alfred-logger-sdk/CHANGELOG.md

Production-ready data collection SDK for feeding structured events to LLM Data Agents with auto-capture capabilities

# Changelog

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [2.0.0] - 2024-12-23

### Added
- **Auto-Capture System**: Automatic HTTP/HTTPS request and response logging
  - Patches Node.js `http` and `https` modules at runtime
  - Configurable sampling, filtering, and body capture
  - Smart header sanitization for security
  - Body size limits to prevent memory issues
  
- **Custom Context Management**: 
  - `setCustomContext()` - Add application-specific context to all events
  - `getCustomContext()` - Retrieve current context values
  - `removeCustomContext()` - Remove specific context keys
  - `clearCustomContext()` - Clear all custom context
  
- **Enhanced Security Features**:
  - Input validation for all configuration and event data
  - Automatic sanitization of sensitive fields (passwords, tokens, keys)
  - Secure random ID generation using crypto module
  - Payload size limits to prevent DoS attacks
  - URL validation to prevent malicious endpoints

- **Memory & Performance Improvements**:
  - Buffer overflow protection with configurable limits
  - Event size limits (1MB default)
  - Rate limiting between HTTP requests
  - Proper error recovery and retry logic with exponential backoff
  - Graceful shutdown process

- **Production-Ready Features**:
  - Comprehensive error handling and recovery
  - Memory leak protection
  - Safe shutdown with pending flush completion
  - No sensitive data in error logs

- **Testing & Quality**:
  - Complete test suite with 95%+ coverage
  - Jest configuration for testing
  - Comprehensive unit tests for all modules
  - Security and performance testing

### Enhanced
- **Logger Class**: Complete rewrite with production-ready features
- **HttpClient**: Enhanced retry logic, rate limiting, better error handling  
- **Express Middleware**: Improved error handling and sanitization
- **Axios Integration**: Enhanced with request/response sanitization

### Security
- All sensitive data automatically redacted from logs
- Header sanitization for authorization, cookies, API keys
- Request/response body sanitization
- Secure ID generation using crypto.randomBytes()
- Protection against log injection attacks

### Breaking Changes
- API updated from `createDataCollector()` to `new Logger()`
- Configuration options restructured for better organization
- Event structure enhanced with additional metadata
- Auto-capture requires explicit configuration

### Documentation
- Complete README rewrite with comprehensive examples
- Security guidelines documentation
- Auto-capture usage examples
- Publishing and deployment guides

## [1.0.0] - 2024-XX-XX

### Added
- Initial release
- Basic event collection functionality
- HTTP client for data transmission
- Express middleware support
- Trace ID management
- Basic error handling
- Simple batching and buffering

### Features
- User action logging
- System event tracking
- Performance metric collection
- Error tracking
- Custom data collection
- Automatic and manual trace ID support
- Configurable batching and retry logic