Logging Not Registering In Flask 0.12

I’m having some trouble getting logging to work with Raven. I noticed today that the handler gets set up properly if I run Flask 0.11.1, but not on 0.12. I made some example code below which is able to reproduce the issue. I’ve been running this on Python 3.5 with just Flask and Raven installed, Raven version 5.32.0.

Symptoms

• Sentry events not reported for the below code, upon hitting the / route, using Flask 0.12, while events show for the same conditions using Flask 0.11.0

Expected Outcome

• Sentry events should be reported across Flask versions

import logging

from flask import Flask
from raven.contrib.flask import Sentry

sentry = Sentry()

def create_app():
    app = Flask(__name__)

    app.config['DEBUG'] = True

    sentry.init_app(
        app,
        dsn='https://<redacted>',
        logging=True,
        level=logging.WARNING
    )

    def internal_server_error(exception):
        app.logger.exception(exception)
        return 'Internal Server Error'

    app.errorhandler(Exception)(internal_server_error)

    return app


app = create_app()


@app.route('/')
def test_route():
    raise Exception('TEST')


if __name__ == '__main__':
    app.run()

[jm66]

Tried setting app.logger.propagate = True and it worked as expected. Got it from https://github.com/pallets/flask/commit/e00e2c22aadf9e5b9dc353c31f1b70dad488b47a

[ghost]

I had the same issue in Raven 6.0.0 and Flask 0.12 (logging to app.logger doesn’t propagate).

@jm66 's fix worked for me, however.