Remit

Remit is a RabbitMQ-backed library for building microservices supporting RPC, pubsub, automatic service discovery, tracing and scaling with no code changes.

// service.js
const endpoint = remit.endpoint('user.get')

endpoint.handler((event) => {
  const user = { name: 'Jack Williams' }
  remit.emit('got user', user)

  return user
})

endpoint.start()

Then in another process…

// api.js
const getUser = remit.request('user.get')
const user = await getUser(123)
// {"name":"Jack Williams"}

Multiple things could then hook in to the "got user" event we emitted…

// listener.js
const listener = remit.listen('got user')

listener.handler((event) => {
  log(`User "${event.data.name}" was requested.`)
})

listener.start()

What is it for?

Remit is generically designed for creating separated services which respond to or listen to events. An endpoint will wait for and respond to individual requests and a listener will receive all emits across the entire system.

With that basic model, Remit expands to allow you to:

• Create “services” that respond to messages
• Trace messages flowing through your system and produce distrubuted stack traces
• Group and scale services automatically
• A/B test
• “Event” your system, creating distrubuted hooks you can use at any time, anywhere
• Easily break apart your system, only creating separate “services” when it suits with minimal code changes

How does it work?

Remit is a wrapper around the fantastic RabbitMQ message broker and tries to be as easy to use as possible. It handles creating the connections, channels and bindings needed for RabbitMQ and provides a pretty API for interacting with your services and messages.