Logging with Winston or Pino in NestJS - Mini Project: Build & Apply

Logging with Winston in NestJS

📖 Scenario: You are building a simple NestJS application that needs to log important messages. Logging helps you track what your app is doing and find problems quickly.We will use Winston, a popular logging library, to add logging to your app.

🎯 Goal: Learn how to set up Winston logging in a NestJS app. You will create a logger, configure it, use it to log messages, and see the output in the console.

📋 What You'll Learn

Create a Winston logger instance with console transport

Add a log level configuration variable

Use the logger to log an info message

Print the logged message output

💡 Why This Matters

🌍 Real World

Logging is essential in real apps to track events and errors. Winston is a popular tool for this in Node.js and NestJS apps.

💼 Career

Understanding how to set up and use logging libraries like Winston is a key skill for backend developers and DevOps engineers to monitor and debug applications.

1

Create a Winston logger instance

Create a constant called logger and set it to a Winston logger instance using winston.createLogger with a console transport.

NestJS

import * as winston from 'winston';

// Create a Winston logger instance with console transport
# Your code here

Need a hint?

Use winston.createLogger and add new winston.transports.Console() inside the transports array.

2

Add a log level configuration

Create a constant called logLevel and set it to the string 'info'. Then add level: logLevel to the logger configuration.

NestJS

import * as winston from 'winston';

const logger = winston.createLogger({
  format: winston.format.simple(),
  transports: [new winston.transports.Console()]
});

// Add a logLevel constant and set logger level
# Your code here

Need a hint?

Define const logLevel = 'info' and add level: logLevel inside the logger options.

3

Log an info message using the logger

Use logger.info to log the message 'NestJS app started'.

NestJS

import * as winston from 'winston';

const logLevel = 'info';

const logger = winston.createLogger({
  level: logLevel,
  format: winston.format.simple(),
  transports: [new winston.transports.Console()]
});

// Log an info message 'NestJS app started'
# Your code here

Need a hint?

Call logger.info with the exact message 'NestJS app started'.

4

Run and see the logged output

Run the program and observe the console output showing the info log message.

NestJS

import * as winston from 'winston';

const logLevel = 'info';

const logger = winston.createLogger({
  level: logLevel,
  format: winston.format.simple(),
  transports: [new winston.transports.Console()]
});

logger.info('NestJS app started');

// Run the program and see the output

Need a hint?

Run the file with node and check the console for the log message starting with info:.