Moleculer

Moleculer is a fast & powerful microservices framework for NodeJS (>= v6.x).

Documentation: https://moleculer.services/docs

What's included

Promise-based solution
request-reply concept
event bus system
supports middlewares
service mixins
multiple services on a node/server
built-in caching solution (memory, Redis)
pluggable transporters (NATS, MQTT, Redis)
pluggable serializers (JSON, Avro, MsgPack, Protocol Buffer)
load balanced requests (round-robin, random)
every nodes are equal, no master/leader node
auto discovery services
parameter validation with fastest-validator
distributed timeout handling with fallback response
health monitoring, metrics & statistics
supports versioned services (run different versions of the service)
official API gateway module

Installation

$ npm install moleculer --save

$ yarn add moleculer

Create your first microservice

This example shows you how to create a small service with an add action which can add two numbers.

const { ServiceBroker } = require("moleculer");

let broker = new ServiceBroker({ logger: console });

broker.createService({
    name: "math",
    actions: {
        add(ctx) {
            return Number(ctx.params.a) + Number(ctx.params.b);
        }
    }
});

broker.start();

// Call service
broker.call("math.add", { a: 5, b: 3 })
    .then(res => console.log("5 + 3 =", res))
    .catch(err => console.error(`Error occured! ${err.message}`));

Try it on Runkit

Create a Moleculer project

Use the Moleculer CLI tool to create a new Moleculer based microservices project.

Install moleculer-cli globally
```
$ npm install moleculer-cli -g
```
Create a new project (named first-demo)
```
$ moleculer init project-simple first-demo
```
Add API Gateway and press Y to npm install
Open project folder
```
$ cd first-demo
```
Start project
```
$ npm run dev
```
Open the http://localhost:3000/math.add?a=5&b=3 link in your browser. It will call the add action of math service with two params via API gateway and returns with the result.