In this article, we'll be discussing how to work with Node.js workers for concurrent processing.
Concurrent processing is a form of parallelism where multiple processing units work on different parts of a task at the same time. In computer programming, this is often achieved by dividing a task into smaller sub-tasks that can be executed in parallel.
Node.js is a JavaScript runtime built on the V8 JavaScript engine that allows for concurrent processing. Node.js workers are separate processes that can run independently of the main Node.js process. These workers can be used to perform CPU-intensive tasks such as image processing or data encryption.
There are two ways to create a worker in Node.js:
child_process.fork()
method to create a new process.cluster
module to create a worker.The child_process.fork()
method is the recommended way to create workers. This method allows you to pass data between the parent and child processes, and it also provides a send()
method for sending messages between processes.
The cluster
module is a built-in module that allows you to create workers. The cluster module is helpful if you need to create a large number of workers.
Let's start by creating a worker using the child_process.fork()
method.
const {fork} = require('child_process');
const worker = fork('worker.js');
The code above creates a new process by calling the fork()
method. The fork()
method takes a path to the JavaScript file that will be executed in the new process. In this case, we're passing the path to the worker.js
file.
The worker.js
file contains the following code:
console.log('Worker started');
process.on('message', (message) => {
console.log(`Message from parent: ${message}`);
});
process.send('Hello from the child!');
The code above sets up a listener for the message
event. This event is emitted when the parent process sends a message to the child process. The listener logs the message to the console.
The child process also sends a message to the parent process using the send()
method.
Now that we've seen how to create a worker and send messages between the parent and child processes, let's take a look at how to send messages from the parent to the child process.
worker.send('Hello from the parent!');
The code above sends a message from the parent to the child process. The message will be received by the message
event listener we created in the worker.js
file.
It's important to handle errors when working with workers. Otherwise, the errors will go unnoticed and could cause unexpected behavior.
To handle errors in the child process, you can use the error
event:
worker.on('error', (err) => {
console.error(err);
});
The code above sets up an error
event listener on the child process. This event is emitted when there is an error in the child process. The listener logs the error to the console.
You can terminate a worker using the kill()
method:
worker.kill();
The code above terminates the worker process.
In this article, we've seen how to work with Node.js workers for concurrent processing. We've also seen how to create a worker, send messages between the parent and child processes, and handle errors.