Redis: Lebih dari Sekadar Cache — Cara Penggunaan yang Sering Diabaikan Developer

Redis sering diperkenalkan sebagai "database key-value in-memory untuk caching". Ini tidak salah, tapi ini hanya 20% dari apa yang Redis bisa lakukan.

Setup Cepat

# Dengan Docker
docker run -d -p 6379:6379 redis:7-alpine

# Install client Node.js
npm install ioredis

import Redis from "ioredis";
const redis = new Redis(process.env.REDIS_URL);

Use Case 1: Caching (yang Semua Orang Tahu)

async function getUserProfile(userId: string) {
  const cacheKey = `user:profile:${userId}`;
  
  // Cek cache dulu
  const cached = await redis.get(cacheKey);
  if (cached) return JSON.parse(cached);
  
  // Cache miss — query database
  const user = await db.users.findById(userId);
  
  // Simpan ke cache, expire 1 jam
  await redis.setex(cacheKey, 3600, JSON.stringify(user));
  
  return user;
}

Use Case 2: Rate Limiting

async function rateLimit(ip: string, limit = 100, windowSeconds = 60) {
  const key = `ratelimit:${ip}`;
  const current = await redis.incr(key);
  
  if (current === 1) {
    // Set expiry hanya saat pertama kali
    await redis.expire(key, windowSeconds);
  }
  
  if (current > limit) {
    throw new Error("Too Many Requests");
  }
  
  return { current, limit, remaining: limit - current };
}

Use Case 3: Session Management

// Simpan session dengan auto-expire
async function createSession(userId: string, sessionData: object) {
  const sessionId = crypto.randomUUID();
  await redis.setex(
    `session:${sessionId}`, 
    86400, // 24 jam
    JSON.stringify({ userId, ...sessionData })
  );
  return sessionId;
}

// Hapus session saat logout — instant invalidation
async function destroySession(sessionId: string) {
  await redis.del(`session:${sessionId}`);
}

Use Case 4: Real-time Leaderboard

// Sorted Set — perfect untuk leaderboard
// Tambah/update skor
await redis.zadd("leaderboard:game1", score, userId);

// Top 10
const top10 = await redis.zrevrange("leaderboard:game1", 0, 9, "WITHSCORES");

// Rank user tertentu
const rank = await redis.zrevrank("leaderboard:game1", userId);

Use Case 5: Pub/Sub untuk Real-time Features

// Publisher — kirim notifikasi
const publisher = new Redis();
await publisher.publish("notifications", JSON.stringify({
  userId: "123",
  message: "Order kamu sudah dikirim!"
}));

// Subscriber — terima notifikasi
const subscriber = new Redis();
await subscriber.subscribe("notifications");
subscriber.on("message", (channel, message) => {
  const data = JSON.parse(message);
  // Push ke user via WebSocket
  io.to(data.userId).emit("notification", data);
});

Use Case 6: Distributed Lock

// Cegah race condition di distributed system
async function processOrderOnce(orderId: string) {
  const lockKey = `lock:order:${orderId}`;
  const lockId = crypto.randomUUID();
  
  // Coba acquire lock
  const acquired = await redis.set(lockKey, lockId, "NX", "EX", 30);
  if (!acquired) throw new Error("Order sedang diproses");
  
  try {
    await processOrder(orderId);
  } finally {
    // Release lock — hanya kalau kita yang punya
    const current = await redis.get(lockKey);
    if (current === lockId) await redis.del(lockKey);
  }
}