fix(redis): apply TLS SNI override to pub/sub clients

apps/sim/lib/core/config/redis.ts

@@ -1,7 +1,7 @@
 import { createLogger } from '@sim/logger'
 import { toError } from '@sim/utils/errors'
 import { randomFloat } from '@sim/utils/random'
-import Redis from 'ioredis'
+import Redis, { type RedisOptions } from 'ioredis'
 import { env } from '@/lib/core/config/env'
 
 const logger = createLogger('Redis')
@@ -16,7 +16,7 @@ const redisUrl = env.REDIS_URL
  *
  * For DNS hosts: no override needed, default verification works.
  */
-function resolveTlsOptions(url: string | undefined): { servername: string } | undefined {
+function resolveRedisTlsOptions(url: string | undefined): { servername: string } | undefined {
   if (!url) return undefined
   let parsed: URL
   try {
@@ -37,6 +37,23 @@ function resolveTlsOptions(url: string | undefined): { servername: string } | un
   return { servername: env.REDIS_TLS_SERVERNAME }
 }
 
+/**
+ * Shared connection defaults — keepAlive, connectTimeout, enableOfflineQueue,
+ * and TLS SNI when REDIS_URL targets an IP. Every Redis client we open should
+ * spread this; callers add their own retry / timeout policy on top.
+ */
+export function getRedisConnectionDefaults(
+  url: string | undefined
+): Pick<RedisOptions, 'keepAlive' | 'connectTimeout' | 'enableOfflineQueue' | 'tls'> {
+  const tls = resolveRedisTlsOptions(url)
+  return {
+    keepAlive: 1000,
+    connectTimeout: 10000,
+    enableOfflineQueue: true,
+    ...(tls ? { tls } : {}),
+  }
+}
+
 let globalRedisClient: Redis | null = null
 let pingFailures = 0
 let pingInterval: NodeJS.Timeout | null = null
@@ -117,18 +134,15 @@ export function getRedisClient(): Redis | null {
   if (globalRedisClient) return globalRedisClient
 
   // Outside the try/catch so config errors aren't silently swallowed.
-  const tls = resolveTlsOptions(redisUrl)
+  const defaults = getRedisConnectionDefaults(redisUrl)
 
   try {
     logger.info('Initializing Redis client')
 
     globalRedisClient = new Redis(redisUrl, {
-      keepAlive: 1000,
-      connectTimeout: 10000,
+      ...defaults,
       commandTimeout: 5000,
       maxRetriesPerRequest: 5,
-      enableOfflineQueue: true,
-      ...(tls ? { tls } : {}),
 
       retryStrategy: (times) => {
         if (times > 10) {

apps/sim/lib/events/pubsub.ts

@@ -9,6 +9,7 @@ import { EventEmitter } from 'events'
 import { createLogger } from '@sim/logger'
 import Redis, { type RedisOptions } from 'ioredis'
 import { env } from '@/lib/core/config/env'
+import { getRedisConnectionDefaults } from '@/lib/core/config/redis'
 
 const logger = createLogger('PubSub')
 
@@ -31,13 +32,12 @@ class RedisPubSubChannel<T> implements PubSubChannel<T> {
 
   constructor(
     redisUrl: string,
+    connectionDefaults: ReturnType<typeof getRedisConnectionDefaults>,
     private config: PubSubChannelConfig
   ) {
     const commonOpts = {
-      keepAlive: 1000,
-      connectTimeout: 10000,
+      ...connectionDefaults,
       maxRetriesPerRequest: null,
-      enableOfflineQueue: true,
       retryStrategy: (times: number) => {
         if (times > 10) return 30000
         return Math.min(times * 500, 5000)
@@ -139,16 +139,18 @@ class LocalPubSubChannel<T> implements PubSubChannel<T> {
 
 export function createPubSubChannel<T>(config: PubSubChannelConfig): PubSubChannel<T> {
   const redisUrl = env.REDIS_URL
-
-  if (redisUrl) {
-    try {
-      logger.info(`${config.label}: Using Redis`)
-      return new RedisPubSubChannel<T>(redisUrl, config)
-    } catch (err) {
-      logger.error(`Failed to create Redis ${config.label}, falling back to local:`, err)
-      return new LocalPubSubChannel<T>(config)
-    }
+  if (!redisUrl) return new LocalPubSubChannel<T>(config)
+
+  // Resolve config-derived defaults outside the try so a missing
+  // REDIS_TLS_SERVERNAME (config error) surfaces instead of silently degrading
+  // to the in-process EventEmitter — that would break cross-replica pub/sub.
+  const connectionDefaults = getRedisConnectionDefaults(redisUrl)
+
+  try {
+    logger.info(`${config.label}: Using Redis`)
+    return new RedisPubSubChannel<T>(redisUrl, connectionDefaults, config)
+  } catch (err) {
+    logger.error(`Failed to create Redis ${config.label}, falling back to local:`, err)
+    return new LocalPubSubChannel<T>(config)
   }
-
-  return new LocalPubSubChannel<T>(config)
 }