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Redis Events

Distributed event system using Redis pub/sub for cross-process communication.

Installation​

import '@unchainedshop/plugins/events/redis';
Explicit Configuration Required

Unlike the Node.js event emitter (which is the default), this plugin requires explicit configuration. You must call setEmitAdapter() to activate Redis as your event system:

import { setEmitAdapter } from '@unchainedshop/events';
import { RedisEventEmitter } from '@unchainedshop/plugins/events/redis';

setEmitAdapter(RedisEventEmitter());

Environment Variables​

VariableDefaultDescription
REDIS_HOST-Redis server hostname (required)
REDIS_PORT6379Redis server port
REDIS_DB0Redis database number

Features​

  • Distributed: Events work across multiple application instances
  • Persistent Connections: Maintains Redis pub/sub connections
  • JSON Serialization: Automatic payload serialization/deserialization
  • Scalable: Supports horizontal scaling
  • Reliable: Redis provides reliability and persistence options

Use Cases​

  • Multi-Instance Deployments: Applications running on multiple servers
  • Microservices: Communication between different services
  • Horizontal Scaling: When you need to scale beyond a single instance
  • Production Deployments: Robust event handling for production

Redis Setup​

Docker​

docker run -d \
  --name redis \
  -p 6379:6379 \
  redis:alpine

Docker Compose​

version: '3'
services:
  redis:
    image: redis:alpine
    ports:
      - "6379:6379"

Configuration​

REDIS_HOST=localhost
REDIS_PORT=6379
REDIS_DB=0

Usage​

Publishing Events​

import { emit } from '@unchainedshop/events';

// Events are automatically distributed to all instances
await emit('ORDER_CREATE', {
  orderId: '12345',
  userId: 'user123',
  total: 99.99
});

Subscribing to Events​

import { subscribe } from '@unchainedshop/events';

// Each instance receives the event
subscribe('ORDER_CREATE', async (payload) => {
  const { orderId, userId, total } = payload;
  await processOrder(orderId);
});

Performance​

  • Pros: Distributed, reliable, cost-effective
  • Cons: Network latency, requires Redis infrastructure

When to Use​

Use Redis Events for:

  • Horizontal scaling requirements
  • Multiple application instances
  • Production deployments
  • Cost-effective distributed events

Adapter Details​

PropertyValue
Sourceevents/redis.ts