module(pihole-container): make it a module factory; WIP: start adding systemd service

The factory function returns the pihole module and allows to pass the flake itself to refer to its outputs.

flake.nix

@@ -34,7 +34,7 @@
         default = piholeImage;
       };
 
-      nixosModule = import ./modules/pihole-container.nix;
+      nixosModules.default = import ./modules/pihole-container.factory.nix { piholeFlake = self; };
 
       devShells.default = let
         updatePiholeImageInfoScript = pkgs.writeShellScriptBin "update-pihole-image-info" ''

modules/pihole-container.factory.nix

@@ -1,4 +1,6 @@
-{ config, pkgs, lib, ... }: with lib; let
+{ piholeFlake }: { config, pkgs, lib, ... }: with lib; let
+  cfg = config.services.piholeRootlessContainer;
+
   mkHostPortsOption = { service, publicDefaultPort }: {
     host-internal-port = mkOption {
       type = types.port;
@@ -235,6 +237,17 @@ in {
     };
   };
 
-  config = {
+  config = mkIf cfg.enable {
+    systemd.services."pihole-rootless-container" = {
+      serviceConfig = {
+        ExecStart = ''
+          ${pkgs.podman}/bin/podman run \
+          --rm \
+          --rmi \
+          docker-archive:${self.packages.piholeImage}
+        '';
+        User = null;
+      };
+    };
   };
 }