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Diffstat (limited to 'doc/manual/command-ref/env-common.xml')
| -rw-r--r-- | doc/manual/command-ref/env-common.xml | 133 |
1 files changed, 0 insertions, 133 deletions
diff --git a/doc/manual/command-ref/env-common.xml b/doc/manual/command-ref/env-common.xml index c757cb17bd10..a83aeaf2e575 100644 --- a/doc/manual/command-ref/env-common.xml +++ b/doc/manual/command-ref/env-common.xml @@ -148,139 +148,6 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen> </varlistentry> -<varlistentry xml:id="envar-build-hook"><term><envar>NIX_BUILD_HOOK</envar></term> - - <listitem> - - <para>Specifies the location of the <emphasis>build hook</emphasis>, - which is a program (typically some script) that Nix will call - whenever it wants to build a derivation. This is used to implement - distributed builds<phrase condition="manual"> (see <xref - linkend="chap-distributed-builds" />)</phrase>.</para> - - <!-- - The protocol by - which the calling Nix process and the build hook communicate is as - follows. - - <para>The build hook is called with the following command-line - arguments: - - <orderedlist> - - <listitem><para>A boolean value <literal>0</literal> or - <literal>1</literal> specifying whether Nix can locally execute - more builds, as per the <link - linkend="opt-max-jobs"><option>- -max-jobs</option> option</link>. - The purpose of this argument is to allow the hook to not have to - maintain bookkeeping for the local machine.</para></listitem> - - <listitem><para>The Nix platform identifier for the local machine - (e.g., <literal>i686-linux</literal>).</para></listitem> - - <listitem><para>The Nix platform identifier for the derivation, - i.e., its <link linkend="attr-system"><varname>system</varname> - attribute</link>.</para></listitem> - - <listitem><para>The store path of the derivation.</para></listitem> - - </orderedlist> - - </para> - - <para>On the basis of this information, and whatever persistent - state the build hook keeps about other machines and their current - load, it has to decide what to do with the build. It should print - out on standard error one of the following responses (terminated by - a newline, <literal>"\n"</literal>): - - <variablelist> - - <varlistentry><term><literal># decline</literal></term> - - <listitem><para>The build hook is not willing or able to perform - the build; the calling Nix process should do the build itself, - if possible.</para></listitem> - - </varlistentry> - - <varlistentry><term><literal># postpone</literal></term> - - <listitem><para>The build hook cannot perform the build now, but - can do so in the future (e.g., because all available build slots - on remote machines are in use). The calling Nix process should - postpone this build until at least one currently running build - has terminated.</para></listitem> - - </varlistentry> - - <varlistentry><term><literal># accept</literal></term> - - <listitem><para>The build hook has accepted the - build.</para></listitem> - - </varlistentry> - - </variablelist> - - </para> - - <para>After sending <literal># accept</literal>, the hook should - read one line from standard input, which will be the string - <literal>okay</literal>. It can then proceed with the build. - Before sending <literal>okay</literal>, Nix will store in the hook’s - current directory a number of text files that contain information - about the derivation: - - <variablelist> - - <varlistentry><term><filename>inputs</filename></term> - - <listitem><para>The set of store paths that are inputs to the - build process (one per line). These have to be copied - <emphasis>to</emphasis> the remote machine (in addition to the - store derivation itself).</para></listitem> - - </varlistentry> - - <varlistentry><term><filename>outputs</filename></term> - - <listitem><para>The set of store paths that are outputs of the - derivation (one per line). These have to be copied - <emphasis>from</emphasis> the remote machine if the build - succeeds.</para></listitem> - - </varlistentry> - - <varlistentry><term><filename>references</filename></term> - - <listitem><para>The reference graph of the inputs, in the format - accepted by the command <command>nix-store - - -register-validity</command>. It is necessary to run this - command on the remote machine after copying the inputs to inform - Nix on the remote machine that the inputs are valid - paths.</para></listitem> - - </varlistentry> - - </variablelist> - - </para> - - <para>The hook should copy the inputs to the remote machine, - register the validity of the inputs, perform the remote build, and - copy the outputs back to the local machine. An exit code other than - <literal>0</literal> indicates that the hook has failed. An exit - code equal to 100 means that the remote build failed (as opposed to, - e.g., a network error).</para> - --> - - </listitem> - - -</varlistentry> - - <varlistentry xml:id="envar-remote"><term><envar>NIX_REMOTE</envar></term> <listitem><para>This variable should be set to |