nixos-config/nixos/flake-module.nix

{
  withSystem,
  lib,
  inputs,
  ...
}: {
  flake = {
    nixosConfigurations = withSystem "x86_64-linux" ({
      system,
      self',
      pkgs,
      ...
    }: let
      machines = builtins.attrNames (builtins.readDir ./machines);
      makeSystem = name:
        pkgs.nixos {
          imports = [
            (import (./. + "/machines/${name}/configuration.nix") inputs)
            inputs.secrets.nixosModules.default
            inputs.impermanence.nixosModules.impermanence
          ];
        };
    in
      lib.genAttrs machines makeSystem);
  };
}