Pusher's Channels interaction

communication.js

const PusherServer = require('pusher');
const PusherClient = require('pusher-js');
const express = require('express');
const router = express.Router();
const config = require("config");

const pusherServer = new PusherServer(config.get('pusher.config'));
const pusherClient = new PusherClient(config.get('pusher.config.key'), {
        cluster: config.get('pusher.config.cluster')
})

/* POST main api for a processing job. */
router.post('/', function(req, res, next) {

  //code require to receive the message, parse it 
  //and maybe validate the data?
  //then communicate with the processing service through Channels               
   pusherServer.trigger('main-channel', 'message', {
     "message": //... information for other services
   });

    res.send(/* the response */);
});

function messageHandler(data) {
        ///your logic to handle new messsages
}

module.exports = function  () {
        const channel = pusherClient.subscribe('main-channel')        
        channel.bind('message', messageHandler)
        return router;
}

heartbeats.js

const PusherServer = require('pusher')
const PusherClient = require("pusher-js")
const config = require("config")


const pusherServer = new PusherServer(config.get('pusher.config'));
const pusherClient = new PusherClient(config.get('pusher.config.key'), {
        cluster: config.get('pusher.config.cluster')
})

const HB_TIMEOUT = 10100;
let TIMEOUTS = {}

// your routes definition goes here...

function sendHeartBeat(modId) {
        console.log("Sending hearbeat: ", Date.now())
        pusherServer.trigger(modId + '-hb', 'heartbeat', {
                "message": {
                        "timestamp": Date.now(),
                        "payload": ""///other data goes here
                }
        }, null, (err, req, resp) => {
                if(err) console.log("Error:: ", err)
        })
}

function handleHearbeat(serviceName) {

        return function () {
                ///your logic to handle hearbeats

                clearTimeout(TIMEOUTS[serviceName]) //reset the timeout in case we actually get a hearbeat before it's up
                console.log("Hearbeat received from Module '" + serviceName + "' at: ", Date.now())
                TIMEOUTS[serviceName] = setTimeout(heartBeatNotReceived, HB_TIMEOUT, serviceName)
        }

}

function heartBeatNotReceived(serviceName) {
        console.log("WARNING: Module ='" + serviceName + "'= has not sent a heartbeat recently...")
}


module.exports = function(modId, linkedServices) {


        linkedServices.forEach((serviceName) => {
                let channel = pusherClient.subscribe(serviceName + '-hb')
                channel.bind('heartbeat', handleHearbeat(serviceName))
        })
        
        setInterval(sendHeartBeat, 10000, modId); //send one every 10 seconds

}