Master and worker processes 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]');

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Acluster

Bhttp

Cfs

Dos

Attempts:

3 left

💡 Hint

Common Mistakes

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

The cluster module is imported using require('cluster') to create master and worker processes.

2fill in blank

medium

Complete the code to check if the current process is the master process.

Node.js

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

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AisMaster

BisPrimary

CisMain

DisWorker

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'isWorker' or 'isMaster' instead of 'isPrimary'.

The property cluster.isPrimary is true if the current process is the primary (master) process in recent Node.js versions.

3fill in blank

hard

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

Node.js

if (cluster.isPrimary) {
  cluster.[1]();
}

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Afork

Bstart

Cspawn

Dcreate

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' or 'spawn' which are not cluster methods.

The method cluster.fork() creates a new worker process.

4fill in blank

hard

Fill both blanks to listen for 'message' events in the master and worker processes.

Node.js

if (cluster.isPrimary) {
  const worker = cluster.fork();
  worker.[1]('message', (msg) => {
    console.log('Master received:', msg);
  });
} else {
  process.[2]('message', (msg) => {
    console.log('Worker received:', msg);
  });
}

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Aon

Bsend

Cemit

Dlisten

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'send' or 'emit' to listen for messages instead of 'on'.

Both the worker and master listen for messages using the on method.

5fill in blank

hard

Fill all three blanks to send a message from the master to the worker and reply back.

Node.js

if (cluster.isPrimary) {
  const worker = cluster.fork();
  worker.[1]({ cmd: 'start' });
  worker.[2]('message', (msg) => {
    console.log('Master got reply:', msg);
  });
} else {
  process.[3]('message', (msg) => {
    if (msg.cmd === 'start') {
      process.send({ reply: 'done' });
    }
  });
}

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Asend

Bon

Cemit

Dlisten

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'emit' or 'listen' instead of 'send' or 'on'.

The master sends a message with send, listens with on, and the worker listens with on.