playing around with signals 1

import atexit
import os
import signal
import subprocess
import sys
import threading
import time


class SignalException(Exception):
    ...


pid = os.getpid()
print("PID is", pid)


def raiser(signal, *rest):
    raise SignalException(f"Got signal {signal}", signal)


def kill(pid, sig, delay):
    time.sleep(delay)
    os.kill(pid, sig)


if len(sys.argv) == 2:
    try:
        signal_value = int(sys.argv[1])
    except ValueError:
        try:
            sig = sys.argv[1].upper()
            signal_value = signal.Signals[sig]
        except KeyError:
            raise SystemExit("A valid signal number or signal name is required")

    try:
        signal_type = signal.Signals(signal_value)
    except ValueError:
        raise SystemExit("Signal is unkown")
else:
    signal_value = None
    signal_type = None


class Button:
    buttons = []

    def __init__(self, pin):
        self.pin = pin
        self.buttons.append(self)

    @classmethod
    def close_all(cls):
        for button in cls.buttons:
            print("Closing button", button.pin)
            button.close()

    def close(self):
        ...


atexit.register(Button.close_all)
[Button(x) for x in range(10)]

if signal_type:
    # must be set in MainThread
    try:
        signal.signal(signal_type, raiser)
    except OSError:
        raise SystemExit("Invalid Signal")


    # Run a worker thread to signal myself.
    threading.Thread(target=kill, args=(pid, signal_type, 2), daemon=True).start()

try:
    time.sleep(3600)
except KeyboardInterrupt:
    print("Got CTRL+C")
except SignalException as sig:
    print(sig.args[0])
    sys.exit(sig.args[1])