nix manual: add bundlerEnv.env and .wrapper items descriptions

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Nikolay Amiantov 2016-01-21 13:07:56 +03:00
parent 75358ad0e7
commit a98dfaa6b9

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@ -42,5 +42,37 @@ and scalable.";
<para>Please check in the <filename>Gemfile</filename>, <filename>Gemfile.lock</filename> and the <filename>gemset.nix</filename> so future updates can be run easily.
</para>
<para>Resulting derivations also have two helpful items, <literal>env</literal> and <literal>wrapper</literal>. The first one allows one to quickly drop into
<command>nix-shell</command> with the specified environment present. E.g. <command>nix-shell -A sensu.env</command> would give you an environment with Ruby preset
so it has all the libraries necessary for <literal>sensu</literal> in its paths. The second one can be used to make derivations from custom Ruby scripts which have
<filename>Gemfile</filename>s with their dependencies specified. It is a derivation with <command>ruby</command> wrapped so it can find all the needed dependencies.
For example, to make a derivation <literal>my-script</literal> for a <filename>my-script.rb</filename> (which should be placed in <filename>bin</filename>) you should
run <command>bundix</command> as specified above and then use <literal>bundlerEnv</literal> lile this:</para>
<programlisting>
<![CDATA[let env = bundlerEnv {
name = "my-script-env";
inherit ruby;
gemfile = ./Gemfile;
lockfile = ./Gemfile.lock;
gemset = ./gemset.nix;
};
in stdenv.mkDerivation {
name = "my-script";
buildInputs = [ env.wrapper ];
script = ./my-script.rb;
buildCommand = ''
mkdir -p $out/bin
install -D -m755 $script $out/bin/my-script
patchShebangs $out/bin/my-script
'';
}]]>
</programlisting>
</section>