nats-micro

NATS Microservice Library

Tiny microservice library based on NATS

and compatible with nats-go microservices

Description

This is a typescript-first library that provides a convinient (in 10 lines of code or less!) way to write microservises with out of the box auto discovery, observability and load balancing.

Full interoperability with to-be-released nastcli v0.0.36 that adds nats micro info, nats micro stats and nats micro ping commands

Limitations / TODO

1. No multi-reply support yet. When you send a message you will be getting exactly one response (or a timeout error)
2. No microservice and endpoint name validation
3. (WIP) Zod library is used for method arguments and result typing. However:
4. No actual validation is implemented yet.
5. No microservice interface discovery is specified in the current version of nats micro protocol thus method interface cannot be discovered over NATS yet.

Usage

It is extremely simple:

  const broker = await new Broker('echo' + process.pid).connect();
  
  await Microservice.create(
    broker,
    {
      name: 'echo-service',
      description: 'Simple echo microservice',
      version: '0.0.1',
      methods: {
        echo: {
          handler: (text) => text,
          // subject is autogenerated according to nats micro protocol
        },
        'config-change-event': {
          handler: console.log,
          // subject is manually specified which allows for broadcast
          // event bus
          subject: '$EVT.config.change',
        },
      },
    }
  );