fix(redis): handle offline state in rate limiter and mount health routes under /api/v1 (!18) · Merge Requests · ThinhNC / upgrade-data-crawler-be

fix(redis): handle offline state in rate limiter and mount health routes under /api/v1

Summary of Changes

This PR fixes a critical unhandled Connection is closed error during authentication/API requests when Redis is offline or reconnected, and resolves 404 Not Found errors when accessing /api/v1/health/* endpoints through the Next.js BFF proxy.

Key Improvements

1. Rate Limiter Resilience & Fail-Open Behavior

Redis Readiness Guard: Updated createRateLimitStore in rate-limit.middleware.ts to check isRedisConnected(). If Redis is offline or not ready, it cleanly falls back to the in-memory MemoryStore.
Fail-Open Strategy: Added passOnStoreError: true to both rateLimitMiddleware and authRateLimiter. Any transient Redis hiccups or network drops will no longer throw an unhandled 500 error or block user logins.

2. Redis Connection Lifecycle

Connection Status Validation: Added exported isRedisConnected() helper in redis-client.ts to verify client.status === 'ready'.
Dead Instance Cleanup: Automatically reset generalClient = null when Redis connection transitions into 'end' or 'close' states, or when initial handshake fails during server startup.

3. Health Routes Mounting

BFF Proxy Compatibility: Mounted healthRoute under router.use("/health", healthRoute) in src/routes/index.ts, making /api/v1/health/readiness, /liveness, and /metrics accessible to the frontend proxy while preserving root-level /health for container orchestrators.

## Summary of Changes

This PR fixes a critical unhandled `Connection is closed` error during authentication/API requests when Redis is offline or reconnected, and resolves `404 Not Found` errors when accessing `/api/v1/health/*` endpoints through the Next.js BFF proxy.

### Key Improvements

#### 1. Rate Limiter Resilience & Fail-Open Behavior
- **Redis Readiness Guard:** Updated `createRateLimitStore` in `rate-limit.middleware.ts` to check `isRedisConnected()`. If Redis is offline or not ready, it cleanly falls back to the in-memory `MemoryStore`.
- **Fail-Open Strategy:** Added `passOnStoreError: true` to both `rateLimitMiddleware` and `authRateLimiter`. Any transient Redis hiccups or network drops will no longer throw an unhandled 500 error or block user logins.

#### 2. Redis Connection Lifecycle
- **Connection Status Validation:** Added exported `isRedisConnected()` helper in `redis-client.ts` to verify `client.status === 'ready'`.
- **Dead Instance Cleanup:** Automatically reset `generalClient = null` when Redis connection transitions into `'end'` or `'close'` states, or when initial handshake fails during server startup.

#### 3. Health Routes Mounting
- **BFF Proxy Compatibility:** Mounted `healthRoute` under `router.use("/health", healthRoute)` in `src/routes/index.ts`, making `/api/v1/health/readiness`, `/liveness`, and `/metrics` accessible to the frontend proxy while preserving root-level `/health` for container orchestrators.