lbry-sdk/lbrynet/core/call_later_manager.py
2018-04-19 15:47:19 -04:00

89 lines
2.6 KiB
Python

import logging
log = logging.getLogger()
MIN_DELAY = 0.0
MAX_DELAY = 0.01
DELAY_INCREMENT = 0.0001
QUEUE_SIZE_THRESHOLD = 100
class CallLaterManager(object):
_callLater = None
_pendingCallLaters = []
_delay = MIN_DELAY
@classmethod
def get_min_delay(cls):
cls._pendingCallLaters = [cl for cl in cls._pendingCallLaters if cl.active()]
queue_size = len(cls._pendingCallLaters)
if queue_size > QUEUE_SIZE_THRESHOLD:
cls._delay = min((cls._delay + DELAY_INCREMENT), MAX_DELAY)
else:
cls._delay = max((cls._delay - 2.0 * DELAY_INCREMENT), MIN_DELAY)
return cls._delay
@classmethod
def _cancel(cls, call_later):
"""
:param call_later: DelayedCall
:return: (callable) canceller function
"""
def cancel(reason=None):
"""
:param reason: reason for cancellation, this is returned after cancelling the DelayedCall
:return: reason
"""
if call_later.active():
call_later.cancel()
cls._pendingCallLaters.remove(call_later)
return reason
return cancel
@classmethod
def stop(cls):
"""
Cancel any callLaters that are still running
"""
from twisted.internet import defer
while cls._pendingCallLaters:
canceller = cls._cancel(cls._pendingCallLaters[0])
try:
canceller()
except (defer.CancelledError, defer.AlreadyCalledError):
pass
@classmethod
def call_later(cls, when, what, *args, **kwargs):
"""
Schedule a call later and get a canceller callback function
:param when: (float) delay in seconds
:param what: (callable)
:param args: (*tuple) args to be passed to the callable
:param kwargs: (**dict) kwargs to be passed to the callable
:return: (tuple) twisted.internet.base.DelayedCall object, canceller function
"""
call_later = cls._callLater(when, what, *args, **kwargs)
canceller = cls._cancel(call_later)
cls._pendingCallLaters.append(call_later)
return call_later, canceller
@classmethod
def call_soon(cls, what, *args, **kwargs):
delay = cls.get_min_delay()
return cls.call_later(delay, what, *args, **kwargs)
@classmethod
def setup(cls, callLater):
"""
Setup the callLater function to use, supports the real reactor as well as task.Clock
:param callLater: (IReactorTime.callLater)
"""
cls._callLater = callLater