echortech-logging

A robust logging middleware for Express.js applications that provides structured logging with correlation IDs, trace IDs, and standardized log formats.

Installation

npm install echortech-logging

Features

• Structured logging for Express.js applications
• Support for info, warn, and error log levels
• Automatic correlation ID and trace ID tracking
• Request timing and response metrics
• Custom tagging support

Usage

const express = require('express');
const echorLogger = require('echortech-logging'); 

const app = express();
const PORT = process.env.PORT || 3000;

// Middleware to simulate request info
app.use((req, res, next) => {
  req.info = { received: Date.now() };
  req.auth = { credentials: { sub: 'user123' } };
  req.correlationId = 'correlation-id-123';
  req.traceId = 'trace-id-123';
  next();
});

// Success route
app.get('/success', (req, res) => {
  const data = {
    statusCode: 200,
    message: 'This is a success message',
    responseTime: 123,
    result: { key: 'value' }
  };
  echorLogger.info(req, ['SUCCESS_TAG'], data);
  res.status(200).send('Success logged');
});

// Warning route
app.get('/warn', (req, res) => {
  const data = {
    statusCode: 200,
    message: 'This is a warning message',
    responseTime: 150,
    result: { key: 'value' }
  };
  echorLogger.warn(req, ['WARN_TAG'], data);
  res.status(200).send('Warning logged');
});

// Error route
app.get('/error', (req, res) => {
  const error = new Error('This is an error message');
  const data = {
    statusCode: 500,
    error: error.message,
    message: 'An error occurred',
    responseTime: 200
  };
  echorLogger.error(req, ['ERROR_TAG'], data, error);
  res.status(500).send('Error logged');
});

app.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});

API Reference

echorLogger.info(req, tags, data)

Logs information level messages.

echorLogger.warn(req, tags, data)

Logs warning level messages.

echorLogger.error(req, tags, data, error)

Logs error level messages with error stack traces.

Parameters

• req: Express request object containing:
  • info.received: Request receipt timestamp
  • auth.credentials.sub: User identifier
  • correlationId: Request correlation ID
  • traceId: Request trace ID
• tags: Array of string tags for log categorization
• data: Object containing log data
• error: (Optional) Error object for error logging

Example Data Structure

{
  statusCode: 200,
  message: 'Log message',
  responseTime: 123,
  result: { key: 'value' }
}