let
  inherit (nixpkgs) lib;
  nixpkgs = import <nixpkgs> { config = {}; overlay = []; };
  file = (builtins.getEnv "FILE");
  property = (builtins.getEnv "PROPERTY");
  processor = if (builtins.stringLength property > 0)
    then
      (_: lib.attrsets.getAttrFromPath (lib.strings.splitString "." property) _)
    else
      (_: _);
in
  processor (lib.evalModules {
      modules = [
        (import file)
      ];
    }).config