forked from celery/celery
/
timer2.py
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timer2.py
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"""timer2 - Scheduler for Python functions."""
from __future__ import generators
import atexit
import heapq
import sys
import traceback
import warnings
from itertools import count
from threading import Thread, Event
from time import time, sleep, mktime
from datetime import datetime, timedelta
VERSION = (0, 1, 0)
__version__ = ".".join(map(str, VERSION))
__author__ = "Ask Solem"
__contact__ = "ask@celeryproject.org"
__homepage__ = "http://github.com/ask/timer/"
__docformat__ = "restructuredtext"
DEFAULT_MAX_INTERVAL = 2
class TimedFunctionFailed(UserWarning):
pass
class Entry(object):
cancelled = False
def __init__(self, fun, args=None, kwargs=None):
self.fun = fun
self.args = args or []
self.kwargs = kwargs or {}
self.tref = self
def __call__(self):
return self.fun(*self.args, **self.kwargs)
def cancel(self):
self.tref.cancelled = True
def to_timestamp(d):
if isinstance(d, datetime):
return mktime(d.timetuple())
return d
class Schedule(object):
"""ETA scheduler."""
on_error = None
def __init__(self, max_interval=DEFAULT_MAX_INTERVAL, on_error=None):
self.max_interval = float(max_interval)
self.on_error = on_error or self.on_error
self._queue = []
def handle_error(self, exc_info):
if self.on_error:
self.on_error(exc_info)
return True
def enter(self, entry, eta=None, priority=0):
"""Enter function into the scheduler.
:param entry: Item to enter.
:keyword eta: Scheduled time as a :class:`datetime.datetime` object.
:keyword priority: Unused.
"""
try:
eta = to_timestamp(eta)
except OverflowError:
self.handle_error(sys.exc_info())
return
if eta is None:
# schedule now.
eta = time()
heapq.heappush(self._queue, (eta, priority, entry))
return entry
def __iter__(self):
"""The iterator yields the time to sleep for between runs."""
# localize variable access
nowfun = time
pop = heapq.heappop
while 1:
if self._queue:
eta, priority, entry = verify = self._queue[0]
now = nowfun()
if now < eta:
yield min(eta - now, self.max_interval)
else:
event = pop(self._queue)
if event is verify:
if not entry.cancelled:
try:
entry()
except Exception, exc:
typ, val, tb = einfo = sys.exc_info()
if not self.handle_error(einfo):
warnings.warn(repr(exc),
TimedFunctionFailed)
traceback.print_exception(typ, val, tb)
continue
else:
heapq.heappush(self._queue, event)
yield None
def empty(self):
"""Is the schedule empty?"""
return not self._queue
def clear(self):
self._queue = []
def info(self):
return ({"eta": eta, "priority": priority, "item": item}
for eta, priority, item in self.queue)
@property
def queue(self):
events = list(self._queue)
return map(heapq.heappop, [events] * len(events))
class Timer(Thread):
Entry = Entry
precision = 0.3
running = False
on_tick = None
_timer_count = count(1).next
def __init__(self, schedule=None, precision=None, on_error=None,
on_tick=None):
if precision is not None:
self.precision = precision
self.schedule = schedule or Schedule(on_error=on_error)
self.on_tick = on_tick or self.on_tick
Thread.__init__(self)
self._shutdown = Event()
self._stopped = Event()
self.setDaemon(True)
self.setName("Timer-%s" % (self._timer_count(), ))
def run(self):
self.running = True
scheduler = iter(self.schedule)
while not self._shutdown.isSet():
delay = scheduler.next() or self.precision
if self.on_tick:
self.on_tick(delay)
if sleep is None:
break
sleep(delay)
try:
self._stopped.set()
except TypeError: # pragma: no cover
# we lost the race at interpreter shutdown,
# so gc collected built-in modules.
pass
def stop(self):
if self.running:
self._shutdown.set()
self._stopped.wait()
self.join(1e100)
self.running = False
def enter(self, entry, eta, priority=None):
if not self.running:
self.start()
return self.schedule.enter(entry, eta, priority)
def apply_at(self, eta, fun, args=(), kwargs={}, priority=0):
return self.enter(self.Entry(fun, args, kwargs), eta, priority)
def enter_after(self, msecs, entry, priority=0):
eta = datetime.now() + timedelta(seconds=msecs / 1000.0)
return self.enter(entry, eta, priority)
def apply_after(self, msecs, fun, args=(), kwargs={}, priority=0):
return self.enter_after(msecs, Entry(fun, args, kwargs), priority)
def apply_interval(self, msecs, fun, args=(), kwargs={}, priority=0):
tref = Entry(fun, args, kwargs)
def _reschedules(*args, **kwargs):
try:
return fun(*args, **kwargs)
finally:
self.enter_after(msecs, tref, priority)
tref.fun = _reschedules
return self.enter_after(msecs, tref, priority)
def exit_after(self, msecs, priority=10):
self.apply_after(msecs, sys.exit, priority)
def cancel(self, tref):
tref.cancel()
def clear(self):
self.schedule.clear()
def empty(self):
return self.schedule.empty()
@property
def queue(self):
return self.schedule.queue
_default_timer = Timer()
apply_after = _default_timer.apply_after
apply_at = _default_timer.apply_at
apply_interval = _default_timer.apply_interval
enter_after = _default_timer.enter_after
enter = _default_timer.enter
exit_after = _default_timer.exit_after
cancel = _default_timer.cancel
clear = _default_timer.clear
atexit.register(_default_timer.stop)