skill-database-redis: Скилл для оптимизации Redis

--- name: skill-database-redis description: Best practices dùng Redis: caching patterns, session management, pub/sub, rate limiting và data structures. --- # Skill: Redis ## Connection Setup ```typescript import { createClient } from 'redis' const redis = createClient({ url: process.env.REDIS_URL, socket: { reconnectStrategy: (retries) => Math.min(retries * 50, 2000), connectTimeout: 5000, }, }) redis.on('error', err => console.error('Redis error:', err)) redis.on('reconnecting', () => console.log('Redis reconnecting...')) await redis.connect() export { redis } ``` ## Caching Patterns ```typescript // ✅ Cache-aside pattern với TTL async function getUser(id: string): Promise<User | null> { const key = `user:${id}` // Try cache first const cached = await redis.get(key) if (cached) return JSON.parse(cached) // Fallback to DB const user = await db.users.findById(id) if (!user) return null // Store with TTL (15 minutes) await redis.setEx(key, 900, JSON.stringify(user)) return user } // ✅ Invalidate on update async function updateUser(id: string, data: Partial<User>): Promise<User> { const user = await db.users.update(id, data) await redis.del(`user:${id}`) // Invalidate cache return user } // ✅ Bulk invalidation với pattern async function invalidateUserCache(userId: string): Promise<void> { const keys = await redis.keys(`user:${userId}:*`) if (keys.length > 0) await redis.del(keys) } ``` ## Rate Limiting ```typescript // ✅ Sliding window rate limiter async function checkRateLimit( identifier: string, limit: number, windowSeconds: number, ): Promise<{ allowed: boolean; remaining: number; resetAt: number }> { const key = `rate:${identifier}` const now = Date.now() const windowStart = now - windowSeconds * 1000 // Remove old entries + count current const [, count] = await redis .multi() .zRemRangeByScore(key, '-inf', windowStart) .zCard(key) .exec() as [unknown, number] if (count >= limit) { const oldest = await redis.zRange(key, 0, 0, { REV: false, BY: 'SCORE' }) const resetAt = oldest.length ? Number(oldest[0]) + windowSeconds * 1000 : now return { allowed: false, remaining: 0, resetAt } } // Add current request await redis .multi() .zAdd(key, [{ score: now, value: `${now}-${Math.random()}` }]) .expire(key, windowSeconds) .exec() return { allowed: true, remaining: limit - count - 1, resetAt: now + windowSeconds * 1000 } } ``` ## Session Management ```typescript // ✅ Session store interface Session { userId: string email: string roles: string[] expiresAt: number } const SESSION_TTL = 7 * 24 * 60 * 60 // 7 days async function createSession(userId: string, data: Omit<Session, 'expiresAt'>): Promise<string> { const sessionId = crypto.randomUUID() const session: Session = { ...data, expiresAt: Date.now() + SESSION_TTL * 1000 } await redis.setEx(`session:${sessionId}`, SESSION_TTL, JSON.stringify(session)) return sessionId } async function getSession(sessionId: string): Promise<Session | null> { const raw = await redis.get(`session:${sessionId}`) if (!raw) return null return JSON.parse(raw) } async function destroySession(sessionId: string): Promise<void> { await redis.del(`session:${sessionId}`) } ``` ## Pub/Sub ```typescript // ✅ Publisher async function publishEvent(channel: string, data: unknown): Promise<void> { await redis.publish(channel, JSON.stringify(data)) } // ✅ Subscriber (separate connection!) const subscriber = redis.duplicate() await subscriber.connect() await subscriber.subscribe('user:events', (message) => { const event = JSON.parse(message) handleUserEvent(event) }) ``` ## Data Structures ```typescript // ✅ Hash cho objects await redis.hSet(`user:profile:${id}`, { bio: user.bio, avatar: user.avatar, updatedAt: new Date().toISOString(), }) const profile = await redis.hGetAll(`user:profile:${id}`) // ✅ Sorted Set cho leaderboard await redis.zAdd('leaderboard', [{ score: points, value: userId }]) const top10 = await redis.zRange('leaderboard', 0, 9, { REV: true }) // ✅ List cho queue/recent items await redis.lPush(`user:${id}:recent`, itemId) await redis.lTrim(`user:${id}:recent`, 0, 49) // Keep last 50 const recentItems = await redis.lRange(`user:${id}:recent`, 0, -1) // ✅ Set cho unique members await redis.sAdd(`post:${postId}:likes`, userId) const likeCount = await redis.sCard(`post:${postId}:likes`) const hasLiked = await redis.sIsMember(`post:${postId}:likes`, userId) ``` ## Anti-patterns ```typescript // ❌ Lưu quá nhiều data trong 1 key (max ~1MB reasonable) await redis.set('all_users', JSON.stringify(millionUsers)) // ❌ // ❌ Không đặt TTL cho cached data await redis.set(key, data) // Memory leak! // ✅ Luôn setEx hoặc expire // ❌ KEYS command trong production (blocks Redis) const keys = await redis.keys('user:*') // Blocks all ops! // ✅ Dùng SCAN for await (const key of redis.scanIterator({ MATCH: 'user:*', COUNT: 100 })) { // process key } // ❌ Không handle connection errors redis.get(key) // Crash nếu Redis down // ✅ Fallback to DB if Redis unavailable ```