Nix Docker Image creation

release.nix

let
  config = {
    packageOverrides = pkgs: rec {
      haskellPackages = pkgs.haskellPackages.override {
        overrides = haskellPackagesNew: haskellPackagesOld: rec {
          myApp =
            haskellPackagesNew.callCabal2nix "my-app" (./.) { };
        };
      };
    };
  };

  pkgs = import (builtins.fetchTarball {
    url = "https://github.com/NixOS/nixpkgs/archive/20.09.tar.gz";
  }) { inherit config; };

  
in
  { myAppImage = pkgs.dockerTools.buildImage {
      name = "domainofmyregistry.com/mycompany/my-app-image-name";
      contents = [ 
        pkgs.haskellPackages.myApp
        pkgs.bash
        pkgs.coreutils
        pkgs.htop
        pkgs.cacert
      ];
      tag = "latest";
      config = {
        Cmd = [ 
          ""
        ];
        ExposedPorts = {
          "8000/tcp" = {};
        };
        extraCommands = ''
        '';
        Env = [
          "APP_MODE:production"
        ];
      };
    };
  }