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Errors & debugging

Handle failures gracefully, raise helpful errors, and debug with confidence.

5 matches

How to Configure Python Logging with File Rotation

A complete demo that sets up a logger with a rotating file handler, writes several log entries, and shows the contents of the current log file.

logging file-handler rotating-file-handler

Python

import logging
from logging.handlers import RotatingFileHandler

logger = logging.getLogger("rotating_logger")
logger.setLevel(logging.DEBUG)

file_handler = RotatingFileHandler(
    "app.log",
    maxBytes=100,
    backupCount=3
)
file_handler.setFormatter(
    logging.Formatter("%(asctime)s - %(levelname)s - %(messa…

13 0 Open

Errors & debugging easy

How to Debug Print Behind a DEBUG Environment Flag in Python

Create a debug_print function that only outputs when the DEBUG environment variable is set to a truthy value like 1, true, yes, or on.

debugging environment-variables logging

Python

import os


def debug_print(*args, **kwargs):
    """Print only when DEBUG environment variable is set to a truthy value."""
    if os.environ.get("DEBUG", "").lower() in ("1", "true", "yes", "on"):
        print(*args, **kwargs)


if __name__ == "__main__":
    # Example usage: run as `DEBUG=1 python script.py` to se…

11 0 Open

Errors & debugging easy

How to Log Exceptions with traceback.format_exc in Python

Capture and log a full traceback string when an exception occurs using Python's traceback.format_exc() and logging module.

traceback logging exception

Python

import traceback
import logging

def risky_operation(value):
    return 10 / value

logging.basicConfig(level=logging.ERROR, format='%(asctime)s - %(levelname)s - %(message)s')

def main():
    try:
        result = risky_operation(0)
        print(f"Result: {result}")
    except ZeroDivisionError:
        error_msg =…

14 0 Open

Errors & debugging easy

How to Serialize an Exception to a JSON-Safe Dict in Python

Convert any Python exception into a JSON-safe dictionary with type, message, and the last few traceback lines for logging.

exceptions json logging

Python

import json
import traceback
from typing import Any


def exception_to_dict(exc: Exception) -> dict[str, Any]:
    """Convert an exception into a JSON-safe dictionary."""
    return {
        "type": type(exc).__name__,
        "message": str(exc),
        "traceback": traceback.format_exc().strip().split("\n")[-3:],
…

15 0 Open

Errors & debugging easy

Log to stderr with Python logging basicConfig

Configure Python's logging module to send all log messages to standard error (stderr) instead of the default stderr, with a readable timestamped format.

logging stderr debugging

Python

import logging

def main():
    logging.basicConfig(
        level=logging.DEBUG,
        format="%(asctime)s — %(name)s — %(levelname)s — %(message)s",
        stream=__import__("sys").stderr,
    )
    logger = logging.getLogger("example")
    logger.debug("Debug message")
    logger.info("Info message")
    logger.…

12 0 Open

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