148 lines
4.7 KiB
Python
148 lines
4.7 KiB
Python
# Copyright 2010 United States Government as represented by the
|
|
# Administrator of the National Aeronautics and Space Administration.
|
|
# Copyright 2011 Justin Santa Barbara
|
|
# All Rights Reserved.
|
|
#
|
|
# 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
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# 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.
|
|
|
|
import logging
|
|
import sys
|
|
import time
|
|
|
|
from eventlet import event
|
|
from eventlet import greenthread
|
|
|
|
from magnum.openstack.common._i18n import _LE, _LW
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
|
|
# NOTE(zyluo): This lambda function was declared to avoid mocking collisions
|
|
# with time.time() called in the standard logging module
|
|
# during unittests.
|
|
_ts = lambda: time.time()
|
|
|
|
|
|
class LoopingCallDone(Exception):
|
|
"""Exception to break out and stop a LoopingCallBase.
|
|
|
|
The poll-function passed to LoopingCallBase can raise this exception to
|
|
break out of the loop normally. This is somewhat analogous to
|
|
StopIteration.
|
|
|
|
An optional return-value can be included as the argument to the exception;
|
|
this return-value will be returned by LoopingCallBase.wait()
|
|
|
|
"""
|
|
|
|
def __init__(self, retvalue=True):
|
|
""":param retvalue: Value that LoopingCallBase.wait() should return."""
|
|
self.retvalue = retvalue
|
|
|
|
|
|
class LoopingCallBase(object):
|
|
def __init__(self, f=None, *args, **kw):
|
|
self.args = args
|
|
self.kw = kw
|
|
self.f = f
|
|
self._running = False
|
|
self.done = None
|
|
|
|
def stop(self):
|
|
self._running = False
|
|
|
|
def wait(self):
|
|
return self.done.wait()
|
|
|
|
|
|
class FixedIntervalLoopingCall(LoopingCallBase):
|
|
"""A fixed interval looping call."""
|
|
|
|
def start(self, interval, initial_delay=None):
|
|
self._running = True
|
|
done = event.Event()
|
|
|
|
def _inner():
|
|
if initial_delay:
|
|
greenthread.sleep(initial_delay)
|
|
|
|
try:
|
|
while self._running:
|
|
start = _ts()
|
|
self.f(*self.args, **self.kw)
|
|
end = _ts()
|
|
if not self._running:
|
|
break
|
|
delay = end - start - interval
|
|
if delay > 0:
|
|
LOG.warning(_LW('task %(func_name)r run outlasted '
|
|
'interval by %(delay).2f sec'),
|
|
{'func_name': self.f, 'delay': delay})
|
|
greenthread.sleep(-delay if delay < 0 else 0)
|
|
except LoopingCallDone as e:
|
|
self.stop()
|
|
done.send(e.retvalue)
|
|
except Exception:
|
|
LOG.exception(_LE('in fixed duration looping call'))
|
|
done.send_exception(*sys.exc_info())
|
|
return
|
|
else:
|
|
done.send(True)
|
|
|
|
self.done = done
|
|
|
|
greenthread.spawn_n(_inner)
|
|
return self.done
|
|
|
|
|
|
class DynamicLoopingCall(LoopingCallBase):
|
|
"""A looping call which sleeps until the next known event.
|
|
|
|
The function called should return how long to sleep for before being
|
|
called again.
|
|
"""
|
|
|
|
def start(self, initial_delay=None, periodic_interval_max=None):
|
|
self._running = True
|
|
done = event.Event()
|
|
|
|
def _inner():
|
|
if initial_delay:
|
|
greenthread.sleep(initial_delay)
|
|
|
|
try:
|
|
while self._running:
|
|
idle = self.f(*self.args, **self.kw)
|
|
if not self._running:
|
|
break
|
|
|
|
if periodic_interval_max is not None:
|
|
idle = min(idle, periodic_interval_max)
|
|
LOG.debug('Dynamic looping call %(func_name)r sleeping '
|
|
'for %(idle).02f seconds',
|
|
{'func_name': self.f, 'idle': idle})
|
|
greenthread.sleep(idle)
|
|
except LoopingCallDone as e:
|
|
self.stop()
|
|
done.send(e.retvalue)
|
|
except Exception:
|
|
LOG.exception(_LE('in dynamic looping call'))
|
|
done.send_exception(*sys.exc_info())
|
|
return
|
|
else:
|
|
done.send(True)
|
|
|
|
self.done = done
|
|
|
|
greenthread.spawn(_inner)
|
|
return self.done
|