openstack
/
deb-python-concurrent.futures
Code Issues Proposed changes

Redid the port from scratch using Python 3.2.5 as base

This commit is contained in:
Alex Gr?nholm 2013-06-24 01:20:47 +03:00
parent c0d77fd5bd
commit ecc0a67bb4
8 changed files with 515 additions and 598 deletions
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11
.hgignore Normal file
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@ -0,0 +1,11 @@
syntax: glob
*.egg-info
syntax: regexp
^\.tox$
syntax: regexp
^\.project$
syntax: regexp
^\.pydevproject$
syntax: regexp
^dist$

6
CHANGES
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@ -1,3 +1,9 @@
2.1.4
=====
- Ported the library again from Python 3.2.5 to get the latest bug fixes
2.1.3
=====

12
concurrent/futures/_base.py
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@ -2,7 +2,6 @@
# Licensed to PSF under a Contributor Agreement.
from __future__ import with_statement
import functools
import logging
import threading
import time
@ -46,8 +45,6 @@ _STATE_TO_DESCRIPTION_MAP = {
# Logger for internal use by the futures package.
LOGGER = logging.getLogger("concurrent.futures")
STDERR_HANDLER = logging.StreamHandler()
LOGGER.addHandler(STDERR_HANDLER)
class Error(Exception):
"""Base class for all future-related exceptions."""
@ -119,11 +116,14 @@ class _AllCompletedWaiter(_Waiter):
def __init__(self, num_pending_calls, stop_on_exception):
self.num_pending_calls = num_pending_calls
self.stop_on_exception = stop_on_exception
self.lock = threading.Lock()
super(_AllCompletedWaiter, self).__init__()
def _decrement_pending_calls(self):
if self.num_pending_calls == len(self.finished_futures):
self.event.set()
with self.lock:
self.num_pending_calls -= 1
if not self.num_pending_calls:
self.event.set()
def add_result(self, future):
super(_AllCompletedWaiter, self).add_result(future)
@ -523,7 +523,7 @@ class Executor(object):
"""Returns a iterator equivalent to map(fn, iter).
Args:
fn: A callable that will take take as many arguments as there are
fn: A callable that will take as many arguments as there are
passed iterables.
timeout: The maximum number of seconds to wait. If None, then there
is no limit on the wait time.

170
concurrent/futures/process.py
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@ -73,28 +73,17 @@ __author__ = 'Brian Quinlan (brian@sweetapp.com)'
# workers to exit when their work queues are empty and then waits until the
# threads/processes finish.
_thread_references = set()
_threads_queues = weakref.WeakKeyDictionary()
_shutdown = False
def _python_exit():
global _shutdown
_shutdown = True
for thread_reference in _thread_references:
thread = thread_reference()
if thread is not None:
thread.join()
def _remove_dead_thread_references():
"""Remove inactive threads from _thread_references.
Should be called periodically to prevent memory leaks in scenarios such as:
>>> while True:
>>> ... t = ThreadPoolExecutor(max_workers=5)
>>> ... t.map(int, ['1', '2', '3', '4', '5'])
"""
for thread_reference in set(_thread_references):
if thread_reference() is None:
_thread_references.discard(thread_reference)
items = list(_threads_queues.items())
for t, q in items:
q.put(None)
for t, q in items:
t.join()
# Controls how many more calls than processes will be queued in the call queue.
# A smaller number will mean that processes spend more time idle waiting for
@ -122,10 +111,10 @@ class _CallItem(object):
self.args = args
self.kwargs = kwargs
def _process_worker(call_queue, result_queue, shutdown):
def _process_worker(call_queue, result_queue):
"""Evaluates calls from call_queue and places the results in result_queue.
This worker is run in a seperate process.
This worker is run in a separate process.
Args:
call_queue: A multiprocessing.Queue of _CallItems that will be read and
@ -136,21 +125,20 @@ def _process_worker(call_queue, result_queue, shutdown):
worker that it should exit when call_queue is empty.
"""
while True:
call_item = call_queue.get(block=True)
if call_item is None:
# Wake up queue management thread
result_queue.put(None)
return
try:
call_item = call_queue.get(block=True, timeout=0.1)
except queue.Empty:
if shutdown.is_set():
return
r = call_item.fn(*call_item.args, **call_item.kwargs)
except BaseException:
e = sys.exc_info()[1]
result_queue.put(_ResultItem(call_item.work_id,
exception=e))
else:
try:
r = call_item.fn(*call_item.args, **call_item.kwargs)
except BaseException:
e = sys.exc_info()[1]
result_queue.put(_ResultItem(call_item.work_id,
exception=e))
else:
result_queue.put(_ResultItem(call_item.work_id,
result=r))
result_queue.put(_ResultItem(call_item.work_id,
result=r))
def _add_call_item_to_queue(pending_work_items,
work_ids,
@ -189,13 +177,12 @@ def _add_call_item_to_queue(pending_work_items,
del pending_work_items[work_id]
continue
def _queue_manangement_worker(executor_reference,
processes,
pending_work_items,
work_ids_queue,
call_queue,
result_queue,
shutdown_process_event):
def _queue_management_worker(executor_reference,
processes,
pending_work_items,
work_ids_queue,
call_queue,
result_queue):
"""Manages the communication between this process and the worker processes.
This function is run in a local thread.
@ -213,37 +200,19 @@ def _queue_manangement_worker(executor_reference,
derived from _WorkItems for processing by the process workers.
result_queue: A multiprocessing.Queue of _ResultItems generated by the
process workers.
shutdown_process_event: A multiprocessing.Event used to signal the
process workers that they should exit when their work queue is
empty.
"""
nb_shutdown_processes = [0]
def shutdown_one_process():
"""Tell a worker to terminate, which will in turn wake us again"""
call_queue.put(None)
nb_shutdown_processes[0] += 1
while True:
_add_call_item_to_queue(pending_work_items,
work_ids_queue,
call_queue)
try:
result_item = result_queue.get(block=True, timeout=0.1)
except queue.Empty:
executor = executor_reference()
# No more work items can be added if:
# - The interpreter is shutting down OR
# - The executor that owns this worker has been collected OR
# - The executor that owns this worker has been shutdown.
if _shutdown or executor is None or executor._shutdown_thread:
# Since no new work items can be added, it is safe to shutdown
# this thread if there are no pending work items.
if not pending_work_items:
shutdown_process_event.set()
# If .join() is not called on the created processes then
# some multiprocessing.Queue methods may deadlock on Mac OS
# X.
for p in processes:
p.join()
return
del executor
else:
result_item = result_queue.get(block=True)
if result_item is not None:
work_item = pending_work_items[result_item.work_id]
del pending_work_items[result_item.work_id]
@ -251,6 +220,51 @@ def _queue_manangement_worker(executor_reference,
work_item.future.set_exception(result_item.exception)
else:
work_item.future.set_result(result_item.result)
# Check whether we should start shutting down.
executor = executor_reference()
# No more work items can be added if:
# - The interpreter is shutting down OR
# - The executor that owns this worker has been collected OR
# - The executor that owns this worker has been shutdown.
if _shutdown or executor is None or executor._shutdown_thread:
# Since no new work items can be added, it is safe to shutdown
# this thread if there are no pending work items.
if not pending_work_items:
while nb_shutdown_processes[0] < len(processes):
shutdown_one_process()
# If .join() is not called on the created processes then
# some multiprocessing.Queue methods may deadlock on Mac OS
# X.
for p in processes:
p.join()
call_queue.close()
return
del executor
_system_limits_checked = False
_system_limited = None
def _check_system_limits():
global _system_limits_checked, _system_limited
if _system_limits_checked:
if _system_limited:
raise NotImplementedError(_system_limited)
_system_limits_checked = True
try:
import os
nsems_max = os.sysconf("SC_SEM_NSEMS_MAX")
except (AttributeError, ValueError):
# sysconf not available or setting not available
return
if nsems_max == -1:
# indetermine limit, assume that limit is determined
# by available memory only
return
if nsems_max >= 256:
# minimum number of semaphores available
# according to POSIX
return
_system_limited = "system provides too few semaphores (%d available, 256 necessary)" % nsems_max
raise NotImplementedError(_system_limited)
class ProcessPoolExecutor(_base.Executor):
def __init__(self, max_workers=None):
@ -261,7 +275,7 @@ class ProcessPoolExecutor(_base.Executor):
execute the given calls. If None or not given then as many
worker processes will be created as the machine has processors.
"""
_remove_dead_thread_references()
_check_system_limits()
if max_workers is None:
self._max_workers = multiprocessing.cpu_count()
@ -280,33 +294,34 @@ class ProcessPoolExecutor(_base.Executor):
# Shutdown is a two-step process.
self._shutdown_thread = False
self._shutdown_process_event = multiprocessing.Event()
self._shutdown_lock = threading.Lock()
self._queue_count = 0
self._pending_work_items = {}
def _start_queue_management_thread(self):
# When the executor gets lost, the weakref callback will wake up
# the queue management thread.
def weakref_cb(_, q=self._result_queue):
q.put(None)
if self._queue_management_thread is None:
self._queue_management_thread = threading.Thread(
target=_queue_manangement_worker,
args=(weakref.ref(self),
target=_queue_management_worker,
args=(weakref.ref(self, weakref_cb),
self._processes,
self._pending_work_items,
self._work_ids,
self._call_queue,
self._result_queue,
self._shutdown_process_event))
self._result_queue))
self._queue_management_thread.daemon = True
self._queue_management_thread.start()
_thread_references.add(weakref.ref(self._queue_management_thread))
_threads_queues[self._queue_management_thread] = self._result_queue
def _adjust_process_count(self):
for _ in range(len(self._processes), self._max_workers):
p = multiprocessing.Process(
target=_process_worker,
args=(self._call_queue,
self._result_queue,
self._shutdown_process_event))
self._result_queue))
p.start()
self._processes.add(p)
@ -321,6 +336,8 @@ class ProcessPoolExecutor(_base.Executor):
self._pending_work_items[self._queue_count] = w
self._work_ids.put(self._queue_count)
self._queue_count += 1
# Wake up queue management thread
self._result_queue.put(None)
self._start_queue_management_thread()
self._adjust_process_count()
@ -330,15 +347,16 @@ class ProcessPoolExecutor(_base.Executor):
def shutdown(self, wait=True):
with self._shutdown_lock:
self._shutdown_thread = True
if wait:
if self._queue_management_thread:
if self._queue_management_thread:
# Wake up queue management thread
self._result_queue.put(None)
if wait:
self._queue_management_thread.join()
# To reduce the risk of openning too many files, remove references to
# objects that use file descriptors.
self._queue_management_thread = None
self._call_queue = None
self._result_queue = None
self._shutdown_process_event = None
self._processes = None
shutdown.__doc__ = _base.Executor.shutdown.__doc__

60
concurrent/futures/thread.py
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@ -32,28 +32,17 @@ __author__ = 'Brian Quinlan (brian@sweetapp.com)'
# workers to exit when their work queues are empty and then waits until the
# threads finish.
_thread_references = set()
_threads_queues = weakref.WeakKeyDictionary()
_shutdown = False
def _python_exit():
global _shutdown
_shutdown = True
for thread_reference in _thread_references:
thread = thread_reference()
if thread is not None:
thread.join()
def _remove_dead_thread_references():
"""Remove inactive threads from _thread_references.
Should be called periodically to prevent memory leaks in scenarios such as:
>>> while True:
... t = ThreadPoolExecutor(max_workers=5)
... t.map(int, ['1', '2', '3', '4', '5'])
"""
for thread_reference in set(_thread_references):
if thread_reference() is None:
_thread_references.discard(thread_reference)
items = list(_threads_queues.items())
for t, q in items:
q.put(None)
for t, q in items:
t.join()
atexit.register(_python_exit)
@ -79,19 +68,20 @@ class _WorkItem(object):
def _worker(executor_reference, work_queue):
try:
while True:
try:
work_item = work_queue.get(block=True, timeout=0.1)
except queue.Empty:
executor = executor_reference()
# Exit if:
# - The interpreter is shutting down OR
# - The executor that owns the worker has been collected OR
# - The executor that owns the worker has been shutdown.
if _shutdown or executor is None or executor._shutdown:
return
del executor
else:
work_item = work_queue.get(block=True)
if work_item is not None:
work_item.run()
continue
executor = executor_reference()
# Exit if:
# - The interpreter is shutting down OR
# - The executor that owns the worker has been collected OR
# - The executor that owns the worker has been shutdown.
if _shutdown or executor is None or executor._shutdown:
# Notice other workers
work_queue.put(None)
return
del executor
except BaseException:
_base.LOGGER.critical('Exception in worker', exc_info=True)
@ -103,8 +93,6 @@ class ThreadPoolExecutor(_base.Executor):
max_workers: The maximum number of threads that can be used to
execute the given calls.
"""
_remove_dead_thread_references()
self._max_workers = max_workers
self._work_queue = queue.Queue()
self._threads = set()
@ -125,19 +113,25 @@ class ThreadPoolExecutor(_base.Executor):
submit.__doc__ = _base.Executor.submit.__doc__
def _adjust_thread_count(self):
# When the executor gets lost, the weakref callback will wake up
# the worker threads.
def weakref_cb(_, q=self._work_queue):
q.put(None)
# TODO(bquinlan): Should avoid creating new threads if there are more
# idle threads than items in the work queue.
if len(self._threads) < self._max_workers:
t = threading.Thread(target=_worker,
args=(weakref.ref(self), self._work_queue))
args=(weakref.ref(self, weakref_cb),
self._work_queue))
t.daemon = True
t.start()
self._threads.add(t)
_thread_references.add(weakref.ref(t))
_threads_queues[t] = self._work_queue
def shutdown(self, wait=True):
with self._shutdown_lock:
self._shutdown = True
self._work_queue.put(None)
if wait:
for t in self._threads:
t.join()

2
setup.py
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@ -11,7 +11,7 @@ except ImportError:
from distutils.core import setup
setup(name='futures',
version='2.1.3',
version='2.1.4',
description='Backport of the concurrent.futures package from Python 3.2',
author='Brian Quinlan',
author_email='brian@sweetapp.com',

843
test_futures.py
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9
tox.ini
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@ -1,11 +1,8 @@
[tox]
envlist = py25,py26,py27,py31
envlist = py26,py27,py31
[testenv]
commands={envpython} test_futures.py []
#[testenv:py24]
#deps=multiprocessing
#
#[testenv:py25]
#deps=multiprocessing
[testenv:py26]
deps=unittest2