nixpkgs/manual: add trivial builders section

Fixes #25507.
This commit is contained in:
Matthew Bauer 2019-01-26 22:34:06 -05:00
parent adb717a153
commit 498a242bf4
2 changed files with 85 additions and 0 deletions

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<xi:include href="functions/generators.xml" />
<xi:include href="functions/debug.xml" />
<xi:include href="functions/fetchers.xml" />
<xi:include href="functions/trivial-builders.xml" />
<xi:include href="functions/fhs-environments.xml" />
<xi:include href="functions/shell.xml" />
<xi:include href="functions/dockertools.xml" />

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<section 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-trivial-builders">
<title>Trivial builders</title>
<para>
There are a couple of functions provide in Nixpkgs that help with
building derivations. The most important one,
<function>stdenv.mkDerivation</function>, has already been
documented above. These wrap
<function>stdenv.mkDerivation</function>, making it easier to use
in certain cases.
</para>
<variablelist>
<varlistentry>
<term>
<literal>runCommand</literal>
</term>
<listitem>
<para>
This takes three arguments, <literal>name</literal>,
<literal>env</literal>, and <literal>buildCommand</literal>.
<literal>name</literal> is just the name that Nix will use to
refer to the derivation. <literal>env</literal> is an attribute
set specifying environment variables that will be set for this
derivation. <literal>buildCommand</literal> specifies the
commands that will be run to create this derivation. Note that
you will need to create <literal>$out</literal> for Nix to
register the command as successful.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<literal>runCommandCC</literal>
</term>
<listitem>
<para>
This works just like <literal>runCommand</literal>. The only
difference is that it also provides a C compiler for your use.
To minimize your dependencies, you should only use this if you
are sure you will need a C compiler as part of running your command.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<literal>writeTextFile</literal>
</term>
<listitem>
<para>
This writes <literal>text</literal> to the Nix store. This is
useful for creating scripts from Nix expressions. This takes an
attribute set and expects two arguments,
<literal>name</literal> and <literal>text</literal>.
<literal>name</literal> corresponds to the name used in the Nix
store path. <literal>text</literal> will be the contents of the
file. You can also set <literal>executable</literal> to true to
make this file have the executable bit set.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<literal>symlinkJoin</literal>
</term>
<listitem>
<para>
This can be used to put many derivations into the same directory
structure. It works by creating a new derivation and adding
symlinks to each of the paths listed. It expects two arguments,
<literal>name</literal>, and <literal>paths</literal>.
<literal>name</literal> is the name used in the Nix store path
for the created derivation. <literal>paths</literal> is a list of
paths that will be symlinked. These paths can be to Nix store
derivations or any other directory.
</para>
</listitem>
</varlistentry>
</variablelist>
</section>