network/nix/lib/salt-support/expand-template.nix

{ pkgs ? import <nixpkgs> {}
}:

name: template: data:
let
  jsonFile =
    builtins.toFile "data.json" (builtins.toJSON data);
  j2custom =
    builtins.toFile "j2custom.py" ''
      def j2_environment(env):
        env.globals.update(
            zip=zip
        )
        return env
    '';
in
pkgs.runCommandLocal name {
  nativeBuildInputs = with pkgs; [
    pythonPackages.j2cli yaml2json
  ];
} ''
  j2 --customize ${j2custom} -f json ${template} ${jsonFile} > $out
''