nixos/regreet: init

nixos/doc/manual/release-notes/rl-2305.section.md

@@ -75,6 +75,8 @@ In addition to numerous new and upgraded packages, this release has the followin
 
 - [woodpecker-server](https://woodpecker-ci.org/), a simple CI engine with great extensibility. Available as [services.woodpecker-server](#opt-services.woodpecker-server.enable).
 
+- [ReGreet](https://github.com/rharish101/ReGreet), a clean and customizable greeter for greetd. Available as [programs.regreet](#opt-programs.regreet.enable).
+
 ## Backward Incompatibilities {#sec-release-23.05-incompatibilities}
 
 <!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->

nixos/modules/module-list.nix

@@ -220,6 +220,7 @@
   ./programs/proxychains.nix
   ./programs/qdmr.nix
   ./programs/qt5ct.nix
+  ./programs/regreet.nix
   ./programs/rog-control-center.nix
   ./programs/rust-motd.nix
   ./programs/screen.nix

nixos/modules/programs/regreet.nix

@@ -0,0 +1,75 @@
+{ lib
+, pkgs
+, config
+, ...
+}:
+let
+  cfg = config.programs.regreet;
+  settingsFormat = pkgs.formats.toml { };
+in
+{
+  options.programs.regreet = {
+    enable = lib.mkEnableOption null // {
+      description = lib.mdDoc ''
+        Enable ReGreet, a clean and customizable greeter for greetd.
+
+        To use ReGreet, {option}`services.greetd` has to be enabled and
+        {option}`services.greetd.settings.default_session` should contain the
+        appropriate configuration to launch
+        {option}`config.programs.regreet.package`. For examples, see the
+        [ReGreet Readme](https://github.com/rharish101/ReGreet#set-as-default-session).
+
+        A minimal configuration that launches ReGreet in {command}`cage` is
+        enabled by this module by default.
+      '';
+    };
+
+    package = lib.mkPackageOptionMD pkgs [ "greetd" "regreet" ] { };
+
+    settings = lib.mkOption {
+      type = lib.types.either lib.types.path settingsFormat.type;
+      default = { };
+      description = lib.mdDoc ''
+        ReGreet configuration file. Refer
+        <https://github.com/rharish101/ReGreet/blob/main/regreet.sample.toml>
+        for options.
+      '';
+    };
+
+    extraCss = lib.mkOption {
+      type = lib.types.either lib.types.path lib.types.lines;
+      default = "";
+      description = lib.mdDoc ''
+        Extra CSS rules to apply on top of the GTK theme. Refer to
+        [GTK CSS Properties](https://docs.gtk.org/gtk4/css-properties.html) for
+        modifiable properties.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    services.greetd = {
+      enable = lib.mkDefault true;
+      settings.default_session.command = lib.mkDefault "${lib.getExe pkgs.cage} -s -- ${lib.getExe cfg.package}";
+    };
+
+    environment.etc = {
+      "greetd/regreet.css" =
+        if lib.isPath cfg.extraCss
+        then {source = cfg.extraCss;}
+        else {text = cfg.extraCss;};
+
+      "greetd/regreet.toml".source =
+        if lib.isPath cfg.settings
+        then cfg.settings
+        else settingsFormat.generate "regreet.toml" cfg.settings;
+    };
+
+    systemd.tmpfiles.rules = let
+      user = config.services.greetd.settings.default_session.user;
+    in [
+      "d /var/log/regreet 0755 greeter ${user} - -"
+      "d /var/cache/regreet 0755 greeter ${user} - -"
+    ];
+  };
+}