Flask APP - ValueError: signal only works in main thread

Question

I try to create a simple flask app:

from flask import Flask

app = Flask(__name__)

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

but when I add

Answer 1

The problem you are facing has to do with a bug in the Flask-SocketIO package which replaces the flask run command. Due to this Flask-SocketIO is always used even if you don’t import it. There are several solutions:

1. Uninstall Flask-SocketIO
2. Do not use flask run but run the main file of your program
3. Disable debugging
4. Disable auto loading if debugging required flask run --no-reload

Reference to the Flask-SocketIO bug: issue 817