@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