redis-patterns

Redis Patterns

Production patterns for Redis as a cache, session store, pub/sub bus, work queue backbone, and distributed coordination primitive.

Use this skill when

• Implementing caching (cache-aside, write-through, write-back)
• Setting up pub/sub or BLPOP-based work queues
• Using Redis data structures (Sorted Sets, Streams, Hash, Sets)
• Configuring ioredis for Node.js production
• Designing key naming and TTL strategies
• Implementing distributed locks with atomic SET NX EX

Do not use this skill when

• The task requires a message broker with guaranteed delivery — use BullMQ, RabbitMQ, or Kafka
• The task is about Redis server-level configuration / cluster setup

Workflow

1. Identify the use case: caching, pub/sub, queue, session, or rate limiting
2. Choose the right data structure for the access pattern
3. Design keys with namespace:entity:id convention
4. Set TTL on every key (unless intentionally persistent: queues, locks-with-expiry)
5. Validate error handling and graceful shutdown

Connection (ioredis — recommended for Node.js)

import Redis from 'ioredis';

export const redis = new Redis({
  host: process.env.REDIS_HOST,
  port: 6379,
  lazyConnect: true,
  connectionName: 'api-server',
  retryStrategy(times) {
    return Math.min(times * 200, 2000);
  },
});

redis.on('error', (err) => logger.error({ err }, 'redis'));
redis.on('ready', () => logger.info('redis ready'));

• Singleton client; lazyConnect defers connection until first command
• retryStrategy for exponential backoff
• Separate dedicated subscriber connection for pub/sub (can't mix with commands)
• BullMQ: maxRetriesPerRequest: null is mandatory

Cache-Aside Pattern

async function getUser(id: string): Promise<User> {
  const key = `cache:user:${id}`;
  const cached = await redis.get(key);
  if (cached) return JSON.parse(cached);

  const user = await db.users.findUnique({ where: { id } });
  if (user) await redis.set(key, JSON.stringify(user), 'EX', 300);
  return user;
}

async function invalidateUser(id: string) {
  await redis.del(`cache:user:${id}`);
}