@aws-lambda-powertools/logger

What is @aws-lambda-powertools/logger?

@aws-lambda-powertools/logger is a structured logging utility designed for AWS Lambda functions. It simplifies the process of creating consistent and meaningful logs, which can be crucial for debugging and monitoring serverless applications.

What are @aws-lambda-powertools/logger's main functionalities?

Basic Logging

This feature allows you to log basic information. The logger.info method is used to log informational messages.

const { Logger } = require('@aws-lambda-powertools/logger');
const logger = new Logger();

exports.handler = async (event) => {
  logger.info('This is an info log');
  return { statusCode: 200, body: 'Hello World' };
};

Structured Logging

Structured logging allows you to add context to your logs, making them more useful for debugging and monitoring. You can add persistent attributes that will be included in every log entry.

const { Logger } = require('@aws-lambda-powertools/logger');
const logger = new Logger({
  persistentLogAttributes: {
    service: 'my-service',
    environment: 'production'
  }
});

exports.handler = async (event) => {
  logger.info('This is a structured log', { userId: '12345' });
  return { statusCode: 200, body: 'Hello World' };
};

Error Logging

This feature allows you to log errors with additional context. The logger.error method is used to log error messages.

const { Logger } = require('@aws-lambda-powertools/logger');
const logger = new Logger();

exports.handler = async (event) => {
  try {
    throw new Error('Something went wrong');
  } catch (error) {
    logger.error('An error occurred', { error });
  }
  return { statusCode: 500, body: 'Internal Server Error' };
};

Other packages similar to @aws-lambda-powertools/logger

winston

Winston is a versatile logging library for Node.js that supports multiple transports (e.g., console, file, HTTP). It offers more flexibility and customization options compared to @aws-lambda-powertools/logger but requires more setup.

bunyan

Bunyan is another structured logging library for Node.js. It provides a JSON-based logging format and includes features like log levels and serializers. It is similar to @aws-lambda-powertools/logger in terms of structured logging but is more general-purpose.

pino

Pino is a fast JSON logger for Node.js applications. It is designed for high performance and low overhead. While it offers similar structured logging capabilities, it is more focused on performance compared to @aws-lambda-powertools/logger.

README

AWS Lambda Powertools for TypeScript

Powertools is a developer toolkit to implement Serverless best practices and increase developer velocity.

You can use the library in both TypeScript and JavaScript code bases.

Also available in Python, Java, and .NET.

Documentation | npm | Roadmap | Examples | Serverless TypeScript Demo

Table of contents

• Features
• Getting started
  • Installation
  • Examples
  • Serverless TypeScript Demo application
• Contribute
• Roadmap
• Connect
• Credits
• License

Features

• Tracer - Utilities to trace Lambda function handlers, and both synchronous and asynchronous functions
• Logger - Structured logging made easier, and a middleware to enrich log items with key details of the Lambda context
• Metrics - Custom Metrics created asynchronously via CloudWatch Embedded Metric Format (EMF)

Getting started

Find the complete project's documentation here.

Installation

The AWS Lambda Powertools for TypeScript utilities follow a modular approach, similar to the official AWS SDK v3 for JavaScript.

Each TypeScript utility is installed as standalone npm package.

Install all three core utilities at once with this single command:

npm install @aws-lambda-powertools/logger @aws-lambda-powertools/tracer @aws-lambda-powertools/metrics

Or refer to the installation guide of each utility:

👉 Installation guide for the Tracer utility

👉 Installation guide for the Logger utility

👉 Installation guide for the Metrics utility

Examples

• CDK
• SAM

Serverless TypeScript Demo application

The Serverless TypeScript Demo shows how to use Lambda Powertools for TypeScript.
You can find instructions on how to deploy and load test this application in the repository.

Contribute

If you are interested in contributing to this project, please refer to our Contributing Guidelines.

Roadmap

The roadmap of Powertools is driven by customers’ demand.
Help us prioritize upcoming functionalities or utilities by upvoting existing RFCs and feature requests, or creating new ones, in this GitHub repository.

Connect

• AWS Lambda Powertools on Discord: #typescript - Invite link
• Email: [e-mail]

Credits

Credits for the Lambda Powertools idea go to DAZN and their DAZN Lambda Powertools.

License

This library is licensed under the MIT-0 License. See the LICENSE file.

Changelog

1.6.0 (2023-03-02)

Bug Fixes

• docs: logger bringYourOwnFormatter snippet #1253 (#1254) (fdbba32)
• hardcoded cdk version in publish_layer.yaml (#1232) (63a3909)
• logger: createChild not passing all parent's attributes (#1267) (84ab4b9)
• logger: middleware stores initial persistent attributes correctly (#1329) (6b32304)
• parameters: handle base64/binaries in transformer (#1326) (bb50c04)
• parameters: Tokenize attribute names in DynamoDBProvider (#1239) (f3e5ed7)

Features

• idempotency: Add function wrapper and decorator (#1262) (eacb1d9)
• layers: add new regions (#1322) (618613b)
• logger: make loglevel types stricter (#1313) (5af51d3)
• parameters: add support for custom AWS SDK v3 clients for providers (#1260) (3a8cfa0)