services/nodemanager/arvnodeman/timedcallback.py

   1 #!/usr/bin/env python
   2 # Copyright (C) The Arvados Authors. All rights reserved.
   3 #
   4 # SPDX-License-Identifier: AGPL-3.0
   5
   6 from __future__ import absolute_import, print_function
   7
   8 import heapq
   9 import time
  10
  11 import pykka
  12
  13 from .config import actor_class
  14
  15 class TimedCallBackActor(actor_class):
  16     """Send messages to other actors on a schedule.
  17
  18     Other actors can call the schedule() method to schedule delivery of a
  19     message at a later time.  This actor runs the necessary event loop for
  20     delivery.
  21     """
  22     def __init__(self, max_sleep=1):
  23         super(TimedCallBackActor, self).__init__()
  24         self._proxy = self.actor_ref.tell_proxy()
  25         self.messages = []
  26         self.max_sleep = max_sleep
  27
  28     def schedule(self, delivery_time, receiver, *args, **kwargs):
  29         if not self.messages:
  30             self._proxy.deliver()
  31         heapq.heappush(self.messages, (delivery_time, receiver, args, kwargs))
  32
  33     def deliver(self):
  34         if not self.messages:
  35             return
  36         til_next = self.messages[0][0] - time.time()
  37         if til_next <= 0:
  38             t, receiver, args, kwargs = heapq.heappop(self.messages)
  39             try:
  40                 receiver(*args, **kwargs)
  41             except pykka.ActorDeadError:
  42                 pass
  43         else:
  44             time.sleep(min(til_next, self.max_sleep))
  45         self._proxy.deliver()