SickGear/sickbeard/scheduler.py

# Author: Nic Wolfe <nic@wolfeden.ca>
# URL: http://code.google.com/p/sickbeard/
#
# This file is part of SickGear.
#
# SickGear is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# SickGear is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with SickGear.  If not, see <http://www.gnu.org/licenses/>.

import datetime
import time
import threading
import traceback

from sickbeard import logger
from sickbeard.exceptions import ex


class Scheduler(threading.Thread):
    def __init__(self, action, cycleTime=datetime.timedelta(minutes=10), run_delay=datetime.timedelta(minutes=0),
                 start_time=None, threadName="ScheduledThread", silent=True, prevent_cycle_run=None, paused=False):
        super(Scheduler, self).__init__()

        self.lastRun = datetime.datetime.now() + run_delay - cycleTime
        self.action = action
        self.cycleTime = cycleTime
        self.start_time = start_time
        self.prevent_cycle_run = prevent_cycle_run

        self.name = threadName
        self.silent = silent
        self._stop = threading.Event()
        self._unpause = threading.Event()
        if not paused:
            self._unpause.set()
        self.lock = threading.Lock()
        self.force = False

    def pause(self):
        self._unpause.clear()

    def unpause(self):
        self._unpause.set()

    def stop(self):
        self._stop.set()
        self.unpause()

    def check_paused(self):
        if hasattr(self.action, 'check_paused'):
            if self.action.check_paused():
                self.pause()
                self.silent = True
            else:
                self.unpause()
                self.silent = False

    def timeLeft(self):
        return self.cycleTime - (datetime.datetime.now() - self.lastRun)

    def forceRun(self):
        if not self.action.amActive:
            self.force = True
            return True
        return False

    def run(self):
        self.check_paused()

        # if self._unpause Event() is NOT set the loop pauses
        while self._unpause.wait() and not self._stop.is_set():

            try:
                current_time = datetime.datetime.now()
                should_run = False

                # check if interval has passed
                if current_time - self.lastRun >= self.cycleTime:
                    # check if wanting to start around certain time taking interval into account
                    if self.start_time:
                        hour_diff = current_time.time().hour - self.start_time.hour
                        if not hour_diff < 0 and hour_diff < self.cycleTime.seconds / 3600:
                            should_run = True
                        else:
                            # set lastRun to only check start_time after another cycleTime
                            self.lastRun = current_time
                    else:
                        should_run = True

                if self.force:
                    should_run = True

                if should_run and self.prevent_cycle_run is not None and self.prevent_cycle_run():
                    logger.log(u'%s skipping this cycleTime' % self.name, logger.WARNING)
                    # set lastRun to only check start_time after another cycleTime
                    self.lastRun = current_time
                    should_run = False

                if should_run:
                    self.lastRun = current_time

                    try:
                        if not self.silent:
                            logger.log(u"Starting new thread: " + self.name, logger.DEBUG)

                        self.action.run()
                    except Exception as e:
                        logger.log(u"Exception generated in thread " + self.name + ": " + ex(e), logger.ERROR)
                        logger.log(repr(traceback.format_exc()), logger.ERROR)

            finally:
                if self.force:
                    self.force = False

            time.sleep(1)

        # exiting thread
        self._stop.clear()
        self._unpause.clear()