How can I implement logging in a multithreaded Python application?

How can I implement logging in a multithreaded Python application?

You can use the logging module in Python, but you need to ensure that your logging calls are thread-safe.

What are some best practices for logging in a multithreaded environment?

Some best practices include using a QueueHandler to send log messages to a queue and a separate thread to handle logging.

Can you show me a code example of using QueueHandler?

Sure! Here's a simple example:

import logging
import logging.handlers
import threading
import time

def worker(queue):
    while True:
        message = queue.get()
        if message is None:
            break
        logging.info(message)

def main():
    queue = queue.Queue()
    listener = threading.Thread(target=worker, args=(queue,))
    listener.start()

    logger = logging.getLogger()
    handler = logging.handlers.QueueHandler(queue)
    logger.addHandler(handler)
    logger.setLevel(logging.INFO)

    logger.info('Starting the application')
    # Your multithreaded code here

    queue.put(None)  # Stop the listener
    listener.join()

This sets up a logging system that is safe for multithreading.