app/utils/log_config.py

import logging
from app.config import settings


class ExtraFormatter(logging.Formatter):
    """Custom formatter that includes extra fields"""
    
    def format(self, record):
        # Get the basic formatted message
        formatted = super().format(record)
        
        # Add extra fields if they exist
        if hasattr(record, '__dict__'):
            extra_fields = {}
            for key, value in record.__dict__.items():
                # Skip standard logging fields
                if key not in ['name', 'msg', 'args', 'levelname', 'levelno', 'pathname', 
                              'filename', 'module', 'exc_info', 'exc_text', 'stack_info',
                              'lineno', 'funcName', 'created', 'msecs', 'relativeCreated',
                              'thread', 'threadName', 'processName', 'process', 'message',
                              'asctime']:
                    extra_fields[key] = value
            
            if extra_fields:
                extra_str = " | ".join([f"{k}={v}" for k, v in extra_fields.items()])
                formatted = f"{formatted} | {extra_str}"
        
        return formatted


def setup_logger() -> logging.Logger:
    """Setup logging configuration using standard logging"""
    logger = logging.getLogger("app")
    # can add different log levels, one global, then separate for file and stream

    stream_handler = logging.StreamHandler()
    file_handler = logging.FileHandler(settings.log_filename, mode="w")
    formatter = ExtraFormatter(
        fmt="%(asctime)s | %(filename)s:%(lineno)d | %(levelname)s | %(name)s | %(message)s"
    )

    logger.setLevel(settings.log_level)
    stream_handler.setFormatter(formatter)
    stream_handler.setLevel(settings.log_level)
    file_handler.setFormatter(formatter)
    file_handler.setLevel(settings.log_level)
    

    logger.addHandler(stream_handler)
    logger.addHandler(file_handler)

    return logger


logger = setup_logger()