First-draft [Nix](http://nixos.org/nix/manual/) expression for building simple [Golang](http://golang.org) programs.

godep.nix

# Copyright (c) 2014 Akamai Technologies, Inc.
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{ stdenv, fetchgit, fetchhg, go, lib }:
let buildGoPackage = {
		name,
		extraSrcs ? [],
		meta ? {},
		vcs ? "git",
		url ? "",
		rev ? "",
		tag ? "",
		sha256,
		repoPath,
		importPath ? "",
		install ? false,
	}:
		let
			goPath = lib.strings.concatStringsSep ":" extraSrcs;
			importPath2 = if importPath == "" then repoPath else importPath;
		in
		stdenv.mkDerivation rec {

			inherit name meta;

			src = if (vcs == "git") then
				fetchgit {
					inherit url rev sha256;
				}
			else
				fetchhg {
					inherit url tag sha256;
				};

			buildInputs = [go] ++ extraSrcs;

			unpackPhase = "echo unpack;";

			buildPhase = "echo build;";

			installPhase = ''
				mkdir -p "$out/src/$(dirname ${repoPath})";
				ln -sf "$src" "$out/src/${repoPath}";
				export GOPATH="$out:${goPath}";
				cd $out;
				go install "${importPath2}";
			'';
		};
in rec {
  kr-fs_20140101 = buildGoPackage {
  	name = "kr-fs-20140101";
  	repoPath = "github.com/kr/fs";
  	url = "https://github.com/kr/fs";
  	rev = "2788f0dbd16903de03cb8186e5c7d97b69ad387b";
  	sha256 = "9e86737d232cf5bc2baad44cb214a5630f445b5053071c69d900ea4ce88d0eb0";
  };

  go-tools_20140101 = buildGoPackage {
  	name = "go.tools-20140101";
  	repoPath = "code.google.com/p/go.tools";
  	importPath = "code.google.com/p/go.tools/go/vcs";
  	vcs = "hg";
  	url = "https://code.google.com/p/go.tools/";
  	tag = "cb7689e25ef00326dcc6258f2293fb31acc5b791";
  	sha256 = "04cv3w51pkp76c27p5s237kl0df2rwili5rp5aai0d4cnpg7b1bg";
  };

  godep_20140101 = buildGoPackage {
    name = "godep-20140101";
    install = true;
	repoPath = "github.com/kr/godep";
	url = "https://github.com/kr/godep";
	rev = "69f78935399499698084fa7829a895f97f0855cf";
	sha256 = "254a8635e1324dc3a65f0bf248c17268ba0224e0ba9c03a8cca5326158d52492";
	extraSrcs = [kr-fs_20140101 go-tools_20140101];
	meta = with stdenv.lib; {
	  	homepage = "https://github.com/kr/godep";
	  	description = "A golang dependency management tool";
	  	longDescription = ''
		  	Command godep helps build packages reproducibly by fixing their dependencies.
	  	'';
	  	maintainers = [
		  	"[email protected]"
	  	];
	  	platforms = platforms.linux;
	};
  };
}