nats_test.js

const env = require('env-var')
const Timeout = require('await-timeout')

const { connect, JSONCodec } = require('nats')

const NATS_AUTH_TOKEN = env
  .get('NATS_AUTH_TOKEN')
  .required()
  .asString()

const NATS_URL = env
  .get('NATS_URL')
  .required()
  .asString()

async function natsInit () {
  return await connect({
    url: NATS_URL,
    name: 'powerflex-cloud-edge-device-manager',
    timeout: 500,
    token: NATS_AUTH_TOKEN
  })
}

async function natsPubSubTest (nc) {
  const testMessage = 'test-message'
  const testChannel = 'test'
  const receivedMessages = []
  const jsonCodec = JSONCodec()
  console.log(`subscribing to ${testChannel}`)
  const testSub = await nc.subscribe(testChannel, (err, msg) => {
    if (err) {
      console.log(err)
    } else receivedMessages.push(jsonCodec.decode(msg.data))
  })
  console.log(`publishing to ${testChannel}`)
  nc.publish(testChannel, jsonCodec.encode(testMessage))
  nc.flush()
  await Timeout.set(2000)
  const testPassed = receivedMessages.includes(testMessage)
  testSub.unsubscribe()
  if (!testPassed) {
    throw new Error(`test publish and subscribe failed. messages received: ${receivedMessages}`)
  } else console.log('test passed :D')
}

process.on('unhandledRejection', err => console.error(err))

natsInit().then(natsPubSubTest)