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# -*- coding: utf-8 -*-
# Copyright: (c) 2011 by the Serge S. Koval, see AUTHORS for more details.
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
This module implements customized PeriodicCallback from tornado with
support of the sliding window.
import time
import logging
class Callback(object):
"""Custom implementation of the Tornado.Callback with support
of callback timeout delays.
def __init__(self, callback, callback_time, io_loop):
Callback function
Callback timeout value (in milliseconds)
io_loop instance
self.callback = callback
self.callback_time = callback_time
self.io_loop = io_loop
self._running = False
self.next_run = None
def calculate_next_run(self):
"""Caltulate next scheduled run"""
return time.time() + self.callback_time / 1000.0
def start(self, timeout=None):
"""Start callbacks"""
self._running = True
if timeout is None:
timeout = self.calculate_next_run()
self.io_loop.add_timeout(timeout, self._run)
def stop(self):
"""Stop callbacks"""
self._running = False
def delay(self):
"""Delay callback"""
self.next_run = self.calculate_next_run()
def _run(self):
if not self._running:
# Support for shifting callback window
if self.next_run is not None and time.time() < self.next_run:
self.next_run = None
next_call = None
next_call = self.callback()
except (KeyboardInterrupt, SystemExit):
logging.error("Error in periodic callback", exc_info=True)
if self._running:
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