thread-bus

Thread-bus is an event bus oriented microservice library.

How it works?

[WIP]

Installation

npm install thread-bus --save

Usage

1. Connect to the AMPQ server

var Thread = require('thread-bus');

/**
 * Specifying options for AMQP server
 * Note: without options - Thread will use default predefined options (described below).
 */
const options = {
  host: '127.0.0.1',
  port: 5672
};

Thread.connect(options).then(() => {
  // Thread is connected to the AMQP server now.
}).catch(errorHandler);

2. Open an exchange channel and publish a message

const channelOptions = {
  channel: 'test' // channel name
  durable: true // durable channels remain active after server restart, default - false
};

Thread.open(channelOptions).then(() => {
  /**
   * Channel with 'test' name is available now.
   * Basically, per one microservice (application) you need to open channel only once.
   */
  return Thread.publish({ channel: 'test', message: 'Hello there' }); // We should provide a channel name, because we have a possibility open channels as much as we wish.
}).then(successHandler).catch(errorHandler); // We have a possibility to get response from published channel.

As you can see, open method will create our Producer, which will share specified message with the help of publish method.

3. Listen an exchange channel

Thread.listen('test', function (req, res) {
  console.log(req.message); // "Hello there"
  res.send('Hi ;)'); // you can send a response to the Producer
});

Advanced usage

Producer

As was described above, let's imagine that we need to deliver some info for all market's customers. (Holiday's sales, etc. :)). For example we have 2 markets: UK and UA. So, how to share desirable sales? - Just to publish a message to '#:customers' channel. Let's have a look:

// ./index.js
var Thread = require('thread-bus');
var express = require('express');
var app = exports;

const config = require('./config.json').thread;
const PORT = process.env.NODE_PORT || 8080;
const HOST = process.env.NODE_IP || 'localhost'

app.init = function (cb) {
  app.server = express();

  // connect to db, etc.
  // ...................

  Thread.connect(config).then(() => {
    cb();
  }).catch(cb);
};

app.init((error) => {
  if (error) throw error;

  app.server.post('/customers', require('./services/customers'));
  app.server.listen(PORT, HOST);

  console.log(`Microservice for ALL CUSTOMERS has started.`);
});

// ./services/customers.js
var Thread = require('thread-bus');
const channel = '#:customers';

Thread.open({ channel: channel });

module.exports = function (req, res) {
  Thread.publish({
    channel: channel,
    message: req.body.message
  });
};

Consumers

// UK market service
var Thread = require('thread-bus');
var app = exports;

app.init = function (cb) {
  Thread.connect().then(() => {
    cb();
  }).catch(cb);
};

app.init((error) => {
  if (error) throw error;

  Thread.listen('uk:customers', require('./customers'));
});

// UK market ./customers.js
var mailer = require('./mailer.js');

module.exports = function (req, res) {
  mailer.sendToAllCustomers({
    message: req.message
  }, (error) => {
    if (error) return res.throw(error);

    res.send({ status: 200, message: 'Messages were sended' });
  });
};

Also the same thing should be done for UA market.