nix-config/modules/nixos/virtualisation/docker.nix

{
  flake.modules.nixos.virtualisation = {
    config,
    lib,
    pkgs,
    userName,
    ...
  }: let
    cfg = config.tnix.virtualisation;
  in {
    options.tnix.virtualisation.docker = {
      enable = lib.mkEnableOption "Docker container runtime";
      nvidia = {
        enable = lib.mkEnableOption "NVIDIA Container Toolkit for Docker";
      };
    };

    config = lib.mkIf cfg.docker.enable {
      virtualisation = {
        oci-containers.backend = "docker";
        docker.enable = true;
      };

      hardware.nvidia-container-toolkit.enable = lib.mkIf cfg.docker.nvidia.enable true;
      environment.systemPackages = with pkgs; [lazydocker];
      users.users.${userName}.extraGroups = ["docker"];
    };
  };
}