Assuming ./nix as nixDIr,

./nix/nixos/default.nix can be:

{ flakelight, lib, inputs, ... }:
let
  addCommonCfg = prev: prev // {
    modules = prev.modules or [ ] ++ [ inputs.some-flake.nixosModules.default ];
  };
in
lib.mapAttrs (_: addCommonCfg) (flakelight.importDir ./.)

and that will add some-flake.nixosModules.default to all you nixos systems, assuming you define your nixos systems something like follows:

./nix/nixos/machineA/default.nix (or ./nix/nixos/machineA.nix):

{
  system = "x86_64-linux";
  modules = [
    ./configuration.nix
    { system.stateVersion = "22.11"; }
  ];
}

In reply to@accelbread:matrix.org
Hey, thanks for reaching out! I appreciate hearing back For, withOverlays and NixOS/home-manager, you'd either have to use the short form (where flakelight calls nixosSystem/homeManagerConfiguration for you) or pass propagationModule to the function yourself Theres a line here (https://github.com/nix-community/flakelight/blob/a55ef9097613d99f293a532356d67b8ba8aff37f/API_GUIDE.md?plain=1#L959); I'll see about making it clearer. I'll add an example for it too. For packages from other flakes' packages outputs, I'll add some docs/examples as well

In reply to@lunik1:lunik.one
I could have sworn when I did this that the nixos config immediately complained about nonfree packages, indicating the config had not been carried over. I will take another look.

{
  inputs = {
    flakelight = {
      url = "github:nix-community/flakelight";
    };
  };

  outputs = { flakelight, ... }:
    flakelight ./. {
      nixpkgs.config.allowUnfree = true;

      nixosConfigurations = {
        host = {
          system = "x86_64-linux";
          modules = [
            {
              boot.loader.grub.device = "/dev/sda";
              fileSystems."/" = {
                device = "/dev/sda";
                fsType = "xfs";
              };
              hardware.enableAllFirmware = true;
            }
          ];
        };
      };
    };
}

       Failed assertions:
       - the list of hardware.enableAllFirmware contains non-redistributable licensed firmware files.
         This requires nixpkgs.config.allowUnfree to be true.
         An alternative is to use the hardware.enableRedistributableFirmware option.