Need help with better-exceptions?
Click the “chat” button below for chat support from the developer who created it, or find similar developers for support.

About the developer

Qix-
3.9K Stars 194 Forks MIT License 97 Commits 29 Opened issues

Description

Pretty and useful exceptions in Python, automatically.

Services available

!
?

Need anything else?

Contributors list

better-exceptions Travis

Pretty and more helpful exceptions in Python, automatically.

Example screenshot of exceptions

Usage

Install

better_exceptions
via pip:
$ pip install better_exceptions

And set the

BETTER_EXCEPTIONS
environment variable to any value:
export BETTER_EXCEPTIONS=1  # Linux / OSX
setx BETTER_EXCEPTIONS 1    # Windows

That's it!

Python REPL (Interactive Shell)

In order to use

better_exceptions
in the Python REPL, first install the package (as instructed above) and run:
$ python -m better_exceptions
Type "help", "copyright", "credits" or "license" for more information.
(BetterExceptionsConsole)
>>>

in order to drop into a

better_exceptions
-enabled Python interactive shell.

Advanced Usage

If you want to allow the entirety of values to be outputted instead of being truncated to a certain amount of characters:

import better_exceptions
better_exceptions.MAX_LENGTH = None

While using

better_exceptions
in production, do not forget to unset the
BETTER_EXCEPTIONS
variable to avoid leaking sensitive data in your logs.

Use with unittest

If you want to use

better_exceptions
to format
unittest
's exception output, you can use the monkey patch below:
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

Note that this uses an undocumented method override, so it is not guaranteed to work on all platforms or versions of Python.

Django Usage

In

settings.py
, add your new class to the
MIDDLEWARE
setting and update your logging configuration:
# ...

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

...

from better_exceptions.integrations.django import skip_errors_filter

if you don't want to override LOGGING because you want to change the default,

you can vendor Django's default logging configuration and update it for

better-exceptions. the default for Django 3.1.4 can be found here:

https://github.com/django/django/blob/3.1.4/django/utils/log.py#L13-L63

LOGGING = { 'version': 1, 'disable_existing_loggers': False, 'filters': { 'skip_errors': { '()': 'django.utils.log.CallbackFilter', 'callback': skip_errors_filter, } }, 'handlers': { 'console': { 'level': 'INFO', # without the 'filters' key, Django will log errors twice: # one time from better-exceptions and one time from Django. # with the 'skip_errors' filter, we remove the repeat log # from Django, which is unformatted. 'filters': ['skip_errors'], 'class': 'logging.StreamHandler', } }, 'loggers': { 'django': { 'handlers': [ 'console', ], } } }

example output:

image

Troubleshooting

If you do not see beautiful exceptions, first make sure that the environment variable does exist. You can try

echo $BETTER_EXCEPTIONS
(Linux / OSX) or
echo %BETTER_EXCEPTIONS%
(Windows). On Linux and OSX, the
export
command does not add the variable permanently, you will probably need to edit the
~/.profile
file to make it persistent. On Windows, you need to open a new terminal after the
setx
command.

Check that there is no conflict with another library, and that the

sys.excepthook
function has been correctly replaced with the
better_exceptions
's one. Sometimes other components can set up their own exception handlers, such as the
python3-apport
Ubuntu package that you may need to uninstall.

Make sure that you have not inadvertently deleted the

better_exceptions_hook.pth
file that should be in the same place as the
better_exceptions
folder where all of your Python packages are installed. Otherwise, try re-installing
better_exceptions
.

You can also try to manually activate the hook by adding

import better_exceptions; better_exceptions.hook()
at the beginning of your script.

Finally, if you still can not get this module to work, open a new issue by describing your problem precisely and detailing your configuration (Python and

better_exceptions
versions, OS, code snippet, interpeter, etc.) so that we can reproduce the bug you are experiencing.

License

Copyright © 2017, Josh Junon. Licensed under the MIT license.

We use cookies. If you continue to browse the site, you agree to the use of cookies. For more information on our use of cookies please see our Privacy Policy.