0.1.4 • Published 6d ago

redis-kafka

Licence

MIT

Version

0.1.4

Deps

Size

15 kB

Vulns

Weekly

522

Summary Dependency Versions

redis-kafka

Lightweight event bus for Node.js microservices powered by Redis Streams.

No Kafka. No Zookeeper. Just Redis.

Install

npm install redis-kafka ioredis

Usage

import { Event_Bus } from "redis-kafka";

const bus = new Event_Bus({ url: "redis://localhost:6379" });

// Each service gets its own group — created automatically if it doesn't exist
const auth    = await bus.group("auth-service");
const mail    = await bus.group("mail-service");
const profile = await bus.group("profile-service");

// Publish an event from one service
await auth.publish("user.registered", {
  userId: "123",
  email: "john@test.com",
});

// Every subscriber receives the same event independently
await mail.subscribe("user.registered", async (payload) => {
  console.log("send welcome email to", payload.email);
});

await profile.subscribe("user.registered", async (payload) => {
  console.log("create profile for", payload.userId);
});

Error handling

By default subscriber errors are printed to console.error. Use onError to route them to your own logger or alerting system.

await mail.subscribe("user.registered", async (payload) => {
  console.log("send welcome email to", payload.email);
}, {
  onError: (err) => console.error("mail subscriber failed", err),
});

Stream trimming

By default the Redis stream grows without limit. Set maxlen to automatically keep only the last N messages and prevent memory growth.

const bus = new Event_Bus({
  url: "redis://localhost:6379",
  maxlen: 10_000,
});

Oldest messages are trimmed automatically on each publish once the stream exceeds maxlen. This is an approximate trim — Redis may keep slightly more than maxlen for performance.

Health check

Use ping() to verify the Redis connection is alive before your app starts accepting traffic.

const ok = await bus.ping();

if (!ok) {
  console.error("Redis is not reachable");
  process.exit(1);
}

Clean shutdown

Call disconnect() when your app is shutting down so the Redis connection closes cleanly and the process exits.

process.on("SIGTERM", async () => {
  await bus.disconnect();
  process.exit(0);
});

How it works

One published event reaches every subscriber independently — just like Kafka, but using Redis Streams under the hood.

Each bus.group() creates a Redis Consumer Group automatically
All groups read from the same stream and receive every event
Consumer groups are reused across restarts — no duplicate setup
Each subscriber runs in its own background polling loop

TypeScript support

This package ships with full TypeScript types out of the box.

import type { Event_Handler, Event_Bus_Options } from "redis-kafka";

const handler: Event_Handler<{ userId: string }> = async (payload) => {
  console.log(payload.userId);
};