Developing with Redis

Quick Start

import Redis from 'ioredis';

const redis = new Redis({
  host: process.env.REDIS_HOST || 'localhost',
  port: parseInt(process.env.REDIS_PORT || '6379'),
  maxRetriesPerRequest: 3,
});

// Basic caching
await redis.setex('user:123', 3600, JSON.stringify(userData));
const cached = await redis.get('user:123');

Features

Common Patterns

Cache-Aside Pattern

async function getOrSet<T>(key: string, factory: () => Promise<T>, ttl = 3600): Promise<T> {
  const cached = await redis.get(key);
  if (cached) return JSON.parse(cached);

  const value = await factory();
  await redis.setex(key, ttl, JSON.stringify(value));
  return value;
}

Sliding Window Rate Limiter

async function checkRateLimit(key: string, limit: number, windowSec: number): Promise<boolean> {
  const now = Date.now();
  const windowStart = now - windowSec * 1000;

  const pipeline = redis.pipeline();
  pipeline.zremrangebyscore(key, '-inf', windowStart);
  pipeline.zadd(key, now, `${now}:${Math.random()}`);
  pipeline.zcard(key);
  pipeline.expire(key, windowSec);

  const results = await pipeline.exec();
  const count = results?.[2]?.[1] as number;
  return count <= limit;
}

Distributed Lock

async function acquireLock(key: string, ttlMs = 10000): Promise<string | null> {
  const lockId = crypto.randomUUID();
  const acquired = await redis.set(`lock:${key}`, lockId, 'PX', ttlMs, 'NX');
  return acquired === 'OK' ? lockId : null;
}

async function releaseLock(key: string, lockId: string): Promise<boolean> {
  const script = `if redis.call("get",KEYS[1])==ARGV[1] then return redis.call("del",KEYS[1]) else return 0 end`;
  return (await redis.eval(script, 1, `lock:${key}`, lockId)) === 1;
}

Best Practices