Files
deb-python-taskflow/taskflow/utils/eventlet_utils.py
Joshua Harlow db15db8186 Fix up python 3.3 incompatabilities
Make the python 3.3 testing work by selectively
disabling & including eventlet, switch to testtools
and testrepository which has 2.6, 2.7, 3.2+ unified
testing support so that we can correctly run our
tests in all supported python versions.

Closes-Bug: #1251660
Co-authored-by: Alexander Gorodnev <agorodnev@griddynamics.com>
Change-Id: I23b6f04387cfd3bf6b5a044edffa446ca897ce3a
2013-11-21 18:38:44 +04:00

132 lines
4.5 KiB
Python

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright (C) 2013 Yahoo! Inc. 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 threading
try:
from eventlet.green import threading as gthreading
from eventlet import greenpool
from eventlet import patcher
from eventlet import queue
EVENTLET_AVAILABLE = True
except ImportError:
EVENTLET_AVAILABLE = False
from concurrent import futures
from taskflow.utils import lock_utils
LOG = logging.getLogger(__name__)
# NOTE(harlowja): this object signals to threads that they should stop
# working and rest in peace.
_TOMBSTONE = object()
class _WorkItem(object):
def __init__(self, future, fn, args, kwargs):
self.future = future
self.fn = fn
self.args = args
self.kwargs = kwargs
def run(self):
if not self.future.set_running_or_notify_cancel():
return
try:
result = self.fn(*self.args, **self.kwargs)
except BaseException as e:
self.future.set_exception(e)
else:
self.future.set_result(result)
class _Worker(object):
def __init__(self, executor, work_queue, worker_id):
self.executor = executor
self.work_queue = work_queue
self.worker_id = worker_id
def __call__(self):
try:
while True:
work = self.work_queue.get(block=True)
if work is _TOMBSTONE:
# NOTE(harlowja): give notice to other workers (this is
# basically a chain of tombstone calls that will cause all
# the workers on the queue to eventually shut-down).
self.work_queue.put(_TOMBSTONE)
break
else:
work.run()
except BaseException:
LOG.critical("Exception in worker %s of '%s'",
self.worker_id, self.executor, exc_info=True)
class _GreenFuture(futures.Future):
def __init__(self):
super(_GreenFuture, self).__init__()
# NOTE(harlowja): replace the built-in condition with a greenthread
# compatible one so that when getting the result of this future the
# functions will correctly yield to eventlet. If this is not done then
# waiting on the future never actually causes the greenthreads to run
# and thus you wait for infinity.
if not patcher.is_monkey_patched('threading'):
self._condition = gthreading.Condition()
class GreenExecutor(futures.Executor):
"""A greenthread backed executor."""
def __init__(self, max_workers=1000):
assert EVENTLET_AVAILABLE, 'eventlet is needed to use GreenExecutor'
assert int(max_workers) > 0, 'Max workers must be greater than zero'
self._max_workers = int(max_workers)
self._pool = greenpool.GreenPool(self._max_workers)
self._work_queue = queue.LightQueue()
self._shutdown_lock = threading.RLock()
self._shutdown = False
@lock_utils.locked(lock='_shutdown_lock')
def submit(self, fn, *args, **kwargs):
if self._shutdown:
raise RuntimeError('cannot schedule new futures after shutdown')
f = _GreenFuture()
w = _WorkItem(f, fn, args, kwargs)
self._work_queue.put(w)
# Spin up any new workers (since they are spun up on demand and
# not at executor initialization).
self._spin_up()
return f
def _spin_up(self):
cur_am = (self._pool.running() + self._pool.waiting())
if cur_am < self._max_workers and cur_am < self._work_queue.qsize():
# Spin up a new worker to do the work as we are behind.
worker = _Worker(self, self._work_queue, cur_am + 1)
self._pool.spawn(worker)
def shutdown(self, wait=True):
with self._shutdown_lock:
self._shutdown = True
self._work_queue.put(_TOMBSTONE)
if wait:
self._pool.waitall()