{
  description = "nixos modules for convenient deployment of cloud resources";

  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";

  outputs = inp: let
    l = inp.nixpkgs.lib;
    pkgsInstances =
      l.genAttrs
      ["x86_64-linux"]
      (s: inp.nixpkgs.legacyPackages.${s});
  in {
    nixosModules = {
      firewall = ./firewall;
      firewall-hetzner = ./firewall/hetzner;
    };
    checks =
      l.mapAttrs
      (_: pkgs: let
        testSystem = l.nixosSystem {
          system = pkgs.system;
          modules = l.attrValues inp.self.nixosModules;
        };
      in {
        firewall-hetzner-app = import ./firewall/hetzner/app.nix {
          inherit pkgs;
          taggedPorts = {
            http.allowedTCPPorts = [80 443];
            ssh.allowedTCPPorts = [22];
            "bla bla" = {
              allowedUDPPortRanges = [{from = 1332; to = 8891;}];
              allowedTCPPorts = [101];
              allowedUDPPorts = [102];
            };
          };
          id = 1;
        };
        test-system-app =
          (inp.self.makeApps {
            inherit pkgs; nixosSystem = testSystem;
          }).run;
      })
      pkgsInstances;
    makeApps = import ./makeApps.nix;
  };
}