Add response auditing capability to Pinot's audit logging system

[suvodeep-pyne]

Summary

This PR enhances Pinot's audit logging system by adding response auditing capability, enabling complete request-response cycle tracking for better observability and compliance.

Changes

• AuditLogFilter: Now implements both ContainerRequestFilter and ContainerResponseFilter interfaces
• Request-Response Correlation: Uses UUID-based request IDs to correlate request and response audit events
• Performance Metrics: Captures API execution duration using high-precision timing (System.nanoTime())
• Conditional Processing: Response context is only created when response auditing is enabled
• JSON Serialization: Fixed duplicate field issues by using JsonAutoDetect annotations

Key Features

1. Response Auditing: Captures HTTP response code and execution duration
2. Request ID Correlation: Each request gets a unique UUID for tracking through the system
3. Configurable: Response auditing can be enabled/disabled via capture.response.enabled config
4. Performance Optimized: Context objects only created when needed
5. Graceful Degradation: Audit failures never affect main request processing

Files Modified

• AuditConfig.java: Added capture.response.enabled configuration field
• AuditEvent.java: Added request_id, response_code, and duration_ms fields with proper JSON annotations
• AuditLogFilter.java: Implemented response filter with timing and correlation logic
• AuditResponseContext.java: New context wrapper for passing data between filters
• AuditRequestProcessor.java: Minor refactoring for consistency

Configuration

To enable response auditing:

pinot.audit.controller.enabled=true
pinot.audit.controller.capture.response.enabled=true

Sample Output

Request audit log:

{
  "request_id": "550e8400-e29b-41d4-a716-446655440000",
  "timestamp": "2025-01-17T10:30:45.123Z",
  "service_id": "controller",
  "endpoint": "/tables/myTable",
  "method": "POST",
  "user_id": {"principal": "user@company.com"}
}

Response audit log:

{
  "request_id": "550e8400-e29b-41d4-a716-446655440000",
  "timestamp": "2025-01-17T10:30:45.456Z",
  "endpoint": "/tables/myTable",
  "method": "POST",
  "response_code": 200,
  "duration_ms": 333
}

Testing

• Compiled successfully with Maven
• Response auditing only activates when explicitly enabled
• JSON serialization produces clean output without duplicate fields