Node js async queue and multi-thread - node.js

Question

I'm building an app with node js that must take request from the users, read in mongodb and update the specific user data before taking another request for this specific user. I was able to do this using async queue with this code:
//Create a queue with concurrency of 1
var tasksQueue = async.queue(function (userInfo, callback) {
User.verifyAndUpdateAccount(userInfo, callback)
}, 1);
router.post('/', function (req, res, next) {
res.setHeader('Content-Type', 'application/json');
//Is required datas present?
if (!req.body.username || !req.body.password) {
return res.send(null);
}
var username = req.body.username;
var password = req.body.password;
//Verify account informations and update them
tasksQueue.push({username: username, password:password}, function (err,
updatedUser) {
if (err == 'NO_MORE_REQUESTS_ALLOW') {
// S'il ne lui reste plus de sms
return res.send({
code: 400,
message: 'NO_MORE_REQUESTS_ALLOW'
})
} else if (err) throw err;
//**********************************************************
// Build the response here and respond to user requests
})
The problem is that it doesn't work well when I use the module cluster.js because each thread has his own queue and don't care about other threads. I would like my app to work like this:
Imagine that a user1 made 2 requests and after that user2 made 1 request. Suppose that I have 4 cores, I would like my first thread to start treating the first request of user1 and all the threads wait that the user1 first request has been treated before treating his second request. But the other thread must be able to treat user2 request before the user1 first request has been treated because 1 request only update data of a single user in mongodb and doesn't affect others so we don't need to wait.

Answer 1

Maybe you can refine code to make response processing fast enough. But in case you do need a non-blocking way for heavy computation, you can try 'napajs', which was released by Microsoft that can work with Node.js to enable multithreading JavaScript scenarios in the same process. Here is a quick introduction for your reference.
your code will then look like:
var napa = require('napajs');
// One-time setup.
// You can change number of workers per your requirement.
var zone = napa.zone.create('response-builders', { workers: 4 });
function serveRequest() {
var request = null;
// Get request from queue.
// ...
zone.execute(() => {
// Build the response here
return response;
}, [request]).then((result) => {
// respond to user
console.log(result.value);
});
}