diff options
Diffstat (limited to 'doc/manual/expressions/advanced-attributes.xml')
| -rw-r--r-- | doc/manual/expressions/advanced-attributes.xml | 73 |
1 files changed, 62 insertions, 11 deletions
diff --git a/doc/manual/expressions/advanced-attributes.xml b/doc/manual/expressions/advanced-attributes.xml index f3cf98371302..07b0d97d3f7d 100644 --- a/doc/manual/expressions/advanced-attributes.xml +++ b/doc/manual/expressions/advanced-attributes.xml @@ -50,6 +50,40 @@ allowedRequisites = [ foobar ]; </varlistentry> + <varlistentry><term><varname>disallowedReferences</varname></term> + + <listitem><para>The optional attribute + <varname>disallowedReferences</varname> specifies a list of illegal + references (dependencies) of the output of the builder. For + example, + +<programlisting> +disallowedReferences = [ foo ]; +</programlisting> + + enforces that the output of a derivation cannot have a direct runtime + dependencies on the derivation <varname>foo</varname>.</para></listitem> + + </varlistentry> + + + <varlistentry><term><varname>disallowedRequisites</varname></term> + + <listitem><para>This attribute is similar to + <varname>disallowedReferences</varname>, but it specifies illegal + requisites for the whole closure, so all the dependencies + recursively. For example, + +<programlisting> +disallowedRequisites = [ foobar ]; +</programlisting> + + enforces that the output of a derivation cannot have any + runtime dependency on <varname>foobar</varname> or any other derivation + depending recursively on <varname>foobar</varname>.</para></listitem> + + </varlistentry> + <varlistentry><term><varname>exportReferencesGraph</varname></term> @@ -112,7 +146,13 @@ impureEnvVars = [ "http_proxy" "https_proxy" <replaceable>...</replaceable> ]; 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> + derivations.</para> + + <warning><para><varname>impureEnvVars</varname> implementation takes + environment variables from the current builder process. When a daemon is + building its environmental variables are used. Without the daemon, the + environmental variables come from the environment of the + <command>nix-build</command>.</para></warning></listitem> </varlistentry> @@ -176,7 +216,7 @@ fetchurl { <programlisting> { stdenv, curl }: # The <command>curl</command> program is used for downloading. -{ url, md5 }: +{ url, sha256 }: stdenv.mkDerivation { name = baseNameOf (toString url); @@ -184,10 +224,10 @@ stdenv.mkDerivation { buildInputs = [ curl ]; # This is a fixed-output derivation; the output must be a regular - # file with MD5 hash <varname>md5</varname>. + # file with SHA256 hash <varname>sha256</varname>. outputHashMode = "flat"; - outputHashAlgo = "md5"; - outputHash = md5; + outputHashAlgo = "sha256"; + outputHash = sha256; inherit url; } @@ -197,8 +237,8 @@ stdenv.mkDerivation { <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> + <literal>"sha1"</literal>, <literal>"sha256"</literal> or + <literal>"sha512"</literal>.</para> <para>The <varname>outputHashMode</varname> attribute determines how the hash is computed. It must be one of the following two @@ -211,7 +251,7 @@ stdenv.mkDerivation { <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 + Unix commands like <command>sha256sum</command> or <command>sha1sum</command> produce).</para> <para>This is the default.</para></listitem> @@ -272,9 +312,7 @@ big = "a very long string"; <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 + <literal>true</literal> and <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 @@ -284,6 +322,19 @@ big = "a very long string"; </varlistentry> + + <varlistentry><term><varname>allowSubstitutes</varname></term> + + <listitem><para>If this attribute is set to + <literal>false</literal>, then Nix will always build this + derivation; it will not try to substitute its outputs. This is + useful for very trivial derivations (such as + <function>writeText</function> in Nixpkgs) that are cheaper to + build than to substitute from a binary cache.</para></listitem> + + </varlistentry> + + </variablelist> </section> |