Adding Custom Packages
It’s possible that a package you need is not available in NixOS. In that
case, you can do two things. First, you can clone the Nixpkgs repository, add
the package to your clone, and (optionally) submit a patch or pull request to
have it accepted into the main Nixpkgs repository. This is described in
detail in the Nixpkgs
manual. In short, you clone Nixpkgs:
$ git clone https://github.com/NixOS/nixpkgs
$ cd nixpkgs
Then you write and test the package as described in the Nixpkgs manual.
Finally, you add it to environment.systemPackages, e.g.
= [ pkgs.my-package ];
and you run nixos-rebuild, specifying your own Nixpkgs
tree:
# nixos-rebuild switch -I nixpkgs=/path/to/my/nixpkgs
The second possibility is to add the package outside of the Nixpkgs tree. For
instance, here is how you specify a build of the
GNU Hello
package directly in configuration.nix:
=
let
my-hello = with pkgs; stdenv.mkDerivation rec {
name = "hello-2.8";
src = fetchurl {
url = "mirror://gnu/hello/${name}.tar.gz";
sha256 = "0wqd8sjmxfskrflaxywc7gqw7sfawrfvdxd9skxawzfgyy0pzdz6";
};
};
in
[ my-hello ];
Of course, you can also move the definition of my-hello
into a separate Nix expression, e.g.
= [ (import ./my-hello.nix) ];
where my-hello.nix contains:
with import <nixpkgs> {}; # bring all of Nixpkgs into scope
stdenv.mkDerivation rec {
name = "hello-2.8";
src = fetchurl {
url = "mirror://gnu/hello/${name}.tar.gz";
sha256 = "0wqd8sjmxfskrflaxywc7gqw7sfawrfvdxd9skxawzfgyy0pzdz6";
};
}
This allows testing the package easily:
$ nix-build my-hello.nix
$ ./result/bin/hello
Hello, world!