CODEWITHSUNDEEP
node.jsmultithreading
bipin
bipin

Reputation: 419

How to use multi threads or processes in nodejs

How I can run node server in multiple threads. Let me start with my scenario first. I have 2 file one is server.js and other is process.js now my requirement is that how I can run process.js in other shared thread like a cluster. note:- cluster will not work in my scenario. I want something else the same as the cluster So my question is that will child_process.folk or spawn is the same as cluster ??? Or how I can achieve multiple threading in node without the use of the cluster. Moreover, I walk through child process document but it hasn't clear my doubt. Excuse for my silly question

Upvotes: 3

Views: 4951

Answers (1)

Sandeep Patel
Sandeep Patel

Reputation: 5148

If the nature of work handled by process.js is CPU intensive you can use Worker threads API. As you don't want to use a cluster module, worker threads can be useful. In fact, recommended way of handling CPU intensive work.

Cluster module use child_process.fork to create the child process.

a special case of the spawn() functionality for spawning Node processes. In addition to having all the methods in a normal ChildProcess instance, the returned object has a communication channel built-in. read here more https://nodejs.org/api/cluster.html#cluster_how_it_works.

What makes Worker Threads special:

  • ArrayBuffers to transfer memory from one thread to another.
  • SharedArrayBuffer that will be accessible from either thread. It lets you share memory between threads (limited to binary data).

  • Atomics available, it lets you do some processes concurrently, more efficiently and allows you to implement conditions variables in JavaScript.

  • MessagePort, used for communicating between different threads. It can be used to transfer structured data, memory regions and other MessagePorts between different Workers.

  • MessageChannel represents an asynchronous, two-way communications channel used for communicating between different threads.
  • WorkerData is used to pass startup data. An arbitrary JavaScript value that contains a clone of the data passed to this thread’s Worker constructor. The data is cloned as if using postMessage()

An Example of worker threads Main.js(server.js in your case)

const { Worker } = require('worker_threads')

function runWorker() {

  const worker = new Worker('./worker.js',{workerData:{i:0}});

    worker.on('message',function(data){

     console.log(data);

    });

    worker.on('error', function(error){

     console.log(error)

    });
    worker.on('exit', (code) => {
      if (code !== 0)
        console.log(new Error(`Worker stopped with exit code ${code}`));
    })
}


runWorker()

worker.js (process.js in your case)

const { workerData, parentPort } = require('worker_threads')

    /* You can do any heavy stuff here, in a synchronous way
     without blocking the "main thread"*/

      console.log(workerData)
      let i=workerData.i
     for(;i<500;i++){
       parentPort.postMessage({I:i})

  }

Resources that can be useful to get started with:

https://nodesource.com/blog/worker-threads-nodejs/

https://medium.com/@Trott/using-worker-threads-in-node-js-80494136dbb6

https://medium.com/nodejsmadeeasy/workers-threads-in-node-js-part2-ec45ac084963

Upvotes: 3

Related Questions