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src/config/redis.ts

@@ -2,6 +2,10 @@ import { createClient } from 'redis';
 
 const redisClient = createClient({
   url: process.env.REDIS_URL,
+  socket: {
+    connectTimeout: 3000,
+    reconnectStrategy: (retries) => Math.min(retries * 200, 5000),
+  },
 });
 
 redisClient.on('connect', () => {

src/stats/repositories/admin-visitor-stats.repository.ts

@@ -1,24 +1,38 @@
 import redisClient from '../../config/redis';
 import { buildHllKey } from '../../utils/visitor-tracking';
 
+const REDIS_TIMEOUT_MS = 2000;
+
+// ponytail: Redis 장애 시 응답이 hang 되지 않도록 짧은 타임아웃 + 폴백. 근본 복구는 인프라 몫.
+const withTimeout = <T>(op: Promise<T>, fallback: T): Promise<T> =>
+  Promise.race([
+    op,
+    new Promise<T>((resolve) => setTimeout(() => resolve(fallback), REDIS_TIMEOUT_MS)),
+  ]);
+
 export const AdminVisitorStatsRepository = {
   countUniqueOnDate: async (kstDate: string): Promise<number> => {
-    return Number(await redisClient.pfCount(buildHllKey(kstDate)));
+    return withTimeout(
+      redisClient.pfCount(buildHllKey(kstDate)).then(Number),
+      0,
+    );
   },
 
   countUniqueOverRange: async (kstDates: string[]): Promise<number> => {
     if (kstDates.length === 0) return 0;
     const keys = kstDates.map(buildHllKey);
-    return Number(await redisClient.pfCount(keys));
+    return withTimeout(redisClient.pfCount(keys).then(Number), 0);
   },
 
   countUniquePerDay: async (
     kstDates: string[],
   ): Promise<{ date: string; count: number }[]> => {
     if (kstDates.length === 0) return [];
     const counts = await Promise.all(
-      kstDates.map((d) => redisClient.pfCount(buildHllKey(d))),
+      kstDates.map((d) =>
+        withTimeout(redisClient.pfCount(buildHllKey(d)).then(Number), 0),
+      ),
     );
-    return kstDates.map((date, i) => ({ date, count: Number(counts[i]) }));
+    return kstDates.map((date, i) => ({ date, count: counts[i] }));
   },
 };