update redis module to allow multiple instances

modules/redis.nix

@@ -64,55 +64,64 @@
         description = "Additional config directives.";
         default = "";
       };
+
+      name = mkOption {
+        type = types.str;
+        description = "The name ides uses for this service.";
+        default = "redis";
+      };
     };
 
-  config.serviceDefs.redis =
+  config.serviceDefs =
     let
       cfg = config.services.redis;
     in
     lib.mkIf cfg.enable {
-      pkg = pkgs.redis;
-      # make sure we get the server binary, not cli
-      exec = "redis-server";
-      args = "%CFG%";
-      config = {
-        ext = ".conf";
-        # these need to be made to match redis config
-        # variable names here
-        content = {
-          inherit (cfg) bind port databases;
-          unixsocket = cfg.socket;
-          unixsocketperm = cfg.socketPerms;
-          loglevel = cfg.logLevel;
+      # use a customisable name in case the user needs several instances
+      "${cfg.name}" = {
+        pkg = pkgs.redis;
+        # make sure we get the server binary, not cli
+        exec = "redis-server";
+        args = "%CFG%";
+        config = {
+          ext = ".conf";
+          # these need to be made to match redis config
+          # variable names here
+          content = {
+            inherit (cfg) bind port databases;
+            unixsocket = cfg.socket;
+            unixsocketperm = cfg.socketPerms;
+            loglevel = cfg.logLevel;
+          };
+          # a formatter needs to take in a set of
+          # attrs and write out a file
+          formatter =
+            let
+              # set up serialisation for all types
+              serialise = {
+                int = builtins.toString;
+                bool = b: if b then "yes" else "no";
+                string = s: s;
+                path = builtins.toString;
+                null = _: _;
+                list = builtins.concatStringsSep " ";
+                float = builtins.toString;
+                set = throw "cannot serialise a set in redis format";
+                lambda = throw "cannot serialise a lambda, wtf?";
+              };
+            in
+            # create a lambda that can serialise to redis config
+            path: attrs:
+            let
+              text =
+                (lib.foldlAttrs (
+                  acc: n: v:
+                  if (v != null) then acc + "${n} ${serialise.${builtins.typeOf v} v}" + "\n" else acc
+                ) "" attrs)
+                + cfg.extraConfig;
+            in
+            (pkgs.writeText path text).outPath;
         };
-        # a formatter needs to take in a set of
-        # attrs and write out a file
-        formatter =
-          let
-            # set up serialisation for all types
-            serialise = {
-              int = builtins.toString;
-              bool = b: if b then "yes" else "no";
-              string = s: s;
-              path = builtins.toString;
-              null = _: _;
-              list = builtins.concatStringsSep " ";
-              float = builtins.toString;
-              set = throw "cannot serialise a set in redis format";
-              lambda = throw "cannot serialise a lambda, wtf?";
-            };
-          in
-          # create a lambda that can serialise to redis config
-          path: attrs:
-          let
-            text =
-              (lib.foldlAttrs (
-                acc: n: v:
-                if (v != null) then acc + "${n} ${serialise.${builtins.typeOf v} v}" + "\n" else acc
-              ) "" attrs)
-              + cfg.extraConfig;
-          in
-          (pkgs.writeText path text).outPath;
       };
     };
 }