nixpkgs/doc/languages-frameworks/go.xml

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<section xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xml:id="sec-language-go">
<title>Go</title>
<para>The function <varname>buildGoPackage</varname> builds
standard Go programs.
</para>
<example xml:id='ex-buildGoPackage'><title>buildGoPackage</title>
<programlisting>
deis = buildGoPackage rec {
name = "deis-${version}";
version = "1.13.0";
goPackagePath = "github.com/deis/deis"; <co xml:id='ex-buildGoPackage-1' />
subPackages = [ "client" ]; <co xml:id='ex-buildGoPackage-2' />
src = fetchFromGitHub {
owner = "deis";
repo = "deis";
rev = "v${version}";
sha256 = "1qv9lxqx7m18029lj8cw3k7jngvxs4iciwrypdy0gd2nnghc68sw";
};
goDeps = ./deps.json; <co xml:id='ex-buildGoPackage-3' />
buildFlags = "--tags release"; <co xml:id='ex-buildGoPackage-4' />
}
</programlisting>
</example>
<para><xref linkend='ex-buildGoPackage'/> is an example expression using buildGoPackage,
the following arguments are of special significance to the function:
<calloutlist>
<callout arearefs='ex-buildGoPackage-1'>
<para>
<varname>goPackagePath</varname> specifies the package's canonical Go import path.
</para>
</callout>
<callout arearefs='ex-buildGoPackage-2'>
<para>
<varname>subPackages</varname> limits the builder from building child packages that
have not been listed. If <varname>subPackages</varname> is not specified, all child
packages will be built.
</para>
<para>
In this example only <literal>github.com/deis/deis/client</literal> will be built.
</para>
</callout>
<callout arearefs='ex-buildGoPackage-3'>
<para>
<varname>goDeps</varname> is where the Go dependencies of a Go program are listed
in a JSON format described below.
</para>
</callout>
<callout arearefs='ex-buildGoPackage-4'>
<para>
<varname>buildFlags</varname> is a list of flags passed to the go build command.
</para>
</callout>
</calloutlist>
</para>
<para>The <varname>goDeps</varname> attribute should point to a JSON file that defines which Go libraries
are needed and should be included in <varname>GOPATH</varname> for <varname>buildPhase</varname>.
</para>
<example xml:id='ex-goDeps'><title>deps.json</title>
<programlisting>
[ <co xml:id='ex-goDeps-1' />
{
"goPackagePath": "gopkg.in/yaml.v2", <co xml:id='ex-goDeps-2' />
"fetch": {
"type": "git", <co xml:id='ex-goDeps-3' />
"url": "https://gopkg.in/yaml.v2",
"rev": "a83829b6f1293c91addabc89d0571c246397bbf4",
"sha256": "1m4dsmk90sbi17571h6pld44zxz7jc4lrnl4f27dpd1l8g5xvjhh"
}
},
{
"include": "../../libs.json", <co xml:id='ex-goDeps-4' />
"packages": [ <co xml:id='ex-goDeps-5' />
"github.com/docopt/docopt-go",
"golang.org/x/crypto",
]
}
]
</programlisting>
</example>
<para>
<calloutlist>
<callout arearefs='ex-goDeps-1'>
<para>
<varname>goDeps</varname> is a list of Go dependencies.
</para>
</callout>
<callout arearefs='ex-goDeps-2'>
<para>
<varname>goPackagePath</varname> specifies Go package import path.
</para>
</callout>
<callout arearefs='ex-goDeps-3'>
<para>
<varname>fetch type</varname> that needs to be used to get package source. If <varname>git</varname>
is used there should be <varname>url</varname>, <varname>rev</varname> and <varname>sha256</varname>
defined next to it.
</para>
</callout>
<callout arearefs='ex-goDeps-4'>
<para>
<varname>include</varname> could be used to reuse <varname>goDeps</varname> between Go programs.
There is a common libs set in <varname>&lt;nixpkgs/pkgs/development/go-modules/libs.json&gt;</varname>
with pinned versions of many packages that you can reuse.
</para>
</callout>
<callout arearefs='ex-goDeps-5'>
<para>
<varname>packages</varname> enumerates all Go packages that will be imported from included file.
</para>
</callout>
</calloutlist>
</para>
<para>
<varname>buildGoPackage</varname> produces <xref linkend='chap-multiple-output' xrefstyle="select: title" />
where <varname>bin</varname> includes program binaries. You can test build a Go binary as follows:
<screen>
$ nix-build -A deis.bin
</screen>
or build all outputs with:
<screen>
$ nix-build -A deis.all
</screen>
<varname>bin</varname> output will be installed by default with <varname>nix-env -i</varname>
or <varname>systemPackages</varname>.
</para>
<para>
You may use Go packages installed into the active Nix profiles by adding
the following to your ~/.bashrc:
<screen>
for p in $NIX_PROFILES; do
GOPATH="$p/share/go:$GOPATH"
done
</screen>
</para>
<para>To extract dependency information from a Go package in automated way use <link xlink:href="https://github.com/kamilchm/go2nix">go2nix</link>.
It can produce complete derivation and <varname>goDeps</varname> file for Go programs.</para>
</section>