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flaskwerkzeugflask-restful

Flask / Werkzeug run_simple not displaying Exception traces

I created two flask apps: frontend and restapi (with flask-restful). I created the following runserver.py to run them in development:

from werkzeug.wsgi import DispatcherMiddleware
from werkzeug.serving import run_simple

from restapi import app as restapi_app
from frontend import app as frontend_app

application = DispatcherMiddleware(frontend_app, {
  '/api': restapi_app,
})

if __name__ == "__main__":
  run_simple(
    'localhost',
    5000,
    application,
    use_reloader=True,
    use_debugger=True,
    use_evalex=True)

Despite having use_debugger=True, whenever one of the flask-restful resources raises an error, I don't get a trace, just a 500 error

{"status": 500, "message": "Internal Server Error"}

Any ideas how to get the full trace to display? Let me know if you need more details/code.

Solution

  • use_debugger option of Werkzeug WSGI server only enables embedded debugger, the server is unaware of Flask app configuration values (DEBUG in this case). To propagate exceptions to the server, you need to enable debug mode for both Flask app objects yourself. Here's one way to do it:

    if __name__ == '__main__':
    restapi_app.debug = True
    frontend_app.debug = True
    run_simple(...)