Flask server won't stop on Ctrl+C in Windows

Question

I created a default basic web server with Flask from Visual Studio templates. When I launch it from the command prompt it says "Press Ctrl+C to quit". When I do press Ctrl+C, nothing happens and the server keeps running.

Question: Is there a way to make Flask stop on Ctrl+C as advertised?

This is the code of server startup:

from os import environ
from myapp import app

if __name__ == '__main__':
    HOST = environ.get('SERVER_HOST', 'localhost')
    try:
        PORT = int(environ.get('SERVER_PORT', '5555'))
    except ValueError:
        PORT = 5555
    app.run(HOST, PORT)

Answer 1

To stop a Flask server running on Windows:

1. Ctrl+c
2. If Flask is still running, try: Ctrl+Break
3. If Flask is still running, open a command terminal or PowerShell and run:

taskkill /f /im python.exe

You can also select a specific Python process to kill:

> tasklist /fi "imagename eq python.exe"

Image Name                     PID Session Name        Session#    Mem Usage
========================= ======== ================ =========== ============
python.exe                    1080 Console                    8     72,456 K
python.exe                   15860 Console                    8     73,344 K

> taskkill /F /pid 15860
SUCCESS: The process with PID 15860 has been terminated.

4. If the server is only run on the local computer, another option is to create an endpoint to kill the server.

from flask import request
def shutdown_server():
    func = request.environ.get('werkzeug.server.shutdown')
    if func is None:
        raise RuntimeError('Not running with the Werkzeug Server')
    func()

@app.route('/shutdown', methods=['POST'])
def shutdown():
    shutdown_server()
    return 'Server shutting down...'

Answer 2

I'm surprised no one has mentioned this command

Although this is not perfect, see below text.

sudo pkill -f "flask"

of course this will have some cons, since it's a kill command. If you have multiple flask instances running, it will kill ALL of them, just as most of the other kill commands. To get around this, you can make a route that is used to programically shutdown the flask server.

Example:

@app.route('/shutdown')
def shutdown():
    sys.exit()
    os.exit(0)
    return

What his does; is, it will exit the program whenever /shutdown is triggered.
Of course this will need security, so no-random can spam shutdown your server.

Lets say you have a session called session['logged_in']
you would want to check if this session is True before shutting down the server.

Below should be working:

@app.route('/shutdown')
def shutdown():

    # If not logged in, return back to the login page.
    if not session or not session['logged_in']:
        return render_template('loginpage.html')

    # Logged_in, continue...
    sys.exit()
    os.exit(0)
    return

Hopefully this helped