Having difficulty with threads and input()

[Gribouillis]

This I am fascinated by... how can I connect to my script? If I can send an external signal to it to start termination activities that could work instead of using an input().

You could use any kind of server such as a http server or whatever. Here is an example using a rpyc server (remote procedure calls). The main program does some work but it also starts a thread running a server on a port that waits for one connection

# rpycserver.py
from threading import Thread, Event
import rpyc
from rpyc.utils.server import OneShotServer
from time import sleep

PORT = 18861
STOPPED = Event()


class StopService(rpyc.Service):
    def exposed_stop(self):
        WORKER.stop()


class ServerThread(Thread):
    def __init__(self):
        Thread.__init__(self)
        self.server = OneShotServer(StopService, port=PORT)

    def run(self):
        self.server.start()

    def stop(self):
        STOPPED.set()
        self.server.close()


if __name__ == "__main__":
    WORKER = ServerThread()
    WORKER.start()
    while True:
        # This is the program's main loop
        # It checks now and then if the STOPPED event is set
        # indicating that the stop_service was invoked from
        # the outside.
        # It could also stop programmatically by calling
        # WORKER.stop()
        if STOPPED.is_set():
            break
        sleep(2)
    WORKER.join()
    print("Running cleanup code")

In order to stop the program, I run another program

# stoprpycserver.py
import rpyc

PORT = 18861

if __name__ == "__main__":
    c = rpyc.connect("localhost", PORT)
    try:
        c.root.stop()
    except EOFError:
        pass

Output:
λ python paillasse/pf/rpycserver.py &
[1] 5091
λ python paillasse/pf/stoprpycserver.py
λ Running cleanup code

[1]+  Done                    python paillasse/pf/rpycserver.py

You could add features to the server, such as authentication etc.