NATS Streaming

The NATS Streaming Library manages message publish/subscribe with NATS.

Prerequisite

• NodeJS

Dependencies

• deepmerge
• node-nats-streaming
• @plmtest/es-api-logger

Installation

npm install --save @plmtest/cosmos-common-nats-streaming

Documentation

Run the message pipe with docker

$ docker run -p 4222:4222 -p 8222:8222 nats-streaming -cid portal

Publish a message

const Nats = require('@plmtest/cosmos-common-nats-streaming')

const natsOptions = {
  configuration: {
    host: '127.0.0.1',
    port: 4222,
    clusterId: 'portal',
    clientId: 'example-publisher'
  },
  logger: {
    name: 'example-publisher',
    level: 'info'
  }
}

const stan = new Nats(natsOptions).connect(() => {
  const msg = { foo: 'bar' }
  const promise = stan.publish('example-subject', msg)
    .then(result => console.log(`Published message with id: ${result}`))
    .catch(err => console.log(`Publishing message failed: ${err.message}`))
  promise.then(() => {
    stan.close()
  })
})

Subscribe to messages

const Nats = require('@plmtest/cosmos-common-nats-streaming')

const natsOptions = {
  configuration: {
    host: '127.0.0.1',
    port: 4222,
    clusterId: 'portal',
    clientId: 'example-subscriber'
  },
  logger: {
    name: 'example-subscriber',
    level: 'info'
  }
}

const stan = new Nats(natsOptions).connect(() => {
  stan.subscribe('example-subject', (msg) => {
    console.log(msg)
  })
})