How Can I Log Unhandled Exceptions in Python Using the Logging Module?

Logging Uncaught Exceptions in Python

Unless explicitly handled, Python exceptions are output by default to the program's standard error stream (stderr). However, there may be instances when it's desirable for uncaught exceptions to be logged using the logging module instead.

The traditional approach to logging uncaught exceptions is to manually use the logging.exception(e) method within an except block, as demonstrated below:

<code class="python">try:
    raise Exception, 'Throwing a boring exception'
except Exception, e:
    logging.exception(e)</code>

However, automatically invoking logging.exception(...) for every uncaught exception eliminates the manual step.

Implementation

Consider the following code snippet:

<code class="python">import sys
import logging

# Custom logger with handler for stdout
logger = logging.getLogger(__name__)
handler = logging.StreamHandler(stream=sys.stdout)
logger.addHandler(handler)

# Custom exception handler to log uncaught exceptions
def handle_exception(exc_type, exc_value, exc_traceback):
    # Ignore KeyboardInterrupt for Ctrl + C exit
    if issubclass(exc_type, KeyboardInterrupt):
        sys.__excepthook__(exc_type, exc_value, exc_traceback)
        return

    logger.error("Uncaught exception", exc_info=(exc_type, exc_value, exc_traceback))

# Assign custom exception handler
sys.excepthook = handle_exception

if __name__ == "__main__":
    raise RuntimeError("Test unhandled")</code>

This modified script accomplishes several key tasks:

• Custom Logging: Utilizing the logging module to format and record uncaught exceptions.
• Standard Output Handling: Directing the exceptions to stdout using a custom handler, ensuring they are displayed in the console window.
• Selective Exception Handling: Ignoring KeyboardInterrupt exceptions to maintain a graceful console exit via Ctrl C.

By overriding the default exception handler with handle_exception, uncaught exceptions are automatically logged using the configured logger, enhancing visibility and facilitating debugging.

The above is the detailed content of How Can I Log Unhandled Exceptions in Python Using the Logging Module?. For more information, please follow other related articles on the PHP Chinese website!