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Redis Store

High-performance store using Redis with TTL support.

Installation​

npm install @saga-bus/store-redis ioredis

Basic Usage​

import { RedisSagaStore } from '@saga-bus/store-redis';

const store = new RedisSagaStore({
  url: 'redis://localhost:6379',
});

const bus = createBus({
  transport,
  store,
  sagas: [{ definition: orderSaga }],
});

await bus.start();

Configuration​

OptionTypeDefaultDescription
urlstring-Redis connection URL
hoststring'localhost'Redis host
portnumber6379Redis port
passwordstring-Redis password
dbnumber0Database number
keyPrefixstring'saga:'Key prefix
ttlnumber-TTL in seconds
clientRedis-Existing ioredis client

Full Configuration Example​

import { RedisSagaStore } from '@saga-bus/store-redis';
import Redis from 'ioredis';

// Option 1: URL
const store = new RedisSagaStore({
  url: 'redis://:password@localhost:6379/0',
});

// Option 2: Individual settings
const store = new RedisSagaStore({
  host: 'localhost',
  port: 6379,
  password: process.env.REDIS_PASSWORD,
  db: 0,
  keyPrefix: 'myapp:saga:',
  ttl: 86400 * 30, // 30 days
});

// Option 3: Existing client
const redis = new Redis({
  host: 'localhost',
  port: 6379,
  maxRetriesPerRequest: 3,
  retryStrategy: (times) => Math.min(times * 50, 2000),
});

const store = new RedisSagaStore({
  client: redis,
  keyPrefix: 'saga:',
});

// Option 4: TLS
const store = new RedisSagaStore({
  host: 'redis.example.com',
  port: 6380,
  tls: {
    rejectUnauthorized: true,
  },
});

Key Structure​

{keyPrefix}{sagaName}:{sagaId}           -> Saga state (Hash)
{keyPrefix}{sagaName}:correlation:{id}   -> Saga ID lookup (String)
{keyPrefix}{sagaName}:index:completed    -> Completed sagas (Set)

Example keys:

  • saga:OrderSaga:abc-123 - Saga state
  • saga:OrderSaga:correlation:order-456 - Correlation lookup
  • saga:OrderSaga:index:completed - Completed index

Redis Cluster​

For cluster deployments:

import Redis from 'ioredis';

const cluster = new Redis.Cluster([
  { host: 'node1', port: 6379 },
  { host: 'node2', port: 6379 },
  { host: 'node3', port: 6379 },
]);

const store = new RedisSagaStore({
  client: cluster,
  keyPrefix: 'saga:',
});

Redis Sentinel​

For high availability:

import Redis from 'ioredis';

const redis = new Redis({
  sentinels: [
    { host: 'sentinel1', port: 26379 },
    { host: 'sentinel2', port: 26379 },
    { host: 'sentinel3', port: 26379 },
  ],
  name: 'mymaster',
});

const store = new RedisSagaStore({
  client: redis,
  keyPrefix: 'saga:',
});

TTL Configuration​

Auto-expire saga data:

// All sagas expire after 30 days
const store = new RedisSagaStore({
  url: 'redis://localhost:6379',
  ttl: 86400 * 30, // 30 days in seconds
});

// Different TTL for completed sagas
const store = new RedisSagaStore({
  url: 'redis://localhost:6379',
  ttl: 86400 * 90,           // Active: 90 days
  completedTtl: 86400 * 7,   // Completed: 7 days
});

Docker Setup​

# docker-compose.yml
services:
  redis:
    image: redis:7-alpine
    ports:
      - "6379:6379"
    command: redis-server --appendonly yes
    volumes:
      - redis_data:/data

volumes:
  redis_data:

Optimistic Concurrency​

Uses WATCH/MULTI/EXEC for atomic updates:

// Built-in optimistic locking via Redis transactions
// Retries automatically on WATCH failure

Best Practices​

Use Appropriate TTL​

// Balance between data retention and memory usage
const store = new RedisSagaStore({
  url: 'redis://localhost:6379',
  ttl: 86400 * 30, // 30 days reasonable default
});

Enable Persistence​

# redis.conf
appendonly yes
appendfsync everysec

Configure Max Memory​

# redis.conf
maxmemory 1gb
maxmemory-policy volatile-lru

Use Key Prefixes​

// Namespace your keys
const store = new RedisSagaStore({
  url: 'redis://localhost:6379',
  keyPrefix: 'myapp:prod:saga:',
});

Monitoring​

# Check memory usage
redis-cli INFO memory

# Find saga keys
redis-cli KEYS "saga:*"

# Monitor commands
redis-cli MONITOR

See Also​