Load balancing between workers in Node.js - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the cluster module in Node.js.

Node.js

const cluster = require([1]);

Drag options to blanks, or click blank then click option'

A"http"

B"os"

C"fs"

D"cluster"

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'http' instead of 'cluster' to import the cluster module.

Confusing 'os' module with 'cluster'.

The cluster module is imported using require('cluster').

2fill in blank

medium

Complete the code to check if the current process is the master in a cluster.

Node.js

if (cluster.[1]) {
  console.log('This is the master process');
}

Drag options to blanks, or click blank then click option'

AisWorker

BisMaster

CisPrimary

DisMain

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'isWorker' instead of 'isMaster'.

Using 'isPrimary' which is from newer Node.js versions, but here we use 'isMaster'.

The property 'isMaster' is used to check if the process is the master in Node.js cluster.

3fill in blank

hard

Fix the error in the code to fork a new worker process.

Node.js

const worker = cluster.[1]();

Drag options to blanks, or click blank then click option'

Aspawn

BcreateWorker

Cfork

DstartWorker

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'spawn' which is from child_process module, not cluster.

Using 'createWorker' which does not exist.

The correct method to create a new worker in Node.js cluster is 'fork()'.

4fill in blank

hard

Fill both blanks to create a simple HTTP server in a worker that listens on port 3000.

Node.js

const http = require('http');

http.createServer((req, res) => {
  res.writeHead(200, [1]);
  res.end('Hello from worker');
}).listen([2]);

Drag options to blanks, or click blank then click option'

A{"Content-Type": "text/plain"}

B3000

C200

D8080

Attempts:

3 left

💡 Hint

Common Mistakes

Using a number instead of an object for headers.

Using port 8080 instead of 3000 as asked.

The response header should be an object with Content-Type, and the server listens on port 3000.

5fill in blank

hard

Fill all three blanks to log when a worker exits and fork a new one.

Node.js

cluster.on('[1]', (worker, code, signal) => {
  console.log(`Worker [2] died with code: ${code}, signal: ${signal}`);
  cluster.[3]();
});

Drag options to blanks, or click blank then click option'

Aexit

Bid

Cfork

Ddisconnect

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'disconnect' event instead of 'exit'.

Using 'worker.pid' instead of 'worker.id'.

Using 'disconnect()' instead of 'fork()' to create a new worker.

The 'exit' event fires when a worker dies, 'worker.id' identifies the worker, and 'fork()' creates a new worker.