nixos/ayatana-indicators: init module

nixos/modules/module-list.nix

@@ -437,6 +437,7 @@
   ./services/databases/surrealdb.nix
   ./services/databases/victoriametrics.nix
   ./services/desktops/accountsservice.nix
+  ./services/desktops/ayatana-indicators.nix
   ./services/desktops/bamf.nix
   ./services/desktops/blueman.nix
   ./services/desktops/cpupower-gui.nix

nixos/modules/services/desktops/ayatana-indicators.nix

@@ -0,0 +1,58 @@
+{ config
+, pkgs
+, lib
+, ...
+}:
+
+let
+  cfg = config.services.ayatana-indicators;
+in
+{
+  options.services.ayatana-indicators = {
+    enable = lib.mkEnableOption (lib.mdDoc ''
+      Ayatana Indicators, a continuation of Canonical's Application Indicators
+    '');
+
+    packages = lib.mkOption {
+      type = lib.types.listOf lib.types.package;
+      default = [ ];
+      example = lib.literalExpression "with pkgs; [ ayatana-indicator-messages ]";
+      description = lib.mdDoc ''
+        List of packages containing Ayatana Indicator services
+        that should be brought up by the SystemD "ayatana-indicators" user target.
+
+        Packages specified here must have passthru.ayatana-indicators set correctly.
+
+        If, how, and where these indicators are displayed will depend on your DE.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    environment = {
+      systemPackages = cfg.packages;
+
+      pathsToLink = [
+        "/share/ayatana"
+      ];
+    };
+
+    # libayatana-common's ayatana-indicators.target with explicit Wants & Before to bring up requested indicator services
+    systemd.user.targets."ayatana-indicators" =
+      let
+        indicatorServices = lib.lists.flatten
+          (map
+            (pkg:
+              (map (ind: "${ind}.service") pkg.passthru.ayatana-indicators))
+            cfg.packages);
+      in
+      {
+        description = "Target representing the lifecycle of the Ayatana Indicators. Each indicator should be bound to it in its individual service file";
+        partOf = [ "graphical-session.target" ];
+        wants = indicatorServices;
+        before = indicatorServices;
+      };
+  };
+
+  meta.maintainers = with lib.maintainers; [ OPNA2608 ];
+}