{
  description = "Tool to build NixOS for GCP.  ";
  nixConfig = {
    extra-substituters = [
      "https://cuda-maintainers.cachix.org"
    ];
    extra-trusted-public-keys = [
      "cuda-maintainers.cachix.org-1:0dq3bujKpuEPMCX6U4WylrUDZ9JyUG0VpVZa7CNfq5E="
    ];
  };
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    flake-utils.url = "github:numtide/flake-utils";
    nixos-generators = {
      url = "github:nix-community/nixos-generators";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, flake-utils, nixos-generators }@inputs:
    let
      gcp = nixos-generators.nixosGenerate {
        system = "x86_64-linux";
        modules = [ ./gcp-configuration.nix ];
        format = "vm";
        pkgs = nixpkgs.legacyPackages.x86_64-linux;
        lib = nixpkgs.legacyPackages.x86_64-linux.lib;
      };

      trainer = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = [ (import ./gcp-configuration.nix) ];
        specialArgs = inputs;
      };

    in flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = nixpkgs.legacyPackages.${system};
        python = pkgs.python312.withPackages (ps: [ ps.click ]);
      in {
        packages.gcp = gcp;
        packages.nixosConfigurations.localhost = trainer;
        packages.nixosConfigurations.trainer-0001 = trainer;
        devShells.default = pkgs.mkShell {
          buildInputs = [ pkgs.google-cloud-sdk python ];
          shellHook = ''
            export PROJECT_ID="all-dressed-programming"
            export BUCKET_NAME="nautilus-plus"
          '';
        };
      });
}