nodepool/nodepool/task_manager.py
James E. Blair df5049f2e2 Don't retry forever when a provider is stopped
When we stop a provider, it does not accept any new tasks.  In that
case, we should raise a specific exception so that loops that retry
for a very long time can exit early since the "error" will never
recover.

Change-Id: I7387849ffdb96c487bae4c31ca7cbdd07b8afd8a
2014-09-03 22:15:54 +00:00

104 lines
2.9 KiB
Python

#!/usr/bin/env python
# Copyright (C) 2011-2013 OpenStack Foundation
#
# 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 sys
import threading
from six.moves import queue as Queue
import logging
import time
class ManagerStoppedException(Exception):
pass
class Task(object):
def __init__(self, **kw):
self._wait_event = threading.Event()
self._exception = None
self._traceback = None
self._result = None
self.args = kw
def done(self, result):
self._result = result
self._wait_event.set()
def exception(self, e, tb):
self._exception = e
self._traceback = tb
self._wait_event.set()
def wait(self):
self._wait_event.wait()
if self._exception:
raise self._exception, None, self._traceback
return self._result
def run(self, client):
try:
self.done(self.main(client))
except Exception as e:
self.exception(e, sys.exc_info()[2])
class TaskManager(threading.Thread):
log = logging.getLogger("nodepool.TaskManager")
def __init__(self, client, name, rate):
super(TaskManager, self).__init__(name=name)
self.daemon = True
self.queue = Queue.Queue()
self._running = True
self.name = name
self.rate = float(rate)
self._client = None
def stop(self):
self._running = False
self.queue.put(None)
def run(self):
last_ts = 0
while True:
task = self.queue.get()
if not task:
if not self._running:
break
continue
while True:
delta = time.time() - last_ts
if delta >= self.rate:
break
time.sleep(self.rate - delta)
self.log.debug("Manager %s running task %s (queue: %s)" %
(self.name, task, self.queue.qsize()))
start = time.time()
task.run(self._client)
last_ts = time.time()
self.log.debug("Manager %s ran task %s in %ss" %
(self.name, task, (last_ts - start)))
self.queue.task_done()
def submitTask(self, task):
if not self._running:
raise ManagerStoppedException(
"Manager %s is no longer running" % self.name)
self.queue.put(task)
return task.wait()