New NixOS module: services.winstone, for running instances of the Winstone Java Servlet container

nixos/modules/module-list.nix

@@ -231,6 +231,7 @@
   ./services/web-servers/phpfpm.nix
   ./services/web-servers/tomcat.nix
   ./services/web-servers/varnish/default.nix
+  ./services/web-servers/winstone.nix
   ./services/web-servers/zope2.nix
   ./services/x11/desktop-managers/default.nix
   ./services/x11/display-managers/auto.nix

nixos/modules/services/web-servers/winstone.nix

@@ -0,0 +1,120 @@
+{ config, pkgs, ... }:
+
+with pkgs.lib;
+
+let
+
+  cfg = config.services.winstone;
+
+  winstoneOpts = { name, ... }: {
+    options = {
+      name = mkOption {
+        default = name;
+        internal = true;
+      };
+
+      warFile = mkOption {
+        type = types.str;
+        description = ''
+          The WAR file that Winstone should serve.
+        '';
+      };
+
+      javaPackage = mkOption {
+        type = types.package;
+        default = pkgs.openjre;
+        description = ''
+          Which Java derivation to use for running Winstone.
+        '';
+      };
+
+      user = mkOption {
+        type = types.str;
+        description = ''
+          The user that should run this Winstone process and
+          own the working directory.
+        '';
+      };
+
+      group = mkOption {
+        type = types.str;
+        description = ''
+          The group that will own the working directory.
+        '';
+      };
+
+      workDir = mkOption {
+        type = types.str;
+        description = ''
+          The working directory for this Winstone instance. Will
+          contain extracted webapps etc. The directory will be
+          created if it doesn't exist.
+        '';
+      };
+
+      extraJavaOptions = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = ''
+          Extra command line options given to the java process running
+          Winstone.
+        '';
+      };
+
+      extraOptions = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = ''
+          Extra command line options given to the Winstone process.
+        '';
+      };
+    };
+
+    config = {
+      workDir = mkDefault "/run/winstone/${name}";
+    };
+  };
+
+  mkService = cfg: let
+    opts = concatStringsSep " " (cfg.extraOptions ++ [
+      "--warfile ${cfg.warFile}"
+    ]);
+
+    javaOpts = concatStringsSep " " (cfg.extraJavaOptions ++ [
+      "-Djava.io.tmpdir=${cfg.workDir}"
+      "-jar ${pkgs.winstone}/lib/winstone.jar"
+    ]);
+  in {
+    wantedBy = [ "multi-user.target" ];
+    description = "winstone service for ${cfg.name}";
+    preStart = ''
+      mkdir -p "${cfg.workDir}"
+      chown ${cfg.user}:${cfg.group} "${cfg.workDir}"
+    '';
+    serviceConfig = {
+      ExecStart = "${cfg.javaPackage}/bin/java ${javaOpts} ${opts}";
+      User = cfg.user;
+      PermissionsStartOnly = true;
+    };
+  };
+
+in {
+
+  options = {
+    services.winstone = mkOption {
+      default = {};
+      type = types.attrsOf types.optionSet;
+      options = [ winstoneOpts ];
+      description = ''
+        Defines independent Winstone services, each serving one WAR-file.
+      '';
+    };
+  };
+
+  config = mkIf (cfg != {}) {
+
+    systemd.services = mapAttrs' (n: c: nameValuePair "winstone-${n}" (mkService c)) cfg;
+
+  };
+
+}