Show Python exception errors in Heroku log

Question

I have a Heroku application written i Python. When it fails it does not log anything, but just stops code execution at the location of failure (it does not execute print statements just below) and then continues to run as nothing happens.

How can I display exception errors and traceback in the log? Is the behaviour different when exceptions are raised using the raise statement?

I have set the following in the config file:

DEBUG = True
PRESERVE_CONTEXT_ON_EXCEPTION = True

Tried with and without PRESERVE_CONTEXT_ON_EXCEPTION.

Answer 1

It depends on your environment.

Try to add these lines:

stream_handler = logging.StreamHandler()
stream_handler.setLevel(logging.INFO)
app.logger.addHandler(stream_handler)

Also, if you run the server with Gunicorn, you should add --log-level debug to your Procfile