src/core/logging.py

"""
Production-Grade Structured Logging
"""

import logging
import sys
import json
from datetime import datetime
from typing import Any, Dict
from pathlib import Path

from pythonjsonlogger import jsonlogger

from .config import settings


class CustomJsonFormatter(jsonlogger.JsonFormatter):
    """Custom JSON formatter with additional fields"""
    
    def add_fields(self, log_record: Dict[str, Any], record: logging.LogRecord, message_dict: dict):
        super().add_fields(log_record, record, message_dict)
        
        # Add timestamp
        log_record['timestamp'] = datetime.utcnow().isoformat()
        
        # Add log level
        log_record['level'] = record.levelname
        
        # Add application context
        log_record['app'] = settings.APP_NAME
        log_record['version'] = settings.APP_VERSION
        log_record['environment'] = settings.ENVIRONMENT
        
        # Add request ID if available (will be set by middleware)
        if hasattr(record, 'request_id'):
            log_record['request_id'] = record.request_id
        
        # Add user ID if available
        if hasattr(record, 'user_id'):
            log_record['user_id'] = record.user_id


def setup_logging():
    """Configure application logging"""
    
    # Create logger
    logger = logging.getLogger()
    logger.setLevel(getattr(logging, settings.LOG_LEVEL.upper()))
    
    # Remove existing handlers
    logger.handlers = []
    
    # Console handler
    console_handler = logging.StreamHandler(sys.stdout)
    
    if settings.LOG_FORMAT == "json":
        console_formatter = CustomJsonFormatter(
            '%(timestamp)s %(level)s %(name)s %(message)s'
        )
    else:
        console_formatter = logging.Formatter(
            '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
        )
    
    console_handler.setFormatter(console_formatter)
    logger.addHandler(console_handler)
    
    # File handler (if configured)
    if settings.LOG_FILE:
        log_file = Path(settings.LOG_FILE)
        log_file.parent.mkdir(parents=True, exist_ok=True)
        
        file_handler = logging.FileHandler(log_file)
        
        if settings.LOG_FORMAT == "json":
            file_formatter = CustomJsonFormatter(
                '%(timestamp)s %(level)s %(name)s %(message)s'
            )
        else:
            file_formatter = logging.Formatter(
                '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
            )
        
        file_handler.setFormatter(file_formatter)
        logger.addHandler(file_handler)
    
    return logger


# Create module-level logger
logger = setup_logging()


def log_api_request(
    method: str,
    path: str,
    status_code: int,
    duration_ms: float,
    user_id: str = None,
    request_id: str = None
):
    """Log API request with structured data"""
    logger.info(
        "API Request",
        extra={
            "method": method,
            "path": path,
            "status_code": status_code,
            "duration_ms": duration_ms,
            "user_id": user_id,
            "request_id": request_id,
            "event_type": "api_request"
        }
    )


def log_prediction(
    model_type: str,
    input_size: int,
    confidence: float,
    duration_ms: float,
    cached: bool = False,
    user_id: str = None
):
    """Log ML prediction with metrics"""
    logger.info(
        "ML Prediction",
        extra={
            "model_type": model_type,
            "input_size": input_size,
            "confidence": confidence,
            "duration_ms": duration_ms,
            "cached": cached,
            "user_id": user_id,
            "event_type": "prediction"
        }
    )


def log_error(
    error: Exception,
    context: Dict[str, Any] = None,
    user_id: str = None,
    request_id: str = None
):
    """Log error with full context"""
    logger.error(
        f"Error: {str(error)}",
        extra={
            "error_type": type(error).__name__,
            "error_message": str(error),
            "context": context or {},
            "user_id": user_id,
            "request_id": request_id,
            "event_type": "error"
        },
        exc_info=True
    )


if __name__ == "__main__":
    # Test logging
    logger.info("Application starting")
    logger.debug("Debug message")
    logger.warning("Warning message")
    logger.error("Error message")
    
    log_api_request("GET", "/api/v1/health", 200, 5.2, request_id="test-123")
    log_prediction("deepfake", 1024, 0.95, 125.5, cached=False, user_id="user-1")