✨ feat: Enhance Redis Config and Error Handling (#8709)

* ✨ feat: Enhance Redis Config and Error Handling

- Added new Redis configuration options: `REDIS_RETRY_MAX_DELAY`, `REDIS_RETRY_MAX_ATTEMPTS`, `REDIS_CONNECT_TIMEOUT`, and `REDIS_ENABLE_OFFLINE_QUEUE` to improve connection resilience.
- Implemented error handling for Redis cache creation and session store initialization in `cacheFactory.js`.
- Enhanced logging for Redis client events and errors in `redisClients.js`.
- Updated `README.md` to document new Redis configuration options.

* chore: Add JSDoc comments to Redis configuration options in cacheConfig.js for improved clarity and documentation

* ci: update cacheFactory tests

* refactor: remove fallback

* fix: Improve error handling in Redis cache creation, re-throw errors when expected

api/cache/cacheFactory.spec.js

@@ -6,13 +6,17 @@ const mockKeyvRedis = {
   keyPrefixSeparator: '',
 };
 
-const mockKeyv = jest.fn().mockReturnValue({ mock: 'keyv' });
+const mockKeyv = jest.fn().mockReturnValue({
+  mock: 'keyv',
+  on: jest.fn(),
+});
 const mockConnectRedis = jest.fn().mockReturnValue({ mock: 'connectRedis' });
 const mockMemoryStore = jest.fn().mockReturnValue({ mock: 'memoryStore' });
 const mockRedisStore = jest.fn().mockReturnValue({ mock: 'redisStore' });
 
 const mockIoredisClient = {
   call: jest.fn(),
+  on: jest.fn(),
 };
 
 const mockKeyvRedisClient = {};
@@ -53,6 +57,14 @@ jest.mock('rate-limit-redis', () => ({
   RedisStore: mockRedisStore,
 }));
 
+jest.mock('@librechat/data-schemas', () => ({
+  logger: {
+    error: jest.fn(),
+    warn: jest.fn(),
+    info: jest.fn(),
+  },
+}));
+
 // Import after mocking
 const { standardCache, sessionCache, violationCache, limiterCache } = require('./cacheFactory');
 const { cacheConfig } = require('./cacheConfig');
@@ -142,6 +154,28 @@ describe('cacheFactory', () => {
       expect(require('@keyv/redis').default).toHaveBeenCalledWith(mockKeyvRedisClient);
       expect(mockKeyv).toHaveBeenCalledWith(mockKeyvRedis, { namespace, ttl });
     });
+
+    it('should throw error when Redis cache creation fails', () => {
+      cacheConfig.USE_REDIS = true;
+      const namespace = 'test-namespace';
+      const ttl = 3600;
+      const testError = new Error('Redis connection failed');
+
+      const KeyvRedis = require('@keyv/redis').default;
+      KeyvRedis.mockImplementationOnce(() => {
+        throw testError;
+      });
+
+      expect(() => standardCache(namespace, ttl)).toThrow('Redis connection failed');
+
+      const { logger } = require('@librechat/data-schemas');
+      expect(logger.error).toHaveBeenCalledWith(
+        `Failed to create Redis cache for namespace ${namespace}:`,
+        testError,
+      );
+
+      expect(mockKeyv).not.toHaveBeenCalled();
+    });
   });
 
   describe('violationCache', () => {
@@ -233,6 +267,86 @@ describe('cacheFactory', () => {
         checkPeriod: Time.ONE_DAY,
       });
     });
+
+    it('should throw error when ConnectRedis constructor fails', () => {
+      cacheConfig.USE_REDIS = true;
+      const namespace = 'sessions';
+      const ttl = 86400;
+
+      // Mock ConnectRedis to throw an error during construction
+      const redisError = new Error('Redis connection failed');
+      mockConnectRedis.mockImplementationOnce(() => {
+        throw redisError;
+      });
+
+      // The error should propagate up, not be caught
+      expect(() => sessionCache(namespace, ttl)).toThrow('Redis connection failed');
+
+      // Verify that MemoryStore was NOT used as fallback
+      expect(mockMemoryStore).not.toHaveBeenCalled();
+    });
+
+    it('should register error handler but let errors propagate to Express', () => {
+      cacheConfig.USE_REDIS = true;
+      const namespace = 'sessions';
+
+      // Create a mock session store with middleware methods
+      const mockSessionStore = {
+        get: jest.fn(),
+        set: jest.fn(),
+        destroy: jest.fn(),
+      };
+      mockConnectRedis.mockReturnValue(mockSessionStore);
+
+      const store = sessionCache(namespace);
+
+      // Verify error handler was registered
+      expect(mockIoredisClient.on).toHaveBeenCalledWith('error', expect.any(Function));
+
+      // Get the error handler
+      const errorHandler = mockIoredisClient.on.mock.calls.find((call) => call[0] === 'error')[1];
+
+      // Simulate an error from Redis during a session operation
+      const redisError = new Error('Socket closed unexpectedly');
+
+      // The error handler should log but not swallow the error
+      const { logger } = require('@librechat/data-schemas');
+      errorHandler(redisError);
+
+      expect(logger.error).toHaveBeenCalledWith(
+        `Session store Redis error for namespace ${namespace}::`,
+        redisError,
+      );
+
+      // Now simulate what happens when session middleware tries to use the store
+      const callback = jest.fn();
+      mockSessionStore.get.mockImplementation((sid, cb) => {
+        cb(new Error('Redis connection lost'));
+      });
+
+      // Call the store's get method (as Express session would)
+      store.get('test-session-id', callback);
+
+      // The error should be passed to the callback, not swallowed
+      expect(callback).toHaveBeenCalledWith(new Error('Redis connection lost'));
+    });
+
+    it('should handle null ioredisClient gracefully', () => {
+      cacheConfig.USE_REDIS = true;
+      const namespace = 'sessions';
+
+      // Temporarily set ioredisClient to null (simulating connection not established)
+      const originalClient = require('./redisClients').ioredisClient;
+      require('./redisClients').ioredisClient = null;
+
+      // ConnectRedis might accept null client but would fail on first use
+      // The important thing is it doesn't throw uncaught exceptions during construction
+      const store = sessionCache(namespace);
+      expect(store).toBeDefined();
+
+      // Restore original client
+      require('./redisClients').ioredisClient = originalClient;
+    });
   });
 
   describe('limiterCache', () => {
@@ -274,8 +388,10 @@ describe('cacheFactory', () => {
       });
     });
 
-    it('should pass sendCommand function that calls ioredisClient.call', () => {
+    it('should pass sendCommand function that calls ioredisClient.call', async () => {
       cacheConfig.USE_REDIS = true;
+      mockIoredisClient.call.mockResolvedValue('test-value');
+
       limiterCache('rate-limit');
 
       const sendCommandCall = mockRedisStore.mock.calls[0][0];
@@ -283,9 +399,29 @@ describe('cacheFactory', () => {
 
       // Test that sendCommand properly delegates to ioredisClient.call
       const args = ['GET', 'test-key'];
-      sendCommand(...args);
+      const result = await sendCommand(...args);
 
       expect(mockIoredisClient.call).toHaveBeenCalledWith(...args);
+      expect(result).toBe('test-value');
+    });
+
+    it('should handle sendCommand errors properly', async () => {
+      cacheConfig.USE_REDIS = true;
+
+      // Mock the call method to reject with an error
+      const testError = new Error('Redis error');
+      mockIoredisClient.call.mockRejectedValue(testError);
+
+      limiterCache('rate-limit');
+
+      const sendCommandCall = mockRedisStore.mock.calls[0][0];
+      const sendCommand = sendCommandCall.sendCommand;
+
+      // Test that sendCommand properly handles errors
+      const args = ['GET', 'test-key'];
+
+      await expect(sendCommand(...args)).rejects.toThrow('Redis error');
+      expect(mockIoredisClient.call).toHaveBeenCalledWith(...args);
     });
 
     it('should handle undefined prefix', () => {