flask: stop server after exception

user_497600 0
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I would like to stop my flask server as soon as an unhandled exception occurs. Here is an example:

from flask import Flask

app = Flask(__name__)


@app.route('/')
def hello_world():
    1/0 # argh, exception
    return 'Hello World!'


if __name__ == '__main__':
    app.run(port=12345)

If you run this and go to localhost:12345, your browser tells you "internal server error" and the python console logs a DivisionByZero exception.

But the server app doesn't crash. Flask wraps your routes into its own error handling and it only prints the exception.

I would like to make the server stop as soon as a route produces an exception. But I didn't find this behaviour in the API. You can specify an errorhandler but that is only to give custom error messages to the client after your route failed.

flask python
1 Answers

Stopping Flask requires getting into Werkzeug internals. See http://flask.pocoo.org/snippets/67/

Extracted from a single-user app:

from flask import request

@app.route('/quit')
def shutdown():
    ...
    shutdown_hook = request.environ.get('werkzeug.server.shutdown')
    if shutdown_hook is not None:
        shutdown_hook()
    return Response("Bye", mimetype='text/plain')

The shutdown_hook bit is what you'd need in an exception handler.

user_622880
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