ground-control/ground-control.py

import json
import requests

from configparser import ConfigParser
from signal import signal
from signal import SIGTERM
from time import sleep

config = ConfigParser()
config.read('ground-control.cfg')

garage_host = config['systems'].get('garage')
marshaller_host = config['systems'].get('marshaller')

ntfy = config['ntfy'].get('host')
topic = config['ntfy'].get('topic')
auth = config['ntfy'].get('auth')

ntfy_uri = f'https://{ntfy}/{topic}/json?auth={auth}'
garage_uri = f'https://{garage_host}'
marshaller_uri = f'https://{marshaller_host}/on'

is_east_door_previously_open = False


class HaltException(Exception):
    pass


def main():
    signal(SIGTERM, raise_halt_exception)

    isRunning = True
    isFirstRun = True

    while isRunning:
        try:
            if isFirstRun:
                isFirstRun = False
            else:
                print('waiting to restart main loop', flush=True)
                sleep(15)

            print('listening for events', flush=True)
            listen_for_notifications()
        except HaltException:
            isRunning = False
        except Exception as e:
            print(e, flush=True)


def listen_for_notifications():
    with requests.get(ntfy_uri, stream=True, timeout=60) as response:
        for line in response.iter_lines():
            if line:
                data = json.loads(line.decode('utf-8'))

                if data['event'] == 'message' and is_east_door_newly_open():
                    activate_marshaller()


def is_east_door_newly_open():
    global is_east_door_previously_open

    is_door_open_now = is_east_door_currently_open()

    if is_door_open_now != is_east_door_previously_open:
        is_east_door_previously_open = is_door_open_now

        return is_door_open_now

    return False


def is_east_door_currently_open():
    return requests.get(garage_uri, timeout=6).json()['east-door'] == 'opened'


def activate_marshaller():
    print('activating marshaller', flush=True)

    for _ in range(2):
        try:
            requests.get(marshaller_uri, timeout=1)
        except requests.exceptions.ReadTimeout:
            print('read timeout - retrying marshaller', flush=True)
            sleep(2)

    requests.get(marshaller_uri, timeout=1)


def raise_halt_exception(signum, frame):
    raise HaltException()


if __name__ == '__main__':
    main()