@evolution-gym/events

Event bus and event handling utilities for Evolution Gym microservices using RabbitMQ.

Installation

npm install @evolution-gym/events

Usage

Initialize Event Bus

import { RabbitMQEventBus } from '@evolution-gym/events';

const eventBus = new RabbitMQEventBus({
  url: process.env.RABBITMQ_URL || 'amqp://localhost',
  exchange: 'evolution-gym-events',
  queuePrefix: 'auth-service-'
});

await eventBus.connect();

Publish Events

import { EventFactory } from '@evolution-gym/events';
import { EventType } from '@evolution-gym/types';

// Create and publish event
const event = EventFactory.createMemberEvent(
  EventType.MEMBER_CREATED,
  memberId,
  tenantId,
  'member-service',
  { name: 'John Doe' }
);

await eventBus.publish(event);

Subscribe to Events

import { EventHandler } from '@evolution-gym/types';
import { EventType } from '@evolution-gym/types';

class MemberCreatedHandler implements EventHandler {
  eventType = EventType.MEMBER_CREATED;

  async handle(event) {
    console.log('Member created:', event.data);
    // Handle the event
  }
}

const handler = new MemberCreatedHandler();
await eventBus.subscribe(EventType.MEMBER_CREATED, handler);

Event Factory Helpers

import { EventFactory } from '@evolution-gym/events';
import { EventType } from '@evolution-gym/types';

// User events
const userEvent = EventFactory.createUserEvent(
  EventType.USER_CREATED,
  userId,
  'auth-service'
);

// Member events
const memberEvent = EventFactory.createMemberEvent(
  EventType.MEMBER_CHECK_IN,
  memberId,
  tenantId,
  'member-service',
  { locationId: 'gym-1' }
);

// Payment events
const paymentEvent = EventFactory.createPaymentEvent(
  EventType.PAYMENT_APPROVED,
  paymentId,
  userId,
  'payment-service',
  { amount: 99.90 }
);

Graceful Shutdown

process.on('SIGTERM', async () => {
  await eventBus.close();
  process.exit(0);
});

Configuration

Environment variables:

• RABBITMQ_URL - RabbitMQ connection URL

Event Flow

1. Service publishes event to exchange
2. Exchange routes event to queues based on routing key
3. Consumers process events from their queues
4. Acknowledgment ensures reliable delivery

Best Practices

1. Always handle errors in event handlers
2. Use idempotency keys to prevent duplicate processing
3. Keep events small - include only necessary data
4. Version your events for backward compatibility
5. Monitor dead letter queues for failed events

License

MIT