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better-exceptions

repository·master·Indexed 26 days ago

https://github.com/qix-/better-exceptions

A Python library that provides pretty and more helpful exception formatting automatically via environment variables or manual hooks. It includes integrations for Django and unittest, as well as a way to run the Python REPL with enhanced exception formatting.

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What's inside better-exceptions

  1. Integrate better-exceptions with Django

    master

    To use better_exceptions in Django, add better_exceptions.integrations.django.BetterExceptionsMiddleware to your MIDDLEWARE setting. To prevent duplicate logs (one from better_exceptions and one from Django), configure your LOGGING dictionary to use the skip_errors_filter from better_exceptions.integrations.django.

    # settings.py

MIDDLEWARE = [
    # ...
    "better_exceptions.integrations.django.BetterExceptionsMiddleware",
]

# ...

from better_exceptions.integrations.django import skip_errors_filter

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'filters': {
        'skip_errors': {
            '()': 'django.utils.log.CallbackFilter',
            'callback': skip_errors_filter,
        }
    },
    'handlers': {
        'console': {
            'level': 'INFO',
            'filters': ['skip_errors'],
            'class': 'logging.StreamHandler',
        }
    },
    'loggers': {
        'django': {
            'handlers': [
                'console',
            ],
        }
    }
}

  3. Install and enable better-exceptions

    master

    Install better_exceptions via pip and enable it by setting the BETTER_EXCEPTIONS environment variable to any value. This automatically provides pretty and helpful exception formatting.

    pip install better_exceptions
    export BETTER_EXCEPTIONS=1  # Linux / OSX
setx BETTER_EXCEPTIONS 1    # Windows

  4. Troubleshoot better-exceptions

    master

    If exceptions are not being formatted correctly, check the following:

    1. Environment Variable: Ensure BETTER_EXCEPTIONS is set. Use echo $BETTER_EXCEPTIONS (Linux/OSX) or echo %BETTER_EXCEPTIONS% (Windows) to verify.
    2. Conflicts: Check for other libraries overriding sys.excepthook. On Ubuntu, the python3-apport package may cause conflicts.
    3. Missing Hook File: Ensure better_exceptions_hook.pth exists in your Python package directory. If missing, reinstall the package.
    4. Manual Activation: You can manually trigger the hook at the start of your script using:
      import better_exceptions
better_exceptions.hook()

  5. Use better-exceptions with unittest

    master

    To format unittest exception output using better_exceptions, you can monkey patch unittest.result.TestResult._exc_info_to_string.

    import sys
import unittest
import better_exceptions

def patch(self, err, test):
    lines = better_exceptions.format_exception(*err)
    if sys.version_info[0] == 2:
        return u"".join(lines).encode("utf-8")
    return "".join(lines)

unittest.result.TestResult._exc_info_to_string = patch

  6. Configure maximum output length

    master

    By default, better_exceptions truncates values. To allow the entirety of values to be outputted without truncation, set better_exceptions.MAX_LENGTH to None.

    import better_exceptions
better_exceptions.MAX_LENGTH = None