multiple nix module instances

nix/module.nix

@@ -8,18 +8,12 @@ let
   cfg = config.services.ugit;
   pkg = pkgs.callPackage ./pkg.nix { inherit pkgs; };
   yamlFormat = pkgs.formats.yaml { };
-  configFile = pkgs.writeText "ugit.yaml" (
+  instanceOptions =
-    builtins.readFile (yamlFormat.generate "ugit-yaml" cfg.config)
-  );
-  authorizedKeysFile = pkgs.writeText "ugit_keys" (builtins.concatStringsSep "\n" cfg.authorizedKeys);
-in
-{
-  options =
     let
       inherit (lib) mkEnableOption mkOption types;
     in
     {
-      services.ugit = {
+      options = {
         enable = mkEnableOption "Enable ugit";
 
         package = mkOption {
@@ -28,6 +22,12 @@ in
           default = pkg;
         };
 
+        homeDir = mkOption {
+          type = types.str;
+          description = "ugit home directory";
+          default = "/var/lib/ugit";
+        };
+
         repoDir = mkOption {
           type = types.str;
           description = "where ugit stores repositories";
@@ -70,11 +70,6 @@ in
           description = "Group account under which ugit runs";
         };
 
-        openFirewall = mkOption {
-          type = types.bool;
-          default = false;
-        };
-
         hooks = mkOption {
           type = types.listOf (
             types.submodule {
@@ -95,51 +90,74 @@ in
         };
       };
     };
-  config = lib.mkIf cfg.enable {
+in
-    users.users."${cfg.user}" = {
+{
-      home = "/var/lib/ugit";
+  options = {
+    services.ugit = lib.mkOption {
+      type = lib.types.attrsOf (lib.types.submodule instanceOptions);
+      default = { };
+      description = "Attribute set of ugit instances";
+    };
+  };
+  config = lib.mkIf (cfg != { }) {
+    users.users = lib.mapAttrs' (
+      name: instanceCfg:
+      lib.nameValuePair instanceCfg.user {
+        home = instanceCfg.homeDir;
         createHome = true;
-      group = "${cfg.group}";
+        group = instanceCfg.group;
         isSystemUser = true;
         isNormalUser = false;
-      description = "user for ugit service";
+        description = "user for ugit ${name} service";
-    };
+      }
-    users.groups."${cfg.group}" = { };
+    ) (lib.filterAttrs (name: instanceCfg: instanceCfg.enable) cfg);
-    networking.firewall = lib.mkIf cfg.openFirewall {
-      allowedTCPPorts = [
-        8448
-        8449
-      ];
-    };
 
-    systemd.services = {
+    users.groups = lib.mapAttrs' (name: instanceCfg: lib.nameValuePair instanceCfg.group { }) (
-      ugit = {
+      lib.filterAttrs (name: instanceCfg: instanceCfg.enable) cfg
+    );
+
+    systemd.services = lib.mapAttrs' (
+      name: instanceCfg:
+      lib.nameValuePair "ugit-${name}" {
+        ugit =
+          let
+            configFile = pkgs.writeText "ugit.yaml" (
+              builtins.readFile (yamlFormat.generate "ugit-yaml" instanceCfg.config)
+            );
+            authorizedKeysFile = pkgs.writeText "ugit_keys" (
+              builtins.concatStringsSep "\n" instanceCfg.authorizedKeys
+            );
+          in
+          {
             enable = true;
             script =
               let
                 authorizedKeysPath =
-              if (builtins.length cfg.authorizedKeys) > 0 then authorizedKeysFile else cfg.authorizedKeysFile;
+                  if (builtins.length instanceCfg.authorizedKeys) > 0 then
+                    authorizedKeysFile
+                  else
+                    instanceCfg.authorizedKeysFile;
                 args = [
                   "--config=${configFile}"
-              "--repo-dir=${cfg.repoDir}"
+                  "--repo-dir=${instanceCfg.repoDir}"
                   "--ssh.authorized-keys=${authorizedKeysPath}"
-              "--ssh.host-key=${cfg.hostKeyFile}"
+                  "--ssh.host-key=${instanceCfg.hostKeyFile}"
                 ];
               in
-          "${cfg.package}/bin/ugitd ${builtins.concatStringsSep " " args}";
+              "${instanceCfg.package}/bin/ugitd ${builtins.concatStringsSep " " args}";
             wantedBy = [ "multi-user.target" ];
             after = [ "network.target" ];
             path = [
-          cfg.package
+              instanceCfg.package
               pkgs.git
               pkgs.bash
             ];
             serviceConfig = {
-          User = cfg.user;
+              User = instanceCfg.user;
-          Group = cfg.group;
+              Group = instanceCfg.group;
               Restart = "always";
               RestartSec = "15";
-          WorkingDirectory = "/var/lib/ugit";
+              WorkingDirectory = instanceCfg.homeDir;
             };
           };
         ugit-hooks = {
@@ -156,17 +174,18 @@ in
                       hook:
                       let
                         script = pkgs.writeShellScript hook.name hook.content;
-                      path = "${cfg.repoDir}/hooks/pre-receive.d/${hook.name}";
+                        path = "${instanceCfg.repoDir}/hooks/pre-receive.d/${hook.name}";
                       in
                       "ln -s ${script} ${path}"
-                  ) cfg.hooks
+                    ) instanceCfg.hooks
                   )
                 );
               in
               "${script}";
           };
         };
-    };
+      }
+    ) (lib.filterAttrs (name: instanceCfg: instanceCfg.enable) cfg);
 
     systemd.tmpfiles.settings.ugit = builtins.listToAttrs (
       map (