module overhaul

module

modules/default.nix

@@ -0,0 +1,6 @@
+{ ... }:
+{
+  imports = [
+    ./redis.nix
+  ];
+}

modules/redis.nix

@@ -0,0 +1,118 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+{
+  # create some options
+  options.services.redis =
+    let
+      inherit (lib) mkOption types;
+    in
+    {
+      enable = lib.mkEnableOption "Enable Redis.";
+
+      bind = mkOption {
+        type = with types; listOf str;
+        description = "List of IPs to bind to.";
+        default = [
+          "127.0.0.1"
+          "::1"
+        ];
+      };
+
+      port = mkOption {
+        type = types.ints.between 1024 65535;
+        description = "Port to bind to.";
+        default = 6379;
+      };
+
+      socket = mkOption {
+        type = with types; nullOr str;
+        description = "Unix socket to bind to.";
+        default = null;
+      };
+
+      socketPerms = mkOption {
+        type = with types; nullOr int;
+        description = "Permissions for the unix socket.";
+        default = null;
+      };
+
+      logLevel = mkOption {
+        type = types.enum [
+          "debug"
+          "verbose"
+          "notice"
+          "warning"
+          "nothing"
+        ];
+        description = "Logging verbosity level.";
+        default = "notice";
+      };
+
+      databases = mkOption {
+        type = types.int;
+        description = "Number of databases.";
+        default = 16;
+      };
+
+      # escape hatch due to redis config being massive
+      extraConfig = mkOption {
+        type = types.str;
+        description = "Additional config directives.";
+        default = "";
+      };
+    };
+
+  config.serviceDefs.redis =
+    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;
+        };
+        # 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;
+      };
+    };
+}