@supplyflavors/sf-messaging

Shared RabbitMQ messaging library for SupplyFlavors microservices.

Installation

npm install @supplyflavors/sf-messaging

Usage

Publishing Events

import { publishEvent } from '@supplyflavors/sf-messaging'

await publishEvent({
  exchange: 'sf.events',
  routingKey: 'orders.created.v1',
  payload: {
    orderId: 123,
    customerId: 456,
    total: 99.99,
  },
  source: 'sf-orders',
  type: 'orders.created',
})

Subscribing to Events

import { subscribe, EventEnvelope } from '@supplyflavors/sf-messaging'

interface OrderCreatedPayload {
  orderId: number
  customerId: number
  total: number
}

await subscribe<OrderCreatedPayload>({
  queue: 'my-service.orders.created',
  exchange: 'sf.events',
  routingKey: 'orders.created.v1',
  onMessage: async (event: EventEnvelope<OrderCreatedPayload>, ctx) => {
    console.log(`Received order ${event.payload.orderId}`)
    // Process the event
  },
})

Configuration

The library reads configuration from environment variables:

| Variable | Default | Description | |----------|---------|-------------| | SF_MQ_URL | - | Full AMQP connection URL (overrides individual settings) | | SF_MQ_HOST | sf-mq | RabbitMQ host | | SF_MQ_PORT | 5672 | RabbitMQ port | | SF_MQ_USER | guest | RabbitMQ username | | SF_MQ_PASSWORD | guest | RabbitMQ password | | SF_MQ_EXCHANGE | sf.events | Default exchange name |

Features

• Topic-based routing: Uses RabbitMQ topic exchanges for flexible routing
• Dead Letter Queue: Failed messages are automatically sent to DLQ after max retries
• Idempotency: Built-in message deduplication to prevent duplicate processing
• Retry logic: Configurable retry attempts with automatic requeue
• Tracing: Automatic trace ID propagation for distributed tracing

API Reference

publishEvent<T>(options: PublishOptions<T>)

Publishes an event to RabbitMQ.

subscribe<T>(options: SubscribeOptions<T>)

Subscribes to events from a queue.

createIdempotencyStore(maxItems?, ttlMs?)

Creates an in-memory idempotency store for message deduplication.

License

UNLICENSED - Private package for SupplyFlavors internal use only.