#!/usr/bin/env python
# ###########################################################################
#
# This file is part of Taurus
#
# http://taurus-scada.org
#
# Copyright 2011 CELLS / ALBA Synchrotron, Bellaterra, Spain
#
# Taurus is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Taurus is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Taurus. If not, see <http://www.gnu.org/licenses/>.
#
# ###########################################################################
"""This module contains a :class:`Timer` class
"""
__all__ = ["Timer"]
__docformat__ = "restructuredtext"
import time
import threading
from .log import Logger
[docs]class Timer(Logger):
"""
Timer Object.
Interval in seconds (The argument may be a floating point number for
subsecond precision).
If strict_timing is True, the timer will try to compensate for drifting
due to the time it takes to execute function in each loop.
"""
def __init__(
self, interval, function, parent, strict_timing=True, *args, **kwargs
):
Logger.__init__(self, "Timer on " + function.__name__, parent)
self.__lock = threading.Lock()
self.__interval = interval
self.__function = function
self.__args = args
self.__kwargs = kwargs
self.__loop = False
self.__alive = False
self.__start_nb = 0
self.__thread = None
self.__strict_timing = strict_timing
[docs] def start(self):
"""Start Timer Object"""
with self.__lock:
if not self.__alive:
self.debug("Timer::start()")
self.__loop = True
self.__alive = True
self.__start_nb += 1
thread_name = "TimerLoop %d" % self.__start_nb
self.__thread = threading.Thread(
target=self.__run, name=thread_name
)
self.__thread.setDaemon(True)
self.__thread.start()
[docs] def stop(self, sync=False):
"""Stop Timer Object"""
self.debug("Timer::stop()")
with self.__lock:
self.__loop = False
if sync and self.__thread is not None:
self.__thread.join()
def __run(self):
"""Private Thread Function"""
self.debug("Timer thread starting")
next_time = time.time() + self.__interval
while self.__loop:
self.__function(*self.__args, **self.__kwargs)
nap = self.__interval
if self.__strict_timing:
curr_time = time.time()
nap = max(0, next_time - curr_time)
if curr_time > next_time:
self.warning(
"loop function took more than loop interval (%ss)",
self.__interval,
)
next_time += self.__interval
time.sleep(nap)
self.__alive = False
self.debug("Timer thread ending")