Star Logger - Logging Module with Winston and MongoDB

Welcome to My Logger, a Node.js module written in TypeScript that simplifies implementing logging in your microservices. It utilizes Winston for log management and MongoDB as the storage destination.

Table of Contents

• Installation
• Usage
• Configuration Options
• Examples
• Capturing Uncaught Exceptions
• Customization
• Testing
• Contribution
• License

Installation

You can install the module via NPM:

$ yarn add @starbemtech/star-logger

Usage

Import the module and initialize the logger by passing the MongoDB URI and optionally the desired configurations:

import { getLogger } from 'my-logger'

const logger = getLogger('mongodb://localhost:27017/my-database', {
  level: 'info',
  collection: 'logs',
})

// Using the logger
logger.info('Server started successfully')
logger.warn('High memory usage detected')
logger.error('Failed to connect to the database')

Configuration Options

The getLogger function accepts two parameters:

1.	mongoUri: string - The MongoDB connection URI.
2.	options: LoggerOptions (optional) - An object with configuration options.

LoggerOptions

Property	Type	Default	Description
level	string	'info'	Minimum severity level of logs to be recorded.
collection	string	'logs'	Name of the MongoDB collection where logs will be stored.
mongoOptions	MongoDBConnectionOptions	{}	Additional options for the MongoDB connection.

Examples

Basic Configuration

import { getLogger } from 'my-logger'

const logger = getLogger('mongodb://localhost:27017/my-database')

// Using the logger
logger.info('Server initialized')
logger.warn('Potential issue detected')
logger.error('An error occurred')

Advanced Configuration

import { getLogger } from 'my-logger'

const logger = getLogger('mongodb://localhost:27017/my-database', {
  level: 'debug',
  collection: 'my-logs',
  mongoOptions: {
    authSource: 'admin',
    ssl: true,
  },
})

// Using the logger
logger.debug('Variable X has value:', x)

Capturing Uncaught Exceptions

To capture uncaught exceptions and ensure they are logged:

import { getLogger } from 'my-logger'
import { transports } from 'winston'

const logger = getLogger('mongodb://localhost:27017/my-database')

// Configure to capture exceptions
logger.exceptions.handle(
  new transports.Console(),
  new transports.MongoDB({
    db: 'mongodb://localhost:27017/my-database',
    collection: 'exceptions',
  })
)

// Application code
process.on('unhandledRejection', (reason) => {
  throw reason
})

Customization

You can customize the log format or add new transports as needed.

Customizing the Format

import { getLogger } from 'my-logger'
import { format } from 'winston'

const customFormat = format.printf(({ level, message, timestamp }) => {
  return `${timestamp} [${level.toUpperCase()}]: ${message}`
})

const logger = getLogger('mongodb://localhost:27017/my-database', {
  level: 'info',
})

logger.format = format.combine(format.timestamp(), customFormat)

// Using the logger
logger.info('Message with custom format')

Adding New Transports

import { getLogger } from 'my-logger'
import { transports } from 'winston'

const logger = getLogger('mongodb://localhost:27017/my-database')

// Adding a new file transport
logger.add(new transports.File({ filename: 'combined.log' }))

// Using the logger
logger.info('This log will be saved in MongoDB and the file')

Testing

The module includes unit tests written with Jest to ensure reliability.

Running Tests

First, install the development dependencies:

$ yarn

Then, run the tests:

$ yarn test

Note on Tests

Ensure that all resources are properly closed after tests to prevent Jest from hanging. This includes:

•	Closing Winston logger transports
•	Closing MongoDB connections
•	Stopping the in-memory MongoDB server used in tests

Contribution

Contributions are welcome! Feel free to open issues or pull requests on the project’s repository.

Steps to Contribute

1.	Fork the project.
2.	Create a new branch with your feature or fix: git checkout -b my-feature.
3.	Commit your changes: git commit -m 'Add new feature'.
4.	Push to the branch: git push origin my-feature.
5.	Open a pull request on GitHub.

License

This project is licensed under the MIT License - see the LICENSE file for details.