Redis Backend

Import

import createRedisBackend from '@requence/cache/redis'

Signature

function createRedisBackend(options: RedisBackendOptions): RedisBackend

Options

interface RedisBackendOptions {
  prefix?: string    // Key prefix. Default: 'cache'
  url?: string       // Redis connection URL
  ttl?: number       // Time-to-live in ms. Default: 0 (infinite)
  lockTTL?: number   // Lock timeout in ms. Default: 10000
  database?: number  // Redis database number
}

Peer Dependencies

The Redis backend requires two peer dependencies:

bun add ioredis superjson

• ioredis — Redis client for Node.js
• superjson — Serialization that preserves Date, Map, Set, BigInt, etc.

How It Works

Serialization

Values are serialized with superjson.stringify() before storage and deserialized with superjson.parse() on retrieval. This preserves rich JavaScript types that JSON.stringify() would lose.

Lock Coordination

When a cache miss occurs, the Redis backend sets a lock key (PX expiry) to prevent thundering herd. Other processes waiting for the same key subscribe to a Redis Pub/Sub channel and wait for the DONE or ERROR signal.

Duplicate Detection

Each Redis backend instance registers its (url, database, prefix) combination. Creating a second backend with the same combination throws an error to prevent data corruption.

Usage

import { createCache } from '@requence/cache'
import createRedisBackend from '@requence/cache/redis'

const cache = createCache({
  memoryTTL: 5_000,
  backend: createRedisBackend({
    url: process.env.REDIS_URL,
    prefix: 'myapp',
    ttl: 300_000,
  }),
})
  .define('getUser', async (id: string) => {
    return db.users.findById(id)
  })