programlisting> + +into the users’ login scripts.</para> + +</simplesect> + +<simplesect> + +<title>Restricting access</title> + +<para>To limit which users can perform Nix operations, you can use the +permissions on the directory +<filename>/nix/var/nix/daemon-socket</filename>. For instance, if you +want to restrict the use of Nix to the members of a group called +<literal>nix-users</literal>, do + +<screen> +$ chgrp nix-users /nix/var/nix/daemon-socket +$ chmod ug=rwx,o= /nix/var/nix/daemon-socket +</screen> + +This way, users who are not in the <literal>nix-users</literal> group +cannot connect to the Unix domain socket +<filename>/nix/var/nix/daemon-socket/socket</filename>, so they cannot +perform Nix operations.</para> + +</simplesect> + + +</section> \ No newline at end of file diff --git a/doc/manual/installation/nix-security.xml b/doc/manual/installation/nix-security.xml new file mode 100644 index 000000000000..d888ff14d457 --- /dev/null +++ b/doc/manual/installation/nix-security.xml @@ -0,0 +1,27 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-nix-security"> + +<title>Security</title> + +<para>Nix has two basic security models. First, it can be used in +“single-user mode”, which is similar to what most other package +management tools do: there is a single user (typically <systemitem +class="username">root</systemitem>) who performs all package +management operations. All other users can then use the installed +packages, but they cannot perform package management operations +themselves.</para> + +<para>Alternatively, you can configure Nix in “multi-user mode”. In +this model, all users can perform package management operations — for +instance, every user can install software without requiring root +privileges. Nix ensures that this is secure. For instance, it’s not +possible for one user to overwrite a package used by another user with +a Trojan horse.</para> + +<xi:include href="single-user.xml" /> +<xi:include href="multi-user.xml" /> + +</chapter> \ No newline at end of file diff --git a/doc/manual/installation/obtaining-source.xml b/doc/manual/installation/obtaining-source.xml new file mode 100644 index 000000000000..968822cc066e --- /dev/null +++ b/doc/manual/installation/obtaining-source.xml @@ -0,0 +1,30 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-obtaining-source"> + +<title>Obtaining a Source Distribution</title> + +<para>The source tarball of the most recent stable release can be +downloaded from the <link +xlink:href="http://nixos.org/nix/download.html">Nix homepage</link>. +You can also grab the <link +xlink:href="http://hydra.nixos.org/job/nix/master/release/latest-finished#tabs-constituents">most +recent development release</link>.</para> + +<para>Alternatively, the most recent sources of Nix can be obtained +from its <link +xlink:href="https://github.com/NixOS/nix">Git +repository</link>. For example, the following command will check out +the latest revision into a directory called +<filename>nix</filename>:</para> + +<screen> +$ git clone https://github.com/NixOS/nix</screen> + +<para>Likewise, specific releases can be obtained from the <link +xlink:href="https://github.com/NixOS/nix/tags">tags</link> of the +repository.</para> + +</section> \ No newline at end of file diff --git a/doc/manual/installation/prerequisites-source.xml b/doc/manual/installation/prerequisites-source.xml new file mode 100644 index 000000000000..47adc9a4fd67 --- /dev/null +++ b/doc/manual/installation/prerequisites-source.xml @@ -0,0 +1,73 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-prerequisites-source"> + +<title>Prerequisites</title> + +<itemizedlist> + + <listitem><para>GNU Make.</para></listitem> + + <listitem><para>A version of GCC or Clang that supports C++11.</para></listitem> + + <listitem><para>Perl 5.8 or higher.</para></listitem> + + <listitem><para><command>pkg-config</command> to locate + dependencies. If your distribution does not provide it, you can get + it from <link + xlink:href="http://www.freedesktop.org/wiki/Software/pkg-config" + />.</para></listitem> + + <listitem><para>The bzip2 compressor program and the + <literal>libbz2</literal> library. Thus you must have bzip2 + installed, including development headers and libraries. If your + distribution does not provide these, you can obtain bzip2 from <link + xlink:href="http://www.bzip.org/"/>.</para></listitem> + + <listitem><para>The SQLite embedded database library, version 3.6.19 + or higher. If your distribution does not provide it, please install + it from <link xlink:href="http://www.sqlite.org/" />.</para></listitem> + + <listitem><para>The Perl DBI and DBD::SQLite libraries, which are + available from <link + xlink:href="http://search.cpan.org/">CPAN</link> if your + distribution does not provide them.</para></listitem> + + <listitem><para>The <link + xlink:href="http://www.hpl.hp.com/personal/Hans_Boehm/gc/">Boehm + garbage collector</link> to reduce the evaluator’s memory + consumption (optional). To enable it, install + <literal>pkgconfig</literal> and the Boehm garbage collector, and + pass the flag <option>--enable-gc</option> to + <command>configure</command>.</para></listitem> + + <listitem><para>The <command>xmllint</command> and + <command>xsltproc</command> programs to build this manual and the + man-pages. These are part of the <literal>libxml2</literal> and + <literal>libxslt</literal> packages, respectively. You also need + the <link + xlink:href="http://docbook.sourceforge.net/projects/xsl/">DocBook + XSL stylesheets</link> and optionally the <link + xlink:href="http://www.docbook.org/schemas/5x"> DocBook 5.0 RELAX NG + schemas</link>. Note that these are only required if you modify the + manual sources or when you are building from the Git + repository.</para></listitem> + + <listitem><para>Recent versions of Bison and Flex to build the + parser. (This is because Nix needs GLR support in Bison and + reentrancy support in Flex.) For Bison, you need version 2.6, which + can be obtained from the <link + xlink:href="ftp://alpha.gnu.org/pub/gnu/bison">GNU FTP + server</link>. For Flex, you need version 2.5.35, which is + available on <link + xlink:href="http://lex.sourceforge.net/">SourceForge</link>. + Slightly older versions may also work, but ancient versions like the + ubiquitous 2.5.4a won't. Note that these are only required if you + modify the parser or when you are building from the Git + repository.</para></listitem> + +</itemizedlist> + +</section> \ No newline at end of file diff --git a/doc/manual/installation/single-user.xml b/doc/manual/installation/single-user.xml new file mode 100644 index 000000000000..09cdaa5d4898 --- /dev/null +++ b/doc/manual/installation/single-user.xml @@ -0,0 +1,21 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-single-user"> + +<title>Single-User Mode</title> + +<para>In single-user mode, all Nix operations that access the database +in <filename><replaceable>prefix</replaceable>/var/nix/db</filename> +or modify the Nix store in +<filename><replaceable>prefix</replaceable>/store</filename> must be +performed under the user ID that owns those directories. This is +typically <systemitem class="username">root</systemitem>. (If you +install from RPM packages, that’s in fact the default ownership.) +However, on single-user machines, it is often convenient to +<command>chown</command> those directories to your normal user account +so that you don’t have to <command>su</command> to <systemitem +class="username">root</systemitem> all the time.</para> + +</section> \ No newline at end of file diff --git a/doc/manual/installation/supported-platforms.xml b/doc/manual/installation/supported-platforms.xml new file mode 100644 index 000000000000..a31c6431f002 --- /dev/null +++ b/doc/manual/installation/supported-platforms.xml @@ -0,0 +1,38 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-supported-platforms"> + +<title>Supported Platforms</title> + +<para>Nix is currently supported on the following platforms: + +<itemizedlist> + + <listitem><para>Linux (particularly on x86, x86_64, and + PowerPC).</para></listitem> + + <listitem><para>Mac OS X.</para></listitem> + + <listitem><para>FreeBSD (only tested on Intel).</para></listitem> + + <!-- + <listitem><para>Windows through <link + xlink:href="http://www.cygwin.com/">Cygwin</link>.</para> + + <warning><para>On Cygwin, Nix <emphasis>must</emphasis> be installed + on an NTFS partition. It will not work correctly on a FAT + partition.</para></warning> + + </listitem> + --> + +</itemizedlist> + +</para> + +<para>Nix is pretty portable, so it should work on most other Unix +platforms as well.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/introduction.xml b/doc/manual/introduction/about-nix.xml index e0300dc86cb9..38dd7e6657a3 100644 --- a/doc/manual/introduction.xml +++ b/doc/manual/introduction/about-nix.xml @@ -1,11 +1,10 @@ <chapter xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xml:id="chap-introduction"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-about-nix"> -<title>Introduction</title> - - -<section><title>About Nix</title> +<title>About Nix</title> <para>Nix is a <emphasis>purely functional package manager</emphasis>. This means that it treats packages like values in purely functional @@ -251,23 +250,4 @@ xlink:href="http://nixos.org/">NixOS homepage</link>.</para> --> -</section> - - -<section><title>License</title> - -<para>Nix is free software; you can redistribute it and/or modify it -under the terms of the <link -xlink:href="http://www.gnu.org/licenses/lgpl.html">GNU Lesser General -Public License</link> as published by the <link -xlink:href="http://www.fsf.org/">Free Software Foundation</link>; -either version 2.1 of the License, or (at your option) any later -version. Nix is distributed in the hope that it will be useful, but -WITHOUT ANY WARRANTY; without even the implied warranty of -MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -Lesser General Public License for more details.</para> - -</section> - - -</chapter> +</chapter> \ No newline at end of file diff --git a/doc/manual/introduction/introduction.xml b/doc/manual/introduction/introduction.xml new file mode 100644 index 000000000000..f7f0b012d3fd --- /dev/null +++ b/doc/manual/introduction/introduction.xml @@ -0,0 +1,16 @@ +<part xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="chap-introduction"> + +<title>Introduction</title> + +<partintro> +<para>This section describes the main features of Nix and the license under which you can use Nix.</para> +</partintro> + +<xi:include href="about-nix.xml" /> +<xi:include href="nix-license.xml" /> + +</part> diff --git a/doc/manual/introduction/nix-license.xml b/doc/manual/introduction/nix-license.xml new file mode 100644 index 000000000000..af9cef70eef9 --- /dev/null +++ b/doc/manual/introduction/nix-license.xml @@ -0,0 +1,20 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-nix-license"> + +<title>License</title> + +<para>Nix is free software; you can redistribute it and/or modify it +under the terms of the <link +xlink:href="http://www.gnu.org/licenses/lgpl.html">GNU Lesser General +Public License</link> as published by the <link +xlink:href="http://www.fsf.org/">Free Software Foundation</link>; +either version 2.1 of the License, or (at your option) any later +version. Nix is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Lesser General Public License for more details.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/manual.xml b/doc/manual/manual.xml index 6593d13987ab..8fae04f6148b 100644 --- a/doc/manual/manual.xml +++ b/doc/manual/manual.xml @@ -1,9 +1,12 @@ <book xmlns="http://docbook.org/ns/docbook" - xmlns:xi="http://www.w3.org/2001/XInclude"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="NixManual"> <info> - <title>Nix User's Guide</title> + <title>Nix Package Manager Guide</title> <edition>Version <xi:include href="version.txt" parse="text" /></edition> @@ -27,58 +30,30 @@ </info> - - <xi:include href="introduction.xml" /> - <xi:include href="quick-start.xml" /> - <xi:include href="installation.xml" /> - <xi:include href="package-management.xml" /> - <xi:include href="writing-nix-expressions.xml" /> - <xi:include href="build-farm.xml" /> - - - <appendix> - <title>Command Reference</title> - <xi:include href="opt-common.xml" /> - <xi:include href="env-common.xml" /> - - <section> - <title>Main commands</title> - <xi:include href="nix-env.xml" /> - <xi:include href="nix-build.xml" /> - <xi:include href="nix-shell.xml" /> - <xi:include href="nix-store.xml" /> - </section> - - <section> - <title>Utilities</title> - <xi:include href="nix-channel.xml" /> - <xi:include href="nix-collect-garbage.xml" /> - <xi:include href="nix-copy-closure.xml" /> - <xi:include href="nix-daemon.xml" /> - <xi:include href="nix-hash.xml" /> - <xi:include href="nix-install-package.xml" /> - <xi:include href="nix-instantiate.xml" /> - <xi:include href="nix-prefetch-url.xml" /> - <xi:include href="nix-pull.xml" /> - <xi:include href="nix-push.xml" /> - </section> - - <section> - <title>Files</title> - <xi:include href="conf-file.xml" /> - </section> - - </appendix> - - <xi:include href="troubleshooting.xml" /> +<preface> +<title>Preface</title> +<para>This manual describes how to set up and use Nix package manager and Nix expressions.</para> +</preface> + + <xi:include href="introduction/introduction.xml" /> + <xi:include href="quicks-start/quick-start.xml" /> + <xi:include href="installation/installation.xml" /> + <xi:include href="packages/package-management.xml" /> + <xi:include href="expressions/writing-nix-expressions.xml" /> + <xi:include href="builds/build-farm.xml" /> + <xi:include href="command-ref/command-ref.xml" /> + <xi:include href="troubleshooting/troubleshooting.xml" /> <!-- <xi:include href="bugs.xml" /> --> - <xi:include href="glossary.xml" /> + <xi:include href="glossary/glossary.xml" /> <xi:include href="hacking.xml" /> - - <appendix> + <xi:include href="release-notes/release-notes.xml" /> + +<!-- +<appendix> <title>Nix Release Notes</title> - <xi:include href="release-notes.xml" + <xi:include href="release-notes/release-notes.xml" xpointer="xmlns(x=http://docbook.org/ns/docbook)xpointer(x:article/x:section)" /> </appendix> +--> </book> diff --git a/doc/manual/package-management.xml b/doc/manual/package-management.xml deleted file mode 100644 index e1d24b14772c..000000000000 --- a/doc/manual/package-management.xml +++ /dev/null @@ -1,591 +0,0 @@ -<chapter xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xml:id='chap-package-management'> - -<title>Package Management</title> - - -<para>This chapter discusses how to do package management with Nix, -i.e., how to obtain, install, upgrade, and erase packages. This is -the “user’s” perspective of the Nix system — people -who want to <emphasis>create</emphasis> packages should consult -<xref linkend='chap-writing-nix-expressions' />.</para> - - -<section><title>Basic package management</title> - -<para>The main command for package management is <link -linkend="sec-nix-env"><command>nix-env</command></link>. You can use -it to install, upgrade, and erase packages, and to query what -packages are installed or are available for installation.</para> - -<para>In Nix, different users can have different “views” -on the set of installed applications. That is, there might be lots of -applications present on the system (possibly in many different -versions), but users can have a specific selection of those active — -where “active” just means that it appears in a directory -in the user’s <envar>PATH</envar>. Such a view on the set of -installed applications is called a <emphasis>user -environment</emphasis>, which is just a directory tree consisting of -symlinks to the files of the active applications. </para> - -<para>Components are installed from a set of <emphasis>Nix -expressions</emphasis> that tell Nix how to build those packages, -including, if necessary, their dependencies. There is a collection of -Nix expressions called the Nix Package collection that contains -packages ranging from basic development stuff such as GCC and Glibc, -to end-user applications like Mozilla Firefox. (Nix is however not -tied to the Nix Package collection; you could write your own Nix -expressions based on it, or completely new ones.) You can download -the latest version from <link -xlink:href='http://nixos.org/nixpkgs/download.html' />.</para> - -<para>Assuming that you have downloaded and unpacked a release of Nix -Packages, you can view the set of available packages in the release: - -<screen> -$ nix-env -qaf nixpkgs-<replaceable>version</replaceable> '*' -ant-blackdown-1.4.2 -aterm-2.2 -bash-3.0 -binutils-2.15 -bison-1.875d -blackdown-1.4.2 -bzip2-1.0.2 -...</screen> - -where <literal>nixpkgs-<replaceable>version</replaceable></literal> is -where you’ve unpacked the release. The flag <option>-q</option> -specifies a query operation; <option>-a</option> means that you want -to show the “available” (i.e., installable) packages, as opposed to -the installed packages; and <option>-f</option> -<filename>nixpkgs-<replaceable>version</replaceable></filename> -specifies the source of the packages. The argument -<literal>'*'</literal> shows all installable packages. (The quotes are -necessary to prevent shell expansion.) You can also select specific -packages by name: - -<screen> -$ nix-env -qaf nixpkgs-<replaceable>version</replaceable> gcc -gcc-3.4.6 -gcc-4.0.3 -gcc-4.1.1</screen> - -</para> - -<para>It is also possible to see the <emphasis>status</emphasis> of -available packages, i.e., whether they are installed into the user -environment and/or present in the system: - -<screen> -$ nix-env -qasf nixpkgs-<replaceable>version</replaceable> '*' -... --PS bash-3.0 ---S binutils-2.15 -IPS bison-1.875d -...</screen> - -The first character (<literal>I</literal>) indicates whether the -package is installed in your current user environment. The second -(<literal>P</literal>) indicates whether it is present on your system -(in which case installing it into your user environment would be a -very quick operation). The last one (<literal>S</literal>) indicates -whether there is a so-called <emphasis>substitute</emphasis> for the -package, which is Nix’s mechanism for doing binary deployment. It -just means that Nix knows that it can fetch a pre-built package from -somewhere (typically a network server) instead of building it -locally.</para> - -<para>So now that we have a set of Nix expressions we can build the -packages contained in them. This is done using <literal>nix-env --i</literal>. For instance, - -<screen> -$ nix-env -f nixpkgs-<replaceable>version</replaceable> -i subversion</screen> - -will install the package called <literal>subversion</literal> (which -is, of course, the <link -xlink:href='http://subversion.tigris.org/'>Subversion version -management system</link>).</para> - -<para>When you do this for the first time, Nix will start building -Subversion and all its dependencies. This will take quite a while — -typically an hour or two on modern machines. Fortunately, there is a -faster way (so do a Ctrl-C on that install operation!): you just need -to tell Nix that pre-built binaries of all those packages are -available somewhere. This is done using the -<command>nix-pull</command> command, which must be supplied with a URL -containing a <emphasis>manifest</emphasis> describing what binaries -are available. This URL should correspond to the Nix Packages release -that you’re using. For instance, if you obtained a release from <link -xlink:href='http://nixos.org/releases/nixpkgs/nixpkgs-0.12pre11712-4lrp7j8x' -/>, then you should do: - -<screen> -$ nix-pull http://nixos.org/releases/nixpkgs/nixpkgs-0.12pre11712-4lrp7j8x/MANIFEST</screen> - -If you then issue the installation command, it should start -downloading binaries from <systemitem -class='fqdomainname'>nixos.org</systemitem>, instead of building -them from source. This might still take a while since all -dependencies must be downloaded, but on a reasonably fast connection -such as a DSL line it’s on the order of a few minutes.</para> - -<para>Naturally, packages can also be uninstalled: - -<screen> -$ nix-env -e subversion</screen> - -</para> - -<para>Upgrading to a new version is just as easy. If you have a new -release of Nix Packages, you can do: - -<screen> -$ nix-env -f nixpkgs-<replaceable>version</replaceable> -u subversion</screen> - -This will <emphasis>only</emphasis> upgrade Subversion if there is a -“newer” version in the new set of Nix expressions, as -defined by some pretty arbitrary rules regarding ordering of version -numbers (which generally do what you’d expect of them). To just -unconditionally replace Subversion with whatever version is in the Nix -expressions, use <parameter>-i</parameter> instead of -<parameter>-u</parameter>; <parameter>-i</parameter> will remove -whatever version is already installed.</para> - -<para>You can also upgrade all packages for which there are newer -versions: - -<screen> -$ nix-env -f nixpkgs-<replaceable>version</replaceable> -u '*'</screen> - -</para> - -<para>Sometimes it’s useful to be able to ask what -<command>nix-env</command> would do, without actually doing it. For -instance, to find out what packages would be upgraded by -<literal>nix-env -u '*'</literal>, you can do - -<screen> -$ nix-env ... -u '*' --dry-run -(dry run; not doing anything) -upgrading `libxslt-1.1.0' to `libxslt-1.1.10' -upgrading `graphviz-1.10' to `graphviz-1.12' -upgrading `coreutils-5.0' to `coreutils-5.2.1'</screen> - -</para> - -</section> - - -<section xml:id="sec-profiles"><title>Profiles</title> - -<para>Profiles and user environments are Nix’s mechanism for -implementing the ability to allow different users to have different -configurations, and to do atomic upgrades and rollbacks. To -understand how they work, it’s useful to know a bit about how Nix -works. In Nix, packages are stored in unique locations in the -<emphasis>Nix store</emphasis> (typically, -<filename>/nix/store</filename>). For instance, a particular version -of the Subversion package might be stored in a directory -<filename>/nix/store/dpmvp969yhdqs7lm2r1a3gng7pyq6vy4-subversion-1.1.3/</filename>, -while another version might be stored in -<filename>/nix/store/5mq2jcn36ldlmh93yj1n8s9c95pj7c5s-subversion-1.1.2</filename>. -The long strings prefixed to the directory names are cryptographic -hashes<footnote><para>160-bit truncations of SHA-256 hashes encoded in -a base-32 notation, to be precise.</para></footnote> of -<emphasis>all</emphasis> inputs involved in building the package — -sources, dependencies, compiler flags, and so on. So if two -packages differ in any way, they end up in different locations in -the file system, so they don’t interfere with each other. <xref -linkend='fig-user-environments' /> shows a part of a typical Nix -store.</para> - -<figure xml:id='fig-user-environments'><title>User environments</title> - <mediaobject> - <imageobject> - <imagedata fileref='figures/user-environments.png' format='PNG' /> - </imageobject> - </mediaobject> -</figure> - -<para>Of course, you wouldn’t want to type - -<screen> -$ /nix/store/dpmvp969yhdq...-subversion-1.1.3/bin/svn</screen> - -every time you want to run Subversion. Of course we could set up the -<envar>PATH</envar> environment variable to include the -<filename>bin</filename> directory of every package we want to use, -but this is not very convenient since changing <envar>PATH</envar> -doesn’t take effect for already existing processes. The solution Nix -uses is to create directory trees of symlinks to -<emphasis>activated</emphasis> packages. These are called -<emphasis>user environments</emphasis> and they are packages -themselves (though automatically generated by -<command>nix-env</command>), so they too reside in the Nix store. For -instance, in <xref linkend='fig-user-environments' /> the user -environment <filename>/nix/store/0c1p5z4kda11...-user-env</filename> -contains a symlink to just Subversion 1.1.2 (arrows in the figure -indicate symlinks). This would be what we would obtain if we had done - -<screen> -$ nix-env -i subversion</screen> - -on a set of Nix expressions that contained Subversion 1.1.2.</para> - -<para>This doesn’t in itself solve the problem, of course; you -wouldn’t want to type -<filename>/nix/store/0c1p5z4kda11...-user-env/bin/svn</filename> -either. That’s why there are symlinks outside of the store that point -to the user environments in the store; for instance, the symlinks -<filename>default-42-link</filename> and -<filename>default-43-link</filename> in the example. These are called -<emphasis>generations</emphasis> since every time you perform a -<command>nix-env</command> operation, a new user environment is -generated based on the current one. For instance, generation 43 was -created from generation 42 when we did - -<screen> -$ nix-env -i subversion mozilla</screen> - -on a set of Nix expressions that contained Mozilla and a new version -of Subversion.</para> - -<para>Generations are grouped together into -<emphasis>profiles</emphasis> so that different users don’t interfere -with each other if they don’t want to. For example: - -<screen> -$ ls -l /nix/var/nix/profiles/ -... -lrwxrwxrwx 1 eelco ... default-42-link -> /nix/store/0c1p5z4kda11...-user-env -lrwxrwxrwx 1 eelco ... default-43-link -> /nix/store/3aw2pdyx2jfc...-user-env -lrwxrwxrwx 1 eelco ... default -> default-43-link</screen> - -This shows a profile called <filename>default</filename>. The file -<filename>default</filename> itself is actually a symlink that points -to the current generation. When we do a <command>nix-env</command> -operation, a new user environment and generation link are created -based on the current one, and finally the <filename>default</filename> -symlink is made to point at the new generation. This last step is -atomic on Unix, which explains how we can do atomic upgrades. (Note -that the building/installing of new packages doesn’t interfere in -any way with old packages, since they are stored in different -locations in the Nix store.)</para> - -<para>If you find that you want to undo a <command>nix-env</command> -operation, you can just do - -<screen> -$ nix-env --rollback</screen> - -which will just make the current generation link point at the previous -link. E.g., <filename>default</filename> would be made to point at -<filename>default-42-link</filename>. You can also switch to a -specific generation: - -<screen> -$ nix-env --switch-generation 43</screen> - -which in this example would roll forward to generation 43 again. You -can also see all available generations: - -<screen> -$ nix-env --list-generations</screen></para> - -<para>Actually, there is another level of indirection not shown in the -figure above. You generally wouldn’t have -<filename>/nix/var/nix/profiles/<replaceable>some-profile</replaceable>/bin</filename> -in your <envar>PATH</envar>. Rather, there is a symlink -<filename>~/.nix-profile</filename> that points to your current -profile. This means that you should put -<filename>~/.nix-profile/bin</filename> in your <envar>PATH</envar> -(and indeed, that’s what the initialisation script -<filename>/nix/etc/profile.d/nix.sh</filename> does). This makes it -easier to switch to a different profile. You can do that using the -command <command>nix-env --switch-profile</command>: - -<screen> -$ nix-env --switch-profile /nix/var/nix/profiles/my-profile - -$ nix-env --switch-profile /nix/var/nix/profiles/default</screen> - -These commands switch to the <filename>my-profile</filename> and -default profile, respectively. If the profile doesn’t exist, it will -be created automatically. You should be careful about storing a -profile in another location than the <filename>profiles</filename> -directory, since otherwise it might not be used as a root of the -garbage collector (see <xref linkend='sec-garbage-collection' -/>).</para> - -<para>All <command>nix-env</command> operations work on the profile -pointed to by <command>~/.nix-profile</command>, but you can override -this using the <option>--profile</option> option (abbreviation -<option>-p</option>): - -<screen> -$ nix-env -p /nix/var/nix/profiles/other-profile -i subversion</screen> - -This will <emphasis>not</emphasis> change the -<command>~/.nix-profile</command> symlink.</para> - -</section> - - -<section xml:id='sec-garbage-collection'><title>Garbage collection</title> - -<para><command>nix-env</command> operations such as upgrades -(<option>-u</option>) and uninstall (<option>-e</option>) never -actually delete packages from the system. All they do (as shown -above) is to create a new user environment that no longer contains -symlinks to the “deleted” packages.</para> - -<para>Of course, since disk space is not infinite, unused packages -should be removed at some point. You can do this by running the Nix -garbage collector. It will remove from the Nix store any package -not used (directly or indirectly) by any generation of any -profile.</para> - -<para>Note however that as long as old generations reference a -package, it will not be deleted. After all, we wouldn’t be able to -do a rollback otherwise. So in order for garbage collection to be -effective, you should also delete (some) old generations. Of course, -this should only be done if you are certain that you will not need to -roll back.</para> - -<para>To delete all old (non-current) generations of your current -profile: - -<screen> -$ nix-env --delete-generations old</screen> - -Instead of <literal>old</literal> you can also specify a list of -generations, e.g., - -<screen> -$ nix-env --delete-generations 10 11 14</screen> - -</para> - -<para>After removing appropriate old generations you can run the -garbage collector as follows: - -<screen> -$ nix-store --gc</screen> - -If you are feeling uncertain, you can also first view what files would -be deleted: - -<screen> -$ nix-store --gc --print-dead</screen> - -Likewise, the option <option>--print-live</option> will show the paths -that <emphasis>won’t</emphasis> be deleted.</para> - -<para>There is also a convenient little utility -<command>nix-collect-garbage</command>, which when invoked with the -<option>-d</option> (<option>--delete-old</option>) switch deletes all -old generations of all profiles in -<filename>/nix/var/nix/profiles</filename>. So - -<screen> -$ nix-collect-garbage -d</screen> - -is a quick and easy way to clean up your system.</para> - - - - -<section xml:id="ssec-gc-roots"><title>Garbage collector roots</title> - -<para>The roots of the garbage collector are all store paths to which -there are symlinks in the directory -<filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename>. -For instance, the following command makes the path -<filename>/nix/store/d718ef...-foo</filename> a root of the collector: - -<screen> -$ ln -s /nix/store/d718ef...-foo /nix/var/nix/gcroots/bar</screen> - -That is, after this command, the garbage collector will not remove -<filename>/nix/store/d718ef...-foo</filename> or any of its -dependencies.</para> - -<para>Subdirectories of -<filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename> -are also searched for symlinks. Symlinks to non-store paths are -followed and searched for roots, but symlinks to non-store paths -<emphasis>inside</emphasis> the paths reached in that way are not -followed to prevent infinite recursion.</para> - -</section> - -</section> - - -<section xml:id="sec-channels"><title>Channels</title> - -<para>If you want to stay up to date with a set of packages, it’s not -very convenient to manually download the latest set of Nix expressions -for those packages, use <command>nix-pull</command> to register -pre-built binaries (if available), and upgrade using -<command>nix-env</command>. Fortunately, there’s a better way: -<emphasis>Nix channels</emphasis>.</para> - -<para>A Nix channel is just a URL that points to a place that contains -a set of Nix expressions and a manifest. Using the command <link -linkend="sec-nix-channel"><command>nix-channel</command></link> you -can automatically stay up to date with whatever is available at that -URL.</para> - -<para>You can “subscribe” to a channel using -<command>nix-channel --add</command>, e.g., - -<screen> -$ nix-channel --add http://nixos.org/channels/nixpkgs-unstable</screen> - -subscribes you to a channel that always contains that latest version -of the Nix Packages collection. (Instead of -<literal>nixpkgs-unstable</literal> you could also subscribe to -<literal>nixpkgs-stable</literal>, which should have a higher level of -stability, but right now is just outdated.) Subscribing really just -means that the URL is added to the file -<filename>~/.nix-channels</filename>. Right now there is no command -to “unsubscribe”; you should just edit that file manually -and delete the offending URL.</para> - -<para>To obtain the latest Nix expressions available in a channel, do - -<screen> -$ nix-channel --update</screen> - -This downloads the Nix expressions in every channel (downloaded from -<literal><replaceable>url</replaceable>/nixexprs.tar.bz2</literal>) -and registers any available pre-built binaries in every channel -(by <command>nix-pull</command>ing -<literal><replaceable>url</replaceable>/MANIFEST</literal>). It also -makes the union of each channel’s Nix expressions the default for -<command>nix-env</command> operations. Consequently, you can then say - -<screen> -$ nix-env -u '*'</screen> - -to upgrade all packages in your profile to the latest versions -available in the subscribed channels.</para> - -</section> - - -<section xml:id="sec-one-click"><title>One-click installs</title> - -<para>Often, when you want to install a specific package (e.g., from -the <link -xlink:href="http://nixos.org/nixpkgs/">Nix -Packages collection</link>), subscribing to a channel is a bit -cumbersome. And channels don’t help you at all if you want to install -an older version of a package than the one provided by the current -contents of the channel, or a package that has been removed from the -channel. That’s when <emphasis>one-click installs</emphasis> come in -handy: you can just go to the web page that contains the package, -click on it, and it will be installed with all the necessary -dependencies.</para> - -<para>For instance, you can go to <link -xlink:href="http://hydra.nixos.org/jobset/nixpkgs/trunk/channel/latest" -/> and click on any link for the individual packages for your -platform. The first time you do this, your browser will ask what to -do with <literal>application/nix-package</literal> files. You should -open them with <filename>/nix/bin/nix-install-package</filename>. -This will open a window that asks you to confirm that you want to -install the package. When you answer <literal>Y</literal>, the -package and all its dependencies will be installed. This is a binary -deployment mechanism — you get packages pre-compiled for the selected -platform type.</para> - -<para>You can also install <literal>application/nix-package</literal> -files from the command line directly. See <xref -linkend='sec-nix-install-package' /> for details.</para> - -</section> - - -<section xml:id="sec-sharing-packages"><title>Sharing packages between machines</title> - -<para>Sometimes you want to copy a package from one machine to -another. Or, you want to install some packages and you know that -another machine already has some or all of those packages or their -dependencies. In that case there are mechanisms to quickly copy -packages between machines.</para> - -<para>The command <command -linkend="sec-nix-copy-closure">nix-copy-closure</command> copies a Nix -store path along with all its dependencies to or from another machine -via the SSH protocol. It doesn’t copy store paths that are already -present on the target machine. For example, the following command -copies Firefox with all its dependencies: - -<screen> -$ nix-copy-closure --to alice@itchy.example.org $(type -p firefox)</screen> - -See <xref linkend='sec-nix-copy-closure' /> for details.</para> - -<para>With <command linkend='refsec-nix-store-export'>nix-store ---export</command> and <command -linkend='refsec-nix-store-import'>nix-store --import</command> you can -write the closure of a store path (that is, the path and all its -dependencies) to a file, and then unpack that file into another Nix -store. For example, - -<screen> -$ nix-store --export $(nix-store -qR $(type -p firefox)) > firefox.closure</screen> - -writes the closure of Firefox to a file. You can then copy this file -to another machine and install the closure: - -<screen> -$ nix-store --import < firefox.closure</screen> - -Any store paths in the closure that are already present in the target -store are ignored. It is also possible to pipe the export into -another command, e.g. to copy and install a closure directly to/on -another machine: - -<screen> -$ nix-store --export $(nix-store -qR $(type -p firefox)) | bzip2 | \ - ssh alice@itchy.example.org "bunzip2 | nix-store --import"</screen> - -But note that <command>nix-copy-closure</command> is generally more -efficient in this example because it only copies paths that are not -already present in the target Nix store.</para> - -<para>Finally, if you can mount the Nix store of a remote machine in -your local filesystem, Nix can copy paths from the remote Nix store to -the local Nix store <emphasis>on demand</emphasis>. For instance, -suppose that you mount a remote machine containing a Nix store via -<command -xlink:href="http://fuse.sourceforge.net/sshfs.html">sshfs</command>: - -<screen> -$ sshfs alice@itchy.example.org:/ /mnt</screen> - -You should then set the <envar>NIX_OTHER_STORES</envar> environment -variable to tell Nix about this remote Nix store: - -<screen> -$ export NIX_OTHER_STORES=/mnt/nix</screen> - -Then if you do any Nix operation, e.g. - -<screen> -$ nix-env -i firefox</screen> - -and Nix has to build a path that it sees is already present in -<filename>/mnt/nix</filename>, then it will just copy from there -instead of building it from source.</para> - - -</section> - - -</chapter> diff --git a/doc/manual/packages/basic-package-mgmt.xml b/doc/manual/packages/basic-package-mgmt.xml new file mode 100644 index 000000000000..69c955c1dd11 --- /dev/null +++ b/doc/manual/packages/basic-package-mgmt.xml @@ -0,0 +1,170 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-basic-package-mgmt"> + +<title>Basic Package Management</title> + +<para>The main command for package management is <link +linkend="sec-nix-env"><command>nix-env</command></link>. You can use +it to install, upgrade, and erase packages, and to query what +packages are installed or are available for installation.</para> + +<para>In Nix, different users can have different “views” +on the set of installed applications. That is, there might be lots of +applications present on the system (possibly in many different +versions), but users can have a specific selection of those active — +where “active” just means that it appears in a directory +in the user’s <envar>PATH</envar>. Such a view on the set of +installed applications is called a <emphasis>user +environment</emphasis>, which is just a directory tree consisting of +symlinks to the files of the active applications. </para> + +<para>Components are installed from a set of <emphasis>Nix +expressions</emphasis> that tell Nix how to build those packages, +including, if necessary, their dependencies. There is a collection of +Nix expressions called the Nix Package collection that contains +packages ranging from basic development stuff such as GCC and Glibc, +to end-user applications like Mozilla Firefox. (Nix is however not +tied to the Nix Package collection; you could write your own Nix +expressions based on it, or completely new ones.) You can download +the latest version from <link +xlink:href='http://nixos.org/nixpkgs/download.html' />.</para> + +<para>Assuming that you have downloaded and unpacked a release of Nix +Packages, you can view the set of available packages in the release: + +<screen> +$ nix-env -qaf nixpkgs-<replaceable>version</replaceable> '*' +ant-blackdown-1.4.2 +aterm-2.2 +bash-3.0 +binutils-2.15 +bison-1.875d +blackdown-1.4.2 +bzip2-1.0.2 +...</screen> + +where <literal>nixpkgs-<replaceable>version</replaceable></literal> is +where you’ve unpacked the release. The flag <option>-q</option> +specifies a query operation; <option>-a</option> means that you want +to show the “available” (i.e., installable) packages, as opposed to +the installed packages; and <option>-f</option> +<filename>nixpkgs-<replaceable>version</replaceable></filename> +specifies the source of the packages. The argument +<literal>'*'</literal> shows all installable packages. (The quotes are +necessary to prevent shell expansion.) You can also select specific +packages by name: + +<screen> +$ nix-env -qaf nixpkgs-<replaceable>version</replaceable> gcc +gcc-3.4.6 +gcc-4.0.3 +gcc-4.1.1</screen> + +</para> + +<para>It is also possible to see the <emphasis>status</emphasis> of +available packages, i.e., whether they are installed into the user +environment and/or present in the system: + +<screen> +$ nix-env -qasf nixpkgs-<replaceable>version</replaceable> '*' +... +-PS bash-3.0 +--S binutils-2.15 +IPS bison-1.875d +...</screen> + +The first character (<literal>I</literal>) indicates whether the +package is installed in your current user environment. The second +(<literal>P</literal>) indicates whether it is present on your system +(in which case installing it into your user environment would be a +very quick operation). The last one (<literal>S</literal>) indicates +whether there is a so-called <emphasis>substitute</emphasis> for the +package, which is Nix’s mechanism for doing binary deployment. It +just means that Nix knows that it can fetch a pre-built package from +somewhere (typically a network server) instead of building it +locally.</para> + +<para>So now that we have a set of Nix expressions we can build the +packages contained in them. This is done using <literal>nix-env +-i</literal>. For instance, + +<screen> +$ nix-env -f nixpkgs-<replaceable>version</replaceable> -i subversion</screen> + +will install the package called <literal>subversion</literal> (which +is, of course, the <link +xlink:href='http://subversion.tigris.org/'>Subversion version +management system</link>).</para> + +<para>When you do this for the first time, Nix will start building +Subversion and all its dependencies. This will take quite a while — +typically an hour or two on modern machines. Fortunately, there is a +faster way (so do a Ctrl-C on that install operation!): you just need +to tell Nix that pre-built binaries of all those packages are +available somewhere. This is done using the +<command>nix-pull</command> command, which must be supplied with a URL +containing a <emphasis>manifest</emphasis> describing what binaries +are available. This URL should correspond to the Nix Packages release +that you’re using. For instance, if you obtained a release from <link +xlink:href='http://nixos.org/releases/nixpkgs/nixpkgs-0.12pre11712-4lrp7j8x' +/>, then you should do: + +<screen> +$ nix-pull http://nixos.org/releases/nixpkgs/nixpkgs-0.12pre11712-4lrp7j8x/MANIFEST</screen> + +If you then issue the installation command, it should start +downloading binaries from <systemitem +class='fqdomainname'>nixos.org</systemitem>, instead of building +them from source. This might still take a while since all +dependencies must be downloaded, but on a reasonably fast connection +such as a DSL line it’s on the order of a few minutes.</para> + +<para>Naturally, packages can also be uninstalled: + +<screen> +$ nix-env -e subversion</screen> + +</para> + +<para>Upgrading to a new version is just as easy. If you have a new +release of Nix Packages, you can do: + +<screen> +$ nix-env -f nixpkgs-<replaceable>version</replaceable> -u subversion</screen> + +This will <emphasis>only</emphasis> upgrade Subversion if there is a +“newer” version in the new set of Nix expressions, as +defined by some pretty arbitrary rules regarding ordering of version +numbers (which generally do what you’d expect of them). To just +unconditionally replace Subversion with whatever version is in the Nix +expressions, use <parameter>-i</parameter> instead of +<parameter>-u</parameter>; <parameter>-i</parameter> will remove +whatever version is already installed.</para> + +<para>You can also upgrade all packages for which there are newer +versions: + +<screen> +$ nix-env -f nixpkgs-<replaceable>version</replaceable> -u '*'</screen> + +</para> + +<para>Sometimes it’s useful to be able to ask what +<command>nix-env</command> would do, without actually doing it. For +instance, to find out what packages would be upgraded by +<literal>nix-env -u '*'</literal>, you can do + +<screen> +$ nix-env ... -u '*' --dry-run +(dry run; not doing anything) +upgrading `libxslt-1.1.0' to `libxslt-1.1.10' +upgrading `graphviz-1.10' to `graphviz-1.12' +upgrading `coreutils-5.0' to `coreutils-5.2.1'</screen> + +</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/packages/channels.xml b/doc/manual/packages/channels.xml new file mode 100644 index 000000000000..094e11fe3b15 --- /dev/null +++ b/doc/manual/packages/channels.xml @@ -0,0 +1,57 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-channels"> + +<title>Channels</title> + +<para>If you want to stay up to date with a set of packages, it’s not +very convenient to manually download the latest set of Nix expressions +for those packages, use <command>nix-pull</command> to register +pre-built binaries (if available), and upgrade using +<command>nix-env</command>. Fortunately, there’s a better way: +<emphasis>Nix channels</emphasis>.</para> + +<para>A Nix channel is just a URL that points to a place that contains +a set of Nix expressions and a manifest. Using the command <link +linkend="sec-nix-channel"><command>nix-channel</command></link> you +can automatically stay up to date with whatever is available at that +URL.</para> + +<para>You can “subscribe” to a channel using +<command>nix-channel --add</command>, e.g., + +<screen> +$ nix-channel --add http://nixos.org/channels/nixpkgs-unstable</screen> + +subscribes you to a channel that always contains that latest version +of the Nix Packages collection. (Instead of +<literal>nixpkgs-unstable</literal> you could also subscribe to +<literal>nixpkgs-stable</literal>, which should have a higher level of +stability, but right now is just outdated.) Subscribing really just +means that the URL is added to the file +<filename>~/.nix-channels</filename>. Right now there is no command +to “unsubscribe”; you should just edit that file manually +and delete the offending URL.</para> + +<para>To obtain the latest Nix expressions available in a channel, do + +<screen> +$ nix-channel --update</screen> + +This downloads the Nix expressions in every channel (downloaded from +<literal><replaceable>url</replaceable>/nixexprs.tar.bz2</literal>) +and registers any available pre-built binaries in every channel +(by <command>nix-pull</command>ing +<literal><replaceable>url</replaceable>/MANIFEST</literal>). It also +makes the union of each channel’s Nix expressions the default for +<command>nix-env</command> operations. Consequently, you can then say + +<screen> +$ nix-env -u '*'</screen> + +to upgrade all packages in your profile to the latest versions +available in the subscribed channels.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/packages/garbage-collection.xml b/doc/manual/packages/garbage-collection.xml new file mode 100644 index 000000000000..ae28c485f076 --- /dev/null +++ b/doc/manual/packages/garbage-collection.xml @@ -0,0 +1,70 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='sec-garbage-collection'> + +<title>Garbage Collection</title> + +<para><command>nix-env</command> operations such as upgrades +(<option>-u</option>) and uninstall (<option>-e</option>) never +actually delete packages from the system. All they do (as shown +above) is to create a new user environment that no longer contains +symlinks to the “deleted” packages.</para> + +<para>Of course, since disk space is not infinite, unused packages +should be removed at some point. You can do this by running the Nix +garbage collector. It will remove from the Nix store any package +not used (directly or indirectly) by any generation of any +profile.</para> + +<para>Note however that as long as old generations reference a +package, it will not be deleted. After all, we wouldn’t be able to +do a rollback otherwise. So in order for garbage collection to be +effective, you should also delete (some) old generations. Of course, +this should only be done if you are certain that you will not need to +roll back.</para> + +<para>To delete all old (non-current) generations of your current +profile: + +<screen> +$ nix-env --delete-generations old</screen> + +Instead of <literal>old</literal> you can also specify a list of +generations, e.g., + +<screen> +$ nix-env --delete-generations 10 11 14</screen> + +</para> + +<para>After removing appropriate old generations you can run the +garbage collector as follows: + +<screen> +$ nix-store --gc</screen> + +If you are feeling uncertain, you can also first view what files would +be deleted: + +<screen> +$ nix-store --gc --print-dead</screen> + +Likewise, the option <option>--print-live</option> will show the paths +that <emphasis>won’t</emphasis> be deleted.</para> + +<para>There is also a convenient little utility +<command>nix-collect-garbage</command>, which when invoked with the +<option>-d</option> (<option>--delete-old</option>) switch deletes all +old generations of all profiles in +<filename>/nix/var/nix/profiles</filename>. So + +<screen> +$ nix-collect-garbage -d</screen> + +is a quick and easy way to clean up your system.</para> + +<xi:include href="garbage-collector-roots.xml" /> + +</chapter> \ No newline at end of file diff --git a/doc/manual/packages/garbage-collector-roots.xml b/doc/manual/packages/garbage-collector-roots.xml new file mode 100644 index 000000000000..8338e539202f --- /dev/null +++ b/doc/manual/packages/garbage-collector-roots.xml @@ -0,0 +1,29 @@ +<section xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-gc-roots"> + +<title>Garbage Collector Roots</title> + +<para>The roots of the garbage collector are all store paths to which +there are symlinks in the directory +<filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename>. +For instance, the following command makes the path +<filename>/nix/store/d718ef...-foo</filename> a root of the collector: + +<screen> +$ ln -s /nix/store/d718ef...-foo /nix/var/nix/gcroots/bar</screen> + +That is, after this command, the garbage collector will not remove +<filename>/nix/store/d718ef...-foo</filename> or any of its +dependencies.</para> + +<para>Subdirectories of +<filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename> +are also searched for symlinks. Symlinks to non-store paths are +followed and searched for roots, but symlinks to non-store paths +<emphasis>inside</emphasis> the paths reached in that way are not +followed to prevent infinite recursion.</para> + +</section> \ No newline at end of file diff --git a/doc/manual/packages/one-click.xml b/doc/manual/packages/one-click.xml new file mode 100644 index 000000000000..cef9a2bbff4e --- /dev/null +++ b/doc/manual/packages/one-click.xml @@ -0,0 +1,37 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-one-click"> + +<title>One-Click Installation</title> + +<para>Often, when you want to install a specific package (e.g., from +the <link +xlink:href="http://nixos.org/nixpkgs/">Nix +Packages collection</link>), subscribing to a channel is a bit +cumbersome. And channels don’t help you at all if you want to install +an older version of a package than the one provided by the current +contents of the channel, or a package that has been removed from the +channel. That’s when <emphasis>one-click installs</emphasis> come in +handy: you can just go to the web page that contains the package, +click on it, and it will be installed with all the necessary +dependencies.</para> + +<para>For instance, you can go to <link +xlink:href="http://hydra.nixos.org/jobset/nixpkgs/trunk/channel/latest" +/> and click on any link for the individual packages for your +platform. The first time you do this, your browser will ask what to +do with <literal>application/nix-package</literal> files. You should +open them with <filename>/nix/bin/nix-install-package</filename>. +This will open a window that asks you to confirm that you want to +install the package. When you answer <literal>Y</literal>, the +package and all its dependencies will be installed. This is a binary +deployment mechanism — you get packages pre-compiled for the selected +platform type.</para> + +<para>You can also install <literal>application/nix-package</literal> +files from the command line directly. See <xref +linkend='sec-nix-install-package' /> for details.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/packages/package-management.xml b/doc/manual/packages/package-management.xml new file mode 100644 index 000000000000..5cc5c381bb43 --- /dev/null +++ b/doc/manual/packages/package-management.xml @@ -0,0 +1,24 @@ +<part xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id='chap-package-management'> + +<title>Package Management</title> + +<partintro> +<para>This chapter discusses how to do package management with Nix, +i.e., how to obtain, install, upgrade, and erase packages. This is +the “user’s” perspective of the Nix system — people +who want to <emphasis>create</emphasis> packages should consult +<xref linkend='chap-writing-nix-expressions' />.</para> +</partintro> + +<xi:include href="basic-package-mgmt.xml" /> +<xi:include href="profiles.xml" /> +<xi:include href="garbage-collection.xml" /> +<xi:include href="channels.xml" /> +<xi:include href="one-click.xml" /> +<xi:include href="sharing-packages.xml" /> + +</part> diff --git a/doc/manual/packages/profiles.xml b/doc/manual/packages/profiles.xml new file mode 100644 index 000000000000..ad5e92aeb64b --- /dev/null +++ b/doc/manual/packages/profiles.xml @@ -0,0 +1,159 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-profiles"> + +<title>Profiles</title> + +<para>Profiles and user environments are Nix’s mechanism for +implementing the ability to allow different users to have different +configurations, and to do atomic upgrades and rollbacks. To +understand how they work, it’s useful to know a bit about how Nix +works. In Nix, packages are stored in unique locations in the +<emphasis>Nix store</emphasis> (typically, +<filename>/nix/store</filename>). For instance, a particular version +of the Subversion package might be stored in a directory +<filename>/nix/store/dpmvp969yhdqs7lm2r1a3gng7pyq6vy4-subversion-1.1.3/</filename>, +while another version might be stored in +<filename>/nix/store/5mq2jcn36ldlmh93yj1n8s9c95pj7c5s-subversion-1.1.2</filename>. +The long strings prefixed to the directory names are cryptographic +hashes<footnote><para>160-bit truncations of SHA-256 hashes encoded in +a base-32 notation, to be precise.</para></footnote> of +<emphasis>all</emphasis> inputs involved in building the package — +sources, dependencies, compiler flags, and so on. So if two +packages differ in any way, they end up in different locations in +the file system, so they don’t interfere with each other. <xref +linkend='fig-user-environments' /> shows a part of a typical Nix +store.</para> + +<figure xml:id='fig-user-environments'><title>User environments</title> + <mediaobject> + <imageobject> + <imagedata fileref='figures/user-environments.png' format='PNG' /> + </imageobject> + </mediaobject> +</figure> + +<para>Of course, you wouldn’t want to type + +<screen> +$ /nix/store/dpmvp969yhdq...-subversion-1.1.3/bin/svn</screen> + +every time you want to run Subversion. Of course we could set up the +<envar>PATH</envar> environment variable to include the +<filename>bin</filename> directory of every package we want to use, +but this is not very convenient since changing <envar>PATH</envar> +doesn’t take effect for already existing processes. The solution Nix +uses is to create directory trees of symlinks to +<emphasis>activated</emphasis> packages. These are called +<emphasis>user environments</emphasis> and they are packages +themselves (though automatically generated by +<command>nix-env</command>), so they too reside in the Nix store. For +instance, in <xref linkend='fig-user-environments' /> the user +environment <filename>/nix/store/0c1p5z4kda11...-user-env</filename> +contains a symlink to just Subversion 1.1.2 (arrows in the figure +indicate symlinks). This would be what we would obtain if we had done + +<screen> +$ nix-env -i subversion</screen> + +on a set of Nix expressions that contained Subversion 1.1.2.</para> + +<para>This doesn’t in itself solve the problem, of course; you +wouldn’t want to type +<filename>/nix/store/0c1p5z4kda11...-user-env/bin/svn</filename> +either. That’s why there are symlinks outside of the store that point +to the user environments in the store; for instance, the symlinks +<filename>default-42-link</filename> and +<filename>default-43-link</filename> in the example. These are called +<emphasis>generations</emphasis> since every time you perform a +<command>nix-env</command> operation, a new user environment is +generated based on the current one. For instance, generation 43 was +created from generation 42 when we did + +<screen> +$ nix-env -i subversion mozilla</screen> + +on a set of Nix expressions that contained Mozilla and a new version +of Subversion.</para> + +<para>Generations are grouped together into +<emphasis>profiles</emphasis> so that different users don’t interfere +with each other if they don’t want to. For example: + +<screen> +$ ls -l /nix/var/nix/profiles/ +... +lrwxrwxrwx 1 eelco ... default-42-link -> /nix/store/0c1p5z4kda11...-user-env +lrwxrwxrwx 1 eelco ... default-43-link -> /nix/store/3aw2pdyx2jfc...-user-env +lrwxrwxrwx 1 eelco ... default -> default-43-link</screen> + +This shows a profile called <filename>default</filename>. The file +<filename>default</filename> itself is actually a symlink that points +to the current generation. When we do a <command>nix-env</command> +operation, a new user environment and generation link are created +based on the current one, and finally the <filename>default</filename> +symlink is made to point at the new generation. This last step is +atomic on Unix, which explains how we can do atomic upgrades. (Note +that the building/installing of new packages doesn’t interfere in +any way with old packages, since they are stored in different +locations in the Nix store.)</para> + +<para>If you find that you want to undo a <command>nix-env</command> +operation, you can just do + +<screen> +$ nix-env --rollback</screen> + +which will just make the current generation link point at the previous +link. E.g., <filename>default</filename> would be made to point at +<filename>default-42-link</filename>. You can also switch to a +specific generation: + +<screen> +$ nix-env --switch-generation 43</screen> + +which in this example would roll forward to generation 43 again. You +can also see all available generations: + +<screen> +$ nix-env --list-generations</screen></para> + +<para>Actually, there is another level of indirection not shown in the +figure above. You generally wouldn’t have +<filename>/nix/var/nix/profiles/<replaceable>some-profile</replaceable>/bin</filename> +in your <envar>PATH</envar>. Rather, there is a symlink +<filename>~/.nix-profile</filename> that points to your current +profile. This means that you should put +<filename>~/.nix-profile/bin</filename> in your <envar>PATH</envar> +(and indeed, that’s what the initialisation script +<filename>/nix/etc/profile.d/nix.sh</filename> does). This makes it +easier to switch to a different profile. You can do that using the +command <command>nix-env --switch-profile</command>: + +<screen> +$ nix-env --switch-profile /nix/var/nix/profiles/my-profile + +$ nix-env --switch-profile /nix/var/nix/profiles/default</screen> + +These commands switch to the <filename>my-profile</filename> and +default profile, respectively. If the profile doesn’t exist, it will +be created automatically. You should be careful about storing a +profile in another location than the <filename>profiles</filename> +directory, since otherwise it might not be used as a root of the +garbage collector (see <xref linkend='sec-garbage-collection' +/>).</para> + +<para>All <command>nix-env</command> operations work on the profile +pointed to by <command>~/.nix-profile</command>, but you can override +this using the <option>--profile</option> option (abbreviation +<option>-p</option>): + +<screen> +$ nix-env -p /nix/var/nix/profiles/other-profile -i subversion</screen> + +This will <emphasis>not</emphasis> change the +<command>~/.nix-profile</command> symlink.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/packages/sharing-packages.xml b/doc/manual/packages/sharing-packages.xml new file mode 100644 index 000000000000..573b7c1e77a6 --- /dev/null +++ b/doc/manual/packages/sharing-packages.xml @@ -0,0 +1,82 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-sharing-packages"> + +<title>Sharing Packages Between Machines</title> + +<para>Sometimes you want to copy a package from one machine to +another. Or, you want to install some packages and you know that +another machine already has some or all of those packages or their +dependencies. In that case there are mechanisms to quickly copy +packages between machines.</para> + +<para>The command <command +linkend="sec-nix-copy-closure">nix-copy-closure</command> copies a Nix +store path along with all its dependencies to or from another machine +via the SSH protocol. It doesn’t copy store paths that are already +present on the target machine. For example, the following command +copies Firefox with all its dependencies: + +<screen> +$ nix-copy-closure --to alice@itchy.example.org $(type -p firefox)</screen> + +See <xref linkend='sec-nix-copy-closure' /> for details.</para> + +<para>With <command linkend='refsec-nix-store-export'>nix-store +--export</command> and <command +linkend='refsec-nix-store-import'>nix-store --import</command> you can +write the closure of a store path (that is, the path and all its +dependencies) to a file, and then unpack that file into another Nix +store. For example, + +<screen> +$ nix-store --export $(nix-store -qR $(type -p firefox)) > firefox.closure</screen> + +writes the closure of Firefox to a file. You can then copy this file +to another machine and install the closure: + +<screen> +$ nix-store --import < firefox.closure</screen> + +Any store paths in the closure that are already present in the target +store are ignored. It is also possible to pipe the export into +another command, e.g. to copy and install a closure directly to/on +another machine: + +<screen> +$ nix-store --export $(nix-store -qR $(type -p firefox)) | bzip2 | \ + ssh alice@itchy.example.org "bunzip2 | nix-store --import"</screen> + +But note that <command>nix-copy-closure</command> is generally more +efficient in this example because it only copies paths that are not +already present in the target Nix store.</para> + +<para>Finally, if you can mount the Nix store of a remote machine in +your local filesystem, Nix can copy paths from the remote Nix store to +the local Nix store <emphasis>on demand</emphasis>. For instance, +suppose that you mount a remote machine containing a Nix store via +<command +xlink:href="http://fuse.sourceforge.net/sshfs.html">sshfs</command>: + +<screen> +$ sshfs alice@itchy.example.org:/ /mnt</screen> + +You should then set the <envar>NIX_OTHER_STORES</envar> environment +variable to tell Nix about this remote Nix store: + +<screen> +$ export NIX_OTHER_STORES=/mnt/nix</screen> + +Then if you do any Nix operation, e.g. + +<screen> +$ nix-env -i firefox</screen> + +and Nix has to build a path that it sees is already present in +<filename>/mnt/nix</filename>, then it will just copy from there +instead of building it from source.</para> + + +</chapter> \ No newline at end of file diff --git a/doc/manual/quick-start.xml b/doc/manual/quick-start/getting-started.xml index 17079906396c..a6b1f47b6cf6 100644 --- a/doc/manual/quick-start.xml +++ b/doc/manual/quick-start/getting-started.xml @@ -1,17 +1,15 @@ <chapter xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xml:id="chap-quick-start"> + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-getting-started-nix"> -<title>Quick Start</title> +<title>Getting Started with Nix</title> +<para>This tutorial takes you through the basic tasks you might perform when you start using Nix.</para> +<procedure> -<para>This chapter is for impatient people who don't like reading -documentation. For more in-depth information you are kindly referred -to the following chapters.</para> - -<orderedlist> - -<listitem><para>Install Nix by running the following: +<step><para>Install Nix by running the following: <screen> $ bash <(curl https://nixos.org/nix/install) @@ -20,9 +18,9 @@ $ bash <(curl https://nixos.org/nix/install) This will install Nix in <filename>/nix</filename>. The install script will create <filename>/nix</filename> using <command>sudo</command>, so make sure you have sufficient rights. (For other installation -methods, see <xref linkend="chap-installation"/>.)</para></listitem> +methods, see <xref linkend="chap-installation"/>.)</para></step> -<listitem><para>See what installable packages are currently available +<step><para>See what installable packages are currently available in the channel: <screen> @@ -33,17 +31,17 @@ hello-2.1.1 libxslt-1.1.0 <replaceable>...</replaceable></screen> -</para></listitem> +</para></step> -<listitem><para>Install some packages from the channel: +<step><para>Install some packages from the channel: <screen> $ nix-env -i hello <replaceable>...</replaceable> </screen> This should download pre-built packages; it should not build them -locally (if it does, something went wrong).</para></listitem> +locally (if it does, something went wrong).</para></step> -<listitem><para>Test that they work: +<step><para>Test that they work: <screen> $ which hello @@ -52,16 +50,16 @@ $ hello Hello, world! </screen> -</para></listitem> +</para></step> -<listitem><para>Uninstall a package: +<step><para>Uninstall a package: <screen> $ nix-env -e hello</screen> -</para></listitem> +</para></step> -<listitem><para>To keep up-to-date with the channel, do: +<step><para>To keep up-to-date with the channel, do: <screen> $ nix-channel --update nixpkgs @@ -69,9 +67,9 @@ $ nix-env -u '*'</screen> The latter command will upgrade each installed package for which there is a “newer” version (as determined by comparing the version -numbers).</para></listitem> +numbers).</para></step> -<listitem><para>You can also install specific packages directly from +<step><para>You can also install specific packages directly from your web browser. For instance, you can go to <link xlink:href="http://hydra.nixos.org/jobset/nixpkgs/trunk/channel/latest" /> and click on any link for the individual packages for your @@ -79,18 +77,18 @@ platform. Associate <literal>application/nix-package</literal> with the program <command>nix-install-package</command>. A window should appear asking you whether it’s okay to install the package. Say <literal>Y</literal>. The package and all its dependencies will be -installed.</para></listitem> +installed.</para></step> -<listitem><para>If you're unhappy with the result of a +<step><para>If you're unhappy with the result of a <command>nix-env</command> action (e.g., an upgraded package turned out not to work properly), you can go back: <screen> $ nix-env --rollback</screen> -</para></listitem> +</para></step> -<listitem><para>You should periodically run the Nix garbage collector +<step><para>You should periodically run the Nix garbage collector to get rid of unused packages, since uninstalls or upgrades don't actually delete them: @@ -103,8 +101,8 @@ rollbacks impossible, but also making the packages in those old generations available for garbage collection), while the second command actually deletes them.--> -</para></listitem> +</para></step> -</orderedlist> +</procedure> -</chapter> +</chapter> \ No newline at end of file diff --git a/doc/manual/quick-start/quick-start.xml b/doc/manual/quick-start/quick-start.xml new file mode 100644 index 000000000000..b4757cb22043 --- /dev/null +++ b/doc/manual/quick-start/quick-start.xml @@ -0,0 +1,17 @@ +<part xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="chap-quick-start"> + +<title>Quick-Start</title> + +<partintro> +<para>This section is for impatient people who don't like reading +documentation. For more in-depth information you are kindly referred +to subsequent chapters.</para> +</partintro> + +<xi:include href="getting-started.xml" /> + +</part> diff --git a/doc/manual/release-notes.xml b/doc/manual/release-notes.xml deleted file mode 100644 index f64b6cb1749b..000000000000 --- a/doc/manual/release-notes.xml +++ /dev/null @@ -1,2533 +0,0 @@ -<article xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xml:id="sec-relnotes"> - -<title>Nix Release Notes</title> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.8"><title>Release 1.8 (TBA)</title> - -<para>TODO</para> - -<itemizedlist> - - <listitem><para>Derivations can specify the new special attribute - <varname>allowedRequisites</varname>, which has a similar meaning to - <varname>allowedReferences</varname>. But instead of only enforcing - to explicitly specify the immediate references, it requires the - derivation to specify all the dependencies recursively (hence the - name, requisites) that are used by the resulting - output.</para></listitem> - -</itemizedlist> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.7"><title>Release 1.7 (April 11, 2014)</title> - -<para>In addition to the usual bug fixes, this release has the -following new features:</para> - -<itemizedlist> - - <listitem> - <para>Antiquotation is now allowed inside of quoted attribute - names (e.g. <literal>set."${foo}"</literal>). In the case where - the attribute name is just a single antiquotation, the quotes can - be dropped (e.g. the above example can be written - <literal>set.${foo}</literal>). If an attribute name inside of a - set declaration evaluates to <literal>null</literal> (e.g. - <literal>{ ${null} = false; }</literal>), then that attribute is - not added to the set.</para> - </listitem> - - <listitem> - <para>Experimental support for cryptographically signed binary - caches. See <link - xlink:href="https://github.com/NixOS/nix/commit/0fdf4da0e979f992db75cc17376e455ddc5a96d8">the - commit for details</link>.</para> - </listitem> - - <listitem> - <para>An experimental new substituter, - <command>download-via-ssh</command>, that fetches binaries from - remote machines via SSH. Specifying the flags <literal>--option - use-ssh-substituter true --option ssh-substituter-hosts - <replaceable>user@hostname</replaceable></literal> will cause Nix - to download binaries from the specified machine, if it has - them.</para> - </listitem> - - <listitem> - <para><command>nix-store -r</command> and - <command>nix-build</command> have a new flag, - <option>--check</option>, that builds a previously built - derivation again, and prints an error message if the output is not - exactly the same. This helps to verify whether a derivation is - truly deterministic. For example: - -<screen> -$ nix-build '<nixpkgs>' -A patchelf -<replaceable>…</replaceable> -$ nix-build '<nixpkgs>' -A patchelf --check -<replaceable>…</replaceable> -error: derivation `/nix/store/1ipvxs…-patchelf-0.6' may not be deterministic: - hash mismatch in output `/nix/store/4pc1dm…-patchelf-0.6.drv' -</screen> - - </para> - - </listitem> - - <listitem> - <para>The <command>nix-instantiate</command> flags - <option>--eval-only</option> and <option>--parse-only</option> - have been renamed to <option>--eval</option> and - <option>--parse</option>, respectively.</para> - </listitem> - - <listitem> - <para><command>nix-instantiate</command>, - <command>nix-build</command> and <command>nix-shell</command> now - have a flag <option>--expr</option> (or <option>-E</option>) that - allows you to specify the expression to be evaluated as a command - line argument. For instance, <literal>nix-instantiate --eval -E - '1 + 2'</literal> will print <literal>3</literal>.</para> - </listitem> - - <listitem> - <para><command>nix-shell</command> improvements:</para> - - <itemizedlist> - - <listitem> - <para>It has a new flag, <option>--packages</option> (or - <option>-p</option>), that sets up a build environment - containing the specified packages from Nixpkgs. For example, - the command - -<screen> -$ nix-shell -p sqlite xorg.libX11 hello -</screen> - - will start a shell in which the given packages are - present.</para> - </listitem> - - <listitem> - <para>It now uses <filename>shell.nix</filename> as the - default expression, falling back to - <filename>default.nix</filename> if the former doesn’t - exist. This makes it convenient to have a - <filename>shell.nix</filename> in your project to set up a - nice development environment.</para> - </listitem> - - <listitem> - <para>It evaluates the derivation attribute - <varname>shellHook</varname>, if set. Since - <literal>stdenv</literal> does not normally execute this hook, - it allows you to do <command>nix-shell</command>-specific - setup.</para> - </listitem> - - <listitem> - <para>It preserves the user’s timezone setting.</para> - </listitem> - - </itemizedlist> - - </listitem> - - <listitem> - <para>In chroots, Nix now sets up a <filename>/dev</filename> - containing only a minimal set of devices (such as - <filename>/dev/null</filename>). Note that it only does this if - you <emphasis>don’t</emphasis> have <filename>/dev</filename> - listed in your <option>build-chroot-dirs</option> setting; - otherwise, it will bind-mount the <literal>/dev</literal> from - outside the chroot.</para> - - <para>Similarly, if you don’t have <filename>/dev/pts</filename> listed - in <option>build-chroot-dirs</option>, Nix will mount a private - <literal>devpts</literal> filesystem on the chroot’s - <filename>/dev/pts</filename>.</para> - - </listitem> - - <listitem> - <para>New built-in function: <function>builtins.toJSON</function>, - which returns a JSON representation of a value.</para> - </listitem> - - <listitem> - <para><command>nix-env -q</command> has a new flag - <option>--json</option> to print a JSON representation of the - installed or available packages.</para> - </listitem> - - <listitem> - <para><command>nix-env</command> now supports meta attributes with - more complex values, such as attribute sets.</para> - </listitem> - - <listitem> - <para>The <option>-A</option> flag now allows attribute names with - dots in them, e.g. - -<screen> -$ nix-instantiate --eval '<nixos>' -A 'config.systemd.units."nscd.service".text' -</screen> - - </para> - </listitem> - - <listitem> - <para>The <option>--max-freed</option> option to - <command>nix-store --gc</command> now accepts a unit - specifier. For example, <literal>nix-store --gc --max-freed - 1G</literal> will free up to 1 gigabyte of disk space.</para> - </listitem> - - <listitem> - <para><command>nix-collect-garbage</command> has a new flag - <option>--delete-older-than</option> - <replaceable>N</replaceable><literal>d</literal>, which deletes - all user environment generations older than - <replaceable>N</replaceable> days. Likewise, <command>nix-env - --delete-generations</command> accepts a - <replaceable>N</replaceable><literal>d</literal> age limit.</para> - </listitem> - - <listitem> - <para>Nix now heuristically detects whether a build failure was - due to a disk-full condition. In that case, the build is not - flagged as “permanently failed”. This is mostly useful for Hydra, - which needs to distinguish between permanent and transient build - failures.</para> - </listitem> - - <listitem> - <para>There is a new symbol <literal>__curPos</literal> that - expands to an attribute set containing its file name and line and - column numbers, e.g. <literal>{ file = "foo.nix"; line = 10; - column = 5; }</literal>. There also is a new builtin function, - <varname>unsafeGetAttrPos</varname>, that returns the position of - an attribute. This is used by Nixpkgs to provide location - information in error messages, e.g. - -<screen> -$ nix-build '<nixpkgs>' -A libreoffice --argstr system x86_64-darwin -error: the package ‘libreoffice-4.0.5.2’ in ‘.../applications/office/libreoffice/default.nix:263’ - is not supported on ‘x86_64-darwin’ -</screen> - - </para> - </listitem> - - <listitem> - <para>The garbage collector is now more concurrent with other Nix - processes because it releases certain locks earlier.</para> - </listitem> - - <listitem> - <para>The binary tarball installer has been improved. You can now - install Nix by running: - -<screen> -$ bash <(curl https://nixos.org/nix/install) -</screen> - - </para> - </listitem> - - <listitem> - <para>More evaluation errors include position information. For - instance, selecting a missing attribute will print something like - -<screen> -error: attribute `nixUnstabl' missing, at /etc/nixos/configurations/misc/eelco/mandark.nix:216:15 -</screen> - - </para> - </listitem> - - <listitem> - <para>The command <command>nix-setuid-helper</command> is - gone.</para> - </listitem> - - <listitem> - <para>Nix no longer uses Automake, but instead has a - non-recursive, GNU Make-based build system.</para> - </listitem> - - <listitem> - <para>All installed libraries now have the prefix - <literal>libnix</literal>. In particular, this gets rid of - <literal>libutil</literal>, which could clash with libraries with - the same name from other packages.</para> - </listitem> - - <listitem> - <para>Nix now requires a compiler that supports C++11.</para> - </listitem> - -</itemizedlist> - -<para>This release has contributions from Danny Wilson, Domen Kožar, -Eelco Dolstra, Ian-Woo Kim, Ludovic Courtès, Maxim Ivanov, Petr -Rockai, Ricardo M. Correia and Shea Levy.</para> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.6.1"><title>Release 1.6.1 (October 28, 2013)</title> - -<para>This is primarily a bug fix release. Changes of interest -are:</para> - -<itemizedlist> - - <listitem> - <para>Nix 1.6 accidentally changed the semantics of antiquoted - paths in strings, such as <literal>"${/foo}/bar"</literal>. This - release reverts to the Nix 1.5.3 behaviour.</para> - </listitem> - - <listitem> - <para>Previously, Nix optimised expressions such as - <literal>"${<replaceable>expr</replaceable>}"</literal> to - <replaceable>expr</replaceable>. Thus it neither checked whether - <replaceable>expr</replaceable> could be coerced to a string, nor - applied such coercions. This meant that - <literal>"${123}"</literal> evaluatued to <literal>123</literal>, - and <literal>"${./foo}"</literal> evaluated to - <literal>./foo</literal> (even though - <literal>"${./foo} "</literal> evaluates to - <literal>"/nix/store/<replaceable>hash</replaceable>-foo "</literal>). - Nix now checks the type of antiquoted expressions and - applies coercions.</para> - </listitem> - - <listitem> - <para>Nix now shows the exact position of undefined variables. In - particular, undefined variable errors in a <literal>with</literal> - previously didn't show <emphasis>any</emphasis> position - information, so this makes it a lot easier to fix such - errors.</para> - </listitem> - - <listitem> - <para>Undefined variables are now treated consistently. - Previously, the <function>tryEval</function> function would catch - undefined variables inside a <literal>with</literal> but not - outside. Now <function>tryEval</function> never catches undefined - variables.</para> - </listitem> - - <listitem> - <para>Bash completion in <command>nix-shell</command> now works - correctly.</para> - </listitem> - - <listitem> - <para>Stack traces are less verbose: they no longer show calls to - builtin functions and only show a single line for each derivation - on the call stack.</para> - </listitem> - - <listitem> - <para>New built-in function: <function>builtins.typeOf</function>, - which returns the type of its argument as a string.</para> - </listitem> - -</itemizedlist> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.6.0"><title>Release 1.6 (September 10, 2013)</title> - -<para>In addition to the usual bug fixes, this release has several new -features:</para> - -<itemizedlist> - - <listitem> - <para>The command <command>nix-build --run-env</command> has been - renamed to <command>nix-shell</command>.</para> - </listitem> - - <listitem> - <para><command>nix-shell</command> now sources - <filename>$stdenv/setup</filename> <emphasis>inside</emphasis> the - interactive shell, rather than in a parent shell. This ensures - that shell functions defined by <literal>stdenv</literal> can be - used in the interactive shell.</para> - </listitem> - - <listitem> - <para><command>nix-shell</command> has a new flag - <option>--pure</option> to clear the environment, so you get an - environment that more closely corresponds to the “real” Nix build. - </para> - </listitem> - - <listitem> - <para><command>nix-shell</command> now sets the shell prompt - (<envar>PS1</envar>) to ensure that Nix shells are distinguishable - from your regular shells.</para> - </listitem> - - <listitem> - <para><command>nix-env</command> no longer requires a - <literal>*</literal> argument to match all packages, so - <literal>nix-env -qa</literal> is equivalent to <literal>nix-env - -qa '*'</literal>.</para> - </listitem> - - <listitem> - <para><command>nix-env -i</command> has a new flag - <option>--remove-all</option> (<option>-r</option>) to remove all - previous packages from the profile. This makes it easier to do - declarative package management similar to NixOS’s - <option>environment.systemPackages</option>. For instance, if you - have a specification <filename>my-packages.nix</filename> like this: - -<programlisting> -with import <nixpkgs> {}; -[ thunderbird - geeqie - ... -] -</programlisting> - - then after any change to this file, you can run: - -<screen> -$ nix-env -f my-packages.nix -ir -</screen> - - to update your profile to match the specification.</para> - </listitem> - - <listitem> - <para>The ‘<literal>with</literal>’ language construct is now more - lazy. It only evaluates its argument if a variable might actually - refer to an attribute in the argument. For instance, this now - works: - -<programlisting> -let - pkgs = with pkgs; { foo = "old"; bar = foo; } // overrides; - overrides = { foo = "new"; }; -in pkgs.bar -</programlisting> - - This evaluates to <literal>"new"</literal>, while previously it - gave an “infinite recursion” error.</para> - </listitem> - - <listitem> - <para>Nix now has proper integer arithmetic operators. For - instance, you can write <literal>x + y</literal> instead of - <literal>builtins.add x y</literal>, or <literal>x < - y</literal> instead of <literal>builtins.lessThan x y</literal>. - The comparison operators also work on strings.</para> - </listitem> - - <listitem> - <para>On 64-bit systems, Nix integers are now 64 bits rather than - 32 bits.</para> - </listitem> - - <listitem> - <para>When using the Nix daemon, the <command>nix-daemon</command> - worker process now runs on the same CPU as the client, on systems - that support setting CPU affinity. This gives a significant speedup - on some systems.</para> - </listitem> - - <listitem> - <para>If a stack overflow occurs in the Nix evaluator, you now get - a proper error message (rather than “Segmentation fault”) on some - systems.</para> - </listitem> - - <listitem> - <para>In addition to directories, you can now bind-mount regular - files in chroots through the (now misnamed) option - <option>build-chroot-dirs</option>.</para> - </listitem> - -</itemizedlist> - -<para>This release has contributions from Domen Kožar, Eelco Dolstra, -Florian Friesdorf, Gergely Risko, Ivan Kozik, Ludovic Courtès and Shea -Levy.</para> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.5.3"><title>Release 1.5.3 (June 17, 2013)</title> - -<para>This is primarily a bug fix release. The following changes are -noteworthy:</para> - -<itemizedlist> - - <listitem> - <para>Yet another security bug involving hard links to files - outside the store was fixed. This bug only affected multi-user - installations that do not have hard link restrictions - enabled. (NixOS is thus not vulnerable.)</para> - </listitem> - - <listitem> - <para>The default binary cache URL has changed from - <uri>http://nixos.org/binary-cache</uri> to - <uri>http://cache.nixos.org</uri>. The latter is hosted on Amazon - CloudFront (courtesy of <link - xlink:href="http://www.logicblox.com/">LogicBlox</link>) and - should provide better performance for users in both Europe and - North America.</para> - </listitem> - - <listitem> - <para>The binary cache substituter now prints a warning message if - fetching information from the cache takes more than five seconds. - Thus network or server problems no longer make Nix appear to just - hang.</para> - </listitem> - - <listitem> - <para>Stack traces now show function names, e.g. -<screen> -while evaluating `concatMapStrings' at `<replaceable>...</replaceable>/nixpkgs/pkgs/lib/strings.nix:18:25': -</screen> - Also, if a function is called with an unexpected argument, Nix - now shows the name of the argument. - </para> - </listitem> - -</itemizedlist> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.5.2"><title>Release 1.5.2 (May 13, 2013)</title> - -<para>This is primarily a bug fix release. It has contributions from -Eelco Dolstra, Lluís Batlle i Rossell and Shea Levy.</para> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.5.1"><title>Release 1.5.1 (February 28, 2013)</title> - -<para>The bug fix to the bug fix had a bug itself, of course. But -this time it will work for sure!</para> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.5"><title>Release 1.5 (February 27, 2013)</title> - -<para>This is a brown paper bag release to fix a regression introduced -by the hard link security fix in 1.4.</para> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.4"><title>Release 1.4 (February 26, 2013)</title> - -<para>This release fixes a security bug in multi-user operation. It -was possible for derivations to cause the mode of files outside of the -Nix store to be changed to 444 (read-only but world-readable) by -creating hard links to those files (<link -xlink:href="https://github.com/NixOS/nix/commit/5526a282b5b44e9296e61e07d7d2626a79141ac4">details</link>).</para> - -<para>There are also the following improvements:</para> - -<itemizedlist> - - <listitem><para>New built-in function: - <function>builtins.hashString</function>.</para></listitem> - - <listitem><para>Build logs are now stored in - <filename>/nix/var/log/nix/drvs/<replaceable>XX</replaceable>/</filename>, - where <replaceable>XX</replaceable> is the first two characters of - the derivation. This is useful on machines that keep a lot of build - logs (such as Hydra servers).</para></listitem> - - <listitem><para>The function <function>corepkgs/fetchurl</function> - can now make the downloaded file executable. This will allow - getting rid of all bootstrap binaries in the Nixpkgs source - tree.</para></listitem> - - <listitem><para>Language change: The expression <literal>"${./path} - ..."</literal> now evaluates to a string instead of a - path.</para></listitem> - -</itemizedlist> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.3"><title>Release 1.3 (January 4, 2013)</title> - -<para>This is primarily a bug fix release. When this version is first -run on Linux, it removes any immutable bits from the Nix store and -increases the schema version of the Nix store. (The previous release -removed support for setting the immutable bit; this release clears any -remaining immutable bits to make certain operations more -efficient.)</para> - -<para>This release has contributions from Eelco Dolstra and Stuart -Pernsteiner.</para> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.2"><title>Release 1.2 (December 6, 2012)</title> - -<para>This release has the following improvements and changes:</para> - -<itemizedlist> - - <listitem> - <para>Nix has a new binary substituter mechanism: the - <emphasis>binary cache</emphasis>. A binary cache contains - pre-built binaries of Nix packages. Whenever Nix wants to build a - missing Nix store path, it will check a set of binary caches to - see if any of them has a pre-built binary of that path. The - configuration setting <option>binary-caches</option> contains a - list of URLs of binary caches. For instance, doing -<screen> -$ nix-env -i thunderbird --option binary-caches http://cache.nixos.org -</screen> - will install Thunderbird and its dependencies, using the available - pre-built binaries in <uri>http://cache.nixos.org</uri>. - The main advantage over the old “manifest”-based method of getting - pre-built binaries is that you don’t have to worry about your - manifest being in sync with the Nix expressions you’re installing - from; i.e., you don’t need to run <command>nix-pull</command> to - update your manifest. It’s also more scalable because you don’t - need to redownload a giant manifest file every time. - </para> - - <para>A Nix channel can provide a binary cache URL that will be - used automatically if you subscribe to that channel. If you use - the Nixpkgs or NixOS channels - (<uri>http://nixos.org/channels</uri>) you automatically get the - cache <uri>http://cache.nixos.org</uri>.</para> - - <para>Binary caches are created using <command>nix-push</command>. - For details on the operation and format of binary caches, see the - <command>nix-push</command> manpage. More details are provided in - <link xlink:href="http://lists.science.uu.nl/pipermail/nix-dev/2012-September/009826.html">this - nix-dev posting</link>.</para> - </listitem> - - <listitem> - <para>Multiple output support should now be usable. A derivation - can declare that it wants to produce multiple store paths by - saying something like -<programlisting> -outputs = [ "lib" "headers" "doc" ]; -</programlisting> - This will cause Nix to pass the intended store path of each output - to the builder through the environment variables - <literal>lib</literal>, <literal>headers</literal> and - <literal>doc</literal>. Other packages can refer to a specific - output by referring to - <literal><replaceable>pkg</replaceable>.<replaceable>output</replaceable></literal>, - e.g. -<programlisting> -buildInputs = [ pkg.lib pkg.headers ]; -</programlisting> - If you install a package with multiple outputs using - <command>nix-env</command>, each output path will be symlinked - into the user environment.</para> - </listitem> - - <listitem> - <para>Dashes are now valid as part of identifiers and attribute - names.</para> - </listitem> - - <listitem> - <para>The new operation <command>nix-store --repair-path</command> - allows corrupted or missing store paths to be repaired by - redownloading them. <command>nix-store --verify --check-contents - --repair</command> will scan and repair all paths in the Nix - store. Similarly, <command>nix-env</command>, - <command>nix-build</command>, <command>nix-instantiate</command> - and <command>nix-store --realise</command> have a - <option>--repair</option> flag to detect and fix bad paths by - rebuilding or redownloading them.</para> - </listitem> - - <listitem> - <para>Nix no longer sets the immutable bit on files in the Nix - store. Instead, the recommended way to guard the Nix store - against accidental modification on Linux is to make it a read-only - bind mount, like this: - -<screen> -$ mount --bind /nix/store /nix/store -$ mount -o remount,ro,bind /nix/store -</screen> - - Nix will automatically make <filename>/nix/store</filename> - writable as needed (using a private mount namespace) to allow - modifications.</para> - </listitem> - - <listitem> - <para>Store optimisation (replacing identical files in the store - with hard links) can now be done automatically every time a path - is added to the store. This is enabled by setting the - configuration option <literal>auto-optimise-store</literal> to - <literal>true</literal> (disabled by default).</para> - </listitem> - - <listitem> - <para>Nix now supports <command>xz</command> compression for NARs - in addition to <command>bzip2</command>. It compresses about 30% - better on typical archives and decompresses about twice as - fast.</para> - </listitem> - - <listitem> - <para>Basic Nix expression evaluation profiling: setting the - environment variable <envar>NIX_COUNT_CALLS</envar> to - <literal>1</literal> will cause Nix to print how many times each - primop or function was executed.</para> - </listitem> - - <listitem> - <para>New primops: <varname>concatLists</varname>, - <varname>elem</varname>, <varname>elemAt</varname> and - <varname>filter</varname>.</para> - </listitem> - - <listitem> - <para>The command <command>nix-copy-closure</command> has a new - flag <option>--use-substitutes</option> (<option>-s</option>) to - download missing paths on the target machine using the substitute - mechanism.</para> - </listitem> - - <listitem> - <para>The command <command>nix-worker</command> has been renamed - to <command>nix-daemon</command>. Support for running the Nix - worker in “slave” mode has been removed.</para> - </listitem> - - <listitem> - <para>The <option>--help</option> flag of every Nix command now - invokes <command>man</command>.</para> - </listitem> - - <listitem> - <para>Chroot builds are now supported on systemd machines.</para> - </listitem> - -</itemizedlist> - -<para>This release has contributions from Eelco Dolstra, Florian -Friesdorf, Mats Erik Andersson and Shea Levy.</para> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.1"><title>Release 1.1 (July 18, 2012)</title> - -<para>This release has the following improvements:</para> - -<itemizedlist> - - <listitem> - <para>On Linux, when doing a chroot build, Nix now uses various - namespace features provided by the Linux kernel to improve - build isolation. Namely: - <itemizedlist> - <listitem><para>The private network namespace ensures that - builders cannot talk to the outside world (or vice versa): each - build only sees a private loopback interface. This also means - that two concurrent builds can listen on the same port (e.g. as - part of a test) without conflicting with each - other.</para></listitem> - <listitem><para>The PID namespace causes each build to start as - PID 1. Processes outside of the chroot are not visible to those - on the inside. On the other hand, processes inside the chroot - <emphasis>are</emphasis> visible from the outside (though with - different PIDs).</para></listitem> - <listitem><para>The IPC namespace prevents the builder from - communicating with outside processes using SysV IPC mechanisms - (shared memory, message queues, semaphores). It also ensures - that all IPC objects are destroyed when the builder - exits.</para></listitem> - <listitem><para>The UTS namespace ensures that builders see a - hostname of <literal>localhost</literal> rather than the actual - hostname.</para></listitem> - <listitem><para>The private mount namespace was already used by - Nix to ensure that the bind-mounts used to set up the chroot are - cleaned up automatically.</para></listitem> - </itemizedlist> - </para> - </listitem> - - <listitem> - <para>Build logs are now compressed using - <command>bzip2</command>. The command <command>nix-store - -l</command> decompresses them on the fly. This can be disabled - by setting the option <literal>build-compress-log</literal> to - <literal>false</literal>.</para> - </listitem> - - <listitem> - <para>The creation of build logs in - <filename>/nix/var/log/nix/drvs</filename> can be disabled by - setting the new option <literal>build-keep-log</literal> to - <literal>false</literal>. This is useful, for instance, for Hydra - build machines.</para> - </listitem> - - <listitem> - <para>Nix now reserves some space in - <filename>/nix/var/nix/db/reserved</filename> to ensure that the - garbage collector can run successfully if the disk is full. This - is necessary because SQLite transactions fail if the disk is - full.</para> - </listitem> - - <listitem> - <para>Added a basic <function>fetchurl</function> function. This - is not intended to replace the <function>fetchurl</function> in - Nixpkgs, but is useful for bootstrapping; e.g., it will allow us - to get rid of the bootstrap binaries in the Nixpkgs source tree - and download them instead. You can use it by doing - <literal>import <nix/fetchurl.nix> { url = - <replaceable>url</replaceable>; sha256 = - "<replaceable>hash</replaceable>"; }</literal>. (Shea Levy)</para> - </listitem> - - <listitem> - <para>Improved RPM spec file. (Michel Alexandre Salim)</para> - </listitem> - - <listitem> - <para>Support for on-demand socket-based activation in the Nix - daemon with <command>systemd</command>.</para> - </listitem> - - <listitem> - <para>Added a manpage for - <citerefentry><refentrytitle>nix.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> - </listitem> - - <listitem> - <para>When using the Nix daemon, the <option>-s</option> flag in - <command>nix-env -qa</command> is now much faster.</para> - </listitem> - -</itemizedlist> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-1.0"><title>Release 1.0 (May 11, 2012)</title> - -<para>There have been numerous improvements and bug fixes since the -previous release. Here are the most significant:</para> - -<itemizedlist> - - <listitem> - <para>Nix can now optionally use the Boehm garbage collector. - This significantly reduces the Nix evaluator’s memory footprint, - especially when evaluating large NixOS system configurations. It - can be enabled using the <option>--enable-gc</option> configure - option.</para> - </listitem> - - <listitem> - <para>Nix now uses SQLite for its database. This is faster and - more flexible than the old <emphasis>ad hoc</emphasis> format. - SQLite is also used to cache the manifests in - <filename>/nix/var/nix/manifests</filename>, resulting in a - significant speedup.</para> - </listitem> - - <listitem> - <para>Nix now has an search path for expressions. The search path - is set using the environment variable <envar>NIX_PATH</envar> and - the <option>-I</option> command line option. In Nix expressions, - paths between angle brackets are used to specify files that must - be looked up in the search path. For instance, the expression - <literal><nixpkgs/default.nix></literal> looks for a file - <filename>nixpkgs/default.nix</filename> relative to every element - in the search path.</para> - </listitem> - - <listitem> - <para>The new command <command>nix-build --run-env</command> - builds all dependencies of a derivation, then starts a shell in an - environment containing all variables from the derivation. This is - useful for reproducing the environment of a derivation for - development.</para> - </listitem> - - <listitem> - <para>The new command <command>nix-store --verify-path</command> - verifies that the contents of a store path have not - changed.</para> - </listitem> - - <listitem> - <para>The new command <command>nix-store --print-env</command> - prints out the environment of a derivation in a format that can be - evaluated by a shell.</para> - </listitem> - - <listitem> - <para>Attribute names can now be arbitrary strings. For instance, - you can write <literal>{ "foo-1.2" = …; "bla bla" = …; }."bla - bla"</literal>.</para> - </listitem> - - <listitem> - <para>Attribute selection can now provide a default value using - the <literal>or</literal> operator. For instance, the expression - <literal>x.y.z or e</literal> evaluates to the attribute - <literal>x.y.z</literal> if it exists, and <literal>e</literal> - otherwise.</para> - </listitem> - - <listitem> - <para>The right-hand side of the <literal>?</literal> operator can - now be an attribute path, e.g., <literal>attrs ? - a.b.c</literal>.</para> - </listitem> - - <listitem> - <para>On Linux, Nix will now make files in the Nix store immutable - on filesystems that support it. This prevents accidental - modification of files in the store by the root user.</para> - </listitem> - - <listitem> - <para>Nix has preliminary support for derivations with multiple - outputs. This is useful because it allows parts of a package to - be deployed and garbage-collected separately. For instance, - development parts of a package such as header files or static - libraries would typically not be part of the closure of an - application, resulting in reduced disk usage and installation - time.</para> - </listitem> - - <listitem> - <para>The Nix store garbage collector is faster and holds the - global lock for a shorter amount of time.</para> - </listitem> - - <listitem> - <para>The option <option>--timeout</option> (corresponding to the - configuration setting <literal>build-timeout</literal>) allows you - to set an absolute timeout on builds — if a build runs for more than - the given number of seconds, it is terminated. This is useful for - recovering automatically from builds that are stuck in an infinite - loop but keep producing output, and for which - <literal>--max-silent-time</literal> is ineffective.</para> - </listitem> - - <listitem> - <para>Nix development has moved to GitHub (<link - xlink:href="https://github.com/NixOS/nix" />).</para> - </listitem> - -</itemizedlist> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-0.16"><title>Release 0.16 (August 17, 2010)</title> - -<para>This release has the following improvements:</para> - -<itemizedlist> - - <listitem> - <para>The Nix expression evaluator is now much faster in most - cases: typically, <link - xlink:href="http://www.mail-archive.com/nix-dev@cs.uu.nl/msg04113.html">3 - to 8 times compared to the old implementation</link>. It also - uses less memory. It no longer depends on the ATerm - library.</para> - </listitem> - - <listitem> - <para> - Support for configurable parallelism inside builders. Build - scripts have always had the ability to perform multiple build - actions in parallel (for instance, by running <command>make -j - 2</command>), but this was not desirable because the number of - actions to be performed in parallel was not configurable. Nix - now has an option <option>--cores - <replaceable>N</replaceable></option> as well as a configuration - setting <varname>build-cores = - <replaceable>N</replaceable></varname> that causes the - environment variable <envar>NIX_BUILD_CORES</envar> to be set to - <replaceable>N</replaceable> when the builder is invoked. The - builder can use this at its discretion to perform a parallel - build, e.g., by calling <command>make -j - <replaceable>N</replaceable></command>. In Nixpkgs, this can be - enabled on a per-package basis by setting the derivation - attribute <varname>enableParallelBuilding</varname> to - <literal>true</literal>. - </para> - </listitem> - - <listitem> - <para><command>nix-store -q</command> now supports XML output - through the <option>--xml</option> flag.</para> - </listitem> - - <listitem> - <para>Several bug fixes.</para> - </listitem> - -</itemizedlist> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-0.15"><title>Release 0.15 (March 17, 2010)</title> - -<para>This is a bug-fix release. Among other things, it fixes -building on Mac OS X (Snow Leopard), and improves the contents of -<filename>/etc/passwd</filename> and <filename>/etc/group</filename> -in <literal>chroot</literal> builds.</para> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-0.14"><title>Release 0.14 (February 4, 2010)</title> - -<para>This release has the following improvements:</para> - -<itemizedlist> - - <listitem> - <para>The garbage collector now starts deleting garbage much - faster than before. It no longer determines liveness of all paths - in the store, but does so on demand.</para> - </listitem> - - <listitem> - <para>Added a new operation, <command>nix-store --query - --roots</command>, that shows the garbage collector roots that - directly or indirectly point to the given store paths.</para> - </listitem> - - <listitem> - <para>Removed support for converting Berkeley DB-based Nix - databases to the new schema.</para> - </listitem> - - <listitem> - <para>Removed the <option>--use-atime</option> and - <option>--max-atime</option> garbage collector options. They were - not very useful in practice.</para> - </listitem> - - <listitem> - <para>On Windows, Nix now requires Cygwin 1.7.x.</para> - </listitem> - - <listitem> - <para>A few bug fixes.</para> - </listitem> - -</itemizedlist> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-0.13"><title>Release 0.13 (November 5, -2009)</title> - -<para>This is primarily a bug fix release. It has some new -features:</para> - -<itemizedlist> - - <listitem> - <para>Syntactic sugar for writing nested attribute sets. Instead of - -<programlisting> -{ - foo = { - bar = 123; - xyzzy = true; - }; - a = { b = { c = "d"; }; }; -} -</programlisting> - - you can write - -<programlisting> -{ - foo.bar = 123; - foo.xyzzy = true; - a.b.c = "d"; -} -</programlisting> - - This is useful, for instance, in NixOS configuration files.</para> - - </listitem> - - <listitem> - <para>Support for Nix channels generated by Hydra, the Nix-based - continuous build system. (Hydra generates NAR archives on the - fly, so the size and hash of these archives isn’t known in - advance.)</para> - </listitem> - - <listitem> - <para>Support <literal>i686-linux</literal> builds directly on - <literal>x86_64-linux</literal> Nix installations. This is - implemented using the <function>personality()</function> syscall, - which causes <command>uname</command> to return - <literal>i686</literal> in child processes.</para> - </listitem> - - <listitem> - <para>Various improvements to the <literal>chroot</literal> - support. Building in a <literal>chroot</literal> works quite well - now.</para> - </listitem> - - <listitem> - <para>Nix no longer blocks if it tries to build a path and another - process is already building the same path. Instead it tries to - build another buildable path first. This improves - parallelism.</para> - </listitem> - - <listitem> - <para>Support for large (> 4 GiB) files in NAR archives.</para> - </listitem> - - <listitem> - <para>Various (performance) improvements to the remote build - mechanism.</para> - </listitem> - - <listitem> - <para>New primops: <varname>builtins.addErrorContext</varname> (to - add a string to stack traces — useful for debugging), - <varname>builtins.isBool</varname>, - <varname>builtins.isString</varname>, - <varname>builtins.isInt</varname>, - <varname>builtins.intersectAttrs</varname>.</para> - </listitem> - - <listitem> - <para>OpenSolaris support (Sander van der Burg).</para> - </listitem> - - <listitem> - <para>Stack traces are no longer displayed unless the - <option>--show-trace</option> option is used.</para> - </listitem> - - <listitem> - <para>The scoping rules for <literal>inherit - (<replaceable>e</replaceable>) ...</literal> in recursive - attribute sets have changed. The expression - <replaceable>e</replaceable> can now refer to the attributes - defined in the containing set.</para> - </listitem> - -</itemizedlist> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-0.12"><title>Release 0.12 (November 20, -2008)</title> - -<itemizedlist> - - <listitem> - <para>Nix no longer uses Berkeley DB to store Nix store metadata. - The principal advantages of the new storage scheme are: it works - properly over decent implementations of NFS (allowing Nix stores - to be shared between multiple machines); no recovery is needed - when a Nix process crashes; no write access is needed for - read-only operations; no more running out of Berkeley DB locks on - certain operations.</para> - - <para>You still need to compile Nix with Berkeley DB support if - you want Nix to automatically convert your old Nix store to the - new schema. If you don’t need this, you can build Nix with the - <filename>configure</filename> option - <option>--disable-old-db-compat</option>.</para> - - <para>After the automatic conversion to the new schema, you can - delete the old Berkeley DB files: - - <screen> -$ cd /nix/var/nix/db -$ rm __db* log.* derivers references referrers reserved validpaths DB_CONFIG</screen> - - The new metadata is stored in the directories - <filename>/nix/var/nix/db/info</filename> and - <filename>/nix/var/nix/db/referrer</filename>. Though the - metadata is stored in human-readable plain-text files, they are - not intended to be human-editable, as Nix is rather strict about - the format.</para> - - <para>The new storage schema may or may not require less disk - space than the Berkeley DB environment, mostly depending on the - cluster size of your file system. With 1 KiB clusters (which - seems to be the <literal>ext3</literal> default nowadays) it - usually takes up much less space.</para> - </listitem> - - <listitem><para>There is a new substituter that copies paths - directly from other (remote) Nix stores mounted somewhere in the - filesystem. For instance, you can speed up an installation by - mounting some remote Nix store that already has the packages in - question via NFS or <literal>sshfs</literal>. The environment - variable <envar>NIX_OTHER_STORES</envar> specifies the locations of - the remote Nix directories, - e.g. <literal>/mnt/remote-fs/nix</literal>.</para></listitem> - - <listitem><para>New <command>nix-store</command> operations - <option>--dump-db</option> and <option>--load-db</option> to dump - and reload the Nix database.</para></listitem> - - <listitem><para>The garbage collector has a number of new options to - allow only some of the garbage to be deleted. The option - <option>--max-freed <replaceable>N</replaceable></option> tells the - collector to stop after at least <replaceable>N</replaceable> bytes - have been deleted. The option <option>--max-links - <replaceable>N</replaceable></option> tells it to stop after the - link count on <filename>/nix/store</filename> has dropped below - <replaceable>N</replaceable>. This is useful for very large Nix - stores on filesystems with a 32000 subdirectories limit (like - <literal>ext3</literal>). The option <option>--use-atime</option> - causes store paths to be deleted in order of ascending last access - time. This allows non-recently used stuff to be deleted. The - option <option>--max-atime <replaceable>time</replaceable></option> - specifies an upper limit to the last accessed time of paths that may - be deleted. For instance, - - <screen> - $ nix-store --gc -v --max-atime $(date +%s -d "2 months ago")</screen> - - deletes everything that hasn’t been accessed in two months.</para></listitem> - - <listitem><para><command>nix-env</command> now uses optimistic - profile locking when performing an operation like installing or - upgrading, instead of setting an exclusive lock on the profile. - This allows multiple <command>nix-env -i / -u / -e</command> - operations on the same profile in parallel. If a - <command>nix-env</command> operation sees at the end that the profile - was changed in the meantime by another process, it will just - restart. This is generally cheap because the build results are - still in the Nix store.</para></listitem> - - <listitem><para>The option <option>--dry-run</option> is now - supported by <command>nix-store -r</command> and - <command>nix-build</command>.</para></listitem> - - <listitem><para>The information previously shown by - <option>--dry-run</option> (i.e., which derivations will be built - and which paths will be substituted) is now always shown by - <command>nix-env</command>, <command>nix-store -r</command> and - <command>nix-build</command>. The total download size of - substitutable paths is now also shown. For instance, a build will - show something like - - <screen> -the following derivations will be built: - /nix/store/129sbxnk5n466zg6r1qmq1xjv9zymyy7-activate-configuration.sh.drv - /nix/store/7mzy971rdm8l566ch8hgxaf89x7lr7ik-upstart-jobs.drv - ... -the following paths will be downloaded/copied (30.02 MiB): - /nix/store/4m8pvgy2dcjgppf5b4cj5l6wyshjhalj-samba-3.2.4 - /nix/store/7h1kwcj29ip8vk26rhmx6bfjraxp0g4l-libunwind-0.98.6 - ...</screen> - - </para></listitem> - - <listitem><para>Language features: - - <itemizedlist> - - <listitem><para>@-patterns as in Haskell. For instance, in a - function definition - - <programlisting>f = args @ {x, y, z}: <replaceable>...</replaceable>;</programlisting> - - <varname>args</varname> refers to the argument as a whole, which - is further pattern-matched against the attribute set pattern - <literal>{x, y, z}</literal>.</para></listitem> - - <listitem><para>“<literal>...</literal>” (ellipsis) patterns. - An attribute set pattern can now say <literal>...</literal> at - the end of the attribute name list to specify that the function - takes <emphasis>at least</emphasis> the listed attributes, while - ignoring additional attributes. For instance, - - <programlisting>{stdenv, fetchurl, fuse, ...}: <replaceable>...</replaceable></programlisting> - - defines a function that accepts any attribute set that includes - at least the three listed attributes.</para></listitem> - - <listitem><para>New primops: - <varname>builtins.parseDrvName</varname> (split a package name - string like <literal>"nix-0.12pre12876"</literal> into its name - and version components, e.g. <literal>"nix"</literal> and - <literal>"0.12pre12876"</literal>), - <varname>builtins.compareVersions</varname> (compare two version - strings using the same algorithm that <command>nix-env</command> - uses), <varname>builtins.length</varname> (efficiently compute - the length of a list), <varname>builtins.mul</varname> (integer - multiplication), <varname>builtins.div</varname> (integer - division). - <!-- <varname>builtins.genericClosure</varname> --> - </para></listitem> - - </itemizedlist> - - </para></listitem> - - <listitem><para><command>nix-prefetch-url</command> now supports - <literal>mirror://</literal> URLs, provided that the environment - variable <envar>NIXPKGS_ALL</envar> points at a Nixpkgs - tree.</para></listitem> - - <listitem><para>Removed the commands - <command>nix-pack-closure</command> and - <command>nix-unpack-closure</command>. You can do almost the same - thing but much more efficiently by doing <literal>nix-store --export - $(nix-store -qR <replaceable>paths</replaceable>) > closure</literal> and - <literal>nix-store --import < - closure</literal>.</para></listitem> - - <listitem><para>Lots of bug fixes, including a big performance bug in - the handling of <literal>with</literal>-expressions.</para></listitem> - -</itemizedlist> - -</section> - - -<!--==================================================================--> - -<section xml:id="ssec-relnotes-0.11"><title>Release 0.11 (December 31, -2007)</title> - -<para>Nix 0.11 has many improvements over the previous stable release. -The most important improvement is secure multi-user support. It also -features many usability enhancements and language extensions, many of -them prompted by NixOS, the purely functional Linux distribution based -on Nix. Here is an (incomplete) list:</para> - - -<itemizedlist> - - - <listitem><para>Secure multi-user support. A single Nix store can - now be shared between multiple (possible untrusted) users. This is - an important feature for NixOS, where it allows non-root users to - install software. The old setuid method for sharing a store between - multiple users has been removed. Details for setting up a - multi-user store can be found in the manual.</para></listitem> - - - <listitem><para>The new command <command>nix-copy-closure</command> - gives you an easy and efficient way to exchange software between - machines. It copies the missing parts of the closure of a set of - store path to or from a remote machine via - <command>ssh</command>.</para></listitem> - - - <listitem><para>A new kind of string literal: strings between double - single-quotes (<literal>''</literal>) have indentation - “intelligently” removed. This allows large strings (such as shell - scripts or configuration file fragments in NixOS) to cleanly follow - the indentation of the surrounding expression. It also requires - much less escaping, since <literal>''</literal> is less common in - most languages than <literal>"</literal>.</para></listitem> - - - <listitem><para><command>nix-env</command> <option>--set</option> - modifies the current generation of a profile so that it contains - exactly the specified derivation, and nothing else. For example, - <literal>nix-env -p /nix/var/nix/profiles/browser --set - firefox</literal> lets the profile named - <filename>browser</filename> contain just Firefox.</para></listitem> - - - <listitem><para><command>nix-env</command> now maintains - meta-information about installed packages in profiles. The - meta-information is the contents of the <varname>meta</varname> - attribute of derivations, such as <varname>description</varname> or - <varname>homepage</varname>. The command <literal>nix-env -q --xml - --meta</literal> shows all meta-information.</para></listitem> - - - <listitem><para><command>nix-env</command> now uses the - <varname>meta.priority</varname> attribute of derivations to resolve - filename collisions between packages. Lower priority values denote - a higher priority. For instance, the GCC wrapper package and the - Binutils package in Nixpkgs both have a file - <filename>bin/ld</filename>, so previously if you tried to install - both you would get a collision. Now, on the other hand, the GCC - wrapper declares a higher priority than Binutils, so the former’s - <filename>bin/ld</filename> is symlinked in the user - environment.</para></listitem> - - - <listitem><para><command>nix-env -i / -u</command>: instead of - breaking package ties by version, break them by priority and version - number. That is, if there are multiple packages with the same name, - then pick the package with the highest priority, and only use the - version if there are multiple packages with the same - priority.</para> - - <para>This makes it possible to mark specific versions/variant in - Nixpkgs more or less desirable than others. A typical example would - be a beta version of some package (e.g., - <literal>gcc-4.2.0rc1</literal>) which should not be installed even - though it is the highest version, except when it is explicitly - selected (e.g., <literal>nix-env -i - gcc-4.2.0rc1</literal>).</para></listitem> - - - <listitem><para><command>nix-env --set-flag</command> allows meta - attributes of installed packages to be modified. There are several - attributes that can be usefully modified, because they affect the - behaviour of <command>nix-env</command> or the user environment - build script: - - <itemizedlist> - - <listitem><para><varname>meta.priority</varname> can be changed - to resolve filename clashes (see above).</para></listitem> - - <listitem><para><varname>meta.keep</varname> can be set to - <literal>true</literal> to prevent the package from being - upgraded or replaced. Useful if you want to hang on to an older - version of a package.</para></listitem> - - <listitem><para><varname>meta.active</varname> can be set to - <literal>false</literal> to “disable” the package. That is, no - symlinks will be generated to the files of the package, but it - remains part of the profile (so it won’t be garbage-collected). - Set it back to <literal>true</literal> to re-enable the - package.</para></listitem> - - </itemizedlist> - - </para></listitem> - - - <listitem><para><command>nix-env -q</command> now has a flag - <option>--prebuilt-only</option> (<option>-b</option>) that causes - <command>nix-env</command> to show only those derivations whose - output is already in the Nix store or that can be substituted (i.e., - downloaded from somewhere). In other words, it shows the packages - that can be installed “quickly”, i.e., don’t need to be built from - source. The <option>-b</option> flag is also available in - <command>nix-env -i</command> and <command>nix-env -u</command> to - filter out derivations for which no pre-built binary is - available.</para></listitem> - - - <listitem><para>The new option <option>--argstr</option> (in - <command>nix-env</command>, <command>nix-instantiate</command> and - <command>nix-build</command>) is like <option>--arg</option>, except - that the value is a string. For example, <literal>--argstr system - i686-linux</literal> is equivalent to <literal>--arg system - \"i686-linux\"</literal> (note that <option>--argstr</option> - prevents annoying quoting around shell arguments).</para></listitem> - - - <listitem><para><command>nix-store</command> has a new operation - <option>--read-log</option> (<option>-l</option>) - <parameter>paths</parameter> that shows the build log of the given - paths.</para></listitem> - - - <!-- - <listitem><para>TODO: semantic cleanups of string concatenation - etc. (mostly in r6740).</para></listitem> - --> - - - <listitem><para>Nix now uses Berkeley DB 4.5. The database is - upgraded automatically, but you should be careful not to use old - versions of Nix that still use Berkeley DB 4.4.</para></listitem> - - - <!-- foo - <listitem><para>TODO: option <option>- -reregister</option> in - <command>nix-store - -register-validity</command>.</para></listitem> - --> - - - <listitem><para>The option <option>--max-silent-time</option> - (corresponding to the configuration setting - <literal>build-max-silent-time</literal>) allows you to set a - timeout on builds — if a build produces no output on - <literal>stdout</literal> or <literal>stderr</literal> for the given - number of seconds, it is terminated. This is useful for recovering - automatically from builds that are stuck in an infinite - loop.</para></listitem> - - - <listitem><para><command>nix-channel</command>: each subscribed - channel is its own attribute in the top-level expression generated - for the channel. This allows disambiguation (e.g. <literal>nix-env - -i -A nixpkgs_unstable.firefox</literal>).</para></listitem> - - - <listitem><para>The substitutes table has been removed from the - database. This makes operations such as <command>nix-pull</command> - and <command>nix-channel --update</command> much, much - faster.</para></listitem> - - - <listitem><para><command>nix-pull</command> now supports - bzip2-compressed manifests. This speeds up - channels.</para></listitem> - - - <listitem><para><command>nix-prefetch-url</command> now has a - limited form of caching. This is used by - <command>nix-channel</command> to prevent unnecessary downloads when - the channel hasn’t changed.</para></listitem> - - - <listitem><para><command>nix-prefetch-url</command> now by default - computes the SHA-256 hash of the file instead of the MD5 hash. In - calls to <function>fetchurl</function> you should pass the - <literal>sha256</literal> attribute instead of - <literal>md5</literal>. You can pass either a hexadecimal or a - base-32 encoding of the hash.</para></listitem> - - - <listitem><para>Nix can now perform builds in an automatically - generated “chroot”. This prevents a builder from accessing stuff - outside of the Nix store, and thus helps ensure purity. This is an - experimental feature.</para></listitem> - - - <listitem><para>The new command <command>nix-store - --optimise</command> reduces Nix store disk space usage by finding - identical files in the store and hard-linking them to each other. - It typically reduces the size of the store by something like - 25-35%.</para></listitem> - - - <listitem><para><filename>~/.nix-defexpr</filename> can now be a - directory, in which case the Nix expressions in that directory are - combined into an attribute set, with the file names used as the - names of the attributes. The command <command>nix-env - --import</command> (which set the - <filename>~/.nix-defexpr</filename> symlink) is - removed.</para></listitem> - - - <listitem><para>Derivations can specify the new special attribute - <varname>allowedReferences</varname> to enforce that the references - in the output of a derivation are a subset of a declared set of - paths. For example, if <varname>allowedReferences</varname> is an - empty list, then the output must not have any references. This is - used in NixOS to check that generated files such as initial ramdisks - for booting Linux don’t have any dependencies.</para></listitem> - - - <listitem><para>The new attribute - <varname>exportReferencesGraph</varname> allows builders access to - the references graph of their inputs. This is used in NixOS for - tasks such as generating ISO-9660 images that contain a Nix store - populated with the closure of certain paths.</para></listitem> - - - <listitem><para>Fixed-output derivations (like - <function>fetchurl</function>) can define the attribute - <varname>impureEnvVars</varname> to allow external environment - variables to be passed to builders. This is used in Nixpkgs to - support proxy configuration, among other things.</para></listitem> - - - <listitem><para>Several new built-in functions: - <function>builtins.attrNames</function>, - <function>builtins.filterSource</function>, - <function>builtins.isAttrs</function>, - <function>builtins.isFunction</function>, - <function>builtins.listToAttrs</function>, - <function>builtins.stringLength</function>, - <function>builtins.sub</function>, - <function>builtins.substring</function>, - <function>throw</function>, - <function>builtins.trace</function>, - <function>builtins.readFile</function>.</para></listitem> - - -</itemizedlist> - -</section> - - - -<!--==================================================================--> - -<section><title>Release 0.10.1 (October 11, 2006)</title> - -<para>This release fixes two somewhat obscure bugs that occur when -evaluating Nix expressions that are stored inside the Nix store -(<literal>NIX-67</literal>). These do not affect most users.</para> - -</section> - - - -<!--==================================================================--> - -<section><title>Release 0.10 (October 6, 2006)</title> - -<note><para>This version of Nix uses Berkeley DB 4.4 instead of 4.3. -The database is upgraded automatically, but you should be careful not -to use old versions of Nix that still use Berkeley DB 4.3. In -particular, if you use a Nix installed through Nix, you should run - -<screen> -$ nix-store --clear-substitutes</screen> - -first.</para></note> - -<warning><para>Also, the database schema has changed slighted to fix a -performance issue (see below). When you run any Nix 0.10 command for -the first time, the database will be upgraded automatically. This is -irreversible.</para></warning> - -<itemizedlist> - - - <!-- Usability / features --> - - - <listitem><para><command>nix-env</command> usability improvements: - - <itemizedlist> - - <listitem><para>An option <option>--compare-versions</option> - (or <option>-c</option>) has been added to <command>nix-env - --query</command> to allow you to compare installed versions of - packages to available versions, or vice versa. An easy way to - see if you are up to date with what’s in your subscribed - channels is <literal>nix-env -qc \*</literal>.</para></listitem> - - <listitem><para><literal>nix-env --query</literal> now takes as - arguments a list of package names about which to show - information, just like <option>--install</option>, etc.: for - example, <literal>nix-env -q gcc</literal>. Note that to show - all derivations, you need to specify - <literal>\*</literal>.</para></listitem> - - <listitem><para><literal>nix-env -i - <replaceable>pkgname</replaceable></literal> will now install - the highest available version of - <replaceable>pkgname</replaceable>, rather than installing all - available versions (which would probably give collisions) - (<literal>NIX-31</literal>).</para></listitem> - - <listitem><para><literal>nix-env (-i|-u) --dry-run</literal> now - shows exactly which missing paths will be built or - substituted.</para></listitem> - - <listitem><para><literal>nix-env -qa --description</literal> - shows human-readable descriptions of packages, provided that - they have a <literal>meta.description</literal> attribute (which - most packages in Nixpkgs don’t have yet).</para></listitem> - - </itemizedlist> - - </para></listitem> - - - <listitem><para>New language features: - - <itemizedlist> - - <listitem><para>Reference scanning (which happens after each - build) is much faster and takes a constant amount of - memory.</para></listitem> - - <listitem><para>String interpolation. Expressions like - -<programlisting> -"--with-freetype2-library=" + freetype + "/lib"</programlisting> - - can now be written as - -<programlisting> -"--with-freetype2-library=${freetype}/lib"</programlisting> - - You can write arbitrary expressions within - <literal>${<replaceable>...</replaceable>}</literal>, not just - identifiers.</para></listitem> - - <listitem><para>Multi-line string literals.</para></listitem> - - <listitem><para>String concatenations can now involve - derivations, as in the example <code>"--with-freetype2-library=" - + freetype + "/lib"</code>. This was not previously possible - because we need to register that a derivation that uses such a - string is dependent on <literal>freetype</literal>. The - evaluator now properly propagates this information. - Consequently, the subpath operator (<literal>~</literal>) has - been deprecated.</para></listitem> - - <listitem><para>Default values of function arguments can now - refer to other function arguments; that is, all arguments are in - scope in the default values - (<literal>NIX-45</literal>).</para></listitem> - - <!-- - <listitem><para>TODO: domain checks (r5895).</para></listitem> - --> - - <listitem><para>Lots of new built-in primitives, such as - functions for list manipulation and integer arithmetic. See the - manual for a complete list. All primops are now available in - the set <varname>builtins</varname>, allowing one to test for - the availability of primop in a backwards-compatible - way.</para></listitem> - - <listitem><para>Real let-expressions: <literal>let x = ...; - ... z = ...; in ...</literal>.</para></listitem> - - </itemizedlist> - - </para></listitem> - - - <listitem><para>New commands <command>nix-pack-closure</command> and - <command>nix-unpack-closure</command> than can be used to easily - transfer a store path with all its dependencies to another machine. - Very convenient whenever you have some package on your machine and - you want to copy it somewhere else.</para></listitem> - - - <listitem><para>XML support: - - <itemizedlist> - - <listitem><para><literal>nix-env -q --xml</literal> prints the - installed or available packages in an XML representation for - easy processing by other tools.</para></listitem> - - <listitem><para><literal>nix-instantiate --eval-only - --xml</literal> prints an XML representation of the resulting - term. (The new flag <option>--strict</option> forces ‘deep’ - evaluation of the result, i.e., list elements and attributes are - evaluated recursively.)</para></listitem> - - <listitem><para>In Nix expressions, the primop - <function>builtins.toXML</function> converts a term to an XML - representation. This is primarily useful for passing structured - information to builders.</para></listitem> - - </itemizedlist> - - </para></listitem> - - - <listitem><para>You can now unambiguously specify which derivation to - build or install in <command>nix-env</command>, - <command>nix-instantiate</command> and <command>nix-build</command> - using the <option>--attr</option> / <option>-A</option> flags, which - takes an attribute name as argument. (Unlike symbolic package names - such as <literal>subversion-1.4.0</literal>, attribute names in an - attribute set are unique.) For instance, a quick way to perform a - test build of a package in Nixpkgs is <literal>nix-build - pkgs/top-level/all-packages.nix -A - <replaceable>foo</replaceable></literal>. <literal>nix-env -q - --attr</literal> shows the attribute names corresponding to each - derivation.</para></listitem> - - - <listitem><para>If the top-level Nix expression used by - <command>nix-env</command>, <command>nix-instantiate</command> or - <command>nix-build</command> evaluates to a function whose arguments - all have default values, the function will be called automatically. - Also, the new command-line switch <option>--arg - <replaceable>name</replaceable> - <replaceable>value</replaceable></option> can be used to specify - function arguments on the command line.</para></listitem> - - - <listitem><para><literal>nix-install-package --url - <replaceable>URL</replaceable></literal> allows a package to be - installed directly from the given URL.</para></listitem> - - - <listitem><para>Nix now works behind an HTTP proxy server; just set - the standard environment variables <envar>http_proxy</envar>, - <envar>https_proxy</envar>, <envar>ftp_proxy</envar> or - <envar>all_proxy</envar> appropriately. Functions such as - <function>fetchurl</function> in Nixpkgs also respect these - variables.</para></listitem> - - - <listitem><para><literal>nix-build -o - <replaceable>symlink</replaceable></literal> allows the symlink to - the build result to be named something other than - <literal>result</literal>.</para></listitem> - - - <!-- Stability / performance / etc. --> - - - <listitem><para>Platform support: - - <itemizedlist> - - <listitem><para>Support for 64-bit platforms, provided a <link - xlink:href="http://bugzilla.sen.cwi.nl:8080/show_bug.cgi?id=606">suitably - patched ATerm library</link> is used. Also, files larger than 2 - GiB are now supported.</para></listitem> - - <listitem><para>Added support for Cygwin (Windows, - <literal>i686-cygwin</literal>), Mac OS X on Intel - (<literal>i686-darwin</literal>) and Linux on PowerPC - (<literal>powerpc-linux</literal>).</para></listitem> - - <listitem><para>Users of SMP and multicore machines will - appreciate that the number of builds to be performed in parallel - can now be specified in the configuration file in the - <literal>build-max-jobs</literal> setting.</para></listitem> - - </itemizedlist> - - </para></listitem> - - - <listitem><para>Garbage collector improvements: - - <itemizedlist> - - <listitem><para>Open files (such as running programs) are now - used as roots of the garbage collector. This prevents programs - that have been uninstalled from being garbage collected while - they are still running. The script that detects these - additional runtime roots - (<filename>find-runtime-roots.pl</filename>) is inherently - system-specific, but it should work on Linux and on all - platforms that have the <command>lsof</command> - utility.</para></listitem> - - <listitem><para><literal>nix-store --gc</literal> - (a.k.a. <command>nix-collect-garbage</command>) prints out the - number of bytes freed on standard output. <literal>nix-store - --gc --print-dead</literal> shows how many bytes would be freed - by an actual garbage collection.</para></listitem> - - <listitem><para><literal>nix-collect-garbage -d</literal> - removes all old generations of <emphasis>all</emphasis> profiles - before calling the actual garbage collector (<literal>nix-store - --gc</literal>). This is an easy way to get rid of all old - packages in the Nix store.</para></listitem> - - <listitem><para><command>nix-store</command> now has an - operation <option>--delete</option> to delete specific paths - from the Nix store. It won’t delete reachable (non-garbage) - paths unless <option>--ignore-liveness</option> is - specified.</para></listitem> - - </itemizedlist> - - </para></listitem> - - - <listitem><para>Berkeley DB 4.4’s process registry feature is used - to recover from crashed Nix processes.</para></listitem> - - <!-- <listitem><para>TODO: shared stores.</para></listitem> --> - - <listitem><para>A performance issue has been fixed with the - <literal>referer</literal> table, which stores the inverse of the - <literal>references</literal> table (i.e., it tells you what store - paths refer to a given path). Maintaining this table could take a - quadratic amount of time, as well as a quadratic amount of Berkeley - DB log file space (in particular when running the garbage collector) - (<literal>NIX-23</literal>).</para></listitem> - - <listitem><para>Nix now catches the <literal>TERM</literal> and - <literal>HUP</literal> signals in addition to the - <literal>INT</literal> signal. So you can now do a <literal>killall - nix-store</literal> without triggering a database - recovery.</para></listitem> - - <listitem><para><command>bsdiff</command> updated to version - 4.3.</para></listitem> - - <listitem><para>Substantial performance improvements in expression - evaluation and <literal>nix-env -qa</literal>, all thanks to <link - xlink:href="http://valgrind.org/">Valgrind</link>. Memory use has - been reduced by a factor 8 or so. Big speedup by memoisation of - path hashing.</para></listitem> - - <listitem><para>Lots of bug fixes, notably: - - <itemizedlist> - - <listitem><para>Make sure that the garbage collector can run - successfully when the disk is full - (<literal>NIX-18</literal>).</para></listitem> - - <listitem><para><command>nix-env</command> now locks the profile - to prevent races between concurrent <command>nix-env</command> - operations on the same profile - (<literal>NIX-7</literal>).</para></listitem> - - <listitem><para>Removed misleading messages from - <literal>nix-env -i</literal> (e.g., <literal>installing - `foo'</literal> followed by <literal>uninstalling - `foo'</literal>) (<literal>NIX-17</literal>).</para></listitem> - - </itemizedlist> - - </para></listitem> - - <listitem><para>Nix source distributions are a lot smaller now since - we no longer include a full copy of the Berkeley DB source - distribution (but only the bits we need).</para></listitem> - - <listitem><para>Header files are now installed so that external - programs can use the Nix libraries.</para></listitem> - -</itemizedlist> - -</section> - - - -<!--==================================================================--> - -<section><title>Release 0.9.2 (September 21, 2005)</title> - -<para>This bug fix release fixes two problems on Mac OS X: - -<itemizedlist> - - <listitem><para>If Nix was linked against statically linked versions - of the ATerm or Berkeley DB library, there would be dynamic link - errors at runtime.</para></listitem> - - <listitem><para><command>nix-pull</command> and - <command>nix-push</command> intermittently failed due to race - conditions involving pipes and child processes with error messages - such as <literal>open2: open(GLOB(0x180b2e4), >&=9) failed: Bad - file descriptor at /nix/bin/nix-pull line 77</literal> (issue - <literal>NIX-14</literal>).</para></listitem> - -</itemizedlist> - -</para> - -</section> - - - -<!--==================================================================--> - -<section><title>Release 0.9.1 (September 20, 2005)</title> - -<para>This bug fix release addresses a problem with the ATerm library -when the <option>--with-aterm</option> flag in -<command>configure</command> was <emphasis>not</emphasis> used.</para> - -</section> - - - -<!--==================================================================--> - -<section><title>Release 0.9 (September 16, 2005)</title> - -<para>NOTE: this version of Nix uses Berkeley DB 4.3 instead of 4.2. -The database is upgraded automatically, but you should be careful not -to use old versions of Nix that still use Berkeley DB 4.2. In -particular, if you use a Nix installed through Nix, you should run - -<screen> -$ nix-store --clear-substitutes</screen> - -first.</para> - - -<itemizedlist> - - <listitem><para>Unpacking of patch sequences is much faster now - since we no longer do redundant unpacking and repacking of - intermediate paths.</para></listitem> - - <listitem><para>Nix now uses Berkeley DB 4.3.</para></listitem> - - <listitem><para>The <function>derivation</function> primitive is - lazier. Attributes of dependent derivations can mutually refer to - each other (as long as there are no data dependencies on the - <varname>outPath</varname> and <varname>drvPath</varname> attributes - computed by <function>derivation</function>).</para> - - <para>For example, the expression <literal>derivation - attrs</literal> now evaluates to (essentially) - - <programlisting> -attrs // { - type = "derivation"; - outPath = derivation! attrs; - drvPath = derivation! attrs; -}</programlisting> - - where <function>derivation!</function> is a primop that does the - actual derivation instantiation (i.e., it does what - <function>derivation</function> used to do). The advantage is that - it allows commands such as <command>nix-env -qa</command> and - <command>nix-env -i</command> to be much faster since they no longer - need to instantiate all derivations, just the - <varname>name</varname> attribute.</para> - - <para>Also, it allows derivations to cyclically reference each - other, for example, - - <programlisting> -webServer = derivation { - ... - hostName = "svn.cs.uu.nl"; - services = [svnService]; -}; -  -svnService = derivation { - ... - hostName = webServer.hostName; -};</programlisting> - - Previously, this would yield a black hole (infinite recursion).</para> - - </listitem> - - <listitem><para><command>nix-build</command> now defaults to using - <filename>./default.nix</filename> if no Nix expression is - specified.</para></listitem> - - <listitem><para><command>nix-instantiate</command>, when applied to - a Nix expression that evaluates to a function, will call the - function automatically if all its arguments have - defaults.</para></listitem> - - <listitem><para>Nix now uses libtool to build dynamic libraries. - This reduces the size of executables.</para></listitem> - - <listitem><para>A new list concatenation operator - <literal>++</literal>. For example, <literal>[1 2 3] ++ [4 5 - 6]</literal> evaluates to <literal>[1 2 3 4 5 - 6]</literal>.</para></listitem> - - <listitem><para>Some currently undocumented primops to support - low-level build management using Nix (i.e., using Nix as a Make - replacement). See the commit messages for <literal>r3578</literal> - and <literal>r3580</literal>.</para></listitem> - - <listitem><para>Various bug fixes and performance - improvements.</para></listitem> - -</itemizedlist> - -</section> - - - -<!--==================================================================--> - -<section><title>Release 0.8.1 (April 13, 2005)</title> - -<para>This is a bug fix release.</para> - -<itemizedlist> - - <listitem><para>Patch downloading was broken.</para></listitem> - - <listitem><para>The garbage collector would not delete paths that - had references from invalid (but substitutable) - paths.</para></listitem> - -</itemizedlist> - -</section> - - - -<!--==================================================================--> - -<section><title>Release 0.8 (April 11, 2005)</title> - -<para>NOTE: the hashing scheme in Nix 0.8 changed (as detailed below). -As a result, <command>nix-pull</command> manifests and channels built -for Nix 0.7 and below will now work anymore. However, the Nix -expression language has not changed, so you can still build from -source. Also, existing user environments continue to work. Nix 0.8 -will automatically upgrade the database schema of previous -installations when it is first run.</para> - -<para>If you get the error message - -<screen> -you have an old-style manifest `/nix/var/nix/manifests/[...]'; please -delete it</screen> - -you should delete previously downloaded manifests: - -<screen> -$ rm /nix/var/nix/manifests/*</screen> - -If <command>nix-channel</command> gives the error message - -<screen> -manifest `http://catamaran.labs.cs.uu.nl/dist/nix/channels/[channel]/MANIFEST' -is too old (i.e., for Nix <= 0.7)</screen> - -then you should unsubscribe from the offending channel -(<command>nix-channel --remove -<replaceable>URL</replaceable></command>; leave out -<literal>/MANIFEST</literal>), and subscribe to the same URL, with -<literal>channels</literal> replaced by <literal>channels-v3</literal> -(e.g., <link -xlink:href='http://catamaran.labs.cs.uu.nl/dist/nix/channels-v3/nixpkgs-unstable' -/>).</para> - -<para>Nix 0.8 has the following improvements: - -<itemizedlist> - - <listitem><para>The cryptographic hashes used in store paths are now - 160 bits long, but encoded in base-32 so that they are still only 32 - characters long (e.g., - <filename>/nix/store/csw87wag8bqlqk7ipllbwypb14xainap-atk-1.9.0</filename>). - (This is actually a 160 bit truncation of a SHA-256 - hash.)</para></listitem> - - <listitem><para>Big cleanups and simplifications of the basic store - semantics. The notion of “closure store expressions” is gone (and - so is the notion of “successors”); the file system references of a - store path are now just stored in the database.</para> - - <para>For instance, given any store path, you can query its closure: - - <screen> -$ nix-store -qR $(which firefox) -... lots of paths ...</screen> - - Also, Nix now remembers for each store path the derivation that - built it (the “deriver”): - - <screen> -$ nix-store -qR $(which firefox) -/nix/store/4b0jx7vq80l9aqcnkszxhymsf1ffa5jd-firefox-1.0.1.drv</screen> - - So to see the build-time dependencies, you can do - - <screen> -$ nix-store -qR $(nix-store -qd $(which firefox))</screen> - - or, in a nicer format: - - <screen> -$ nix-store -q --tree $(nix-store -qd $(which firefox))</screen> - - </para> - - <para>File system references are also stored in reverse. For - instance, you can query all paths that directly or indirectly use a - certain Glibc: - - <screen> -$ nix-store -q --referrers-closure \ - /nix/store/8lz9yc6zgmc0vlqmn2ipcpkjlmbi51vv-glibc-2.3.4</screen> - - </para> - - </listitem> - - <listitem><para>The concept of fixed-output derivations has been - formalised. Previously, functions such as - <function>fetchurl</function> in Nixpkgs used a hack (namely, - explicitly specifying a store path hash) to prevent changes to, say, - the URL of the file from propagating upwards through the dependency - graph, causing rebuilds of everything. This can now be done cleanly - by specifying the <varname>outputHash</varname> and - <varname>outputHashAlgo</varname> attributes. Nix itself checks - that the content of the output has the specified hash. (This is - important for maintaining certain invariants necessary for future - work on secure shared stores.)</para></listitem> - - <listitem><para>One-click installation :-) It is now possible to - install any top-level component in Nixpkgs directly, through the web - — see, e.g., <link - xlink:href='http://catamaran.labs.cs.uu.nl/dist/nixpkgs-0.8/' />. - All you have to do is associate - <filename>/nix/bin/nix-install-package</filename> with the MIME type - <literal>application/nix-package</literal> (or the extension - <filename>.nixpkg</filename>), and clicking on a package link will - cause it to be installed, with all appropriate dependencies. If you - just want to install some specific application, this is easier than - subscribing to a channel.</para></listitem> - - <listitem><para><command>nix-store -r - <replaceable>PATHS</replaceable></command> now builds all the - derivations PATHS in parallel. Previously it did them sequentially - (though exploiting possible parallelism between subderivations). - This is nice for build farms.</para></listitem> - - <listitem><para><command>nix-channel</command> has new operations - <option>--list</option> and - <option>--remove</option>.</para></listitem> - - <listitem><para>New ways of installing components into user - environments: - - <itemizedlist> - - <listitem><para>Copy from another user environment: - - <screen> -$ nix-env -i --from-profile .../other-profile firefox</screen> - - </para></listitem> - - <listitem><para>Install a store derivation directly (bypassing the - Nix expression language entirely): - - <screen> -$ nix-env -i /nix/store/z58v41v21xd3...-aterm-2.3.1.drv</screen> - - (This is used to implement <command>nix-install-package</command>, - which is therefore immune to evolution in the Nix expression - language.)</para></listitem> - - <listitem><para>Install an already built store path directly: - - <screen> -$ nix-env -i /nix/store/hsyj5pbn0d9i...-aterm-2.3.1</screen> - - </para></listitem> - - <listitem><para>Install the result of a Nix expression specified - as a command-line argument: - - <screen> -$ nix-env -f .../i686-linux.nix -i -E 'x: x.firefoxWrapper'</screen> - - The difference with the normal installation mode is that - <option>-E</option> does not use the <varname>name</varname> - attributes of derivations. Therefore, this can be used to - disambiguate multiple derivations with the same - name.</para></listitem> - - </itemizedlist></para></listitem> - - <listitem><para>A hash of the contents of a store path is now stored - in the database after a successful build. This allows you to check - whether store paths have been tampered with: <command>nix-store - --verify --check-contents</command>.</para></listitem> - - <listitem> - - <para>Implemented a concurrent garbage collector. It is now - always safe to run the garbage collector, even if other Nix - operations are happening simultaneously.</para> - - <para>However, there can still be GC races if you use - <command>nix-instantiate</command> and <command>nix-store - --realise</command> directly to build things. To prevent races, - use the <option>--add-root</option> flag of those commands.</para> - - </listitem> - - <listitem><para>The garbage collector now finally deletes paths in - the right order (i.e., topologically sorted under the “references” - relation), thus making it safe to interrupt the collector without - risking a store that violates the closure - invariant.</para></listitem> - - <listitem><para>Likewise, the substitute mechanism now downloads - files in the right order, thus preserving the closure invariant at - all times.</para></listitem> - - <listitem><para>The result of <command>nix-build</command> is now - registered as a root of the garbage collector. If the - <filename>./result</filename> link is deleted, the GC root - disappears automatically.</para></listitem> - - <listitem> - - <para>The behaviour of the garbage collector can be changed - globally by setting options in - <filename>/nix/etc/nix/nix.conf</filename>. - - <itemizedlist> - - <listitem><para><literal>gc-keep-derivations</literal> specifies - whether deriver links should be followed when searching for live - paths.</para></listitem> - - <listitem><para><literal>gc-keep-outputs</literal> specifies - whether outputs of derivations should be followed when searching - for live paths.</para></listitem> - - <listitem><para><literal>env-keep-derivations</literal> - specifies whether user environments should store the paths of - derivations when they are added (thus keeping the derivations - alive).</para></listitem> - - </itemizedlist> - - </para></listitem> - - <listitem><para>New <command>nix-env</command> query flags - <option>--drv-path</option> and - <option>--out-path</option>.</para></listitem> - - <listitem><para><command>fetchurl</command> allows SHA-1 and SHA-256 - in addition to MD5. Just specify the attribute - <varname>sha1</varname> or <varname>sha256</varname> instead of - <varname>md5</varname>.</para></listitem> - - <listitem><para>Manual updates.</para></listitem> - -</itemizedlist> - -</para> - -</section> - - - -<!--==================================================================--> - -<section><title>Release 0.7 (January 12, 2005)</title> - -<itemizedlist> - - <listitem><para>Binary patching. When upgrading components using - pre-built binaries (through nix-pull / nix-channel), Nix can - automatically download and apply binary patches to already installed - components instead of full downloads. Patching is “smart”: if there - is a <emphasis>sequence</emphasis> of patches to an installed - component, Nix will use it. Patches are currently generated - automatically between Nixpkgs (pre-)releases.</para></listitem> - - <listitem><para>Simplifications to the substitute - mechanism.</para></listitem> - - <listitem><para>Nix-pull now stores downloaded manifests in - <filename>/nix/var/nix/manifests</filename>.</para></listitem> - - <listitem><para>Metadata on files in the Nix store is canonicalised - after builds: the last-modified timestamp is set to 0 (00:00:00 - 1/1/1970), the mode is set to 0444 or 0555 (readable and possibly - executable by all; setuid/setgid bits are dropped), and the group is - set to the default. This ensures that the result of a build and an - installation through a substitute is the same; and that timestamp - dependencies are revealed.</para></listitem> - -</itemizedlist> - -</section> - - - -<!--==================================================================--> - -<section><title>Release 0.6 (November 14, 2004)</title> - -<itemizedlist> - - <listitem> - <para>Rewrite of the normalisation engine. - - <itemizedlist> - - <listitem><para>Multiple builds can now be performed in parallel - (option <option>-j</option>).</para></listitem> - - <listitem><para>Distributed builds. Nix can now call a shell - script to forward builds to Nix installations on remote - machines, which may or may not be of the same platform - type.</para></listitem> - - <listitem><para>Option <option>--fallback</option> allows - recovery from broken substitutes.</para></listitem> - - <listitem><para>Option <option>--keep-going</option> causes - building of other (unaffected) derivations to continue if one - failed.</para></listitem> - - </itemizedlist> - - </para> - - </listitem> - - <listitem><para>Improvements to the garbage collector (i.e., it - should actually work now).</para></listitem> - - <listitem><para>Setuid Nix installations allow a Nix store to be - shared among multiple users.</para></listitem> - - <listitem><para>Substitute registration is much faster - now.</para></listitem> - - <listitem><para>A utility <command>nix-build</command> to build a - Nix expression and create a symlink to the result int the current - directory; useful for testing Nix derivations.</para></listitem> - - <listitem><para>Manual updates.</para></listitem> - - <listitem> - - <para><command>nix-env</command> changes: - - <itemizedlist> - - <listitem><para>Derivations for other platforms are filtered out - (which can be overridden using - <option>--system-filter</option>).</para></listitem> - - <listitem><para><option>--install</option> by default now - uninstall previous derivations with the same - name.</para></listitem> - - <listitem><para><option>--upgrade</option> allows upgrading to a - specific version.</para></listitem> - - <listitem><para>New operation - <option>--delete-generations</option> to remove profile - generations (necessary for effective garbage - collection).</para></listitem> - - <listitem><para>Nicer output (sorted, - columnised).</para></listitem> - - </itemizedlist> - - </para> - - </listitem> - - <listitem><para>More sensible verbosity levels all around (builder - output is now shown always, unless <option>-Q</option> is - given).</para></listitem> - - <listitem> - - <para>Nix expression language changes: - - <itemizedlist> - - <listitem><para>New language construct: <literal>with - <replaceable>E1</replaceable>; - <replaceable>E2</replaceable></literal> brings all attributes - defined in the attribute set <replaceable>E1</replaceable> in - scope in <replaceable>E2</replaceable>.</para></listitem> - - <listitem><para>Added a <function>map</function> - function.</para></listitem> - - <listitem><para>Various new operators (e.g., string - concatenation).</para></listitem> - - </itemizedlist> - - </para> - - </listitem> - - <listitem><para>Expression evaluation is much - faster.</para></listitem> - - <listitem><para>An Emacs mode for editing Nix expressions (with - syntax highlighting and indentation) has been - added.</para></listitem> - - <listitem><para>Many bug fixes.</para></listitem> - -</itemizedlist> - -</section> - - - -<!--==================================================================--> - -<section><title>Release 0.5 and earlier</title> - -<para>Please refer to the Subversion commit log messages.</para> - -</section> - - - -</article> diff --git a/doc/manual/release-notes/release-notes.xml b/doc/manual/release-notes/release-notes.xml new file mode 100644 index 000000000000..c9bb2e18931c --- /dev/null +++ b/doc/manual/release-notes/release-notes.xml @@ -0,0 +1,43 @@ +<part xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="sec-relnotes"> + +<title>Nix Release Notes</title> + +<partintro> +<para>This section lists the release notes for each stable version of Nix.</para> +</partintro> + +<!-- TODO +<xi:include href="rl-18.xml" /> +--> +<xi:include href="rl-17.xml" /> +<xi:include href="rl-161.xml" /> +<xi:include href="rl-16.xml" /> +<xi:include href="rl-152.xml" /> +<xi:include href="rl-15.xml" /> +<xi:include href="rl-14.xml" /> +<xi:include href="rl-13.xml" /> +<xi:include href="rl-12.xml" /> +<xi:include href="rl-11.xml" /> +<xi:include href="rl-10.xml" /> +<xi:include href="rl-016.xml" /> +<xi:include href="rl-015.xml" /> +<xi:include href="rl-014.xml" /> +<xi:include href="rl-013.xml" /> +<xi:include href="rl-012.xml" /> +<xi:include href="rl-011.xml" /> +<xi:include href="rl-0101.xml" /> +<xi:include href="rl-010.xml" /> +<xi:include href="rl-092.xml" /> +<xi:include href="rl-091.xml" /> +<xi:include href="rl-09.xml" /> +<xi:include href="rl-081.xml" /> +<xi:include href="rl-08.xml" /> +<xi:include href="rl-07.xml" /> +<xi:include href="rl-06.xml" /> +<xi:include href="rl-05.xml" /> + +</part> diff --git a/doc/manual/release-notes/rl-010.xml b/doc/manual/release-notes/rl-010.xml new file mode 100644 index 000000000000..fb55bd24fbbf --- /dev/null +++ b/doc/manual/release-notes/rl-010.xml @@ -0,0 +1,323 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-relnotes-0.10"> + +<title>Release 0.10 (October 6, 2006)</title> + +<note><para>This version of Nix uses Berkeley DB 4.4 instead of 4.3. +The database is upgraded automatically, but you should be careful not +to use old versions of Nix that still use Berkeley DB 4.3. In +particular, if you use a Nix installed through Nix, you should run + +<screen> +$ nix-store --clear-substitutes</screen> + +first.</para></note> + +<warning><para>Also, the database schema has changed slighted to fix a +performance issue (see below). When you run any Nix 0.10 command for +the first time, the database will be upgraded automatically. This is +irreversible.</para></warning> + +<itemizedlist> + + + <!-- Usability / features --> + + + <listitem><para><command>nix-env</command> usability improvements: + + <itemizedlist> + + <listitem><para>An option <option>--compare-versions</option> + (or <option>-c</option>) has been added to <command>nix-env + --query</command> to allow you to compare installed versions of + packages to available versions, or vice versa. An easy way to + see if you are up to date with what’s in your subscribed + channels is <literal>nix-env -qc \*</literal>.</para></listitem> + + <listitem><para><literal>nix-env --query</literal> now takes as + arguments a list of package names about which to show + information, just like <option>--install</option>, etc.: for + example, <literal>nix-env -q gcc</literal>. Note that to show + all derivations, you need to specify + <literal>\*</literal>.</para></listitem> + + <listitem><para><literal>nix-env -i + <replaceable>pkgname</replaceable></literal> will now install + the highest available version of + <replaceable>pkgname</replaceable>, rather than installing all + available versions (which would probably give collisions) + (<literal>NIX-31</literal>).</para></listitem> + + <listitem><para><literal>nix-env (-i|-u) --dry-run</literal> now + shows exactly which missing paths will be built or + substituted.</para></listitem> + + <listitem><para><literal>nix-env -qa --description</literal> + shows human-readable descriptions of packages, provided that + they have a <literal>meta.description</literal> attribute (which + most packages in Nixpkgs don’t have yet).</para></listitem> + + </itemizedlist> + + </para></listitem> + + + <listitem><para>New language features: + + <itemizedlist> + + <listitem><para>Reference scanning (which happens after each + build) is much faster and takes a constant amount of + memory.</para></listitem> + + <listitem><para>String interpolation. Expressions like + +<programlisting> +"--with-freetype2-library=" + freetype + "/lib"</programlisting> + + can now be written as + +<programlisting> +"--with-freetype2-library=${freetype}/lib"</programlisting> + + You can write arbitrary expressions within + <literal>${<replaceable>...</replaceable>}</literal>, not just + identifiers.</para></listitem> + + <listitem><para>Multi-line string literals.</para></listitem> + + <listitem><para>String concatenations can now involve + derivations, as in the example <code>"--with-freetype2-library=" + + freetype + "/lib"</code>. This was not previously possible + because we need to register that a derivation that uses such a + string is dependent on <literal>freetype</literal>. The + evaluator now properly propagates this information. + Consequently, the subpath operator (<literal>~</literal>) has + been deprecated.</para></listitem> + + <listitem><para>Default values of function arguments can now + refer to other function arguments; that is, all arguments are in + scope in the default values + (<literal>NIX-45</literal>).</para></listitem> + + <!-- + <listitem><para>TODO: domain checks (r5895).</para></listitem> + --> + + <listitem><para>Lots of new built-in primitives, such as + functions for list manipulation and integer arithmetic. See the + manual for a complete list. All primops are now available in + the set <varname>builtins</varname>, allowing one to test for + the availability of primop in a backwards-compatible + way.</para></listitem> + + <listitem><para>Real let-expressions: <literal>let x = ...; + ... z = ...; in ...</literal>.</para></listitem> + + </itemizedlist> + + </para></listitem> + + + <listitem><para>New commands <command>nix-pack-closure</command> and + <command>nix-unpack-closure</command> than can be used to easily + transfer a store path with all its dependencies to another machine. + Very convenient whenever you have some package on your machine and + you want to copy it somewhere else.</para></listitem> + + + <listitem><para>XML support: + + <itemizedlist> + + <listitem><para><literal>nix-env -q --xml</literal> prints the + installed or available packages in an XML representation for + easy processing by other tools.</para></listitem> + + <listitem><para><literal>nix-instantiate --eval-only + --xml</literal> prints an XML representation of the resulting + term. (The new flag <option>--strict</option> forces ‘deep’ + evaluation of the result, i.e., list elements and attributes are + evaluated recursively.)</para></listitem> + + <listitem><para>In Nix expressions, the primop + <function>builtins.toXML</function> converts a term to an XML + representation. This is primarily useful for passing structured + information to builders.</para></listitem> + + </itemizedlist> + + </para></listitem> + + + <listitem><para>You can now unambiguously specify which derivation to + build or install in <command>nix-env</command>, + <command>nix-instantiate</command> and <command>nix-build</command> + using the <option>--attr</option> / <option>-A</option> flags, which + takes an attribute name as argument. (Unlike symbolic package names + such as <literal>subversion-1.4.0</literal>, attribute names in an + attribute set are unique.) For instance, a quick way to perform a + test build of a package in Nixpkgs is <literal>nix-build + pkgs/top-level/all-packages.nix -A + <replaceable>foo</replaceable></literal>. <literal>nix-env -q + --attr</literal> shows the attribute names corresponding to each + derivation.</para></listitem> + + + <listitem><para>If the top-level Nix expression used by + <command>nix-env</command>, <command>nix-instantiate</command> or + <command>nix-build</command> evaluates to a function whose arguments + all have default values, the function will be called automatically. + Also, the new command-line switch <option>--arg + <replaceable>name</replaceable> + <replaceable>value</replaceable></option> can be used to specify + function arguments on the command line.</para></listitem> + + + <listitem><para><literal>nix-install-package --url + <replaceable>URL</replaceable></literal> allows a package to be + installed directly from the given URL.</para></listitem> + + + <listitem><para>Nix now works behind an HTTP proxy server; just set + the standard environment variables <envar>http_proxy</envar>, + <envar>https_proxy</envar>, <envar>ftp_proxy</envar> or + <envar>all_proxy</envar> appropriately. Functions such as + <function>fetchurl</function> in Nixpkgs also respect these + variables.</para></listitem> + + + <listitem><para><literal>nix-build -o + <replaceable>symlink</replaceable></literal> allows the symlink to + the build result to be named something other than + <literal>result</literal>.</para></listitem> + + + <!-- Stability / performance / etc. --> + + + <listitem><para>Platform support: + + <itemizedlist> + + <listitem><para>Support for 64-bit platforms, provided a <link + xlink:href="http://bugzilla.sen.cwi.nl:8080/show_bug.cgi?id=606">suitably + patched ATerm library</link> is used. Also, files larger than 2 + GiB are now supported.</para></listitem> + + <listitem><para>Added support for Cygwin (Windows, + <literal>i686-cygwin</literal>), Mac OS X on Intel + (<literal>i686-darwin</literal>) and Linux on PowerPC + (<literal>powerpc-linux</literal>).</para></listitem> + + <listitem><para>Users of SMP and multicore machines will + appreciate that the number of builds to be performed in parallel + can now be specified in the configuration file in the + <literal>build-max-jobs</literal> setting.</para></listitem> + + </itemizedlist> + + </para></listitem> + + + <listitem><para>Garbage collector improvements: + + <itemizedlist> + + <listitem><para>Open files (such as running programs) are now + used as roots of the garbage collector. This prevents programs + that have been uninstalled from being garbage collected while + they are still running. The script that detects these + additional runtime roots + (<filename>find-runtime-roots.pl</filename>) is inherently + system-specific, but it should work on Linux and on all + platforms that have the <command>lsof</command> + utility.</para></listitem> + + <listitem><para><literal>nix-store --gc</literal> + (a.k.a. <command>nix-collect-garbage</command>) prints out the + number of bytes freed on standard output. <literal>nix-store + --gc --print-dead</literal> shows how many bytes would be freed + by an actual garbage collection.</para></listitem> + + <listitem><para><literal>nix-collect-garbage -d</literal> + removes all old generations of <emphasis>all</emphasis> profiles + before calling the actual garbage collector (<literal>nix-store + --gc</literal>). This is an easy way to get rid of all old + packages in the Nix store.</para></listitem> + + <listitem><para><command>nix-store</command> now has an + operation <option>--delete</option> to delete specific paths + from the Nix store. It won’t delete reachable (non-garbage) + paths unless <option>--ignore-liveness</option> is + specified.</para></listitem> + + </itemizedlist> + + </para></listitem> + + + <listitem><para>Berkeley DB 4.4’s process registry feature is used + to recover from crashed Nix processes.</para></listitem> + + <!-- <listitem><para>TODO: shared stores.</para></listitem> --> + + <listitem><para>A performance issue has been fixed with the + <literal>referer</literal> table, which stores the inverse of the + <literal>references</literal> table (i.e., it tells you what store + paths refer to a given path). Maintaining this table could take a + quadratic amount of time, as well as a quadratic amount of Berkeley + DB log file space (in particular when running the garbage collector) + (<literal>NIX-23</literal>).</para></listitem> + + <listitem><para>Nix now catches the <literal>TERM</literal> and + <literal>HUP</literal> signals in addition to the + <literal>INT</literal> signal. So you can now do a <literal>killall + nix-store</literal> without triggering a database + recovery.</para></listitem> + + <listitem><para><command>bsdiff</command> updated to version + 4.3.</para></listitem> + + <listitem><para>Substantial performance improvements in expression + evaluation and <literal>nix-env -qa</literal>, all thanks to <link + xlink:href="http://valgrind.org/">Valgrind</link>. Memory use has + been reduced by a factor 8 or so. Big speedup by memoisation of + path hashing.</para></listitem> + + <listitem><para>Lots of bug fixes, notably: + + <itemizedlist> + + <listitem><para>Make sure that the garbage collector can run + successfully when the disk is full + (<literal>NIX-18</literal>).</para></listitem> + + <listitem><para><command>nix-env</command> now locks the profile + to prevent races between concurrent <command>nix-env</command> + operations on the same profile + (<literal>NIX-7</literal>).</para></listitem> + + <listitem><para>Removed misleading messages from + <literal>nix-env -i</literal> (e.g., <literal>installing + `foo'</literal> followed by <literal>uninstalling + `foo'</literal>) (<literal>NIX-17</literal>).</para></listitem> + + </itemizedlist> + + </para></listitem> + + <listitem><para>Nix source distributions are a lot smaller now since + we no longer include a full copy of the Berkeley DB source + distribution (but only the bits we need).</para></listitem> + + <listitem><para>Header files are now installed so that external + programs can use the Nix libraries.</para></listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-0101.xml b/doc/manual/release-notes/rl-0101.xml new file mode 100644 index 000000000000..884b1b8dbf7b --- /dev/null +++ b/doc/manual/release-notes/rl-0101.xml @@ -0,0 +1,13 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-relnotes-0.10.1"> + +<title>Release 0.10.1 (October 11, 2006)</title> + +<para>This release fixes two somewhat obscure bugs that occur when +evaluating Nix expressions that are stored inside the Nix store +(<literal>NIX-67</literal>). These do not affect most users.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-011.xml b/doc/manual/release-notes/rl-011.xml new file mode 100644 index 000000000000..40f83bbc7b49 --- /dev/null +++ b/doc/manual/release-notes/rl-011.xml @@ -0,0 +1,261 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-0.11"> + +<title>Release 0.11 (December 31, 2007)</title> + +<para>Nix 0.11 has many improvements over the previous stable release. +The most important improvement is secure multi-user support. It also +features many usability enhancements and language extensions, many of +them prompted by NixOS, the purely functional Linux distribution based +on Nix. Here is an (incomplete) list:</para> + + +<itemizedlist> + + + <listitem><para>Secure multi-user support. A single Nix store can + now be shared between multiple (possible untrusted) users. This is + an important feature for NixOS, where it allows non-root users to + install software. The old setuid method for sharing a store between + multiple users has been removed. Details for setting up a + multi-user store can be found in the manual.</para></listitem> + + + <listitem><para>The new command <command>nix-copy-closure</command> + gives you an easy and efficient way to exchange software between + machines. It copies the missing parts of the closure of a set of + store path to or from a remote machine via + <command>ssh</command>.</para></listitem> + + + <listitem><para>A new kind of string literal: strings between double + single-quotes (<literal>''</literal>) have indentation + “intelligently” removed. This allows large strings (such as shell + scripts or configuration file fragments in NixOS) to cleanly follow + the indentation of the surrounding expression. It also requires + much less escaping, since <literal>''</literal> is less common in + most languages than <literal>"</literal>.</para></listitem> + + + <listitem><para><command>nix-env</command> <option>--set</option> + modifies the current generation of a profile so that it contains + exactly the specified derivation, and nothing else. For example, + <literal>nix-env -p /nix/var/nix/profiles/browser --set + firefox</literal> lets the profile named + <filename>browser</filename> contain just Firefox.</para></listitem> + + + <listitem><para><command>nix-env</command> now maintains + meta-information about installed packages in profiles. The + meta-information is the contents of the <varname>meta</varname> + attribute of derivations, such as <varname>description</varname> or + <varname>homepage</varname>. The command <literal>nix-env -q --xml + --meta</literal> shows all meta-information.</para></listitem> + + + <listitem><para><command>nix-env</command> now uses the + <varname>meta.priority</varname> attribute of derivations to resolve + filename collisions between packages. Lower priority values denote + a higher priority. For instance, the GCC wrapper package and the + Binutils package in Nixpkgs both have a file + <filename>bin/ld</filename>, so previously if you tried to install + both you would get a collision. Now, on the other hand, the GCC + wrapper declares a higher priority than Binutils, so the former’s + <filename>bin/ld</filename> is symlinked in the user + environment.</para></listitem> + + + <listitem><para><command>nix-env -i / -u</command>: instead of + breaking package ties by version, break them by priority and version + number. That is, if there are multiple packages with the same name, + then pick the package with the highest priority, and only use the + version if there are multiple packages with the same + priority.</para> + + <para>This makes it possible to mark specific versions/variant in + Nixpkgs more or less desirable than others. A typical example would + be a beta version of some package (e.g., + <literal>gcc-4.2.0rc1</literal>) which should not be installed even + though it is the highest version, except when it is explicitly + selected (e.g., <literal>nix-env -i + gcc-4.2.0rc1</literal>).</para></listitem> + + + <listitem><para><command>nix-env --set-flag</command> allows meta + attributes of installed packages to be modified. There are several + attributes that can be usefully modified, because they affect the + behaviour of <command>nix-env</command> or the user environment + build script: + + <itemizedlist> + + <listitem><para><varname>meta.priority</varname> can be changed + to resolve filename clashes (see above).</para></listitem> + + <listitem><para><varname>meta.keep</varname> can be set to + <literal>true</literal> to prevent the package from being + upgraded or replaced. Useful if you want to hang on to an older + version of a package.</para></listitem> + + <listitem><para><varname>meta.active</varname> can be set to + <literal>false</literal> to “disable” the package. That is, no + symlinks will be generated to the files of the package, but it + remains part of the profile (so it won’t be garbage-collected). + Set it back to <literal>true</literal> to re-enable the + package.</para></listitem> + + </itemizedlist> + + </para></listitem> + + + <listitem><para><command>nix-env -q</command> now has a flag + <option>--prebuilt-only</option> (<option>-b</option>) that causes + <command>nix-env</command> to show only those derivations whose + output is already in the Nix store or that can be substituted (i.e., + downloaded from somewhere). In other words, it shows the packages + that can be installed “quickly”, i.e., don’t need to be built from + source. The <option>-b</option> flag is also available in + <command>nix-env -i</command> and <command>nix-env -u</command> to + filter out derivations for which no pre-built binary is + available.</para></listitem> + + + <listitem><para>The new option <option>--argstr</option> (in + <command>nix-env</command>, <command>nix-instantiate</command> and + <command>nix-build</command>) is like <option>--arg</option>, except + that the value is a string. For example, <literal>--argstr system + i686-linux</literal> is equivalent to <literal>--arg system + \"i686-linux\"</literal> (note that <option>--argstr</option> + prevents annoying quoting around shell arguments).</para></listitem> + + + <listitem><para><command>nix-store</command> has a new operation + <option>--read-log</option> (<option>-l</option>) + <parameter>paths</parameter> that shows the build log of the given + paths.</para></listitem> + + + <!-- + <listitem><para>TODO: semantic cleanups of string concatenation + etc. (mostly in r6740).</para></listitem> + --> + + + <listitem><para>Nix now uses Berkeley DB 4.5. The database is + upgraded automatically, but you should be careful not to use old + versions of Nix that still use Berkeley DB 4.4.</para></listitem> + + + <!-- foo + <listitem><para>TODO: option <option>- -reregister</option> in + <command>nix-store - -register-validity</command>.</para></listitem> + --> + + + <listitem><para>The option <option>--max-silent-time</option> + (corresponding to the configuration setting + <literal>build-max-silent-time</literal>) allows you to set a + timeout on builds — if a build produces no output on + <literal>stdout</literal> or <literal>stderr</literal> for the given + number of seconds, it is terminated. This is useful for recovering + automatically from builds that are stuck in an infinite + loop.</para></listitem> + + + <listitem><para><command>nix-channel</command>: each subscribed + channel is its own attribute in the top-level expression generated + for the channel. This allows disambiguation (e.g. <literal>nix-env + -i -A nixpkgs_unstable.firefox</literal>).</para></listitem> + + + <listitem><para>The substitutes table has been removed from the + database. This makes operations such as <command>nix-pull</command> + and <command>nix-channel --update</command> much, much + faster.</para></listitem> + + + <listitem><para><command>nix-pull</command> now supports + bzip2-compressed manifests. This speeds up + channels.</para></listitem> + + + <listitem><para><command>nix-prefetch-url</command> now has a + limited form of caching. This is used by + <command>nix-channel</command> to prevent unnecessary downloads when + the channel hasn’t changed.</para></listitem> + + + <listitem><para><command>nix-prefetch-url</command> now by default + computes the SHA-256 hash of the file instead of the MD5 hash. In + calls to <function>fetchurl</function> you should pass the + <literal>sha256</literal> attribute instead of + <literal>md5</literal>. You can pass either a hexadecimal or a + base-32 encoding of the hash.</para></listitem> + + + <listitem><para>Nix can now perform builds in an automatically + generated “chroot”. This prevents a builder from accessing stuff + outside of the Nix store, and thus helps ensure purity. This is an + experimental feature.</para></listitem> + + + <listitem><para>The new command <command>nix-store + --optimise</command> reduces Nix store disk space usage by finding + identical files in the store and hard-linking them to each other. + It typically reduces the size of the store by something like + 25-35%.</para></listitem> + + + <listitem><para><filename>~/.nix-defexpr</filename> can now be a + directory, in which case the Nix expressions in that directory are + combined into an attribute set, with the file names used as the + names of the attributes. The command <command>nix-env + --import</command> (which set the + <filename>~/.nix-defexpr</filename> symlink) is + removed.</para></listitem> + + + <listitem><para>Derivations can specify the new special attribute + <varname>allowedReferences</varname> to enforce that the references + in the output of a derivation are a subset of a declared set of + paths. For example, if <varname>allowedReferences</varname> is an + empty list, then the output must not have any references. This is + used in NixOS to check that generated files such as initial ramdisks + for booting Linux don’t have any dependencies.</para></listitem> + + + <listitem><para>The new attribute + <varname>exportReferencesGraph</varname> allows builders access to + the references graph of their inputs. This is used in NixOS for + tasks such as generating ISO-9660 images that contain a Nix store + populated with the closure of certain paths.</para></listitem> + + + <listitem><para>Fixed-output derivations (like + <function>fetchurl</function>) can define the attribute + <varname>impureEnvVars</varname> to allow external environment + variables to be passed to builders. This is used in Nixpkgs to + support proxy configuration, among other things.</para></listitem> + + + <listitem><para>Several new built-in functions: + <function>builtins.attrNames</function>, + <function>builtins.filterSource</function>, + <function>builtins.isAttrs</function>, + <function>builtins.isFunction</function>, + <function>builtins.listToAttrs</function>, + <function>builtins.stringLength</function>, + <function>builtins.sub</function>, + <function>builtins.substring</function>, + <function>throw</function>, + <function>builtins.trace</function>, + <function>builtins.readFile</function>.</para></listitem> + + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-012.xml b/doc/manual/release-notes/rl-012.xml new file mode 100644 index 000000000000..173ed79ffd4e --- /dev/null +++ b/doc/manual/release-notes/rl-012.xml @@ -0,0 +1,175 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-0.12"> + +<title>Release 0.12 (November 20, 2008)</title> + +<itemizedlist> + + <listitem> + <para>Nix no longer uses Berkeley DB to store Nix store metadata. + The principal advantages of the new storage scheme are: it works + properly over decent implementations of NFS (allowing Nix stores + to be shared between multiple machines); no recovery is needed + when a Nix process crashes; no write access is needed for + read-only operations; no more running out of Berkeley DB locks on + certain operations.</para> + + <para>You still need to compile Nix with Berkeley DB support if + you want Nix to automatically convert your old Nix store to the + new schema. If you don’t need this, you can build Nix with the + <filename>configure</filename> option + <option>--disable-old-db-compat</option>.</para> + + <para>After the automatic conversion to the new schema, you can + delete the old Berkeley DB files: + + <screen> +$ cd /nix/var/nix/db +$ rm __db* log.* derivers references referrers reserved validpaths DB_CONFIG</screen> + + The new metadata is stored in the directories + <filename>/nix/var/nix/db/info</filename> and + <filename>/nix/var/nix/db/referrer</filename>. Though the + metadata is stored in human-readable plain-text files, they are + not intended to be human-editable, as Nix is rather strict about + the format.</para> + + <para>The new storage schema may or may not require less disk + space than the Berkeley DB environment, mostly depending on the + cluster size of your file system. With 1 KiB clusters (which + seems to be the <literal>ext3</literal> default nowadays) it + usually takes up much less space.</para> + </listitem> + + <listitem><para>There is a new substituter that copies paths + directly from other (remote) Nix stores mounted somewhere in the + filesystem. For instance, you can speed up an installation by + mounting some remote Nix store that already has the packages in + question via NFS or <literal>sshfs</literal>. The environment + variable <envar>NIX_OTHER_STORES</envar> specifies the locations of + the remote Nix directories, + e.g. <literal>/mnt/remote-fs/nix</literal>.</para></listitem> + + <listitem><para>New <command>nix-store</command> operations + <option>--dump-db</option> and <option>--load-db</option> to dump + and reload the Nix database.</para></listitem> + + <listitem><para>The garbage collector has a number of new options to + allow only some of the garbage to be deleted. The option + <option>--max-freed <replaceable>N</replaceable></option> tells the + collector to stop after at least <replaceable>N</replaceable> bytes + have been deleted. The option <option>--max-links + <replaceable>N</replaceable></option> tells it to stop after the + link count on <filename>/nix/store</filename> has dropped below + <replaceable>N</replaceable>. This is useful for very large Nix + stores on filesystems with a 32000 subdirectories limit (like + <literal>ext3</literal>). The option <option>--use-atime</option> + causes store paths to be deleted in order of ascending last access + time. This allows non-recently used stuff to be deleted. The + option <option>--max-atime <replaceable>time</replaceable></option> + specifies an upper limit to the last accessed time of paths that may + be deleted. For instance, + + <screen> + $ nix-store --gc -v --max-atime $(date +%s -d "2 months ago")</screen> + + deletes everything that hasn’t been accessed in two months.</para></listitem> + + <listitem><para><command>nix-env</command> now uses optimistic + profile locking when performing an operation like installing or + upgrading, instead of setting an exclusive lock on the profile. + This allows multiple <command>nix-env -i / -u / -e</command> + operations on the same profile in parallel. If a + <command>nix-env</command> operation sees at the end that the profile + was changed in the meantime by another process, it will just + restart. This is generally cheap because the build results are + still in the Nix store.</para></listitem> + + <listitem><para>The option <option>--dry-run</option> is now + supported by <command>nix-store -r</command> and + <command>nix-build</command>.</para></listitem> + + <listitem><para>The information previously shown by + <option>--dry-run</option> (i.e., which derivations will be built + and which paths will be substituted) is now always shown by + <command>nix-env</command>, <command>nix-store -r</command> and + <command>nix-build</command>. The total download size of + substitutable paths is now also shown. For instance, a build will + show something like + + <screen> +the following derivations will be built: + /nix/store/129sbxnk5n466zg6r1qmq1xjv9zymyy7-activate-configuration.sh.drv + /nix/store/7mzy971rdm8l566ch8hgxaf89x7lr7ik-upstart-jobs.drv + ... +the following paths will be downloaded/copied (30.02 MiB): + /nix/store/4m8pvgy2dcjgppf5b4cj5l6wyshjhalj-samba-3.2.4 + /nix/store/7h1kwcj29ip8vk26rhmx6bfjraxp0g4l-libunwind-0.98.6 + ...</screen> + + </para></listitem> + + <listitem><para>Language features: + + <itemizedlist> + + <listitem><para>@-patterns as in Haskell. For instance, in a + function definition + + <programlisting>f = args @ {x, y, z}: <replaceable>...</replaceable>;</programlisting> + + <varname>args</varname> refers to the argument as a whole, which + is further pattern-matched against the attribute set pattern + <literal>{x, y, z}</literal>.</para></listitem> + + <listitem><para>“<literal>...</literal>” (ellipsis) patterns. + An attribute set pattern can now say <literal>...</literal> at + the end of the attribute name list to specify that the function + takes <emphasis>at least</emphasis> the listed attributes, while + ignoring additional attributes. For instance, + + <programlisting>{stdenv, fetchurl, fuse, ...}: <replaceable>...</replaceable></programlisting> + + defines a function that accepts any attribute set that includes + at least the three listed attributes.</para></listitem> + + <listitem><para>New primops: + <varname>builtins.parseDrvName</varname> (split a package name + string like <literal>"nix-0.12pre12876"</literal> into its name + and version components, e.g. <literal>"nix"</literal> and + <literal>"0.12pre12876"</literal>), + <varname>builtins.compareVersions</varname> (compare two version + strings using the same algorithm that <command>nix-env</command> + uses), <varname>builtins.length</varname> (efficiently compute + the length of a list), <varname>builtins.mul</varname> (integer + multiplication), <varname>builtins.div</varname> (integer + division). + <!-- <varname>builtins.genericClosure</varname> --> + </para></listitem> + + </itemizedlist> + + </para></listitem> + + <listitem><para><command>nix-prefetch-url</command> now supports + <literal>mirror://</literal> URLs, provided that the environment + variable <envar>NIXPKGS_ALL</envar> points at a Nixpkgs + tree.</para></listitem> + + <listitem><para>Removed the commands + <command>nix-pack-closure</command> and + <command>nix-unpack-closure</command>. You can do almost the same + thing but much more efficiently by doing <literal>nix-store --export + $(nix-store -qR <replaceable>paths</replaceable>) > closure</literal> and + <literal>nix-store --import < + closure</literal>.</para></listitem> + + <listitem><para>Lots of bug fixes, including a big performance bug in + the handling of <literal>with</literal>-expressions.</para></listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-013.xml b/doc/manual/release-notes/rl-013.xml new file mode 100644 index 000000000000..c116e42f5e4d --- /dev/null +++ b/doc/manual/release-notes/rl-013.xml @@ -0,0 +1,106 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-0.13"> + +<title>Release 0.13 (November 5, 2009)</title> + +<para>This is primarily a bug fix release. It has some new +features:</para> + +<itemizedlist> + + <listitem> + <para>Syntactic sugar for writing nested attribute sets. Instead of + +<programlisting> +{ + foo = { + bar = 123; + xyzzy = true; + }; + a = { b = { c = "d"; }; }; +} +</programlisting> + + you can write + +<programlisting> +{ + foo.bar = 123; + foo.xyzzy = true; + a.b.c = "d"; +} +</programlisting> + + This is useful, for instance, in NixOS configuration files.</para> + + </listitem> + + <listitem> + <para>Support for Nix channels generated by Hydra, the Nix-based + continuous build system. (Hydra generates NAR archives on the + fly, so the size and hash of these archives isn’t known in + advance.)</para> + </listitem> + + <listitem> + <para>Support <literal>i686-linux</literal> builds directly on + <literal>x86_64-linux</literal> Nix installations. This is + implemented using the <function>personality()</function> syscall, + which causes <command>uname</command> to return + <literal>i686</literal> in child processes.</para> + </listitem> + + <listitem> + <para>Various improvements to the <literal>chroot</literal> + support. Building in a <literal>chroot</literal> works quite well + now.</para> + </listitem> + + <listitem> + <para>Nix no longer blocks if it tries to build a path and another + process is already building the same path. Instead it tries to + build another buildable path first. This improves + parallelism.</para> + </listitem> + + <listitem> + <para>Support for large (> 4 GiB) files in NAR archives.</para> + </listitem> + + <listitem> + <para>Various (performance) improvements to the remote build + mechanism.</para> + </listitem> + + <listitem> + <para>New primops: <varname>builtins.addErrorContext</varname> (to + add a string to stack traces — useful for debugging), + <varname>builtins.isBool</varname>, + <varname>builtins.isString</varname>, + <varname>builtins.isInt</varname>, + <varname>builtins.intersectAttrs</varname>.</para> + </listitem> + + <listitem> + <para>OpenSolaris support (Sander van der Burg).</para> + </listitem> + + <listitem> + <para>Stack traces are no longer displayed unless the + <option>--show-trace</option> option is used.</para> + </listitem> + + <listitem> + <para>The scoping rules for <literal>inherit + (<replaceable>e</replaceable>) ...</literal> in recursive + attribute sets have changed. The expression + <replaceable>e</replaceable> can now refer to the attributes + defined in the containing set.</para> + </listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-014.xml b/doc/manual/release-notes/rl-014.xml new file mode 100644 index 000000000000..456be8b80658 --- /dev/null +++ b/doc/manual/release-notes/rl-014.xml @@ -0,0 +1,44 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-0.14"><title>Release 0.14 (February 4, 2010)</title> + +<para>This release has the following improvements:</para> + +<itemizedlist> + + <listitem> + <para>The garbage collector now starts deleting garbage much + faster than before. It no longer determines liveness of all paths + in the store, but does so on demand.</para> + </listitem> + + <listitem> + <para>Added a new operation, <command>nix-store --query + --roots</command>, that shows the garbage collector roots that + directly or indirectly point to the given store paths.</para> + </listitem> + + <listitem> + <para>Removed support for converting Berkeley DB-based Nix + databases to the new schema.</para> + </listitem> + + <listitem> + <para>Removed the <option>--use-atime</option> and + <option>--max-atime</option> garbage collector options. They were + not very useful in practice.</para> + </listitem> + + <listitem> + <para>On Windows, Nix now requires Cygwin 1.7.x.</para> + </listitem> + + <listitem> + <para>A few bug fixes.</para> + </listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-015.xml b/doc/manual/release-notes/rl-015.xml new file mode 100644 index 000000000000..ae6e12adac5b --- /dev/null +++ b/doc/manual/release-notes/rl-015.xml @@ -0,0 +1,14 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-0.15"> + +<title>Release 0.15 (March 17, 2010)</title> + +<para>This is a bug-fix release. Among other things, it fixes +building on Mac OS X (Snow Leopard), and improves the contents of +<filename>/etc/passwd</filename> and <filename>/etc/group</filename> +in <literal>chroot</literal> builds.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-016.xml b/doc/manual/release-notes/rl-016.xml new file mode 100644 index 000000000000..49ac2ce8c4e0 --- /dev/null +++ b/doc/manual/release-notes/rl-016.xml @@ -0,0 +1,55 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-0.16"> + +<title>Release 0.16 (August 17, 2010)</title> + +<para>This release has the following improvements:</para> + +<itemizedlist> + + <listitem> + <para>The Nix expression evaluator is now much faster in most + cases: typically, <link + xlink:href="http://www.mail-archive.com/nix-dev@cs.uu.nl/msg04113.html">3 + to 8 times compared to the old implementation</link>. It also + uses less memory. It no longer depends on the ATerm + library.</para> + </listitem> + + <listitem> + <para> + Support for configurable parallelism inside builders. Build + scripts have always had the ability to perform multiple build + actions in parallel (for instance, by running <command>make -j + 2</command>), but this was not desirable because the number of + actions to be performed in parallel was not configurable. Nix + now has an option <option>--cores + <replaceable>N</replaceable></option> as well as a configuration + setting <varname>build-cores = + <replaceable>N</replaceable></varname> that causes the + environment variable <envar>NIX_BUILD_CORES</envar> to be set to + <replaceable>N</replaceable> when the builder is invoked. The + builder can use this at its discretion to perform a parallel + build, e.g., by calling <command>make -j + <replaceable>N</replaceable></command>. In Nixpkgs, this can be + enabled on a per-package basis by setting the derivation + attribute <varname>enableParallelBuilding</varname> to + <literal>true</literal>. + </para> + </listitem> + + <listitem> + <para><command>nix-store -q</command> now supports XML output + through the <option>--xml</option> flag.</para> + </listitem> + + <listitem> + <para>Several bug fixes.</para> + </listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-05.xml b/doc/manual/release-notes/rl-05.xml new file mode 100644 index 000000000000..f7b40c11903d --- /dev/null +++ b/doc/manual/release-notes/rl-05.xml @@ -0,0 +1,11 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-relnotes-0.5"> + +<title>Release 0.5 and earlier</title> + +<para>Please refer to the Subversion commit log messages.</para> + +</chapter> diff --git a/doc/manual/release-notes/rl-06.xml b/doc/manual/release-notes/rl-06.xml new file mode 100644 index 000000000000..a4d78edb913f --- /dev/null +++ b/doc/manual/release-notes/rl-06.xml @@ -0,0 +1,122 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-relnotes-0.6"> + +<title>Release 0.6 (November 14, 2004)</title> + +<itemizedlist> + + <listitem> + <para>Rewrite of the normalisation engine. + + <itemizedlist> + + <listitem><para>Multiple builds can now be performed in parallel + (option <option>-j</option>).</para></listitem> + + <listitem><para>Distributed builds. Nix can now call a shell + script to forward builds to Nix installations on remote + machines, which may or may not be of the same platform + type.</para></listitem> + + <listitem><para>Option <option>--fallback</option> allows + recovery from broken substitutes.</para></listitem> + + <listitem><para>Option <option>--keep-going</option> causes + building of other (unaffected) derivations to continue if one + failed.</para></listitem> + + </itemizedlist> + + </para> + + </listitem> + + <listitem><para>Improvements to the garbage collector (i.e., it + should actually work now).</para></listitem> + + <listitem><para>Setuid Nix installations allow a Nix store to be + shared among multiple users.</para></listitem> + + <listitem><para>Substitute registration is much faster + now.</para></listitem> + + <listitem><para>A utility <command>nix-build</command> to build a + Nix expression and create a symlink to the result int the current + directory; useful for testing Nix derivations.</para></listitem> + + <listitem><para>Manual updates.</para></listitem> + + <listitem> + + <para><command>nix-env</command> changes: + + <itemizedlist> + + <listitem><para>Derivations for other platforms are filtered out + (which can be overridden using + <option>--system-filter</option>).</para></listitem> + + <listitem><para><option>--install</option> by default now + uninstall previous derivations with the same + name.</para></listitem> + + <listitem><para><option>--upgrade</option> allows upgrading to a + specific version.</para></listitem> + + <listitem><para>New operation + <option>--delete-generations</option> to remove profile + generations (necessary for effective garbage + collection).</para></listitem> + + <listitem><para>Nicer output (sorted, + columnised).</para></listitem> + + </itemizedlist> + + </para> + + </listitem> + + <listitem><para>More sensible verbosity levels all around (builder + output is now shown always, unless <option>-Q</option> is + given).</para></listitem> + + <listitem> + + <para>Nix expression language changes: + + <itemizedlist> + + <listitem><para>New language construct: <literal>with + <replaceable>E1</replaceable>; + <replaceable>E2</replaceable></literal> brings all attributes + defined in the attribute set <replaceable>E1</replaceable> in + scope in <replaceable>E2</replaceable>.</para></listitem> + + <listitem><para>Added a <function>map</function> + function.</para></listitem> + + <listitem><para>Various new operators (e.g., string + concatenation).</para></listitem> + + </itemizedlist> + + </para> + + </listitem> + + <listitem><para>Expression evaluation is much + faster.</para></listitem> + + <listitem><para>An Emacs mode for editing Nix expressions (with + syntax highlighting and indentation) has been + added.</para></listitem> + + <listitem><para>Many bug fixes.</para></listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-07.xml b/doc/manual/release-notes/rl-07.xml new file mode 100644 index 000000000000..d6d61c12bc50 --- /dev/null +++ b/doc/manual/release-notes/rl-07.xml @@ -0,0 +1,35 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-relnotes-0.7"> + +<title>Release 0.7 (January 12, 2005)</title> + +<itemizedlist> + + <listitem><para>Binary patching. When upgrading components using + pre-built binaries (through nix-pull / nix-channel), Nix can + automatically download and apply binary patches to already installed + components instead of full downloads. Patching is “smart”: if there + is a <emphasis>sequence</emphasis> of patches to an installed + component, Nix will use it. Patches are currently generated + automatically between Nixpkgs (pre-)releases.</para></listitem> + + <listitem><para>Simplifications to the substitute + mechanism.</para></listitem> + + <listitem><para>Nix-pull now stores downloaded manifests in + <filename>/nix/var/nix/manifests</filename>.</para></listitem> + + <listitem><para>Metadata on files in the Nix store is canonicalised + after builds: the last-modified timestamp is set to 0 (00:00:00 + 1/1/1970), the mode is set to 0444 or 0555 (readable and possibly + executable by all; setuid/setgid bits are dropped), and the group is + set to the default. This ensures that the result of a build and an + installation through a substitute is the same; and that timestamp + dependencies are revealed.</para></listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-08.xml b/doc/manual/release-notes/rl-08.xml new file mode 100644 index 000000000000..5f1e940bb794 --- /dev/null +++ b/doc/manual/release-notes/rl-08.xml @@ -0,0 +1,246 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-relnotes-0.8"> + +<title>Release 0.8 (April 11, 2005)</title> + +<para>NOTE: the hashing scheme in Nix 0.8 changed (as detailed below). +As a result, <command>nix-pull</command> manifests and channels built +for Nix 0.7 and below will now work anymore. However, the Nix +expression language has not changed, so you can still build from +source. Also, existing user environments continue to work. Nix 0.8 +will automatically upgrade the database schema of previous +installations when it is first run.</para> + +<para>If you get the error message + +<screen> +you have an old-style manifest `/nix/var/nix/manifests/[...]'; please +delete it</screen> + +you should delete previously downloaded manifests: + +<screen> +$ rm /nix/var/nix/manifests/*</screen> + +If <command>nix-channel</command> gives the error message + +<screen> +manifest `http://catamaran.labs.cs.uu.nl/dist/nix/channels/[channel]/MANIFEST' +is too old (i.e., for Nix <= 0.7)</screen> + +then you should unsubscribe from the offending channel +(<command>nix-channel --remove +<replaceable>URL</replaceable></command>; leave out +<literal>/MANIFEST</literal>), and subscribe to the same URL, with +<literal>channels</literal> replaced by <literal>channels-v3</literal> +(e.g., <link +xlink:href='http://catamaran.labs.cs.uu.nl/dist/nix/channels-v3/nixpkgs-unstable' +/>).</para> + +<para>Nix 0.8 has the following improvements: + +<itemizedlist> + + <listitem><para>The cryptographic hashes used in store paths are now + 160 bits long, but encoded in base-32 so that they are still only 32 + characters long (e.g., + <filename>/nix/store/csw87wag8bqlqk7ipllbwypb14xainap-atk-1.9.0</filename>). + (This is actually a 160 bit truncation of a SHA-256 + hash.)</para></listitem> + + <listitem><para>Big cleanups and simplifications of the basic store + semantics. The notion of “closure store expressions” is gone (and + so is the notion of “successors”); the file system references of a + store path are now just stored in the database.</para> + + <para>For instance, given any store path, you can query its closure: + + <screen> +$ nix-store -qR $(which firefox) +... lots of paths ...</screen> + + Also, Nix now remembers for each store path the derivation that + built it (the “deriver”): + + <screen> +$ nix-store -qR $(which firefox) +/nix/store/4b0jx7vq80l9aqcnkszxhymsf1ffa5jd-firefox-1.0.1.drv</screen> + + So to see the build-time dependencies, you can do + + <screen> +$ nix-store -qR $(nix-store -qd $(which firefox))</screen> + + or, in a nicer format: + + <screen> +$ nix-store -q --tree $(nix-store -qd $(which firefox))</screen> + + </para> + + <para>File system references are also stored in reverse. For + instance, you can query all paths that directly or indirectly use a + certain Glibc: + + <screen> +$ nix-store -q --referrers-closure \ + /nix/store/8lz9yc6zgmc0vlqmn2ipcpkjlmbi51vv-glibc-2.3.4</screen> + + </para> + + </listitem> + + <listitem><para>The concept of fixed-output derivations has been + formalised. Previously, functions such as + <function>fetchurl</function> in Nixpkgs used a hack (namely, + explicitly specifying a store path hash) to prevent changes to, say, + the URL of the file from propagating upwards through the dependency + graph, causing rebuilds of everything. This can now be done cleanly + by specifying the <varname>outputHash</varname> and + <varname>outputHashAlgo</varname> attributes. Nix itself checks + that the content of the output has the specified hash. (This is + important for maintaining certain invariants necessary for future + work on secure shared stores.)</para></listitem> + + <listitem><para>One-click installation :-) It is now possible to + install any top-level component in Nixpkgs directly, through the web + — see, e.g., <link + xlink:href='http://catamaran.labs.cs.uu.nl/dist/nixpkgs-0.8/' />. + All you have to do is associate + <filename>/nix/bin/nix-install-package</filename> with the MIME type + <literal>application/nix-package</literal> (or the extension + <filename>.nixpkg</filename>), and clicking on a package link will + cause it to be installed, with all appropriate dependencies. If you + just want to install some specific application, this is easier than + subscribing to a channel.</para></listitem> + + <listitem><para><command>nix-store -r + <replaceable>PATHS</replaceable></command> now builds all the + derivations PATHS in parallel. Previously it did them sequentially + (though exploiting possible parallelism between subderivations). + This is nice for build farms.</para></listitem> + + <listitem><para><command>nix-channel</command> has new operations + <option>--list</option> and + <option>--remove</option>.</para></listitem> + + <listitem><para>New ways of installing components into user + environments: + + <itemizedlist> + + <listitem><para>Copy from another user environment: + + <screen> +$ nix-env -i --from-profile .../other-profile firefox</screen> + + </para></listitem> + + <listitem><para>Install a store derivation directly (bypassing the + Nix expression language entirely): + + <screen> +$ nix-env -i /nix/store/z58v41v21xd3...-aterm-2.3.1.drv</screen> + + (This is used to implement <command>nix-install-package</command>, + which is therefore immune to evolution in the Nix expression + language.)</para></listitem> + + <listitem><para>Install an already built store path directly: + + <screen> +$ nix-env -i /nix/store/hsyj5pbn0d9i...-aterm-2.3.1</screen> + + </para></listitem> + + <listitem><para>Install the result of a Nix expression specified + as a command-line argument: + + <screen> +$ nix-env -f .../i686-linux.nix -i -E 'x: x.firefoxWrapper'</screen> + + The difference with the normal installation mode is that + <option>-E</option> does not use the <varname>name</varname> + attributes of derivations. Therefore, this can be used to + disambiguate multiple derivations with the same + name.</para></listitem> + + </itemizedlist></para></listitem> + + <listitem><para>A hash of the contents of a store path is now stored + in the database after a successful build. This allows you to check + whether store paths have been tampered with: <command>nix-store + --verify --check-contents</command>.</para></listitem> + + <listitem> + + <para>Implemented a concurrent garbage collector. It is now + always safe to run the garbage collector, even if other Nix + operations are happening simultaneously.</para> + + <para>However, there can still be GC races if you use + <command>nix-instantiate</command> and <command>nix-store + --realise</command> directly to build things. To prevent races, + use the <option>--add-root</option> flag of those commands.</para> + + </listitem> + + <listitem><para>The garbage collector now finally deletes paths in + the right order (i.e., topologically sorted under the “references” + relation), thus making it safe to interrupt the collector without + risking a store that violates the closure + invariant.</para></listitem> + + <listitem><para>Likewise, the substitute mechanism now downloads + files in the right order, thus preserving the closure invariant at + all times.</para></listitem> + + <listitem><para>The result of <command>nix-build</command> is now + registered as a root of the garbage collector. If the + <filename>./result</filename> link is deleted, the GC root + disappears automatically.</para></listitem> + + <listitem> + + <para>The behaviour of the garbage collector can be changed + globally by setting options in + <filename>/nix/etc/nix/nix.conf</filename>. + + <itemizedlist> + + <listitem><para><literal>gc-keep-derivations</literal> specifies + whether deriver links should be followed when searching for live + paths.</para></listitem> + + <listitem><para><literal>gc-keep-outputs</literal> specifies + whether outputs of derivations should be followed when searching + for live paths.</para></listitem> + + <listitem><para><literal>env-keep-derivations</literal> + specifies whether user environments should store the paths of + derivations when they are added (thus keeping the derivations + alive).</para></listitem> + + </itemizedlist> + + </para></listitem> + + <listitem><para>New <command>nix-env</command> query flags + <option>--drv-path</option> and + <option>--out-path</option>.</para></listitem> + + <listitem><para><command>fetchurl</command> allows SHA-1 and SHA-256 + in addition to MD5. Just specify the attribute + <varname>sha1</varname> or <varname>sha256</varname> instead of + <varname>md5</varname>.</para></listitem> + + <listitem><para>Manual updates.</para></listitem> + +</itemizedlist> + +</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-081.xml b/doc/manual/release-notes/rl-081.xml new file mode 100644 index 000000000000..986e4cb834ef --- /dev/null +++ b/doc/manual/release-notes/rl-081.xml @@ -0,0 +1,21 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-relnotes-0.8.1"> + +<title>Release 0.8.1 (April 13, 2005)</title> + +<para>This is a bug fix release.</para> + +<itemizedlist> + + <listitem><para>Patch downloading was broken.</para></listitem> + + <listitem><para>The garbage collector would not delete paths that + had references from invalid (but substitutable) + paths.</para></listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-09.xml b/doc/manual/release-notes/rl-09.xml new file mode 100644 index 000000000000..be0e5fa289e5 --- /dev/null +++ b/doc/manual/release-notes/rl-09.xml @@ -0,0 +1,98 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-relnotes-0.9"> + +<title>Release 0.9 (September 16, 2005)</title> + +<para>NOTE: this version of Nix uses Berkeley DB 4.3 instead of 4.2. +The database is upgraded automatically, but you should be careful not +to use old versions of Nix that still use Berkeley DB 4.2. In +particular, if you use a Nix installed through Nix, you should run + +<screen> +$ nix-store --clear-substitutes</screen> + +first.</para> + + +<itemizedlist> + + <listitem><para>Unpacking of patch sequences is much faster now + since we no longer do redundant unpacking and repacking of + intermediate paths.</para></listitem> + + <listitem><para>Nix now uses Berkeley DB 4.3.</para></listitem> + + <listitem><para>The <function>derivation</function> primitive is + lazier. Attributes of dependent derivations can mutually refer to + each other (as long as there are no data dependencies on the + <varname>outPath</varname> and <varname>drvPath</varname> attributes + computed by <function>derivation</function>).</para> + + <para>For example, the expression <literal>derivation + attrs</literal> now evaluates to (essentially) + + <programlisting> +attrs // { + type = "derivation"; + outPath = derivation! attrs; + drvPath = derivation! attrs; +}</programlisting> + + where <function>derivation!</function> is a primop that does the + actual derivation instantiation (i.e., it does what + <function>derivation</function> used to do). The advantage is that + it allows commands such as <command>nix-env -qa</command> and + <command>nix-env -i</command> to be much faster since they no longer + need to instantiate all derivations, just the + <varname>name</varname> attribute.</para> + + <para>Also, it allows derivations to cyclically reference each + other, for example, + + <programlisting> +webServer = derivation { + ... + hostName = "svn.cs.uu.nl"; + services = [svnService]; +}; +  +svnService = derivation { + ... + hostName = webServer.hostName; +};</programlisting> + + Previously, this would yield a black hole (infinite recursion).</para> + + </listitem> + + <listitem><para><command>nix-build</command> now defaults to using + <filename>./default.nix</filename> if no Nix expression is + specified.</para></listitem> + + <listitem><para><command>nix-instantiate</command>, when applied to + a Nix expression that evaluates to a function, will call the + function automatically if all its arguments have + defaults.</para></listitem> + + <listitem><para>Nix now uses libtool to build dynamic libraries. + This reduces the size of executables.</para></listitem> + + <listitem><para>A new list concatenation operator + <literal>++</literal>. For example, <literal>[1 2 3] ++ [4 5 + 6]</literal> evaluates to <literal>[1 2 3 4 5 + 6]</literal>.</para></listitem> + + <listitem><para>Some currently undocumented primops to support + low-level build management using Nix (i.e., using Nix as a Make + replacement). See the commit messages for <literal>r3578</literal> + and <literal>r3580</literal>.</para></listitem> + + <listitem><para>Various bug fixes and performance + improvements.</para></listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-091.xml b/doc/manual/release-notes/rl-091.xml new file mode 100644 index 000000000000..f90206d9532c --- /dev/null +++ b/doc/manual/release-notes/rl-091.xml @@ -0,0 +1,13 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-relnotes-0.9.1"> + +<title>Release 0.9.1 (September 20, 2005)</title> + +<para>This bug fix release addresses a problem with the ATerm library +when the <option>--with-aterm</option> flag in +<command>configure</command> was <emphasis>not</emphasis> used.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-092.xml b/doc/manual/release-notes/rl-092.xml new file mode 100644 index 000000000000..ea0412df2fa2 --- /dev/null +++ b/doc/manual/release-notes/rl-092.xml @@ -0,0 +1,28 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-relnotes-0.9.2"> + +<title>Release 0.9.2 (September 21, 2005)</title> + +<para>This bug fix release fixes two problems on Mac OS X: + +<itemizedlist> + + <listitem><para>If Nix was linked against statically linked versions + of the ATerm or Berkeley DB library, there would be dynamic link + errors at runtime.</para></listitem> + + <listitem><para><command>nix-pull</command> and + <command>nix-push</command> intermittently failed due to race + conditions involving pipes and child processes with error messages + such as <literal>open2: open(GLOB(0x180b2e4), >&=9) failed: Bad + file descriptor at /nix/bin/nix-pull line 77</literal> (issue + <literal>NIX-14</literal>).</para></listitem> + +</itemizedlist> + +</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-10.xml b/doc/manual/release-notes/rl-10.xml new file mode 100644 index 000000000000..21721b6cc6de --- /dev/null +++ b/doc/manual/release-notes/rl-10.xml @@ -0,0 +1,119 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.0"> + +<title>Release 1.0 (May 11, 2012)</title> + +<para>There have been numerous improvements and bug fixes since the +previous release. Here are the most significant:</para> + +<itemizedlist> + + <listitem> + <para>Nix can now optionally use the Boehm garbage collector. + This significantly reduces the Nix evaluator’s memory footprint, + especially when evaluating large NixOS system configurations. It + can be enabled using the <option>--enable-gc</option> configure + option.</para> + </listitem> + + <listitem> + <para>Nix now uses SQLite for its database. This is faster and + more flexible than the old <emphasis>ad hoc</emphasis> format. + SQLite is also used to cache the manifests in + <filename>/nix/var/nix/manifests</filename>, resulting in a + significant speedup.</para> + </listitem> + + <listitem> + <para>Nix now has an search path for expressions. The search path + is set using the environment variable <envar>NIX_PATH</envar> and + the <option>-I</option> command line option. In Nix expressions, + paths between angle brackets are used to specify files that must + be looked up in the search path. For instance, the expression + <literal><nixpkgs/default.nix></literal> looks for a file + <filename>nixpkgs/default.nix</filename> relative to every element + in the search path.</para> + </listitem> + + <listitem> + <para>The new command <command>nix-build --run-env</command> + builds all dependencies of a derivation, then starts a shell in an + environment containing all variables from the derivation. This is + useful for reproducing the environment of a derivation for + development.</para> + </listitem> + + <listitem> + <para>The new command <command>nix-store --verify-path</command> + verifies that the contents of a store path have not + changed.</para> + </listitem> + + <listitem> + <para>The new command <command>nix-store --print-env</command> + prints out the environment of a derivation in a format that can be + evaluated by a shell.</para> + </listitem> + + <listitem> + <para>Attribute names can now be arbitrary strings. For instance, + you can write <literal>{ "foo-1.2" = …; "bla bla" = …; }."bla + bla"</literal>.</para> + </listitem> + + <listitem> + <para>Attribute selection can now provide a default value using + the <literal>or</literal> operator. For instance, the expression + <literal>x.y.z or e</literal> evaluates to the attribute + <literal>x.y.z</literal> if it exists, and <literal>e</literal> + otherwise.</para> + </listitem> + + <listitem> + <para>The right-hand side of the <literal>?</literal> operator can + now be an attribute path, e.g., <literal>attrs ? + a.b.c</literal>.</para> + </listitem> + + <listitem> + <para>On Linux, Nix will now make files in the Nix store immutable + on filesystems that support it. This prevents accidental + modification of files in the store by the root user.</para> + </listitem> + + <listitem> + <para>Nix has preliminary support for derivations with multiple + outputs. This is useful because it allows parts of a package to + be deployed and garbage-collected separately. For instance, + development parts of a package such as header files or static + libraries would typically not be part of the closure of an + application, resulting in reduced disk usage and installation + time.</para> + </listitem> + + <listitem> + <para>The Nix store garbage collector is faster and holds the + global lock for a shorter amount of time.</para> + </listitem> + + <listitem> + <para>The option <option>--timeout</option> (corresponding to the + configuration setting <literal>build-timeout</literal>) allows you + to set an absolute timeout on builds — if a build runs for more than + the given number of seconds, it is terminated. This is useful for + recovering automatically from builds that are stuck in an infinite + loop but keep producing output, and for which + <literal>--max-silent-time</literal> is ineffective.</para> + </listitem> + + <listitem> + <para>Nix development has moved to GitHub (<link + xlink:href="https://github.com/NixOS/nix" />).</para> + </listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-11.xml b/doc/manual/release-notes/rl-11.xml new file mode 100644 index 000000000000..db9939be1f28 --- /dev/null +++ b/doc/manual/release-notes/rl-11.xml @@ -0,0 +1,100 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.1"> + +<title>Release 1.1 (July 18, 2012)</title> + +<para>This release has the following improvements:</para> + +<itemizedlist> + + <listitem> + <para>On Linux, when doing a chroot build, Nix now uses various + namespace features provided by the Linux kernel to improve + build isolation. Namely: + <itemizedlist> + <listitem><para>The private network namespace ensures that + builders cannot talk to the outside world (or vice versa): each + build only sees a private loopback interface. This also means + that two concurrent builds can listen on the same port (e.g. as + part of a test) without conflicting with each + other.</para></listitem> + <listitem><para>The PID namespace causes each build to start as + PID 1. Processes outside of the chroot are not visible to those + on the inside. On the other hand, processes inside the chroot + <emphasis>are</emphasis> visible from the outside (though with + different PIDs).</para></listitem> + <listitem><para>The IPC namespace prevents the builder from + communicating with outside processes using SysV IPC mechanisms + (shared memory, message queues, semaphores). It also ensures + that all IPC objects are destroyed when the builder + exits.</para></listitem> + <listitem><para>The UTS namespace ensures that builders see a + hostname of <literal>localhost</literal> rather than the actual + hostname.</para></listitem> + <listitem><para>The private mount namespace was already used by + Nix to ensure that the bind-mounts used to set up the chroot are + cleaned up automatically.</para></listitem> + </itemizedlist> + </para> + </listitem> + + <listitem> + <para>Build logs are now compressed using + <command>bzip2</command>. The command <command>nix-store + -l</command> decompresses them on the fly. This can be disabled + by setting the option <literal>build-compress-log</literal> to + <literal>false</literal>.</para> + </listitem> + + <listitem> + <para>The creation of build logs in + <filename>/nix/var/log/nix/drvs</filename> can be disabled by + setting the new option <literal>build-keep-log</literal> to + <literal>false</literal>. This is useful, for instance, for Hydra + build machines.</para> + </listitem> + + <listitem> + <para>Nix now reserves some space in + <filename>/nix/var/nix/db/reserved</filename> to ensure that the + garbage collector can run successfully if the disk is full. This + is necessary because SQLite transactions fail if the disk is + full.</para> + </listitem> + + <listitem> + <para>Added a basic <function>fetchurl</function> function. This + is not intended to replace the <function>fetchurl</function> in + Nixpkgs, but is useful for bootstrapping; e.g., it will allow us + to get rid of the bootstrap binaries in the Nixpkgs source tree + and download them instead. You can use it by doing + <literal>import <nix/fetchurl.nix> { url = + <replaceable>url</replaceable>; sha256 = + "<replaceable>hash</replaceable>"; }</literal>. (Shea Levy)</para> + </listitem> + + <listitem> + <para>Improved RPM spec file. (Michel Alexandre Salim)</para> + </listitem> + + <listitem> + <para>Support for on-demand socket-based activation in the Nix + daemon with <command>systemd</command>.</para> + </listitem> + + <listitem> + <para>Added a manpage for + <citerefentry><refentrytitle>nix.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> + </listitem> + + <listitem> + <para>When using the Nix daemon, the <option>-s</option> flag in + <command>nix-env -qa</command> is now much faster.</para> + </listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-12.xml b/doc/manual/release-notes/rl-12.xml new file mode 100644 index 000000000000..72d164f00c01 --- /dev/null +++ b/doc/manual/release-notes/rl-12.xml @@ -0,0 +1,157 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.2"> + +<title>Release 1.2 (December 6, 2012)</title> + +<para>This release has the following improvements and changes:</para> + +<itemizedlist> + + <listitem> + <para>Nix has a new binary substituter mechanism: the + <emphasis>binary cache</emphasis>. A binary cache contains + pre-built binaries of Nix packages. Whenever Nix wants to build a + missing Nix store path, it will check a set of binary caches to + see if any of them has a pre-built binary of that path. The + configuration setting <option>binary-caches</option> contains a + list of URLs of binary caches. For instance, doing +<screen> +$ nix-env -i thunderbird --option binary-caches http://cache.nixos.org +</screen> + will install Thunderbird and its dependencies, using the available + pre-built binaries in <uri>http://cache.nixos.org</uri>. + The main advantage over the old “manifest”-based method of getting + pre-built binaries is that you don’t have to worry about your + manifest being in sync with the Nix expressions you’re installing + from; i.e., you don’t need to run <command>nix-pull</command> to + update your manifest. It’s also more scalable because you don’t + need to redownload a giant manifest file every time. + </para> + + <para>A Nix channel can provide a binary cache URL that will be + used automatically if you subscribe to that channel. If you use + the Nixpkgs or NixOS channels + (<uri>http://nixos.org/channels</uri>) you automatically get the + cache <uri>http://cache.nixos.org</uri>.</para> + + <para>Binary caches are created using <command>nix-push</command>. + For details on the operation and format of binary caches, see the + <command>nix-push</command> manpage. More details are provided in + <link xlink:href="http://lists.science.uu.nl/pipermail/nix-dev/2012-September/009826.html">this + nix-dev posting</link>.</para> + </listitem> + + <listitem> + <para>Multiple output support should now be usable. A derivation + can declare that it wants to produce multiple store paths by + saying something like +<programlisting> +outputs = [ "lib" "headers" "doc" ]; +</programlisting> + This will cause Nix to pass the intended store path of each output + to the builder through the environment variables + <literal>lib</literal>, <literal>headers</literal> and + <literal>doc</literal>. Other packages can refer to a specific + output by referring to + <literal><replaceable>pkg</replaceable>.<replaceable>output</replaceable></literal>, + e.g. +<programlisting> +buildInputs = [ pkg.lib pkg.headers ]; +</programlisting> + If you install a package with multiple outputs using + <command>nix-env</command>, each output path will be symlinked + into the user environment.</para> + </listitem> + + <listitem> + <para>Dashes are now valid as part of identifiers and attribute + names.</para> + </listitem> + + <listitem> + <para>The new operation <command>nix-store --repair-path</command> + allows corrupted or missing store paths to be repaired by + redownloading them. <command>nix-store --verify --check-contents + --repair</command> will scan and repair all paths in the Nix + store. Similarly, <command>nix-env</command>, + <command>nix-build</command>, <command>nix-instantiate</command> + and <command>nix-store --realise</command> have a + <option>--repair</option> flag to detect and fix bad paths by + rebuilding or redownloading them.</para> + </listitem> + + <listitem> + <para>Nix no longer sets the immutable bit on files in the Nix + store. Instead, the recommended way to guard the Nix store + against accidental modification on Linux is to make it a read-only + bind mount, like this: + +<screen> +$ mount --bind /nix/store /nix/store +$ mount -o remount,ro,bind /nix/store +</screen> + + Nix will automatically make <filename>/nix/store</filename> + writable as needed (using a private mount namespace) to allow + modifications.</para> + </listitem> + + <listitem> + <para>Store optimisation (replacing identical files in the store + with hard links) can now be done automatically every time a path + is added to the store. This is enabled by setting the + configuration option <literal>auto-optimise-store</literal> to + <literal>true</literal> (disabled by default).</para> + </listitem> + + <listitem> + <para>Nix now supports <command>xz</command> compression for NARs + in addition to <command>bzip2</command>. It compresses about 30% + better on typical archives and decompresses about twice as + fast.</para> + </listitem> + + <listitem> + <para>Basic Nix expression evaluation profiling: setting the + environment variable <envar>NIX_COUNT_CALLS</envar> to + <literal>1</literal> will cause Nix to print how many times each + primop or function was executed.</para> + </listitem> + + <listitem> + <para>New primops: <varname>concatLists</varname>, + <varname>elem</varname>, <varname>elemAt</varname> and + <varname>filter</varname>.</para> + </listitem> + + <listitem> + <para>The command <command>nix-copy-closure</command> has a new + flag <option>--use-substitutes</option> (<option>-s</option>) to + download missing paths on the target machine using the substitute + mechanism.</para> + </listitem> + + <listitem> + <para>The command <command>nix-worker</command> has been renamed + to <command>nix-daemon</command>. Support for running the Nix + worker in “slave” mode has been removed.</para> + </listitem> + + <listitem> + <para>The <option>--help</option> flag of every Nix command now + invokes <command>man</command>.</para> + </listitem> + + <listitem> + <para>Chroot builds are now supported on systemd machines.</para> + </listitem> + +</itemizedlist> + +<para>This release has contributions from Eelco Dolstra, Florian +Friesdorf, Mats Erik Andersson and Shea Levy.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-13.xml b/doc/manual/release-notes/rl-13.xml new file mode 100644 index 000000000000..8e5264840c38 --- /dev/null +++ b/doc/manual/release-notes/rl-13.xml @@ -0,0 +1,19 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.3"> + +<title>Release 1.3 (January 4, 2013)</title> + +<para>This is primarily a bug fix release. When this version is first +run on Linux, it removes any immutable bits from the Nix store and +increases the schema version of the Nix store. (The previous release +removed support for setting the immutable bit; this release clears any +remaining immutable bits to make certain operations more +efficient.)</para> + +<para>This release has contributions from Eelco Dolstra and Stuart +Pernsteiner.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-14.xml b/doc/manual/release-notes/rl-14.xml new file mode 100644 index 000000000000..d1a8cd6d867f --- /dev/null +++ b/doc/manual/release-notes/rl-14.xml @@ -0,0 +1,39 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.4"> + +<title>Release 1.4 (February 26, 2013)</title> + +<para>This release fixes a security bug in multi-user operation. It +was possible for derivations to cause the mode of files outside of the +Nix store to be changed to 444 (read-only but world-readable) by +creating hard links to those files (<link +xlink:href="https://github.com/NixOS/nix/commit/5526a282b5b44e9296e61e07d7d2626a79141ac4">details</link>).</para> + +<para>There are also the following improvements:</para> + +<itemizedlist> + + <listitem><para>New built-in function: + <function>builtins.hashString</function>.</para></listitem> + + <listitem><para>Build logs are now stored in + <filename>/nix/var/log/nix/drvs/<replaceable>XX</replaceable>/</filename>, + where <replaceable>XX</replaceable> is the first two characters of + the derivation. This is useful on machines that keep a lot of build + logs (such as Hydra servers).</para></listitem> + + <listitem><para>The function <function>corepkgs/fetchurl</function> + can now make the downloaded file executable. This will allow + getting rid of all bootstrap binaries in the Nixpkgs source + tree.</para></listitem> + + <listitem><para>Language change: The expression <literal>"${./path} + ..."</literal> now evaluates to a string instead of a + path.</para></listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-15.xml b/doc/manual/release-notes/rl-15.xml new file mode 100644 index 000000000000..7319b52d81dc --- /dev/null +++ b/doc/manual/release-notes/rl-15.xml @@ -0,0 +1,12 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.5"> + +<title>Release 1.5 (February 27, 2013)</title> + +<para>This is a brown paper bag release to fix a regression introduced +by the hard link security fix in 1.4.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-151.xml b/doc/manual/release-notes/rl-151.xml new file mode 100644 index 000000000000..625d0afc4290 --- /dev/null +++ b/doc/manual/release-notes/rl-151.xml @@ -0,0 +1,12 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.5.1"> + +<title>Release 1.5.1 (February 28, 2013)</title> + +<para>The bug fix to the bug fix had a bug itself, of course. But +this time it will work for sure!</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-152.xml b/doc/manual/release-notes/rl-152.xml new file mode 100644 index 000000000000..1446992a9ff1 --- /dev/null +++ b/doc/manual/release-notes/rl-152.xml @@ -0,0 +1,12 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.5.2"> + +<title>Release 1.5.2 (May 13, 2013)</title> + +<para>This is primarily a bug fix release. It has contributions from +Eelco Dolstra, Lluís Batlle i Rossell and Shea Levy.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-16.xml b/doc/manual/release-notes/rl-16.xml new file mode 100644 index 000000000000..c0285b66f1ad --- /dev/null +++ b/doc/manual/release-notes/rl-16.xml @@ -0,0 +1,127 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.6.0"> + +<title>Release 1.6 (September 10, 2013)</title> + +<para>In addition to the usual bug fixes, this release has several new +features:</para> + +<itemizedlist> + + <listitem> + <para>The command <command>nix-build --run-env</command> has been + renamed to <command>nix-shell</command>.</para> + </listitem> + + <listitem> + <para><command>nix-shell</command> now sources + <filename>$stdenv/setup</filename> <emphasis>inside</emphasis> the + interactive shell, rather than in a parent shell. This ensures + that shell functions defined by <literal>stdenv</literal> can be + used in the interactive shell.</para> + </listitem> + + <listitem> + <para><command>nix-shell</command> has a new flag + <option>--pure</option> to clear the environment, so you get an + environment that more closely corresponds to the “real” Nix build. + </para> + </listitem> + + <listitem> + <para><command>nix-shell</command> now sets the shell prompt + (<envar>PS1</envar>) to ensure that Nix shells are distinguishable + from your regular shells.</para> + </listitem> + + <listitem> + <para><command>nix-env</command> no longer requires a + <literal>*</literal> argument to match all packages, so + <literal>nix-env -qa</literal> is equivalent to <literal>nix-env + -qa '*'</literal>.</para> + </listitem> + + <listitem> + <para><command>nix-env -i</command> has a new flag + <option>--remove-all</option> (<option>-r</option>) to remove all + previous packages from the profile. This makes it easier to do + declarative package management similar to NixOS’s + <option>environment.systemPackages</option>. For instance, if you + have a specification <filename>my-packages.nix</filename> like this: + +<programlisting> +with import <nixpkgs> {}; +[ thunderbird + geeqie + ... +] +</programlisting> + + then after any change to this file, you can run: + +<screen> +$ nix-env -f my-packages.nix -ir +</screen> + + to update your profile to match the specification.</para> + </listitem> + + <listitem> + <para>The ‘<literal>with</literal>’ language construct is now more + lazy. It only evaluates its argument if a variable might actually + refer to an attribute in the argument. For instance, this now + works: + +<programlisting> +let + pkgs = with pkgs; { foo = "old"; bar = foo; } // overrides; + overrides = { foo = "new"; }; +in pkgs.bar +</programlisting> + + This evaluates to <literal>"new"</literal>, while previously it + gave an “infinite recursion” error.</para> + </listitem> + + <listitem> + <para>Nix now has proper integer arithmetic operators. For + instance, you can write <literal>x + y</literal> instead of + <literal>builtins.add x y</literal>, or <literal>x < + y</literal> instead of <literal>builtins.lessThan x y</literal>. + The comparison operators also work on strings.</para> + </listitem> + + <listitem> + <para>On 64-bit systems, Nix integers are now 64 bits rather than + 32 bits.</para> + </listitem> + + <listitem> + <para>When using the Nix daemon, the <command>nix-daemon</command> + worker process now runs on the same CPU as the client, on systems + that support setting CPU affinity. This gives a significant speedup + on some systems.</para> + </listitem> + + <listitem> + <para>If a stack overflow occurs in the Nix evaluator, you now get + a proper error message (rather than “Segmentation fault”) on some + systems.</para> + </listitem> + + <listitem> + <para>In addition to directories, you can now bind-mount regular + files in chroots through the (now misnamed) option + <option>build-chroot-dirs</option>.</para> + </listitem> + +</itemizedlist> + +<para>This release has contributions from Domen Kožar, Eelco Dolstra, +Florian Friesdorf, Gergely Risko, Ivan Kozik, Ludovic Courtès and Shea +Levy.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-161.xml b/doc/manual/release-notes/rl-161.xml new file mode 100644 index 000000000000..f6d3a6ba6aa9 --- /dev/null +++ b/doc/manual/release-notes/rl-161.xml @@ -0,0 +1,69 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.6.1"> + +<title>Release 1.6.1 (October 28, 2013)</title> + +<para>This is primarily a bug fix release. Changes of interest +are:</para> + +<itemizedlist> + + <listitem> + <para>Nix 1.6 accidentally changed the semantics of antiquoted + paths in strings, such as <literal>"${/foo}/bar"</literal>. This + release reverts to the Nix 1.5.3 behaviour.</para> + </listitem> + + <listitem> + <para>Previously, Nix optimised expressions such as + <literal>"${<replaceable>expr</replaceable>}"</literal> to + <replaceable>expr</replaceable>. Thus it neither checked whether + <replaceable>expr</replaceable> could be coerced to a string, nor + applied such coercions. This meant that + <literal>"${123}"</literal> evaluatued to <literal>123</literal>, + and <literal>"${./foo}"</literal> evaluated to + <literal>./foo</literal> (even though + <literal>"${./foo} "</literal> evaluates to + <literal>"/nix/store/<replaceable>hash</replaceable>-foo "</literal>). + Nix now checks the type of antiquoted expressions and + applies coercions.</para> + </listitem> + + <listitem> + <para>Nix now shows the exact position of undefined variables. In + particular, undefined variable errors in a <literal>with</literal> + previously didn't show <emphasis>any</emphasis> position + information, so this makes it a lot easier to fix such + errors.</para> + </listitem> + + <listitem> + <para>Undefined variables are now treated consistently. + Previously, the <function>tryEval</function> function would catch + undefined variables inside a <literal>with</literal> but not + outside. Now <function>tryEval</function> never catches undefined + variables.</para> + </listitem> + + <listitem> + <para>Bash completion in <command>nix-shell</command> now works + correctly.</para> + </listitem> + + <listitem> + <para>Stack traces are less verbose: they no longer show calls to + builtin functions and only show a single line for each derivation + on the call stack.</para> + </listitem> + + <listitem> + <para>New built-in function: <function>builtins.typeOf</function>, + which returns the type of its argument as a string.</para> + </listitem> + +</itemizedlist> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-17.xml b/doc/manual/release-notes/rl-17.xml new file mode 100644 index 000000000000..7257bc869b25 --- /dev/null +++ b/doc/manual/release-notes/rl-17.xml @@ -0,0 +1,263 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.7"> + +<title>Release 1.7 (April 11, 2014)</title> + +<para>In addition to the usual bug fixes, this release has the +following new features:</para> + +<itemizedlist> + + <listitem> + <para>Antiquotation is now allowed inside of quoted attribute + names (e.g. <literal>set."${foo}"</literal>). In the case where + the attribute name is just a single antiquotation, the quotes can + be dropped (e.g. the above example can be written + <literal>set.${foo}</literal>). If an attribute name inside of a + set declaration evaluates to <literal>null</literal> (e.g. + <literal>{ ${null} = false; }</literal>), then that attribute is + not added to the set.</para> + </listitem> + + <listitem> + <para>Experimental support for cryptographically signed binary + caches. See <link + xlink:href="https://github.com/NixOS/nix/commit/0fdf4da0e979f992db75cc17376e455ddc5a96d8">the + commit for details</link>.</para> + </listitem> + + <listitem> + <para>An experimental new substituter, + <command>download-via-ssh</command>, that fetches binaries from + remote machines via SSH. Specifying the flags <literal>--option + use-ssh-substituter true --option ssh-substituter-hosts + <replaceable>user@hostname</replaceable></literal> will cause Nix + to download binaries from the specified machine, if it has + them.</para> + </listitem> + + <listitem> + <para><command>nix-store -r</command> and + <command>nix-build</command> have a new flag, + <option>--check</option>, that builds a previously built + derivation again, and prints an error message if the output is not + exactly the same. This helps to verify whether a derivation is + truly deterministic. For example: + +<screen> +$ nix-build '<nixpkgs>' -A patchelf +<replaceable>…</replaceable> +$ nix-build '<nixpkgs>' -A patchelf --check +<replaceable>…</replaceable> +error: derivation `/nix/store/1ipvxs…-patchelf-0.6' may not be deterministic: + hash mismatch in output `/nix/store/4pc1dm…-patchelf-0.6.drv' +</screen> + + </para> + + </listitem> + + <listitem> + <para>The <command>nix-instantiate</command> flags + <option>--eval-only</option> and <option>--parse-only</option> + have been renamed to <option>--eval</option> and + <option>--parse</option>, respectively.</para> + </listitem> + + <listitem> + <para><command>nix-instantiate</command>, + <command>nix-build</command> and <command>nix-shell</command> now + have a flag <option>--expr</option> (or <option>-E</option>) that + allows you to specify the expression to be evaluated as a command + line argument. For instance, <literal>nix-instantiate --eval -E + '1 + 2'</literal> will print <literal>3</literal>.</para> + </listitem> + + <listitem> + <para><command>nix-shell</command> improvements:</para> + + <itemizedlist> + + <listitem> + <para>It has a new flag, <option>--packages</option> (or + <option>-p</option>), that sets up a build environment + containing the specified packages from Nixpkgs. For example, + the command + +<screen> +$ nix-shell -p sqlite xorg.libX11 hello +</screen> + + will start a shell in which the given packages are + present.</para> + </listitem> + + <listitem> + <para>It now uses <filename>shell.nix</filename> as the + default expression, falling back to + <filename>default.nix</filename> if the former doesn’t + exist. This makes it convenient to have a + <filename>shell.nix</filename> in your project to set up a + nice development environment.</para> + </listitem> + + <listitem> + <para>It evaluates the derivation attribute + <varname>shellHook</varname>, if set. Since + <literal>stdenv</literal> does not normally execute this hook, + it allows you to do <command>nix-shell</command>-specific + setup.</para> + </listitem> + + <listitem> + <para>It preserves the user’s timezone setting.</para> + </listitem> + + </itemizedlist> + + </listitem> + + <listitem> + <para>In chroots, Nix now sets up a <filename>/dev</filename> + containing only a minimal set of devices (such as + <filename>/dev/null</filename>). Note that it only does this if + you <emphasis>don’t</emphasis> have <filename>/dev</filename> + listed in your <option>build-chroot-dirs</option> setting; + otherwise, it will bind-mount the <literal>/dev</literal> from + outside the chroot.</para> + + <para>Similarly, if you don’t have <filename>/dev/pts</filename> listed + in <option>build-chroot-dirs</option>, Nix will mount a private + <literal>devpts</literal> filesystem on the chroot’s + <filename>/dev/pts</filename>.</para> + + </listitem> + + <listitem> + <para>New built-in function: <function>builtins.toJSON</function>, + which returns a JSON representation of a value.</para> + </listitem> + + <listitem> + <para><command>nix-env -q</command> has a new flag + <option>--json</option> to print a JSON representation of the + installed or available packages.</para> + </listitem> + + <listitem> + <para><command>nix-env</command> now supports meta attributes with + more complex values, such as attribute sets.</para> + </listitem> + + <listitem> + <para>The <option>-A</option> flag now allows attribute names with + dots in them, e.g. + +<screen> +$ nix-instantiate --eval '<nixos>' -A 'config.systemd.units."nscd.service".text' +</screen> + + </para> + </listitem> + + <listitem> + <para>The <option>--max-freed</option> option to + <command>nix-store --gc</command> now accepts a unit + specifier. For example, <literal>nix-store --gc --max-freed + 1G</literal> will free up to 1 gigabyte of disk space.</para> + </listitem> + + <listitem> + <para><command>nix-collect-garbage</command> has a new flag + <option>--delete-older-than</option> + <replaceable>N</replaceable><literal>d</literal>, which deletes + all user environment generations older than + <replaceable>N</replaceable> days. Likewise, <command>nix-env + --delete-generations</command> accepts a + <replaceable>N</replaceable><literal>d</literal> age limit.</para> + </listitem> + + <listitem> + <para>Nix now heuristically detects whether a build failure was + due to a disk-full condition. In that case, the build is not + flagged as “permanently failed”. This is mostly useful for Hydra, + which needs to distinguish between permanent and transient build + failures.</para> + </listitem> + + <listitem> + <para>There is a new symbol <literal>__curPos</literal> that + expands to an attribute set containing its file name and line and + column numbers, e.g. <literal>{ file = "foo.nix"; line = 10; + column = 5; }</literal>. There also is a new builtin function, + <varname>unsafeGetAttrPos</varname>, that returns the position of + an attribute. This is used by Nixpkgs to provide location + information in error messages, e.g. + +<screen> +$ nix-build '<nixpkgs>' -A libreoffice --argstr system x86_64-darwin +error: the package ‘libreoffice-4.0.5.2’ in ‘.../applications/office/libreoffice/default.nix:263’ + is not supported on ‘x86_64-darwin’ +</screen> + + </para> + </listitem> + + <listitem> + <para>The garbage collector is now more concurrent with other Nix + processes because it releases certain locks earlier.</para> + </listitem> + + <listitem> + <para>The binary tarball installer has been improved. You can now + install Nix by running: + +<screen> +$ bash <(curl https://nixos.org/nix/install) +</screen> + + </para> + </listitem> + + <listitem> + <para>More evaluation errors include position information. For + instance, selecting a missing attribute will print something like + +<screen> +error: attribute `nixUnstabl' missing, at /etc/nixos/configurations/misc/eelco/mandark.nix:216:15 +</screen> + + </para> + </listitem> + + <listitem> + <para>The command <command>nix-setuid-helper</command> is + gone.</para> + </listitem> + + <listitem> + <para>Nix no longer uses Automake, but instead has a + non-recursive, GNU Make-based build system.</para> + </listitem> + + <listitem> + <para>All installed libraries now have the prefix + <literal>libnix</literal>. In particular, this gets rid of + <literal>libutil</literal>, which could clash with libraries with + the same name from other packages.</para> + </listitem> + + <listitem> + <para>Nix now requires a compiler that supports C++11.</para> + </listitem> + +</itemizedlist> + +<para>This release has contributions from Danny Wilson, Domen Kožar, +Eelco Dolstra, Ian-Woo Kim, Ludovic Courtès, Maxim Ivanov, Petr +Rockai, Ricardo M. Correia and Shea Levy.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/release-notes/rl-18.xml b/doc/manual/release-notes/rl-18.xml new file mode 100644 index 000000000000..aace95210ff7 --- /dev/null +++ b/doc/manual/release-notes/rl-18.xml @@ -0,0 +1,21 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ssec-relnotes-1.8"> + +<title>Release 1.8 (TBA)</title> + +<itemizedlist> + + <listitem><para>Derivations can specify the new special attribute + <varname>allowedRequisites</varname>, which has a similar meaning to + <varname>allowedReferences</varname>. But instead of only enforcing + to explicitly specify the immediate references, it requires the + derivation to specify all the dependencies recursively (hence the + name, requisites) that are used by the resulting + output.</para></listitem> + +</itemizedlist> + +</chapter> diff --git a/doc/manual/troubleshooting.xml b/doc/manual/troubleshooting.xml deleted file mode 100644 index ec8c4c924fc7..000000000000 --- a/doc/manual/troubleshooting.xml +++ /dev/null @@ -1,92 +0,0 @@ -<appendix xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink"> - -<title>Troubleshooting</title> - - -<para>This section provides solutions for some common problems. See -the <link xlink:href="http://bugs.strategoxt.org/browse/NIX">Nix -bug tracker</link> for a list of currently known issues.</para> - - -<section><title>Collisions in <command>nix-env</command></title> - -<para>Symptom: when installing or upgrading, you get an error message such as - -<screen> -$ nix-env -i docbook-xml -... -adding /nix/store/s5hyxgm62gk2...-docbook-xml-4.2 -collision between `/nix/store/s5hyxgm62gk2...-docbook-xml-4.2/xml/dtd/docbook/calstblx.dtd' - and `/nix/store/06h377hr4b33...-docbook-xml-4.3/xml/dtd/docbook/calstblx.dtd' - at /nix/store/...-builder.pl line 62.</screen> - -</para> - -<para>The cause is that two installed packages in the user environment -have overlapping filenames (e.g., -<filename>xml/dtd/docbook/calstblx.dtd</filename>. This usually -happens when you accidentally try to install two versions of the same -package. For instance, in the example above, the Nix Packages -collection contains two versions of <literal>docbook-xml</literal>, so -<command>nix-env -i</command> will try to install both. The default -user environment builder has no way to way to resolve such conflicts, -so it just gives up.</para> - -<para>Solution: remove one of the offending packages from the user -environment (if already installed) using <command>nix-env --e</command>, or specify exactly which version should be installed -(e.g., <literal>nix-env -i docbook-xml-4.2</literal>).</para> - -<para>Alternatively, you can modify the user environment builder -script (in -<filename><replaceable>prefix</replaceable>/share/nix/corepkgs/buildenv/builder.pl</filename>) -to implement some conflict resolution policy. E.g., the script could -be modified to rename conflicting file names, or to pick one over the -other.</para> - -</section> - - -<section><title><quote>Too many links</quote> error in the Nix -store</title> - - -<para>Symptom: when building something, you get an error message such as - -<screen> -... -<literal>mkdir: cannot create directory `/nix/store/<replaceable>name</replaceable>': Too many links</literal></screen> - -</para> - -<para>This is usually because you have more than 32,000 subdirectories -in <filename>/nix/store</filename>, as can be seen using <command>ls --l</command>: - -<screen> -$ ls -l /nix/store -drwxrwxrwt 32000 nix nix 4620288 Sep 8 15:08 store</screen> - -The <literal>ext2</literal> file system is limited to an inode link -count of 32,000 (each subdirectory increasing the count by one). -Furthermore, the <literal>st_nlink</literal> field of the -<function>stat</function> system call is a 16-bit value.</para> - -<para>This only happens on very large Nix installations (such as build -machines).</para> - -<para>Quick solution: run the garbage collector. You may want to use -the <option>--max-links</option> option.</para> - -<para>Real solution: put the Nix store on a file system that supports -more than 32,000 subdirectories per directory, such as ReiserFS. -(This doesn’t solve the <literal>st_nlink</literal> limit, but -ReiserFS lies to the kernel by reporting a link count of 1 if it -exceeds the limit.)</para> - -</section> - - - -</appendix> diff --git a/doc/manual/troubleshooting/collisions-nixenv.xml b/doc/manual/troubleshooting/collisions-nixenv.xml new file mode 100644 index 000000000000..addc4cc29249 --- /dev/null +++ b/doc/manual/troubleshooting/collisions-nixenv.xml @@ -0,0 +1,43 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-collisions-nixenv"> + +<title>Collisions in <command>nix-env</command></title> + +<para>Symptom: when installing or upgrading, you get an error message such as + +<screen> +$ nix-env -i docbook-xml +... +adding /nix/store/s5hyxgm62gk2...-docbook-xml-4.2 +collision between `/nix/store/s5hyxgm62gk2...-docbook-xml-4.2/xml/dtd/docbook/calstblx.dtd' + and `/nix/store/06h377hr4b33...-docbook-xml-4.3/xml/dtd/docbook/calstblx.dtd' + at /nix/store/...-builder.pl line 62.</screen> + +</para> + +<para>The cause is that two installed packages in the user environment +have overlapping filenames (e.g., +<filename>xml/dtd/docbook/calstblx.dtd</filename>. This usually +happens when you accidentally try to install two versions of the same +package. For instance, in the example above, the Nix Packages +collection contains two versions of <literal>docbook-xml</literal>, so +<command>nix-env -i</command> will try to install both. The default +user environment builder has no way to way to resolve such conflicts, +so it just gives up.</para> + +<para>Solution: remove one of the offending packages from the user +environment (if already installed) using <command>nix-env +-e</command>, or specify exactly which version should be installed +(e.g., <literal>nix-env -i docbook-xml-4.2</literal>).</para> + +<para>Alternatively, you can modify the user environment builder +script (in +<filename><replaceable>prefix</replaceable>/share/nix/corepkgs/buildenv/builder.pl</filename>) +to implement some conflict resolution policy. E.g., the script could +be modified to rename conflicting file names, or to pick one over the +other.</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/troubleshooting/links-nix-store.xml b/doc/manual/troubleshooting/links-nix-store.xml new file mode 100644 index 000000000000..5efec8e8bc53 --- /dev/null +++ b/doc/manual/troubleshooting/links-nix-store.xml @@ -0,0 +1,43 @@ +<chapter xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="ch-links-nix-store"> + +<title><quote>Too many links</quote> Error in the Nix store</title> + + +<para>Symptom: when building something, you get an error message such as + +<screen> +... +<literal>mkdir: cannot create directory `/nix/store/<replaceable>name</replaceable>': Too many links</literal></screen> + +</para> + +<para>This is usually because you have more than 32,000 subdirectories +in <filename>/nix/store</filename>, as can be seen using <command>ls +-l</command>: + +<screen> +$ ls -l /nix/store +drwxrwxrwt 32000 nix nix 4620288 Sep 8 15:08 store</screen> + +The <literal>ext2</literal> file system is limited to an inode link +count of 32,000 (each subdirectory increasing the count by one). +Furthermore, the <literal>st_nlink</literal> field of the +<function>stat</function> system call is a 16-bit value.</para> + +<para>This only happens on very large Nix installations (such as build +machines).</para> + +<para>Quick solution: run the garbage collector. You may want to use +the <option>--max-links</option> option.</para> + +<para>Real solution: put the Nix store on a file system that supports +more than 32,000 subdirectories per directory, such as ReiserFS. +(This doesn’t solve the <literal>st_nlink</literal> limit, but +ReiserFS lies to the kernel by reporting a link count of 1 if it +exceeds the limit.)</para> + +</chapter> \ No newline at end of file diff --git a/doc/manual/troubleshooting/troubleshooting.xml b/doc/manual/troubleshooting/troubleshooting.xml new file mode 100644 index 000000000000..e538e536f2ce --- /dev/null +++ b/doc/manual/troubleshooting/troubleshooting.xml @@ -0,0 +1,18 @@ +<part xmlns="http://docbook.org/ns/docbook" + xmlns:xlink="http://www.w3.org/1999/xlink" + xmlns:xi="http://www.w3.org/2001/XInclude" + version="5.0" + xml:id="part-troubleshooting"> + +<title>Troubleshooting</title> + +<partintro> +<para>This section provides solutions for some common problems. See +the <link xlink:href="http://bugs.strategoxt.org/browse/NIX">Nix +bug tracker</link> for a list of currently known issues.</para> +</partintro> + +<xi:include href="collisions-nixenv.xml" /> +<xi:include href="links-nix-store.xml" /> + +</part> diff --git a/doc/manual/writing-nix-expressions.xml b/doc/manual/writing-nix-expressions.xml deleted file mode 100644 index c4f069893371..000000000000 --- a/doc/manual/writing-nix-expressions.xml +++ /dev/null @@ -1,1918 +0,0 @@ -<chapter xmlns="http://docbook.org/ns/docbook" - xmlns:xlink="http://www.w3.org/1999/xlink" - xml:id='chap-writing-nix-expressions' - xmlns:xi="http://www.w3.org/2001/XInclude"> - -<title>Writing Nix Expressions</title> - - -<para>This chapter shows you how to write Nix expressions, which are -the things that tell Nix how to build packages. It starts with a -simple example (a Nix expression for GNU Hello), and then moves -on to a more in-depth look at the Nix expression language.</para> - -<note><para>This chapter is mostly about the Nix expression language. -For more extensive information on adding packages to the Nix Packages -collection (such as functions in the standard environment and coding -conventions), please consult <link -xlink:href="http://nixos.org/nixpkgs/manual/">its -manual</link>.</para></note> - - -<section><title>A simple Nix expression</title> - -<para>This section shows how to add and test the <link -xlink:href='http://www.gnu.org/software/hello/hello.html'>GNU Hello -package</link> to the Nix Packages collection. Hello is a program -that prints out the text <quote>Hello, world!</quote>.</para> - -<para>To add a package to the Nix Packages collection, you generally -need to do three things: - -<orderedlist> - - <listitem><para>Write a Nix expression for the package. This is a - file that describes all the inputs involved in building the package, - such as dependencies, sources, and so on.</para></listitem> - - <listitem><para>Write a <emphasis>builder</emphasis>. This is a - shell script<footnote><para>In fact, it can be written in any - language, but typically it's a <command>bash</command> shell - script.</para></footnote> that actually builds the package from - the inputs.</para></listitem> - - <listitem><para>Add the package to the file - <filename>pkgs/top-level/all-packages.nix</filename>. The Nix - expression written in the first step is a - <emphasis>function</emphasis>; it requires other packages in order - to build it. In this step you put it all together, i.e., you call - the function with the right arguments to build the actual - package.</para></listitem> - -</orderedlist> - -</para> - - -<section><title>The Nix expression</title> - -<example xml:id='ex-hello-nix'><title>Nix expression for GNU Hello -(<filename>default.nix</filename>)</title> -<programlisting> -{ stdenv, fetchurl, perl }: <co xml:id='ex-hello-nix-co-1' /> - -stdenv.mkDerivation { <co xml:id='ex-hello-nix-co-2' /> - name = "hello-2.1.1"; <co xml:id='ex-hello-nix-co-3' /> - builder = ./builder.sh; <co xml:id='ex-hello-nix-co-4' /> - src = fetchurl { <co xml:id='ex-hello-nix-co-5' /> - url = ftp://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz; - md5 = "70c9ccf9fac07f762c24f2df2290784d"; - }; - inherit perl; <co xml:id='ex-hello-nix-co-6' /> -}</programlisting> -</example> - -<para><xref linkend='ex-hello-nix' /> shows a Nix expression for GNU -Hello. It's actually already in the Nix Packages collection in -<filename>pkgs/applications/misc/hello/ex-1/default.nix</filename>. -It is customary to place each package in a separate directory and call -the single Nix expression in that directory -<filename>default.nix</filename>. The file has the following elements -(referenced from the figure by number): - -<calloutlist> - - <callout arearefs='ex-hello-nix-co-1'> - - <para>This states that the expression is a - <emphasis>function</emphasis> that expects to be called with three - arguments: <varname>stdenv</varname>, <varname>fetchurl</varname>, - and <varname>perl</varname>. They are needed to build Hello, but - we don't know how to build them here; that's why they are function - arguments. <varname>stdenv</varname> is a package that is used - by almost all Nix Packages packages; it provides a - <quote>standard</quote> environment consisting of the things you - would expect in a basic Unix environment: a C/C++ compiler (GCC, - to be precise), the Bash shell, fundamental Unix tools such as - <command>cp</command>, <command>grep</command>, - <command>tar</command>, etc. <varname>fetchurl</varname> is a - function that downloads files. <varname>perl</varname> is the - Perl interpreter.</para> - - <para>Nix functions generally have the form <literal>{ x, y, ..., - z }: e</literal> where <varname>x</varname>, <varname>y</varname>, - etc. are the names of the expected arguments, and where - <replaceable>e</replaceable> is the body of the function. So - here, the entire remainder of the file is the body of the - function; when given the required arguments, the body should - describe how to build an instance of the Hello package.</para> - - </callout> - - <callout arearefs='ex-hello-nix-co-2'> - - <para>So we have to build a package. Building something from - other stuff is called a <emphasis>derivation</emphasis> in Nix (as - opposed to sources, which are built by humans instead of - computers). We perform a derivation by calling - <varname>stdenv.mkDerivation</varname>. - <varname>mkDerivation</varname> is a function provided by - <varname>stdenv</varname> that builds a package from a set of - <emphasis>attributes</emphasis>. A set is just a list of - key/value pairs where each key is a string and each value is an - arbitrary Nix expression. They take the general form <literal>{ - <replaceable>name1</replaceable> = - <replaceable>expr1</replaceable>; <replaceable>...</replaceable> - <replaceable>nameN</replaceable> = - <replaceable>exprN</replaceable>; }</literal>.</para> - - </callout> - - <callout arearefs='ex-hello-nix-co-3'> - - <para>The attribute <varname>name</varname> specifies the symbolic - name and version of the package. Nix doesn't really care about - these things, but they are used by for instance <command>nix-env - -q</command> to show a <quote>human-readable</quote> name for - packages. This attribute is required by - <varname>mkDerivation</varname>.</para> - - </callout> - - <callout arearefs='ex-hello-nix-co-4'> - - <para>The attribute <varname>builder</varname> specifies the - builder. This attribute can sometimes be omitted, in which case - <varname>mkDerivation</varname> will fill in a default builder - (which does a <literal>configure; make; make install</literal>, in - essence). Hello is sufficiently simple that the default builder - would suffice, but in this case, we will show an actual builder - for educational purposes. The value - <command>./builder.sh</command> refers to the shell script shown - in <xref linkend='ex-hello-builder' />, discussed below.</para> - - </callout> - - <callout arearefs='ex-hello-nix-co-5'> - - <para>The builder has to know what the sources of the package - are. Here, the attribute <varname>src</varname> is bound to the - result of a call to the <command>fetchurl</command> function. - Given a URL and an MD5 hash of the expected contents of the file - at that URL, this function builds a derivation that downloads the - file and checks its hash. So the sources are a dependency that - like all other dependencies is built before Hello itself is - built.</para> - - <para>Instead of <varname>src</varname> any other name could have - been used, and in fact there can be any number of sources (bound - to different attributes). However, <varname>src</varname> is - customary, and it's also expected by the default builder (which we - don't use in this example).</para> - - </callout> - - <callout arearefs='ex-hello-nix-co-6'> - - <para>Since the derivation requires Perl, we have to pass the - value of the <varname>perl</varname> function argument to the - builder. All attributes in the set are actually passed as - environment variables to the builder, so declaring an attribute - - <programlisting> -perl = perl;</programlisting> - - will do the trick: it binds an attribute <varname>perl</varname> - to the function argument which also happens to be called - <varname>perl</varname>. However, it looks a bit silly, so there - is a shorter syntax. The <literal>inherit</literal> keyword - causes the specified attributes to be bound to whatever variables - with the same name happen to be in scope.</para> - - </callout> - -</calloutlist> - -</para> - -</section> - - -<section><title>The builder</title> - -<example xml:id='ex-hello-builder'><title>Build script for GNU Hello -(<filename>builder.sh</filename>)</title> -<programlisting> -source $stdenv/setup <co xml:id='ex-hello-builder-co-1' /> - -PATH=$perl/bin:$PATH <co xml:id='ex-hello-builder-co-2' /> - -tar xvfz $src <co xml:id='ex-hello-builder-co-3' /> -cd hello-* -./configure --prefix=$out <co xml:id='ex-hello-builder-co-4' /> -make <co xml:id='ex-hello-builder-co-5' /> -make install</programlisting> -</example> - -<para><xref linkend='ex-hello-builder' /> shows the builder referenced -from Hello's Nix expression (stored in -<filename>pkgs/applications/misc/hello/ex-1/builder.sh</filename>). -The builder can actually be made a lot shorter by using the -<emphasis>generic builder</emphasis> functions provided by -<varname>stdenv</varname>, but here we write out the build steps to -elucidate what a builder does. It performs the following -steps:</para> - -<calloutlist> - - <callout arearefs='ex-hello-builder-co-1'> - - <para>When Nix runs a builder, it initially completely clears the - environment (except for the attributes declared in the - derivation). For instance, the <envar>PATH</envar> variable is - empty<footnote><para>Actually, it's initialised to - <filename>/path-not-set</filename> to prevent Bash from setting it - to a default value.</para></footnote>. This is done to prevent - undeclared inputs from being used in the build process. If for - example the <envar>PATH</envar> contained - <filename>/usr/bin</filename>, then you might accidentally use - <filename>/usr/bin/gcc</filename>.</para> - - <para>So the first step is to set up the environment. This is - done by calling the <filename>setup</filename> script of the - standard environment. The environment variable - <envar>stdenv</envar> points to the location of the standard - environment being used. (It wasn't specified explicitly as an - attribute in <xref linkend='ex-hello-nix' />, but - <varname>mkDerivation</varname> adds it automatically.)</para> - - </callout> - - <callout arearefs='ex-hello-builder-co-2'> - - <para>Since Hello needs Perl, we have to make sure that Perl is in - the <envar>PATH</envar>. The <envar>perl</envar> environment - variable points to the location of the Perl package (since it - was passed in as an attribute to the derivation), so - <filename><replaceable>$perl</replaceable>/bin</filename> is the - directory containing the Perl interpreter.</para> - - </callout> - - <callout arearefs='ex-hello-builder-co-3'> - - <para>Now we have to unpack the sources. The - <varname>src</varname> attribute was bound to the result of - fetching the Hello source tarball from the network, so the - <envar>src</envar> environment variable points to the location in - the Nix store to which the tarball was downloaded. After - unpacking, we <command>cd</command> to the resulting source - directory.</para> - - <para>The whole build is performed in a temporary directory - created in <varname>/tmp</varname>, by the way. This directory is - removed after the builder finishes, so there is no need to clean - up the sources afterwards. Also, the temporary directory is - always newly created, so you don't have to worry about files from - previous builds interfering with the current build.</para> - - </callout> - - <callout arearefs='ex-hello-builder-co-4'> - - <para>GNU Hello is a typical Autoconf-based package, so we first - have to run its <filename>configure</filename> script. In Nix - every package is stored in a separate location in the Nix store, - for instance - <filename>/nix/store/9a54ba97fb71b65fda531012d0443ce2-hello-2.1.1</filename>. - Nix computes this path by cryptographically hashing all attributes - of the derivation. The path is passed to the builder through the - <envar>out</envar> environment variable. So here we give - <filename>configure</filename> the parameter - <literal>--prefix=$out</literal> to cause Hello to be installed in - the expected location.</para> - - </callout> - - <callout arearefs='ex-hello-builder-co-5'> - - <para>Finally we build Hello (<literal>make</literal>) and install - it into the location specified by <envar>out</envar> - (<literal>make install</literal>).</para> - - </callout> - -</calloutlist> - -<para>If you are wondering about the absence of error checking on the -result of various commands called in the builder: this is because the -shell script is evaluated with Bash's <option>-e</option> option, -which causes the script to be aborted if any command fails without an -error check.</para> - -</section> - - -<section><title>Composition</title> - -<example xml:id='ex-hello-composition'><title>Composing GNU Hello -(<filename>all-packages.nix</filename>)</title> -<programlisting> -... - -rec { <co xml:id='ex-hello-composition-co-1' /> - - hello = import ../applications/misc/hello/ex-1 <co xml:id='ex-hello-composition-co-2' /> { <co xml:id='ex-hello-composition-co-3' /> - inherit fetchurl stdenv perl; - }; - - perl = import ../development/interpreters/perl { <co xml:id='ex-hello-composition-co-4' /> - inherit fetchurl stdenv; - }; - - fetchurl = import ../build-support/fetchurl { - inherit stdenv; ... - }; - - stdenv = ...; - -} -</programlisting> -</example> - -<para>The Nix expression in <xref linkend='ex-hello-nix' /> is a -function; it is missing some arguments that have to be filled in -somewhere. In the Nix Packages collection this is done in the file -<filename>pkgs/top-level/all-packages.nix</filename>, where all -Nix expressions for packages are imported and called with the -appropriate arguments. <xref linkend='ex-hello-composition' /> shows -some fragments of -<filename>all-packages.nix</filename>.</para> - -<calloutlist> - - <callout arearefs='ex-hello-composition-co-1'> - - <para>This file defines a set of attributes, all of which are - concrete derivations (i.e., not functions). In fact, we define a - <emphasis>mutually recursive</emphasis> set of attributes. That - is, the attributes can refer to each other. This is precisely - what we want since we want to <quote>plug</quote> the - various packages into each other.</para> - - </callout> - - <callout arearefs='ex-hello-composition-co-2'> - - <para>Here we <emphasis>import</emphasis> the Nix expression for - GNU Hello. The import operation just loads and returns the - specified Nix expression. In fact, we could just have put the - contents of <xref linkend='ex-hello-nix' /> in - <filename>all-packages.nix</filename> at this point. That - would be completely equivalent, but it would make the file rather - bulky.</para> - - <para>Note that we refer to - <filename>../applications/misc/hello/ex-1</filename>, not - <filename>../applications/misc/hello/ex-1/default.nix</filename>. - When you try to import a directory, Nix automatically appends - <filename>/default.nix</filename> to the file name.</para> - - </callout> - - <callout arearefs='ex-hello-composition-co-3'> - - <para>This is where the actual composition takes place. Here we - <emphasis>call</emphasis> the function imported from - <filename>../applications/misc/hello/ex-1</filename> with a set - containing the things that the function expects, namely - <varname>fetchurl</varname>, <varname>stdenv</varname>, and - <varname>perl</varname>. We use inherit again to use the - attributes defined in the surrounding scope (we could also have - written <literal>fetchurl = fetchurl;</literal>, etc.).</para> - - <para>The result of this function call is an actual derivation - that can be built by Nix (since when we fill in the arguments of - the function, what we get is its body, which is the call to - <varname>stdenv.mkDerivation</varname> in <xref - linkend='ex-hello-nix' />).</para> - - <note><para>Nixpkgs has a convenience function - <function>callPackage</function> that imports and calls a - function, filling in any missing arguments by passing the - corresponding attribute from the Nixpkgs set, like this: - -<programlisting> -hello = callPackage ../applications/misc/hello/ex-1 { }; -</programlisting> - - If necessary, you can set or override arguments: - -<programlisting> -hello = callPackage ../applications/misc/hello/ex-1 { stdenv = myStdenv; }; -</programlisting> - - </para></note> - - </callout> - - <callout arearefs='ex-hello-composition-co-4'> - - <para>Likewise, we have to instantiate Perl, - <varname>fetchurl</varname>, and the standard environment.</para> - - </callout> - -</calloutlist> - -</section> - - -<section><title>Testing</title> - -<para>You can now try to build Hello. Of course, you could do -<literal>nix-env -f pkgs/top-level/all-packages.nix -i hello</literal>, -but you may not want to install a possibly broken package just yet. -The best way to test the package is by using the command <command -linkend="sec-nix-build">nix-build</command>, which builds a Nix -expression and creates a symlink named <filename>result</filename> in -the current directory: - -<screen> -$ nix-build pkgs/top-level/all-packages.nix -A hello -building path `/nix/store/632d2b22514d...-hello-2.1.1' -hello-2.1.1/ -hello-2.1.1/intl/ -hello-2.1.1/intl/ChangeLog -<replaceable>...</replaceable> - -$ ls -l result -lrwxrwxrwx ... 2006-09-29 10:43 result -> /nix/store/632d2b22514d...-hello-2.1.1 - -$ ./result/bin/hello -Hello, world!</screen> - -The <link linkend='opt-attr'><option>-A</option></link> option selects -the <literal>hello</literal> attribute from -<filename>all-packages.nix</filename>. This is faster than using the -symbolic package name specified by the <literal>name</literal> -attribute (which also happens to be <literal>hello</literal>) and is -unambiguous (there can be multiple packages with the symbolic name -<literal>hello</literal>, but there can be only one attribute in a set -named <literal>hello</literal>).</para> - -<para><command>nix-build</command> registers the -<filename>./result</filename> symlink as a garbage collection root, so -unless and until you delete the <filename>./result</filename> symlink, -the output of the build will be safely kept on your system. You can -use <command>nix-build</command>’s <option -linkend='opt-out-link'>-o</option> switch to give the symlink another -name.</para> - -<para>Nix has a transactional semantics. Once a build finishes -successfully, Nix makes a note of this in its database: it registers -that the path denoted by <envar>out</envar> is now -<quote>valid</quote>. If you try to build the derivation again, Nix -will see that the path is already valid and finish immediately. If a -build fails, either because it returns a non-zero exit code, because -Nix or the builder are killed, or because the machine crashes, then -the output paths will not be registered as valid. If you try to build -the derivation again, Nix will remove the output paths if they exist -(e.g., because the builder died half-way through <literal>make -install</literal>) and try again. Note that there is no -<quote>negative caching</quote>: Nix doesn't remember that a build -failed, and so a failed build can always be repeated. This is because -Nix cannot distinguish between permanent failures (e.g., a compiler -error due to a syntax error in the source) and transient failures -(e.g., a disk full condition).</para> - -<para>Nix also performs locking. If you run multiple Nix builds -simultaneously, and they try to build the same derivation, the first -Nix instance that gets there will perform the build, while the others -block (or perform other derivations if available) until the build -finishes: - -<screen> -$ nix-build pkgs/top-level/all-packages.nix -A hello -waiting for lock on `/nix/store/0h5b7hp8d4hqfrw8igvx97x1xawrjnac-hello-2.1.1x'</screen> - -So it is always safe to run multiple instances of Nix in parallel -(which isn’t the case with, say, <command>make</command>).</para> - -<para>If you have a system with multiple CPUs, you may want to have -Nix build different derivations in parallel (insofar as possible). -Just pass the option <link linkend='opt-max-jobs'><option>-j -<replaceable>N</replaceable></option></link>, where -<replaceable>N</replaceable> is the maximum number of jobs to be run -in parallel, or set. Typically this should be the number of -CPUs.</para> - -</section> - - -<section><title>The generic builder</title> - -<para>Recall from <xref linkend='ex-hello-builder' /> that the builder -looked something like this: - -<programlisting> -PATH=$perl/bin:$PATH -tar xvfz $src -cd hello-* -./configure --prefix=$out -make -make install</programlisting> - -The builders for almost all Unix packages look like this — set up some -environment variables, unpack the sources, configure, build, and -install. For this reason the standard environment provides some Bash -functions that automate the build process. A builder using the -generic build facilities in shown in <xref linkend='ex-hello-builder2' -/>.</para> - -<example xml:id='ex-hello-builder2'><title>Build script using the generic -build functions</title> -<programlisting> -buildInputs="$perl" <co xml:id='ex-hello-builder2-co-1' /> - -source $stdenv/setup <co xml:id='ex-hello-builder2-co-2' /> - -genericBuild <co xml:id='ex-hello-builder2-co-3' /></programlisting> -</example> - -<calloutlist> - - <callout arearefs='ex-hello-builder2-co-1'> - - <para>The <envar>buildInputs</envar> variable tells - <filename>setup</filename> to use the indicated packages as - <quote>inputs</quote>. This means that if a package provides a - <filename>bin</filename> subdirectory, it's added to - <envar>PATH</envar>; if it has a <filename>include</filename> - subdirectory, it's added to GCC's header search path; and so - on.<footnote><para>How does it work? <filename>setup</filename> - tries to source the file - <filename><replaceable>pkg</replaceable>/nix-support/setup-hook</filename> - of all dependencies. These “setup hooks” can then set up whatever - environment variables they want; for instance, the setup hook for - Perl sets the <envar>PERL5LIB</envar> environment variable to - contain the <filename>lib/site_perl</filename> directories of all - inputs.</para></footnote> - </para> - - </callout> - - <callout arearefs='ex-hello-builder2-co-2'> - - <para>The function <function>genericBuild</function> is defined in - the file <literal>$stdenv/setup</literal>.</para> - - </callout> - - <callout arearefs='ex-hello-builder2-co-3'> - - <para>The final step calls the shell function - <function>genericBuild</function>, which performs the steps that - were done explicitly in <xref linkend='ex-hello-builder' />. The - generic builder is smart enough to figure out whether to unpack - the sources using <command>gzip</command>, - <command>bzip2</command>, etc. It can be customised in many ways; - see <xref linkend='sec-standard-environment' />.</para> - - </callout> - -</calloutlist> - -<para>Discerning readers will note that the -<envar>buildInputs</envar> could just as well have been set in the Nix -expression, like this: - -<programlisting> - buildInputs = [ perl ];</programlisting> - -The <varname>perl</varname> attribute can then be removed, and the -builder becomes even shorter: - -<programlisting> -source $stdenv/setup -genericBuild</programlisting> - -In fact, <varname>mkDerivation</varname> provides a default builder -that looks exactly like that, so it is actually possible to omit the -builder for Hello entirely.</para> - -</section> - - -</section> - - - -<section><title>The Nix expression language</title> - -<para>The Nix expression language is a pure, lazy, functional -language. Purity means that operations in the language don't have -side-effects (for instance, there is no variable assignment). -Laziness means that arguments to functions are evaluated only when -they are needed. Functional means that functions are -<quote>normal</quote> values that can be passed around and manipulated -in interesting ways. The language is not a full-featured, general -purpose language. Its main job is to describe packages, -compositions of packages, and the variability within -packages.</para> - -<para>This section presents the various features of the -language.</para> - - -<section xml:id='ssec-values'><title>Values</title> - - -<simplesect><title>Simple values</title> - -<para>Nix has the following basic data types: - -<itemizedlist> - - <listitem> - - <para><emphasis>Strings</emphasis> can be written in three - ways.</para> - - <para>The most common way is to enclose the string between double - quotes, e.g., <literal>"foo bar"</literal>. Strings can span - multiple lines. The special characters <literal>"</literal> and - <literal>\</literal> and the character sequence - <literal>${</literal> must be escaped by prefixing them with a - backslash (<literal>\</literal>). Newlines, carriage returns and - tabs can be written as <literal>\n</literal>, - <literal>\r</literal> and <literal>\t</literal>, - respectively.</para> - - <para>You can include the result of an expression into a string by - enclosing it in - <literal>${<replaceable>...</replaceable>}</literal>, a feature - known as <emphasis>antiquotation</emphasis>. The enclosed - expression must evaluate to something that can be coerced into a - string (meaning that it must be a string, a path, or a - derivation). For instance, rather than writing - -<programlisting> -"--with-freetype2-library=" + freetype + "/lib"</programlisting> - - (where <varname>freetype</varname> is a derivation), you can - instead write the more natural - -<programlisting> -"--with-freetype2-library=${freetype}/lib"</programlisting> - - The latter is automatically translated to the former. A more - complicated example (from the Nix expression for <link - xlink:href='http://www.trolltech.com/products/qt'>Qt</link>): - -<programlisting> -configureFlags = " - -system-zlib -system-libpng -system-libjpeg - ${if openglSupport then "-dlopen-opengl - -L${mesa}/lib -I${mesa}/include - -L${libXmu}/lib -I${libXmu}/include" else ""} - ${if threadSupport then "-thread" else "-no-thread"} -";</programlisting> - - Note that Nix expressions and strings can be arbitrarily nested; - in this case the outer string contains various antiquotations that - themselves contain strings (e.g., <literal>"-thread"</literal>), - some of which in turn contain expressions (e.g., - <literal>${mesa}</literal>).</para> - - <para>The second way to write string literals is as an - <emphasis>indented string</emphasis>, which is enclosed between - pairs of <emphasis>double single-quotes</emphasis>, like so: - -<programlisting> -'' - This is the first line. - This is the second line. - This is the third line. -''</programlisting> - - This kind of string literal intelligently strips indentation from - the start of each line. To be precise, it strips from each line a - number of spaces equal to the minimal indentation of the string as - a whole (disregarding the indentation of empty lines). For - instance, the first and second line are indented two space, while - the third line is indented four spaces. Thus, two spaces are - stripped from each line, so the resulting string is - -<programlisting> -"This is the first line.\nThis is the second line.\n This is the third line.\n"</programlisting> - - </para> - - <para>Note that the whitespace and newline following the opening - <literal>''</literal> is ignored if there is no non-whitespace - text on the initial line.</para> - - <para>Antiquotation - (<literal>${<replaceable>expr</replaceable>}</literal>) is - supported in indented strings.</para> - - <para>Since <literal>${</literal> and <literal>''</literal> have - special meaning in indented strings, you need a way to quote them. - <literal>${</literal> can be escaped by prefixing it with - <literal>''</literal> (that is, two single quotes), i.e., - <literal>''${</literal>. <literal>''</literal> can be escaped by - prefixing it with <literal>'</literal>, i.e., - <literal>'''</literal>. Finally, linefeed, carriage-return and - tab characters can be written as <literal>''\n</literal>, - <literal>''\r</literal>, <literal>''\t</literal>.</para> - - <para>Indented strings are primarily useful in that they allow - multi-line string literals to follow the indentation of the - enclosing Nix expression, and that less escaping is typically - necessary for strings representing languages such as shell scripts - and configuration files because <literal>''</literal> is much less - common than <literal>"</literal>. Example: - -<programlisting> -stdenv.mkDerivation { - <replaceable>...</replaceable> - postInstall = - '' - mkdir $out/bin $out/etc - cp foo $out/bin - echo "Hello World" > $out/etc/foo.conf - ${if enableBar then "cp bar $out/bin" else ""} - ''; - <replaceable>...</replaceable> -} -</programlisting> - - </para> - - <para>Finally, as a convenience, <emphasis>URIs</emphasis> as - defined in appendix B of <link - xlink:href='http://www.ietf.org/rfc/rfc2396.txt'>RFC 2396</link> - can be written <emphasis>as is</emphasis>, without quotes. For - instance, the string - <literal>"http://example.org/foo.tar.bz2"</literal> - can also be written as - <literal>http://example.org/foo.tar.bz2</literal>.</para> - - </listitem> - - <listitem><para><emphasis>Integers</emphasis>, e.g., - <literal>123</literal>.</para></listitem> - - <listitem><para><emphasis>Paths</emphasis>, e.g., - <filename>/bin/sh</filename> or <filename>./builder.sh</filename>. - A path must contain at least one slash to be recognised as such; for - instance, <filename>builder.sh</filename> is not a - path<footnote><para>It's parsed as an expression that selects the - attribute <varname>sh</varname> from the variable - <varname>builder</varname>.</para></footnote>. If the file name is - relative, i.e., if it does not begin with a slash, it is made - absolute at parse time relative to the directory of the Nix - expression that contained it. For instance, if a Nix expression in - <filename>/foo/bar/bla.nix</filename> refers to - <filename>../xyzzy/fnord.nix</filename>, the absolute path is - <filename>/foo/xyzzy/fnord.nix</filename>.</para></listitem> - - <listitem><para><emphasis>Booleans</emphasis> with values - <literal>true</literal> and - <literal>false</literal>.</para></listitem> - - <listitem><para>The null value, denoted as - <literal>null</literal>.</para></listitem> - -</itemizedlist> - -</para> - -</simplesect> - - -<simplesect><title>Lists</title> - -<para>Lists are formed by enclosing a whitespace-separated list of -values between square brackets. For example, - -<programlisting> -[ 123 ./foo.nix "abc" (f { x = y; }) ]</programlisting> - -defines a list of four elements, the last being the result of a call -to the function <varname>f</varname>. Note that function calls have -to be enclosed in parentheses. If they had been omitted, e.g., - -<programlisting> -[ 123 ./foo.nix "abc" f { x = y; } ]</programlisting> - -the result would be a list of five elements, the fourth one being a -function and the fifth being a set.</para> - -</simplesect> - - -<simplesect><title>Sets</title> - -<para>Sets are really the core of the language, since ultimately the -Nix language is all about creating derivations, which are really just -sets of attributes to be passed to build scripts.</para> - -<para>Sets are just a list of name/value pairs (called -<emphasis>attributes</emphasis>) enclosed in curly brackets, where -each value is an arbitrary expression terminated by a semicolon. For -example: - -<programlisting> -{ x = 123; - text = "Hello"; - y = f { bla = 456; }; -}</programlisting> - -This defines a set with attributes named <varname>x</varname>, -<varname>text</varname>, <varname>y</varname>. The order of the -attributes is irrelevant. An attribute name may only occur -once.</para> - -<para>Attributes can be selected from a set using the -<literal>.</literal> operator. For instance, - -<programlisting> -{ a = "Foo"; b = "Bar"; }.a</programlisting> - -evaluates to <literal>"Foo"</literal>. It is possible to provide a -default value in an attribute selection using the -<literal>or</literal> keyword. For example, - -<programlisting> -{ a = "Foo"; b = "Bar"; }.c or "Xyzzy"</programlisting> - -will evaluate to <literal>"Xyzzy"</literal> because there is no -<varname>c</varname> attribute in the set.</para> - -<para>You can use arbitrary double-quoted strings as attribute -names: - -<programlisting> -{ "foo ${bar}" = 123; "nix-1.0" = 456; }."foo ${bar}" -</programlisting> - -This will evaluate to <literal>123</literal> (Assuming -<literal>bar</literal> is antiquotable). In the case where an -attribute name is just a single antiquotation, the quotes can be -dropped: - -<programlisting> -{ foo = 123; }.${bar} or 456 </programlisting> - -This will evaluate to <literal>123</literal> if -<literal>bar</literal> evaluates to <literal>"foo"</literal> when -coerced to a string and <literal>456</literal> otherwise (again -assuming <literal>bar</literal> is antiquotable).</para> - -<para>In the special case where an attribute name inside of a set declaration -evaluates to <literal>null</literal> (which is normally an error, as -<literal>null</literal> is not antiquotable), that attribute is simply not -added to the set: - -<programlisting> -{ ${if foo then "bar" else null} = true; }</programlisting> - -This will evaluate to <literal>{}</literal> if <literal>foo</literal> -evaluates to <literal>false</literal>.</para> - - -</simplesect> - - -</section> - - -<section><title>Language constructs</title> - - -<simplesect><title>Recursive sets</title> - -<para>Recursive sets are just normal sets, but the attributes can -refer to each other. For example, - -<programlisting> -rec { - x = y; - y = 123; -}.x -</programlisting> - -evaluates to <literal>123</literal>. Note that without -<literal>rec</literal> the binding <literal>x = y;</literal> would -refer to the variable <varname>y</varname> in the surrounding scope, -if one exists, and would be invalid if no such variable exists. That -is, in a normal (non-recursive) set, attributes are not added to the -lexical scope; in a recursive set, they are.</para> - -<para>Recursive sets of course introduce the danger of infinite -recursion. For example, - -<programlisting> -rec { - x = y; - y = x; -}.x</programlisting> - -does not terminate<footnote><para>Actually, Nix detects infinite -recursion in this case and aborts (<quote>infinite recursion -encountered</quote>).</para></footnote>.</para> - -</simplesect> - - -<simplesect><title>Let-expressions</title> - -<para>A let-expression allows you define local variables for an -expression. For instance, - -<programlisting> -let - x = "foo"; - y = "bar"; -in x + y</programlisting> - -evaluates to <literal>"foobar"</literal>. - -</para> - -</simplesect> - - -<simplesect><title>Inheriting attributes</title> - -<para>When defining a set it is often convenient to copy variables -from the surrounding lexical scope (e.g., when you want to propagate -attributes). This can be shortened using the -<literal>inherit</literal> keyword. For instance, - -<programlisting> -let x = 123; in -{ inherit x; - y = 456; -}</programlisting> - -evaluates to <literal>{ x = 123; y = 456; }</literal>. (Note that -this works because <varname>x</varname> is added to the lexical scope -by the <literal>let</literal> construct.) It is also possible to -inherit attributes from another set. For instance, in this fragment -from <filename>all-packages.nix</filename>, - -<programlisting> - graphviz = (import ../tools/graphics/graphviz) { - inherit fetchurl stdenv libpng libjpeg expat x11 yacc; - inherit (xlibs) libXaw; - }; - - xlibs = { - libX11 = ...; - libXaw = ...; - ... - } - - libpng = ...; - libjpg = ...; - ...</programlisting> - -the set used in the function call to the function defined in -<filename>../tools/graphics/graphviz</filename> inherits a number of -variables from the surrounding scope (<varname>fetchurl</varname> -... <varname>yacc</varname>), but also inherits -<varname>libXaw</varname> (the X Athena Widgets) from the -<varname>xlibs</varname> (X11 client-side libraries) set.</para> - -</simplesect> - - -<simplesect xml:id="ss-functions"><title>Functions</title> - -<para>Functions have the following form: - -<programlisting> -<replaceable>pattern</replaceable>: <replaceable>body</replaceable></programlisting> - -The pattern specifies what the argument of the function must look -like, and binds variables in the body to (parts of) the -argument. There are three kinds of patterns:</para> - -<itemizedlist> - - - <listitem><para>If a pattern is a single identifier, then the - function matches any argument. Example: - - <programlisting> -let negate = x: !x; - concat = x: y: x + y; -in if negate true then concat "foo" "bar" else ""</programlisting> - - Note that <function>concat</function> is a function that takes one - argument and returns a function that takes another argument. This - allows partial parameterisation (i.e., only filling some of the - arguments of a function); e.g., - - <programlisting> -map (concat "foo") [ "bar" "bla" "abc" ]</programlisting> - - evaluates to <literal>[ "foobar" "foobla" - "fooabc" ]</literal>.</para></listitem> - - - <listitem><para>A <emphasis>set pattern</emphasis> of the form - <literal>{ name1, name2, …, nameN }</literal> matches a set - containing the listed attributes, and binds the values of those - attributes to variables in the function body. For example, the - function - -<programlisting> -{ x, y, z }: z + y + x</programlisting> - - can only be called with a set containing exactly the attributes - <varname>x</varname>, <varname>y</varname> and - <varname>z</varname>. No other attributes are allowed. If you want - to allow additional arguments, you can use an ellipsis - (<literal>...</literal>): - -<programlisting> -{ x, y, z, ... }: z + y + x</programlisting> - - This works on any set that contains at least the three named - attributes.</para> - - <para>It is possible to provide <emphasis>default values</emphasis> - for attributes, in which case they are allowed to be missing. A - default value is specified by writing - <literal><replaceable>name</replaceable> ? - <replaceable>e</replaceable></literal>, where - <replaceable>e</replaceable> is an arbitrary expression. For example, - -<programlisting> -{ x, y ? "foo", z ? "bar" }: z + y + x</programlisting> - - specifies a function that only requires an attribute named - <varname>x</varname>, but optionally accepts <varname>y</varname> - and <varname>z</varname>.</para></listitem> - - - <listitem><para>An <literal>@</literal>-pattern provides a means of referring - to the whole value being matched: - -<programlisting> -args@{ x, y, z, ... }: z + y + x + args.a</programlisting> - - Here <varname>args</varname> is bound to the entire argument, which - is further matched against the pattern <literal>{ x, y, z, - ... }</literal>.</para></listitem> - - -</itemizedlist> - -<para>Note that functions do not have names. If you want to give them -a name, you can bind them to an attribute, e.g., - -<programlisting> -let concat = { x, y }: x + y; -in concat { x = "foo"; y = "bar"; }</programlisting> - -</para> - -</simplesect> - - -<simplesect><title>Conditionals</title> - -<para>Conditionals look like this: - -<programlisting> -if <replaceable>e1</replaceable> then <replaceable>e2</replaceable> else <replaceable>e3</replaceable></programlisting> - -where <replaceable>e1</replaceable> is an expression that should -evaluate to a Boolean value (<literal>true</literal> or -<literal>false</literal>).</para> - -</simplesect> - - -<simplesect><title>Assertions</title> - -<para>Assertions are generally used to check that certain requirements -on or between features and dependencies hold. They look like this: - -<programlisting> -assert <replaceable>e1</replaceable>; <replaceable>e2</replaceable></programlisting> - -where <replaceable>e1</replaceable> is an expression that should -evaluate to a Boolean value. If it evaluates to -<literal>true</literal>, <replaceable>e2</replaceable> is returned; -otherwise expression evaluation is aborted and a backtrace is printed.</para> - -<example xml:id='ex-subversion-nix'><title>Nix expression for Subversion</title> -<programlisting> -{ localServer ? false -, httpServer ? false -, sslSupport ? false -, pythonBindings ? false -, javaSwigBindings ? false -, javahlBindings ? false -, stdenv, fetchurl -, openssl ? null, httpd ? null, db4 ? null, expat, swig ? null, j2sdk ? null -}: - -assert localServer -> db4 != null; <co xml:id='ex-subversion-nix-co-1' /> -assert httpServer -> httpd != null && httpd.expat == expat; <co xml:id='ex-subversion-nix-co-2' /> -assert sslSupport -> openssl != null && (httpServer -> httpd.openssl == openssl); <co xml:id='ex-subversion-nix-co-3' /> -assert pythonBindings -> swig != null && swig.pythonSupport; -assert javaSwigBindings -> swig != null && swig.javaSupport; -assert javahlBindings -> j2sdk != null; - -stdenv.mkDerivation { - name = "subversion-1.1.1"; - ... - openssl = if sslSupport then openssl else null; <co xml:id='ex-subversion-nix-co-4' /> - ... -}</programlisting> -</example> - -<para><xref linkend='ex-subversion-nix' /> show how assertions are -used in the Nix expression for Subversion.</para> - -<calloutlist> - - <callout arearefs='ex-subversion-nix-co-1'> - <para>This assertion states that if Subversion is to have support - for local repositories, then Berkeley DB is needed. So if the - Subversion function is called with the - <varname>localServer</varname> argument set to - <literal>true</literal> but the <varname>db4</varname> argument - set to <literal>null</literal>, then the evaluation fails.</para> - </callout> - - <callout arearefs='ex-subversion-nix-co-2'> - <para>This is a more subtle condition: if Subversion is built with - Apache (<literal>httpServer</literal>) support, then the Expat - library (an XML library) used by Subversion should be same as the - one used by Apache. This is because in this configuration - Subversion code ends up being linked with Apache code, and if the - Expat libraries do not match, a build- or runtime link error or - incompatibility might occur.</para> - </callout> - - <callout arearefs='ex-subversion-nix-co-3'> - <para>This assertion says that in order for Subversion to have SSL - support (so that it can access <literal>https</literal> URLs), an - OpenSSL library must be passed. Additionally, it says that - <emphasis>if</emphasis> Apache support is enabled, then Apache's - OpenSSL should match Subversion's. (Note that if Apache support - is not enabled, we don't care about Apache's OpenSSL.)</para> - </callout> - - <callout arearefs='ex-subversion-nix-co-4'> - <para>The conditional here is not really related to assertions, - but is worth pointing out: it ensures that if SSL support is - disabled, then the Subversion derivation is not dependent on - OpenSSL, even if a non-<literal>null</literal> value was passed. - This prevents an unnecessary rebuild of Subversion if OpenSSL - changes.</para> - </callout> - -</calloutlist> - -</simplesect> - - - -<simplesect><title>With-expressions</title> - -<para>A <emphasis>with-expression</emphasis>, - -<programlisting> -with <replaceable>e1</replaceable>; <replaceable>e2</replaceable></programlisting> - -introduces the set <replaceable>e1</replaceable> into the lexical -scope of the expression <replaceable>e2</replaceable>. For instance, - -<programlisting> -let as = { x = "foo"; y = "bar"; }; -in with as; x + y</programlisting> - -evaluates to <literal>"foobar"</literal> since the -<literal>with</literal> adds the <varname>x</varname> and -<varname>y</varname> attributes of <varname>as</varname> to the -lexical scope in the expression <literal>x + y</literal>. The most -common use of <literal>with</literal> is in conjunction with the -<function>import</function> function. E.g., - -<programlisting> -with (import ./definitions.nix); ...</programlisting> - -makes all attributes defined in the file -<filename>definitions.nix</filename> available as if they were defined -locally in a <literal>rec</literal>-expression.</para> - -</simplesect> - - -<simplesect><title>Comments</title> - -<para>Comments can be single-line, started with a <literal>#</literal> -character, or inline/multi-line, enclosed within <literal>/* -... */</literal>.</para> - -</simplesect> - - -</section> - - -<section><title>Operators</title> - -<para><xref linkend='table-operators' /> lists the operators in the -Nix expression language, in order of precedence (from strongest to -weakest binding).</para> - -<table xml:id='table-operators'> - <title>Operators</title> - <tgroup cols='3'> - <thead> - <row> - <entry>Syntax</entry> - <entry>Associativity</entry> - <entry>Description</entry> - </row> - </thead> - <tbody> - <row> - <entry><replaceable>e</replaceable> <literal>.</literal> - <replaceable>attrpath</replaceable> - [ <literal>or</literal> <replaceable>def</replaceable> ] - </entry> - <entry>none</entry> - <entry>Select attribute denoted by the attribute path - <replaceable>attrpath</replaceable> from set - <replaceable>e</replaceable>. (An attribute path is a - dot-separated list of attribute names.) If the attribute - doesn’t exist, return <replaceable>def</replaceable> if - provided, otherwise abort evaluation.</entry> - </row> - <row> - <entry><replaceable>e1</replaceable> <replaceable>e2</replaceable></entry> - <entry>left</entry> - <entry>Call function <replaceable>e1</replaceable> with - argument <replaceable>e2</replaceable>.</entry> - </row> - <row> - <entry><replaceable>e</replaceable> <literal>?</literal> - <replaceable>attrpath</replaceable></entry> - <entry>none</entry> - <entry>Test whether set <replaceable>e</replaceable> contains - the attribute denoted by <replaceable>attrpath</replaceable>; - return <literal>true</literal> or - <literal>false</literal>.</entry> - </row> - <row> - <entry><replaceable>e1</replaceable> <literal>++</literal> <replaceable>e2</replaceable></entry> - <entry>right</entry> - <entry>List concatenation.</entry> - </row> - <row> - <entry><replaceable>e1</replaceable> <literal>+</literal> <replaceable>e2</replaceable></entry> - <entry>left</entry> - <entry>String or path concatenation.</entry> - </row> - <row> - <entry><literal>!</literal> <replaceable>e</replaceable></entry> - <entry>left</entry> - <entry>Boolean negation.</entry> - </row> - <row> - <entry><replaceable>e1</replaceable> <literal>//</literal> - <replaceable>e2</replaceable></entry> - <entry>right</entry> - <entry>Return a set consisting of the attributes in - <replaceable>e1</replaceable> and - <replaceable>e2</replaceable> (with the latter taking - precedence over the former in case of equally named - attributes).</entry> - </row> - <row> - <entry><replaceable>e1</replaceable> <literal>==</literal> - <replaceable>e2</replaceable></entry> - <entry>none</entry> - <entry>Equality.</entry> - </row> - <row> - <entry><replaceable>e1</replaceable> <literal>!=</literal> - <replaceable>e2</replaceable></entry> - <entry>none</entry> - <entry>Inequality.</entry> - </row> - <row> - <entry><replaceable>e1</replaceable> <literal>&&</literal> - <replaceable>e2</replaceable></entry> - <entry>left</entry> - <entry>Logical AND.</entry> - </row> - <row> - <entry><replaceable>e1</replaceable> <literal>||</literal> - <replaceable>e2</replaceable></entry> - <entry>left</entry> - <entry>Logical OR.</entry> - </row> - <row> - <entry><replaceable>e1</replaceable> <literal>-></literal> - <replaceable>e2</replaceable></entry> - <entry>none</entry> - <entry>Logical implication (equivalent to - <literal>!<replaceable>e1</replaceable> || - <replaceable>e2</replaceable></literal>).</entry> - </row> - </tbody> - </tgroup> -</table> - -</section> - - -<section xml:id="ssec-derivation"><title>Derivations</title> - -<para>The most important built-in function is -<function>derivation</function>, which is used to describe a single -derivation (a build action). It takes as input a set, the attributes -of which specify the inputs of the build.</para> - -<itemizedlist> - - <listitem xml:id="attr-system"><para>There must be an attribute named - <varname>system</varname> whose value must be a string specifying a - Nix platform identifier, such as <literal>"i686-linux"</literal> or - <literal>"powerpc-darwin"</literal><footnote><para>To figure out - your platform identifier, look at the line <quote>Checking for the - canonical Nix system name</quote> in the output of Nix's - <filename>configure</filename> script.</para></footnote> The build - can only be performed on a machine and operating system matching the - platform identifier. (Nix can automatically forward builds for - other platforms by forwarding them to other machines; see <xref - linkend='chap-distributed-builds' />.)</para></listitem> - - <listitem><para>There must be an attribute named - <varname>name</varname> whose value must be a string. This is used - as a symbolic name for the package by <command>nix-env</command>, - and it is appended to the output paths of the - derivation.</para></listitem> - - <listitem><para>There must be an attribute named - <varname>builder</varname> that identifies the program that is - executed to perform the build. It can be either a derivation or a - source (a local file reference, e.g., - <filename>./builder.sh</filename>).</para></listitem> - - <listitem><para>Every attribute is passed as an environment variable - to the builder. Attribute values are translated to environment - variables as follows: - - <itemizedlist> - - <listitem><para>Strings and integers are just passed - verbatim.</para></listitem> - - <listitem><para>A <emphasis>path</emphasis> (e.g., - <filename>../foo/sources.tar</filename>) causes the referenced - file to be copied to the store; its location in the store is put - in the environment variable. The idea is that all sources - should reside in the Nix store, since all inputs to a derivation - should reside in the Nix store.</para></listitem> - - <listitem><para>A <emphasis>derivation</emphasis> causes that - derivation to be built prior to the present derivation; its - default output path is put in the environment - variable.</para></listitem> - - <listitem><para>Lists of the previous types are also allowed. - They are simply concatenated, separated by - spaces.</para></listitem> - - <listitem><para><literal>true</literal> is passed as the string - <literal>1</literal>, <literal>false</literal> and - <literal>null</literal> are passed as an empty string. - </para></listitem> - </itemizedlist> - - </para></listitem> - - <listitem><para>The optional attribute <varname>args</varname> - specifies command-line arguments to be passed to the builder. It - should be a list.</para></listitem> - - <listitem><para>The optional attribute <varname>outputs</varname> - specifies a list of symbolic outputs of the derivation. By default, - a derivation produces a single output path, denoted as - <literal>out</literal>. However, derivations can produce multiple - output paths. This is useful because it allows outputs to be - downloaded or garbage-collected separately. For instance, imagine a - library package that provides a dynamic library, header files, and - documentation. A program that links against the library doesn’t - need the header files and documentation at runtime, and it doesn’t - need the documentation at build time. Thus, the library package - could specify: -<programlisting> -outputs = [ "lib" "headers" "doc" ]; -</programlisting> - This will cause Nix to pass environment variables - <literal>lib</literal>, <literal>headers</literal> and - <literal>doc</literal> to the builder containing the intended store - paths of each output. The builder would typically do something like -<programlisting> -./configure --libdir=$lib/lib --includedir=$headers/include --docdir=$doc/share/doc -</programlisting> - for an Autoconf-style package. You can refer to each output of a - derivation by selecting it as an attribute, e.g. -<programlisting> -buildInputs = [ pkg.lib pkg.headers ]; -</programlisting> - The first element of <varname>output</varname> determines the - <emphasis>default output</emphasis>. Thus, you could also write -<programlisting> -buildInputs = [ pkg pkg.headers ]; -</programlisting> - since <literal>pkg</literal> is equivalent to - <literal>pkg.lib</literal>.</para></listitem> - -</itemizedlist> - -<para>The function <function>mkDerivation</function> in the standard -environment is a wrapper around <function>derivation</function> that -adds a default value for <varname>system</varname> and always uses -Bash as the builder, to which the supplied builder is passed as a -command-line argument. See <xref linkend='sec-standard-environment' -/>.</para> - -<para>The builder is executed as follows: - -<itemizedlist> - - <listitem><para>A temporary directory is created under the directory - specified by <envar>TMPDIR</envar> (default - <filename>/tmp</filename>) where the build will take place. The - current directory is changed to this directory.</para></listitem> - - <listitem><para>The environment is cleared and set to the derivation - attributes, as specified above.</para></listitem> - - <listitem><para>In addition, the following variables are set: - - <itemizedlist> - - <listitem><para><envar>NIX_BUILD_TOP</envar> contains the path of - the temporary directory for this build.</para></listitem> - - <listitem><para>Also, <envar>TMPDIR</envar>, - <envar>TEMPDIR</envar>, <envar>TMP</envar>, <envar>TEMP</envar> - are set to point to the temporary directory. This is to prevent - the builder from accidentally writing temporary files anywhere - else. Doing so might cause interference by other - processes.</para></listitem> - - <listitem><para><envar>PATH</envar> is set to - <filename>/path-not-set</filename> to prevent shells from - initialising it to their built-in default value.</para></listitem> - - <listitem><para><envar>HOME</envar> is set to - <filename>/homeless-shelter</filename> to prevent programs from - using <filename>/etc/passwd</filename> or the like to find the - user's home directory, which could cause impurity. Usually, when - <envar>HOME</envar> is set, it is used as the location of the home - directory, even if it points to a non-existent - path.</para></listitem> - - <listitem><para><envar>NIX_STORE</envar> is set to the path of the - top-level Nix store directory (typically, - <filename>/nix/store</filename>).</para></listitem> - - <listitem><para>For each output declared in - <varname>outputs</varname>, the corresponding environment variable - is set to point to the intended path in the Nix store for that - output. Each output path is a concatenation of the cryptographic - hash of all build inputs, the <varname>name</varname> attribute - and the output name. (The output name is omitted if it’s - <literal>out</literal>.)</para></listitem> - - </itemizedlist> - - </para></listitem> - - <listitem><para>If an output path already exists, it is removed. - Also, locks are acquired to prevent multiple Nix instances from - performing the same build at the same time.</para></listitem> - - <listitem><para>A log of the combined standard output and error is - written to <filename>/nix/var/log/nix</filename>.</para></listitem> - - <listitem><para>The builder is executed with the arguments specified - by the attribute <varname>args</varname>. If it exits with exit - code 0, it is considered to have succeeded.</para></listitem> - - <listitem><para>The temporary directory is removed (unless the - <option>-K</option> option was specified).</para></listitem> - - <listitem><para>If the build was successful, Nix scans each output - path for references to input paths by looking for the hash parts of - the input paths. Since these are potential runtime dependencies, - Nix registers them as dependencies of the output - paths.</para></listitem> - - <listitem><para>After the build, Nix sets the last-modified - timestamp on all files in the build result to 1 (00:00:01 1/1/1970 - UTC), sets the group to the default group, and sets the mode of the - file to 0444 or 0555 (i.e., read-only, with execute permission - enabled if the file was originally executable). Note that possible - <literal>setuid</literal> and <literal>setgid</literal> bits are - cleared. Setuid and setgid programs are not currently supported by - Nix. This is because the Nix archives used in deployment have no - concept of ownership information, and because it makes the build - result dependent on the user performing the build.</para></listitem> - -</itemizedlist> - -</para> - - -<section><title>Advanced attributes</title> - -<para>Derivations can declare some infrequently used optional -attributes.</para> - -<variablelist> - - <varlistentry><term><varname>allowedReferences</varname></term> - - <listitem><para>The optional attribute - <varname>allowedReferences</varname> specifies a list of legal - references (dependencies) of the output of the builder. For - example, - -<programlisting> -allowedReferences = []; -</programlisting> - - enforces that the output of a derivation cannot have any runtime - dependencies on its inputs. To allow an output to have a runtime - dependency on itself, use <literal>"out"</literal> as a list item. - This is used in NixOS to check that generated files such as - initial ramdisks for booting Linux don’t have accidental - dependencies on other paths in the Nix store.</para></listitem> - - </varlistentry> - - <varlistentry><term><varname>allowedRequisites</varname></term> - - <listitem><para>This attribute is similar to - <varname>allowedReferences</varname>, but it specifies the legal - requisites of the whole closure, so all the dependencies - recursively. For example, - -<programlisting> -allowedReferences = [ foobar ]; -</programlisting> - - enforces that the output of a derivation cannot have any other - runtime dependency than <varname>foobar</varname>, and in addition - it enforces that <varname>foobar</varname> itself doesn't - introduce any other dependency itself.</para></listitem> - - </varlistentry> - - <varlistentry><term><varname>exportReferencesGraph</varname></term> - - <listitem><para>This attribute allows builders access to the - references graph of their inputs. The attribute is a list of - inputs in the Nix store whose references graph the builder needs - to know. The value of this attribute should be a list of pairs - <literal>[ <replaceable>name1</replaceable> - <replaceable>path1</replaceable> <replaceable>name2</replaceable> - <replaceable>path2</replaceable> <replaceable>...</replaceable> - ]</literal>. The references graph of each - <replaceable>pathN</replaceable> will be stored in a text file - <replaceable>nameN</replaceable> in the temporary build directory. - The text files have the format used by <command>nix-store - --register-validity</command> (with the deriver fields left - empty). For example, when the following derivation is built: - -<programlisting> -derivation { - ... - exportReferencesGraph = [ "libfoo-graph" libfoo ]; -}; -</programlisting> - - the references graph of <literal>libfoo</literal> is placed in the - file <filename>libfoo-graph</filename> in the temporary build - directory.</para> - - <para><varname>exportReferencesGraph</varname> is useful for - builders that want to do something with the closure of a store - path. Examples include the builders in NixOS that generate the - initial ramdisk for booting Linux (a <command>cpio</command> - archive containing the closure of the boot script) and the - ISO-9660 image for the installation CD (which is populated with a - Nix store containing the closure of a bootable NixOS - configuration).</para></listitem> - - </varlistentry> - - - <varlistentry xml:id="fixed-output-drvs"> - <term><varname>outputHash</varname></term> - <term><varname>outputHashAlgo</varname></term> - <term><varname>outputHashMode</varname></term> - - <listitem><para>These attributes declare that the derivation is a - so-called <emphasis>fixed-output derivation</emphasis>, which - means that a cryptographic hash of the output is already known in - advance. When the build of a fixed-output derivation finishes, - Nix computes the cryptographic hash of the output and compares it - to the hash declared with these attributes. If there is a - mismatch, the build fails.</para> - - <para>The rationale for fixed-output derivations is derivations - such as those produced by the <function>fetchurl</function> - function. This function downloads a file from a given URL. To - ensure that the downloaded file has not been modified, the caller - must also specify a cryptographic hash of the file. For example, - -<programlisting> -fetchurl { - url = http://ftp.gnu.org/pub/gnu/hello/hello-2.1.1.tar.gz; - md5 = "70c9ccf9fac07f762c24f2df2290784d"; -} -</programlisting> - - It sometimes happens that the URL of the file changes, e.g., - because servers are reorganised or no longer available. We then - must update the call to <function>fetchurl</function>, e.g., - -<programlisting> -fetchurl { - url = ftp://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz; - md5 = "70c9ccf9fac07f762c24f2df2290784d"; -} -</programlisting> - - If a <function>fetchurl</function> derivation was treated like a - normal derivation, the output paths of the derivation and - <emphasis>all derivations depending on it</emphasis> would change. - For instance, if we were to change the URL of the Glibc source - distribution in Nixpkgs (a package on which almost all other - packages depend) massive rebuilds would be needed. This is - unfortunate for a change which we know cannot have a real effect - as it propagates upwards through the dependency graph.</para> - - <para>For fixed-output derivations, on the other hand, the name of - the output path only depends on the <varname>outputHash*</varname> - and <varname>name</varname> attributes, while all other attributes - are ignored for the purpose of computing the output path. (The - <varname>name</varname> attribute is included because it is part - of the path.)</para> - - <para>As an example, here is the (simplified) Nix expression for - <varname>fetchurl</varname>: - -<programlisting> -{ stdenv, curl }: # The <command>curl</command> program is used for downloading. - -{ url, md5 }: - -stdenv.mkDerivation { - name = baseNameOf (toString url); - builder = ./builder.sh; - buildInputs = [ curl ]; - - # This is a fixed-output derivation; the output must be a regular - # file with MD5 hash <varname>md5</varname>. - outputHashMode = "flat"; - outputHashAlgo = "md5"; - outputHash = md5; - - inherit url; -} -</programlisting> - - </para> - - <para>The <varname>outputHashAlgo</varname> attribute specifies - the hash algorithm used to compute the hash. It can currently be - <literal>"md5"</literal>, <literal>"sha1"</literal> or - <literal>"sha256"</literal>.</para> - - <para>The <varname>outputHashMode</varname> attribute determines - how the hash is computed. It must be one of the following two - values: - - <variablelist> - - <varlistentry><term><literal>"flat"</literal></term> - - <listitem><para>The output must be a non-executable regular - file. If it isn’t, the build fails. The hash is simply - computed over the contents of that file (so it’s equal to what - Unix commands like <command>md5sum</command> or - <command>sha1sum</command> produce).</para> - - <para>This is the default.</para></listitem> - - </varlistentry> - - <varlistentry><term><literal>"recursive"</literal></term> - - <listitem><para>The hash is computed over the NAR archive dump - of the output (i.e., the result of <link - linkend="refsec-nix-store-dump"><command>nix-store - --dump</command></link>). In this case, the output can be - anything, including a directory tree.</para></listitem> - - </varlistentry> - - </variablelist> - - </para> - - <para>The <varname>outputHash</varname> attribute, finally, must - be a string containing the hash in either hexadecimal or base-32 - notation. (See the <link - linkend="sec-nix-hash"><command>nix-hash</command> command</link> - for information about converting to and from base-32 - notation.)</para></listitem> - - </varlistentry> - - - <varlistentry><term><varname>impureEnvVars</varname></term> - - <listitem><para>This attribute allows you to specify a list of - environment variables that should be passed from the environment - of the calling user to the builder. Usually, the environment is - cleared completely when the builder is executed, but with this - attribute you can allow specific environment variables to be - passed unmodified. For example, <function>fetchurl</function> in - Nixpkgs has the line - -<programlisting> -impureEnvVars = [ "http_proxy" "https_proxy" <replaceable>...</replaceable> ]; -</programlisting> - - to make it use the proxy server configuration specified by the - user in the environment variables <envar>http_proxy</envar> and - friends.</para> - - <para>This attribute is only allowed in <link - linkend="fixed-output-drvs">fixed-output derivations</link>, where - impurities such as these are okay since (the hash of) the output - is known in advance. It is ignored for all other - derivations.</para></listitem> - - </varlistentry> - - - <varlistentry><term><varname>preferLocalBuild</varname></term> - - <listitem><para>If this attribute is set to - <literal>true</literal>, it has two effects. First, the - derivation will always be built, not substituted, even if a - substitute is available. Second, if <link - linkend="chap-distributed-builds">distributed building is - enabled</link>, then, if possible, the derivaton will be built - locally instead of forwarded to a remote machine. This is - appropriate for trivial builders where the cost of doing a - download or remote build would exceed the cost of building - locally.</para></listitem> - - </varlistentry> - -</variablelist> - -</section> - - -</section> - - - -<xi:include href="builtins.xml" /> - - -</section> - - - -<section xml:id='sec-standard-environment'><title>The standard environment</title> - - -<para>The standard environment is used by passing it as an input -called <envar>stdenv</envar> to the derivation, and then doing - -<programlisting> -source $stdenv/setup</programlisting> - -at the top of the builder.</para> - -<para>Apart from adding the aforementioned commands to the -<envar>PATH</envar>, <filename>setup</filename> also does the -following: - -<itemizedlist> - - <listitem><para>All input packages specified in the - <envar>buildInputs</envar> environment variable have their - <filename>/bin</filename> subdirectory added to <envar>PATH</envar>, - their <filename>/include</filename> subdirectory added to the C/C++ - header file search path, and their <filename>/lib</filename> - subdirectory added to the linker search path. This can be extended. - For instance, when the <command>pkgconfig</command> package is - used, the subdirectory <filename>/lib/pkgconfig</filename> of each - input is added to the <envar>PKG_CONFIG_PATH</envar> environment - variable.</para></listitem> - - <listitem><para>The environment variable - <envar>NIX_CFLAGS_STRIP</envar> is set so that the compiler strips - debug information from object files. This can be disabled by - setting <envar>NIX_STRIP_DEBUG</envar> to - <literal>0</literal>.</para></listitem> - -</itemizedlist> - -</para> - -<para>The <filename>setup</filename> script also exports a function -called <function>genericBuild</function> that knows how to build -typical Autoconf-style packages. It can be customised to perform -builds for any type of package. It is advisable to use -<function>genericBuild</function> since it provides facilities that -are almost always useful such as unpacking of sources, patching of -sources, nested logging, etc.</para> - -<para>The definitive, up-to-date documentation of the generic builder -is the source itself, which resides in -<filename>pkgs/stdenv/generic/setup.sh</filename>.</para> - - -<section><title>Customising the generic builder</title> - -<para>The operation of the generic builder can be modified in many -places by setting certain variables. These <emphasis>hook -variables</emphasis> are typically set to the name of some shell -function defined by you. For instance, to perform some additional -steps after <command>make install</command> you would set the -<varname>postInstall</varname> variable: - -<programlisting> -postInstall=myPostInstall - -myPostInstall() { - mkdir $out/share/extra - cp extrafiles/* $out/share/extra -}</programlisting> - -</para> - - -</section> - - -<section><title>Debugging failed builds</title> - -<para>At the beginning of each phase, the set of all shell variables -is written to the file <filename>env-vars</filename> at the top-level -build directory. This is useful for debugging: it allows you to -recreate the environment in which a build was performed. For -instance, if a build fails, then assuming you used the -<option>-K</option> flag, you can go to the output directory and -<quote>switch</quote> to the environment of the builder: - -<screen> -$ nix-build -K ./foo.nix -... fails, keeping build directory `/tmp/nix-1234-0' - -$ cd /tmp/nix-1234-0 - -$ source env-vars - -<lineannotation>(edit some files...)</lineannotation> - -$ make - -<lineannotation>(execution continues with the same GCC, make, etc.)</lineannotation></screen> - -</para> - -</section> - - -</section> - - -</chapter> |