@unidev-hub/logger

A standardized logging package for TypeScript microservices, built on top of Pino.

Features

• 🚀 High-performance logging using Pino
• 🔍 Request ID tracking for service correlation
• 🌐 Express middleware for request/response logging
• 🛡️ Consistent error logging format
• 🧩 Contextual child loggers

Installation

npm install @unidev-hub/logger

Usage

Basic Usage

import { createLogger } from '@unidev-hub/logger';

const logger = createLogger({
  serviceName: 'user-service',
  level: 'info',
  prettyPrint: process.env.NODE_ENV === 'development'
});

logger.info('Server started', { port: 3000 });
logger.error('Failed to connect to database', new Error('Connection timeout'));
// Or with additional context
logger.error('Failed to connect to database', new Error('Connection timeout'), { host: 'db-server-1' });

With Express

import express from 'express';
import { createLogger, createRequestLogger, getRequestLogger } from '@unidev-hub/logger';

const app = express();
const logger = createLogger({ serviceName: 'api-gateway' });

// Apply middleware
app.use(createRequestLogger(logger, {
  getUserId: (req) => req.user?.id,
  skipPaths: ['/health', '/metrics']
}));

// Use in route handlers
app.get('/users', (req, res) => {
  const requestLogger = getRequestLogger(req);
  
  requestLogger.info('Fetching users');
  
  // Your logic here
  
  res.json({ users: [] });
});

app.listen(3000, () => {
  logger.info('Server started', { port: 3000 });
});

Error Logging

// With Error object
logger.error('Failed to connect to database', new Error('Connection timeout'));

// With context object
logger.error('User validation failed', { userId: '123', reason: 'Invalid email' });

// With both Error and additional context
logger.error('Payment processing failed', new Error('Gateway timeout'), { orderId: 'ORD-123' });

Child Loggers

function processOrder(orderId: string, userId: string) {
  const orderLogger = logger.child({ orderId, userId });
  
  orderLogger.info('Processing order');
  
  // All logs from this logger will include orderId and userId
  orderLogger.debug('Validating payment');
  orderLogger.info('Order processed successfully');
}

Configuration

The logger accepts the following configuration options:

Option	Type	Description	Default
serviceName	string	Name of the service	Required
level	string	Minimum log level	'info' or LOG_LEVEL env var
prettyPrint	boolean	Format logs for human readability	true in development
environment	string	Environment name	NODE_ENV or 'development'
additionalFields	object	Extra fields to add to all logs	{}

Request Logger Middleware Options

Option	Type	Description	Default
getUserId	Function	Extract user ID from request	undefined
logRequestBody	boolean	Include request body in logs	false
logResponseBody	boolean	Include response body in logs	false
skipPaths	string[]	Paths to exclude from logging	[]

Best Practices

1. Use child loggers to add context to related log entries
2. Include error objects in error logs for stack traces
3. Use appropriate log levels:
   • trace: Very detailed debugging
   • debug: Debugging information
   • info: Normal operations
   • warn: Warning conditions
   • error: Error conditions
   • fatal: Critical failures

License

MIT