refactor: tighten ws batch typing and queue cleanup logging

server/private/lib/rebuildQueue.ts

@@ -29,6 +29,7 @@ export interface RebuildJobHandlers {
 
 // Redis list holding pending rebuild jobs (RPUSH to enqueue, LPOP to dequeue — FIFO order).
 const QUEUE_KEY = "rebuild-client-associations:queue";
+const QUEUED_SET_KEY = "rebuild-client-associations:queued";
 
 // Distributed lock that serialises queue consumption to a single server instance
 // at a time. TTL is generous enough to cover a full batch of expensive rebuilds.
@@ -54,11 +55,28 @@ class RedisRebuildQueue {
         }
 
         try {
+            const dedupeKey = `${job.type}:${job.id}`;
+            const added = await redis.sadd(QUEUED_SET_KEY, dedupeKey);
+            if (added === 0) {
+                logger.debug(
+                    `Rebuild queue: skipped duplicate queued job ${job.type}:${job.id}`
+                );
+                return;
+            }
+
             await redis.rpush(QUEUE_KEY, JSON.stringify(job));
             logger.debug(
                 `Rebuild queue: enqueued ${job.type}:${job.id} (queue position: tail)`
             );
         } catch (err) {
+            await redis
+                .srem(QUEUED_SET_KEY, `${job.type}:${job.id}`)
+                .catch((cleanupErr) =>
+                    logger.warn(
+                        `Rebuild queue: failed to cleanup dedupe key for ${job.type}:${job.id} after enqueue failure:`,
+                        cleanupErr
+                    )
+                );
             logger.error(
                 `Rebuild queue: failed to enqueue ${job.type}:${job.id}:`,
                 err
@@ -121,6 +139,17 @@ class RedisRebuildQueue {
                             continue;
                         }
 
+                        // Remove from dedupe set once dequeued so the same job
+                        // can be re-queued while this one is in progress.
+                        await redis
+                            .srem(QUEUED_SET_KEY, `${job.type}:${job.id}`)
+                            .catch((cleanupErr) =>
+                                logger.warn(
+                                    `Rebuild queue: failed to remove dedupe key for ${job.type}:${job.id} on dequeue:`,
+                                    cleanupErr
+                                )
+                            );
+
                         logger.debug(
                             `Rebuild queue: processing ${job.type}:${job.id}`
                         );

server/private/routers/ws/ws.ts

@@ -187,6 +187,8 @@ const wss: WebSocketServer = new WebSocketServer({ noServer: true });
 // Generate unique node ID for this instance
 const NODE_ID = uuidv4();
 const REDIS_CHANNEL = "websocket_messages";
+const REDIS_DIRECT_BATCH_SIZE = 250;
+const REDIS_DIRECT_FLUSH_INTERVAL_MS = 10;
 
 // Client tracking map (local to this node)
 const connectedClients: Map<string, AuthenticatedWebSocket[]> = new Map();
@@ -197,6 +199,15 @@ const clientConfigVersions: Map<string, number> = new Map();
 // Recovery tracking
 let isRedisRecoveryInProgress = false;
 
+interface RedisDirectBatchEntry {
+    targetClientId: string;
+    message: WSMessage;
+    resolve: () => void;
+}
+
+let pendingRedisDirectMessages: RedisDirectBatchEntry[] = [];
+let redisDirectFlushTimer: NodeJS.Timeout | null = null;
+
 // Helper to get map key
 const getClientMapKey = (clientId: string) => clientId;
 
@@ -207,6 +218,78 @@ const getNodeConnectionsKey = (nodeId: string, clientId: string) =>
 const getConfigVersionKey = (clientId: string) =>
     `ws:configVersion:${clientId}`;
 
+const clearRedisDirectFlushTimer = (): void => {
+    if (redisDirectFlushTimer) {
+        clearTimeout(redisDirectFlushTimer);
+        redisDirectFlushTimer = null;
+    }
+};
+
+const publishDirectBatch = async (
+    entries: RedisDirectBatchEntry[]
+): Promise<void> => {
+    const redisMessage: RedisMessage = {
+        type: "direct-batch",
+        messages: entries.map((entry) => ({
+            targetClientId: entry.targetClientId,
+            message: entry.message
+        })),
+        fromNodeId: NODE_ID
+    };
+
+    await redisManager.publish(REDIS_CHANNEL, JSON.stringify(redisMessage));
+};
+
+const flushPendingRedisDirectMessages = async (): Promise<void> => {
+    clearRedisDirectFlushTimer();
+
+    if (pendingRedisDirectMessages.length === 0) {
+        return;
+    }
+
+    const entries = pendingRedisDirectMessages;
+    pendingRedisDirectMessages = [];
+
+    if (!redisManager.isRedisEnabled()) {
+        entries.forEach((entry) => entry.resolve());
+        return;
+    }
+
+    for (let i = 0; i < entries.length; i += REDIS_DIRECT_BATCH_SIZE) {
+        const batch = entries.slice(i, i + REDIS_DIRECT_BATCH_SIZE);
+        try {
+            await publishDirectBatch(batch);
+        } catch (error) {
+            logger.error(
+                "Failed to send batched direct messages via Redis, messages may be lost:",
+                error
+            );
+        } finally {
+            batch.forEach((entry) => entry.resolve());
+        }
+    }
+};
+
+const enqueueRedisDirectMessage = async (
+    targetClientId: string,
+    message: WSMessage
+): Promise<void> => {
+    await new Promise<void>((resolve) => {
+        pendingRedisDirectMessages.push({ targetClientId, message, resolve });
+
+        if (pendingRedisDirectMessages.length >= REDIS_DIRECT_BATCH_SIZE) {
+            void flushPendingRedisDirectMessages();
+            return;
+        }
+
+        if (!redisDirectFlushTimer) {
+            redisDirectFlushTimer = setTimeout(() => {
+                void flushPendingRedisDirectMessages();
+            }, REDIS_DIRECT_FLUSH_INTERVAL_MS);
+        }
+    });
+};
+
 // Initialize Redis subscription for cross-node messaging
 const initializeRedisSubscription = async (): Promise<void> => {
     if (!redisManager.isRedisEnabled()) return;
@@ -227,7 +310,16 @@ const initializeRedisSubscription = async (): Promise<void> => {
                     // Send to specific client on this node
                     await sendToClientLocal(
                         redisMessage.targetClientId,
-                        redisMessage.message
+                        redisMessage.message,
+                        {},
+                        redisMessage.message.configVersion
+                    );
+                } else if (
+                    redisMessage.type === "direct-batch" &&
+                    redisMessage.messages
+                ) {
+                    await sendRedisDirectBatchToLocalClients(
+                        redisMessage.messages
                     );
                 } else if (redisMessage.type === "broadcast") {
                     // Broadcast to all clients on this node except excluded
@@ -503,7 +595,8 @@ const incrementClientConfigVersion = async (
 const sendToClientLocal = async (
     clientId: string,
     message: WSMessage,
-    options: SendMessageOptions = {}
+    options: SendMessageOptions = {},
+    preResolvedConfigVersion?: number
 ): Promise<boolean> => {
     const mapKey = getClientMapKey(clientId);
     const clients = connectedClients.get(mapKey);
@@ -512,7 +605,8 @@ const sendToClientLocal = async (
     }
 
     // Handle config version
-    const configVersion = await getClientConfigVersion(clientId);
+    const configVersion =
+        preResolvedConfigVersion ?? (await getClientConfigVersion(clientId));
 
     // Add config version to message
     const messageWithVersion = {
@@ -545,6 +639,20 @@ const sendToClientLocal = async (
     return true;
 };
 
+const sendRedisDirectBatchToLocalClients = async (
+    entries: { targetClientId: string; message: WSMessage }[]
+): Promise<void> => {
+    const jobs = entries.map((entry) =>
+        sendToClientLocal(
+            entry.targetClientId,
+            entry.message,
+            {},
+            entry.message.configVersion
+        )
+    );
+    await Promise.all(jobs);
+};
+
 const broadcastToAllExceptLocal = async (
     message: WSMessage,
     excludeClientId?: string,
@@ -607,23 +715,13 @@ const sendToClient = async (
     // Only send via Redis if the client is not connected locally and Redis is enabled
     if (!localSent && redisManager.isRedisEnabled()) {
         try {
-            const redisMessage: RedisMessage = {
-                type: "direct",
-                targetClientId: clientId,
-                message: {
-                    ...message,
-                    configVersion
-                },
-                fromNodeId: NODE_ID
-            };
-
-            await redisManager.publish(
-                REDIS_CHANNEL,
-                JSON.stringify(redisMessage)
-            );
+            await enqueueRedisDirectMessage(clientId, {
+                ...message,
+                configVersion
+            });
         } catch (error) {
             logger.error(
-                "Failed to send message via Redis, message may be lost:",
+                "Failed to queue batched direct message for Redis delivery, message may be lost:",
                 error
             );
             // Continue execution - local delivery already attempted
@@ -1109,6 +1207,8 @@ const disconnectClient = async (clientId: string): Promise<boolean> => {
 // Cleanup function for graceful shutdown
 const cleanup = async (): Promise<void> => {
     try {
+        await flushPendingRedisDirectMessages();
+
         // Close all WebSocket connections
         connectedClients.forEach((clients) => {
             clients.forEach((client) => {

server/routers/ws/types.ts

@@ -76,12 +76,26 @@ export interface SendMessageOptions {
     compress?: boolean;
 }
 
-// Redis message type for cross-node communication
-export interface RedisMessage {
-    type: "direct" | "broadcast";
-    targetClientId?: string;
-    excludeClientId?: string;
-    message: WSMessage;
-    fromNodeId: string;
-    options?: SendMessageOptions;
-}
+// Redis message types for cross-node communication
+export type RedisMessage =
+    | {
+          type: "direct";
+          targetClientId: string;
+          message: WSMessage;
+          fromNodeId: string;
+      }
+    | {
+          type: "direct-batch";
+          messages: {
+              targetClientId: string;
+              message: WSMessage;
+          }[];
+          fromNodeId: string;
+      }
+    | {
+          type: "broadcast";
+          excludeClientId?: string;
+          message: WSMessage;
+          fromNodeId: string;
+          options?: SendMessageOptions;
+      };