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Node.js is a single-threaded programming environment, which means that it can only process one task at a time. This can be a performance bottleneck for applications that need to handle a high volume of requests. The Node.js cluster module provides a solution to this problem by allowing developers to create a cluster of child processes that can run in parallel, each handling its own requests.
In this tutorial, we will explore the purpose of the Node.js cluster module and how to use it in your applications.
The Node.js cluster module is a built-in module that allows you to create a cluster of child processes. Each child process runs on a separate core of the CPU, allowing you to take full advantage of multi-core processors.
The cluster module provides several methods for creating and managing child processes. These include:
cluster.fork(): This method creates a new child process and returns a reference to the worker object.cluster.isMaster: This property istruein the master process andfalsein the worker processes.cluster.workers: This property is an object that contains references to all the worker processes.
Using these methods, you can create a cluster of child processes that can handle incoming requests in parallel.
To use the Node.js cluster module, you need to perform the following steps:
- Create a new Node.js file and require the cluster module:
const cluster = require('cluster');2. Check if the current process is the master process:
if (cluster.isMaster) {
// Code to run in the master process
} else {
// Code to run in worker processes
}3. If the current process is the master process, create a cluster of child processes using the fork() method:
if (cluster.isMaster) {
// Get the number of CPUs
const numCPUs = require('os').cpus().length; // Fork workers
for (let i = 0; i < numCPUs; i++) {
cluster.fork();
}
}
This code creates a cluster of child processes, with each child process running on a separate core of the CPU.
4. If the current process is a worker process, start your application code:
if (!cluster.isMaster) {
// Code to start your application
}5. Listen for incoming requests on a port:
if (!cluster.isMaster) {
const http = require('http'); // Start the HTTP server
http.createServer((req, res) => {
res.writeHead(200);
res.end('Hello, world!');
}).listen(8000);
}
This code starts an HTTP server on port 8000 and responds to incoming requests with a simple “Hello, world!” message.
6. Start the application by running the Node.js file:
node app.jsThis will start the master process and create a cluster of child processes. Each child process will listen for incoming requests on port 8000.
The Node.js cluster module is a powerful tool for improving the performance of your Node.js applications. By creating a cluster of child processes, you can take full advantage of multi-core processors and handle a high volume of requests in parallel. In this tutorial, we covered the basics of the Node.js cluster module and how to use it to create a cluster of child processes.
