Turn the computer off after specified time. Show notifications.

turn_off.py

#!/usr/bin/env python
# coding: utf-8
import os
import datetime
import time
import pynotify

MAX_UPTIME = 60 * 60  # in seconds: 1 hour


def check_time_diff(ref_time, difference=10):
    """
    Compare current time with reference time.  Epsilon is set for 10 seconds.

    :param ref_time: reference time, which is compared with current time.
    :param difference: max possible difference between compared times (in
                       seconds).  10 seconds by default.
    """
    now = datetime.datetime.now()
    diff = abs(now - ref_time)

    if diff.seconds <= difference or now > ref_time:
        return True
    else:
        return False


def main(start_time, max_usage_time):
    """
    Show notifications 5 minutes, 1 minute, 10 seconds before shutdown.

    :param start_time: the time when the countdown should be started.  Usually
                       it's datetime.datetime.now()
    :param max_usage_time: time (in seconds) when to shutdown.  Should be
                           positive (obviously) and at least 5 minutes.
    """
    max_usage_time = datetime.timedelta(seconds=max_usage_time)

    five_min = start_time + max_usage_time - datetime.timedelta(seconds=5 * 60)
    one_min = start_time + max_usage_time - datetime.timedelta(seconds=1 * 60)

    max_usage_time = start_time + max_usage_time

    five_min_mark = False
    one_min_mark = False

    while 1:
        time.sleep(5)

        if not five_min_mark and check_time_diff(five_min):
            five_min_mark = True

            notification = pynotify.Notification("UWAGA!", "Komputer zostanie"
                                                 " zamkniÄty za 5 minut.")
            notification.show()
            continue

        if not one_min_mark and check_time_diff(one_min):
            one_min_mark = True

            notification = pynotify.Notification("UWAGA!", "Komputer zostanie"
                                                 " zamkniÄty za 1 minutÄ.")
            notification.show()
            continue

        if check_time_diff(max_usage_time):
            notification = pynotify.Notification("UWAGA!", "Komputer zostanie"
                                                 " zamkniÄty za 10 sekund.")
            notification.show()
            time.sleep(10)
            return True

    # just in case
    return False


def shutdown():
    """
    Perform shutdown of the system.  Shouldn't need root priviledges.
    The scripts needs +s chmod flag to run this command.
    """
    os.system("shutdown now -h")


if __name__ == '__main__':
    start_time = datetime.datetime.now()
    pynotify.init("ShutdownNowTimeApp")

    main(start_time, MAX_UPTIME)

    shutdown()