Python Logging Configuration

import logging
import logging.handlers
import json
from datetime import datetime, timezone


# JSON formatter for structured logging
class JSONFormatter(logging.Formatter):
    def format(self, record: logging.LogRecord) -> str:
        log_data = {
            "timestamp": datetime.now(timezone.utc).isoformat(),
            "level": record.levelname,
            "logger": record.name,
            "message": record.getMessage(),
            "module": record.module,
            "function": record.funcName,
            "line": record.lineno,
        }
        if record.exc_info:
            log_data["exception"] = self.formatException(record.exc_info)
        if hasattr(record, "extra_data"):
            log_data["data"] = record.extra_data
        return json.dumps(log_data)


def setup_logging(level: str = "INFO", log_file: str = "app.log") -> None:
    root = logging.getLogger()
    root.setLevel(getattr(logging, level))

    # Console handler (human-readable)
    console = logging.StreamHandler()
    console.setFormatter(logging.Formatter(
        "%(asctime)s [%(levelname)s] %(name)s: %(message)s",
        datefmt="%H:%M:%S",
    ))
    root.addHandler(console)

    # File handler (JSON, rotating)
    file_handler = logging.handlers.RotatingFileHandler(
        log_file, maxBytes=10_000_000, backupCount=5
    )
    file_handler.setFormatter(JSONFormatter())
    root.addHandler(file_handler)


# Usage
setup_logging("DEBUG")
logger = logging.getLogger("myapp.orders")

logger.info("Order created", extra={"extra_data": {"order_id": "123", "amount": 99.99}})
logger.warning("Low inventory for product %s", "SKU-456")

try:
    1 / 0
except ZeroDivisionError:
    logger.exception("Unexpected error processing order")