RabbitMq

A RabbitMq client that's just betterer.

Prereqs & Install

• Node >=9.10.0
• npm >=6.1.0

Please note that the TypeScript target is ES6.

npm install @usefultools/rabbit-mq
npm install @types/amqplib --save-dev # for TypeScript projects

Usage

1) Create a Subscriber ⬇️

import { RabbitMq } from "@usefultools/rabbit-mq"

async function setupSubsriber(): Promise<RabbitMq> {
  const subscriber = new RabbitMq({
    url,
    onConnectionError: (error) => log.error("Subscriber error", error),
    onConnectionClose: () => log.error("Subscriber connection closed"),
    appId,
    name: "subscriber",
    log: console
  })

  await subscriber.assertChannel()

return subscriber
}

export default setupSubsriber

2) Create a Publisher ⬆️

import { RabbitMq } from "@usefultools/rabbit-mq"

async function setupPublisher(): Promise<RabbitMq> {
  const publisher = new RabbitMq({
    url,
    onConnectionError: (error) => log.error("Publisher error", error),
    onConnectionClose: () => log.error("Publisher connection closed"),
    appId,
    name: "publisher",
    log: console
})

  const opts = {
    exchange: "logs",
    type: ExchangeType.Topic,
    bindings: [
      { queue: "logs_critical", routingKey: "*.critical", dlq: "dead_letter_queue", isDurable: true },
      { queue: "logs_all", routingKey: "#", dlq: "dead_letter_queue", isDurable: true },
    ],
  }

  await publisher.assertExchange(opts.exchange, opts.type, { durable: true })

  const bindings = opts.bindings.map(async ({ queue, routingKey, dlq, isDurable }) => {
    await publisher.assertQueue(queue, {
      durable: isDurable,
      arguments: {
        "x-dead-letter-exchange": "",
        "x-dead-letter-routing-key": dlq,
      },
    })

    return publisher.bindQueue(queue, opts.exchange, routingKey)
  })

  await Promise.all(bindings)

  return publisher
}

export default setupPublisher

3) Set up both the publisher and the subscriber upon service start 🔌

async function init(): Promise<void | never> {
  try {
    log.info(`Starting ${appId}...`)

    const [subscriber, publisher] = await Promise.all([
      setupSubsriber(),
      setupPublisher()
    ])

    await receive({ subscriber, publisher })

    log.info(`Started ${appId}...`)
  } catch (error) {
    log.error(`Failed to start ${appId}...`, error)
    return process.exit(1)
  }
}

4) Receive and process messages 😎

async function receive({ subscriber, publisher }): Promise<void> {
  subscriber.subscribe("requests", (msg: Message, channel: ConfirmChannel) => {
    const ctx = buildContext(msg, publisher)

    switch (msg.properties.type) {
      case "request_foo":
        return onRequestFoo(msg, channel, ctx)
      case "request_bar":
        return onRequestBar(msg, channel, ctx)
      default:
        // do not requeue, this will go straight to dlq
        return channel.reject(msg, false)
    }
  })
}

Contributing

If you have comments, complaints, or ideas for improvements, feel free to open an issue or a pull request! See Contributing guide for details about project setup, testing, etc.

Author and license

This library was created by @LITCHI.IO. Main author and maintainer is Slavo Vojacek.

Contributors: Slavo Vojacek

@usefultools/rabbit-mq is available under the ISC license. See the LICENSE file for more info.