utils/cronutil/__init__.py

"""
Scheduler works only on a weekly scale. This is due to the use of the schedule package.

Target format: wD:HH:MM:SS, where:
wD - day of week unit: '1', '2', ... , '6', '7', '*'
HH - hour unit in 24-hours format: '00', '01', ... , '22', '23', '**'
MM - minute unit: '00', '01', ... , '58', '59', '**'
SS - second unit: '00', '01', ... , '58', '59', '**'
Units can be listed separated by commas.

Examples:
'*:**:**:**' - every second of every minute of every hour of every day
'*:**:**:*5' - every 05,15,25,35,45,55 seconds of every minute of every hour of every day
'*:2*:**:**' - every second of every minute of every 20,21,22,23 hours of every day
'*:2*:**:*5' - every 05,15,25,35,45,55 seconds of every minute of every 20,21,22,23 hours of every day
'3,5:2*:**:*5' - every 05,15,25,35,45,55 seconds every minute every 20,21,22,23 hours of Wednesday, Friday
'1,7:12:00:**' - every second 00 minutes 12 hours of Monday, Sunday
'1:07:00:00' - every 00 seconds 00 minutes 07 hours Monday
"""

from itertools import cycle
from time import sleep
from threading import Event, Thread
from . import schedule


class Scheduler:
    """
    Control wrapper for the schedule package
    """
    def __init__(self):
        """
        Object constructor
        """
        self.scheduler_entity = schedule.Scheduler()
        self.scheduler_signal = None

    def _start_thread(self, interval: int = 1):
        """
        Running the scheduler with a thread in the background
        :param interval: an integer specifying the period in seconds to start pending jobs
        """
        signal = Event()

        class ScheduleThread(Thread):
            @classmethod
            def run(cls):
                while not signal.is_set():
                    self.scheduler_entity.run_pending()
                    sleep(interval)

        ScheduleThread().start()
        return signal

    def start(self):
        """
        Scheduler launch
        """
        self.scheduler_signal = self._start_thread()

    def stop(self):
        """
        Stopping the Scheduler
        """
        self.scheduler_signal.set()

    def add(self, target: str, action):
        """
        Adding a job to the execution queue
        :param target: a string in the format wD:HH:MM:SS specifying the target of the launch time
        :param action: a string with the name of the function to run
        """
        target_undefined = target.split(':')
        if len(target_undefined) == 4:
            wd, hh, mm, ss = target_undefined[0], target_undefined[1], target_undefined[2], target_undefined[3]
            if '*' in wd and '**' in hh and '**' in mm and '**' in ss:
                self.scheduler_entity.every().seconds.do(action)
            elif '*' in wd and '**' in hh and '**' in mm:
                for element in self._expand_target(wd.split(','),
                                                   hh.split(','),
                                                   mm.split(','),
                                                   self._expand_time(ss, 'ss')):
                    ss = element[3]
                    self.scheduler_entity.every().minute.at(':' + ss).do(action)
            elif '*' in wd and '**' in hh:
                for element in self._expand_target(wd.split(','),
                                                   hh.split(','),
                                                   self._expand_time(mm, 'mm'),
                                                   self._expand_time(ss, 'ss')):
                    mm, ss = element[2], element[3]
                    self.scheduler_entity.every().hour.at(mm + ':' + ss).do(action)
                pass
            elif '*' in wd:
                for element in self._expand_target(wd.split(','),
                                                   self._expand_time(hh, 'hh'),
                                                   self._expand_time(mm, 'mm'),
                                                   self._expand_time(ss, 'ss')):
                    hh, mm, ss = element[1], element[2], element[3]
                    self.scheduler_entity.every().day.at(hh + ':' + mm + ':' + ss).do(action)
            else:
                for element in self._expand_target(self._expand_time(wd, 'wd'),
                                                   self._expand_time(hh, 'hh'),
                                                   self._expand_time(mm, 'mm'),
                                                   self._expand_time(ss, 'ss')):
                    wd, hh, mm, ss = element[0], element[1], element[2], element[3]
                    if wd == '1':
                        self.scheduler_entity.every().monday.at(hh + ':' + mm + ':' + ss).do(action)
                    elif wd == '2':
                        self.scheduler_entity.every().tuesday.at(hh + ':' + mm + ':' + ss).do(action)
                    elif wd == '3':
                        self.scheduler_entity.every().wednesday.at(hh + ':' + mm + ':' + ss).do(action)
                    elif wd == '4':
                        self.scheduler_entity.every().thursday.at(hh + ':' + mm + ':' + ss).do(action)
                    elif wd == '5':
                        self.scheduler_entity.every().friday.at(hh + ':' + mm + ':' + ss).do(action)
                    elif wd == '6':
                        self.scheduler_entity.every().saturday.at(hh + ':' + mm + ':' + ss).do(action)
                    elif wd == '7':
                        self.scheduler_entity.every().sunday.at(hh + ':' + mm + ':' + ss).do(action)

    @classmethod
    def _expand_time(cls, time_raw: str, unit: str):
        """
        Converts an undefined time units to a list of specific time units
        :param time_raw: a string with time unit
        :param unit: string description of the time unit
        :return: list of specific time units
        """
        if ',' in time_raw:
            pass
        elif '*' in time_raw and (unit == 'wd' or unit == 'hh' or unit == 'mm' or unit == 'ss'):
            time_out, time_min, time_max = [], 0, 60
            if unit == 'hh':
                time_max = 24
            if unit == 'wd':
                time_min, time_max = 1, 8
            for i in range(time_max):
                out = time_raw.replace('**', format(i, '02d')).replace('*', str(i))
                if 0 <= int(out) < time_max:
                    time_out.append(out)
            return time_out
        return time_raw.split(',')

    @classmethod
    def _expand_target(cls, wd: list, hh: list, mm: list, ss: list):
        """
        Converts an undefined target to a list of specific target
        :param wd: list with day of week time units
        :param hh: list with hour time units
        :param mm: list with minute time units
        :param ss: list with second time units
        :return: list of specific time targets
        """
        cwd, chh, cmm, css = cycle(wd), cycle(hh), cycle(mm), cycle(ss)
        target_defined = []
        for a in range(len(wd)):
            a_wd = next(cwd)
            for b in range(len(hh)):
                b_hh = next(chh)
                for c in range(len(mm)):
                    c_mm = next(cmm)
                    for d in range(len(ss)):
                        d_ss = next(css)
                        target_defined.append([a_wd, b_hh, c_mm, d_ss])
        return target_defined


if __name__ == "__main__":
    pass