nixos/livekit{,-ingress}: automatically configure redis for locally distributed setups

nixos/modules/services/networking/livekit-ingress.nix

@@ -8,6 +8,9 @@
 let
   cfg = config.services.livekit.ingress;
   format = pkgs.formats.yaml { };
+  settings = lib.filterAttrsRecursive (_: v: v != null) cfg.settings;
+
+  isLocallyDistributed = config.services.livekit.enable;
 in
 {
   meta.maintainers = with lib.maintainers; [ k900 ];
@@ -51,6 +54,21 @@ in
             description = "TCP port for WHIP connections";
           };
 
+          redis = {
+            address = lib.mkOption {
+              type = with lib.types; nullOr str;
+              default =
+                if isLocallyDistributed then
+                  "${config.services.livekit.redis.host}:${toString config.services.livekit.redis.port}"
+                else
+                  null;
+              example = "redis.example.com:6379";
+              defaultText = "Host and port of the local livekit redis instance, if enabled, or null";
+              description = "Address or hostname and port for redis connection";
+            };
+
+          };
+
           rtc_config = {
             port_range_start = lib.mkOption {
               type = lib.types.int;
@@ -125,7 +143,7 @@ in
       serviceConfig = {
         ExecStart = utils.escapeSystemdExecArgs [
           (lib.getExe cfg.package)
-          "--config=${format.generate "ingress.yaml" cfg.settings}"
+          "--config=${format.generate "ingress.yaml" settings}"
         ];
         EnvironmentFile = lib.mkIf (cfg.environmentFile != null) cfg.environmentFile;
         DynamicUser = true;

nixos/modules/services/networking/livekit.nix

@@ -8,6 +8,9 @@
 let
   cfg = config.services.livekit;
   format = pkgs.formats.json { };
+  settings = lib.filterAttrsRecursive (_: v: v != null) cfg.settings;
+
+  isLocallyDistributed = config.services.livekit.ingress.enable;
 in
 {
   meta.maintainers = with lib.maintainers; [ quadradical ];
@@ -34,6 +37,32 @@ in
       description = "Opens port range for LiveKit on the firewall.";
     };
 
+    redis = {
+      createLocally = lib.mkOption {
+        type = lib.types.bool;
+        default = isLocallyDistributed;
+        defaultText = "true if any other Livekit component is enabled locally else false";
+        description = "Whether to set up a local redis instance.";
+      };
+
+      host = lib.mkOption {
+        type = with lib.types; nullOr str;
+        default = if cfg.redis.createLocally then "127.0.0.1" else null;
+        defaultText = "127.0.0.1 if config.services.livekit.redis.createLocally else null";
+        description = ''
+          Address to bind local redis instance to.
+        '';
+      };
+
+      port = lib.mkOption {
+        type = with lib.types; nullOr port;
+        default = null;
+        description = ''
+          Port to bind local redis instance to.
+        '';
+      };
+    };
+
     settings = lib.mkOption {
       type = lib.types.submodule {
         freeformType = format.type;
@@ -44,6 +73,16 @@ in
             description = "Main TCP port for RoomService and RTC endpoint.";
           };
 
+          redis = {
+            address = lib.mkOption {
+              type = with lib.types; nullOr str;
+              default = if isLocallyDistributed then "${cfg.redis.host}:${toString cfg.redis.port}" else null;
+              defaultText = lib.literalExpression "Local Redis host/port when a local ingress component is enabled else null";
+              example = "redis.example.com:6379";
+              description = "Host and port used to connect to a redis instance.";
+            };
+          };
+
           rtc = {
             port_range_start = lib.mkOption {
               type = lib.types.int;
@@ -79,6 +118,15 @@ in
   };
 
   config = lib.mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = cfg.redis.createLocally -> cfg.redis.port != null;
+        message = ''
+          When `services.livekit.redis.createLocally` is enabled `services.livekit.redis.port` must be configured.
+        '';
+      }
+    ];
+
     networking.firewall = lib.mkIf cfg.openFirewall {
       allowedTCPPorts = [
         cfg.settings.port
@@ -91,6 +139,13 @@ in
       ];
     };
 
+    # Provision a redis instance, when livekit-ingress (or later livekit-egress) are enabled on the same host
+    services.redis.servers.livekit = lib.mkIf cfg.redis.createLocally {
+      enable = true;
+      bind = cfg.redis.host;
+      port = cfg.redis.port;
+    };
+
     systemd.services.livekit = {
       description = "LiveKit SFU server";
       documentation = [ "https://docs.livekit.io" ];
@@ -102,7 +157,7 @@ in
         LoadCredential = [ "livekit-secrets:${cfg.keyFile}" ];
         ExecStart = utils.escapeSystemdExecArgs [
           (lib.getExe cfg.package)
-          "--config=${format.generate "livekit.json" cfg.settings}"
+          "--config=${format.generate "livekit.json" settings}"
           "--key-file=/run/credentials/livekit.service/livekit-secrets"
         ];
         DynamicUser = true;