Limnoria/src/schedule.py
Valentin Lorentz ad05468257 Scheduler: Preserve period offset on restarts.
Partial fix for GH-397.
2020-05-02 18:28:41 +02:00

164 lines
6.0 KiB
Python

###
# Copyright (c) 2002-2005, Jeremiah Fincher
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice,
# this list of conditions, and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions, and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# * Neither the name of the author of this software nor the name of
# contributors to this software may be used to endorse or promote products
# derived from this software without specific prior written consent.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
###
"""
Schedule plugin with a subclass of drivers.IrcDriver in order to be run as a
Supybot driver.
"""
from __future__ import with_statement
import time
import heapq
import functools
from threading import Lock
from . import drivers, log, world
class mytuple(tuple):
def __cmp__(self, other):
return cmp(self[0], other[0])
def __le__(self, other):
return self[0] <= other[0]
def __lt__(self, other):
return self[0] < other[0]
def __gt__(self, other):
return self[0] > other[0]
def __ge__(self, other):
return self[0] >= other[0]
class Schedule(drivers.IrcDriver):
"""An IrcDriver to handling scheduling of events.
Events, in this case, are functions accepting no arguments.
"""
def __init__(self):
drivers.IrcDriver.__init__(self)
self.schedule = []
self.events = {}
self.counter = 0
self.lock = Lock()
def reset(self):
with self.lock:
self.events.clear()
self.schedule[:] = []
# We don't reset the counter here because if someone has held an id of
# one of the nuked events, we don't want them removing new events with
# their old id.
def name(self):
return 'Schedule'
def addEvent(self, f, t, name=None, args=[], kwargs={}):
"""Schedules an event f to run at time t.
name must be hashable and not an int.
"""
if name is None:
name = self.counter
self.counter += 1
assert name not in self.events, \
'An event with the same name has already been scheduled.'
with self.lock:
self.events[name] = f
heapq.heappush(self.schedule, mytuple((t, name, args, kwargs)))
return name
def removeEvent(self, name):
"""Removes the event with the given name from the schedule."""
f = self.events.pop(name)
# We must heapify here because the heap property may not be preserved
# by the above list comprehension. We could, conceivably, just mark
# the elements of the heap as removed and ignore them when we heappop,
# but that would only save a constant factor (we're already linear for
# the listcomp) so I'm not worried about it right now.
with self.lock:
self.schedule = [x for x in self.schedule if x[1] != name]
heapq.heapify(self.schedule)
return f
def rescheduleEvent(self, name, t):
f = self.removeEvent(name)
self.addEvent(f, t, name=name)
def makePeriodicWrapper(
self, f, t, name=None, args=[], kwargs={}, count=None):
"""Returns a function that will run and re-schedule itself every t
seconds."""
def wrapper():
nonlocal count
try:
f(*args, **kwargs)
finally:
# Even if it raises an exception, let's schedule it.
if count is not None:
count -= 1
if count is None or count > 0:
return self.addEvent(wrapper, time.time() + t, name)
return wrapper
def addPeriodicEvent(
self, f, t, name=None, now=True, args=[], kwargs={}, count=None):
"""Adds a periodic event that is called every t seconds."""
wrapper = self.makePeriodicWrapper(
f, t, name, args, kwargs, count)
if now:
return wrapper()
else:
return self.addEvent(wrapper, time.time() + t, name)
removePeriodicEvent = removeEvent
def run(self):
if len(drivers._drivers) == 1 and not world.testing:
log.error('Schedule is the only remaining driver, '
'why do we continue to live?')
time.sleep(1) # We're the only driver; let's pause to think.
while self.schedule and self.schedule[0][0] < time.time():
with self.lock:
(t, name, args, kwargs) = heapq.heappop(self.schedule)
f = self.events.pop(name)
try:
f(*args, **kwargs)
except Exception:
log.exception('Uncaught exception in scheduled function:')
schedule = Schedule()
addEvent = schedule.addEvent
removeEvent = schedule.removeEvent
rescheduleEvent = schedule.rescheduleEvent
addPeriodicEvent = schedule.addPeriodicEvent
removePeriodicEvent = removeEvent
run = schedule.run
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