src/logger_config.py

import os
import logging
from typing import Any

PROJECT_ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))

def setup_logger() -> logging.Logger:
    """Configures structured logging to both standard output and log file."""
    log_dir = os.path.join(PROJECT_ROOT, "logs")
    os.makedirs(log_dir, exist_ok=True)
    
    log_file = os.path.join(log_dir, "customer_analytics.log")
    
    logger = logging.getLogger("customer_analytics")
    logger.setLevel(logging.INFO)
    
    # Avoid duplicate handlers if imported multiple times
    if not logger.handlers:
        formatter = logging.Formatter(
            '[%(asctime)s] %(levelname)s [%(filename)s:%(lineno)d] %(message)s',
            datefmt='%Y-%m-%d %H:%M:%S'
        )
        
        # File Handler
        file_handler = logging.FileHandler(log_file, encoding='utf-8')
        file_handler.setFormatter(formatter)
        logger.addHandler(file_handler)
        
        # Console Handler
        console_handler = logging.StreamHandler()
        console_handler.setFormatter(formatter)
        logger.addHandler(console_handler)
        
    return logger

# Globally available logger instance
logger = setup_logger()