vdr: initial at 2.4.0 and nixos module

used same plugin mechanism as kodi does

nixos/modules/module-list.nix

@@ -299,6 +299,7 @@
   ./services/hardware/usbmuxd.nix
   ./services/hardware/thermald.nix
   ./services/hardware/undervolt.nix
+  ./services/hardware/vdr.nix
   ./services/logging/SystemdJournal2Gelf.nix
   ./services/logging/awstats.nix
   ./services/logging/fluentd.nix

nixos/modules/services/hardware/vdr.nix

@@ -0,0 +1,67 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.vdr;
+  libDir = "/var/lib/vdr";
+in {
+
+  ###### interface
+
+  options = {
+
+    services.vdr = {
+      enable = mkEnableOption "enable VDR. Please put config into ${libDir}.";
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.vdr;
+        defaultText = "pkgs.vdr";
+        example = literalExample "pkgs.wrapVdr.override { plugins = with pkgs.vdrPlugins; [ hello ]; }";
+        description = "Package to use.";
+      };
+
+      videoDir = mkOption {
+        type = types.path;
+        default = "/srv/vdr/video";
+        description = "Recording directory (must exist)";
+      };
+
+      extraArguments = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = "Additional command line arguments to pass to VDR.";
+      };
+    };
+  };
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+
+    systemd.services.vdr = {
+      description = "VDR";
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        ExecStart = ''
+          ${cfg.package}/bin/vdr \
+            --video="${cfg.videoDir}" \
+            --config="${libDir}" \
+            ${escapeShellArgs cfg.extraArguments}
+        '';
+        User = "vdr";
+        CacheDirectory = "vdr";
+        StateDirectory = "vdr";
+        Restart = "on-failure";
+      };
+    };
+
+    users.users.vdr = {
+      group = "vdr";
+      home = libDir;
+    };
+
+    users.groups.vdr = {};
+  };
+}