openstack/deb-python-eventlet
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Ryan Williams
2010-02-20 15:15:06 -05:00
parent dcc7b59876 826b55c1ee
commit 2fd4e9f3b5
17 changed files with 222 additions and 89 deletions
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4
LICENSE
View File

@@ -1,8 +1,8 @@
Unless otherwise noted, the files in Eventlet are under the following MIT license:
Copyright (c) 2005-2006, Bob Ippolito
Copyright (c) 2007-2009, Linden Research, Inc.
Copyright (c) 2008-2009, Individual Contributors (see AUTHORS)
Copyright (c) 2007-2010, Linden Research, Inc.
Copyright (c) 2008-2010, Eventlet Contributors (see AUTHORS)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal

9
doc/basic_usage.rst
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@@ -50,4 +50,13 @@ Though Eventlet has many modules, much of the most-used stuff is accessible simp
Timeout objects are context managers, and so can be used in with statements.
See :class:`Timeout <eventlet.timeout.Timeout>` for more details.
.. function:: eventlet.import_patched(modulename, *additional_modules, **kw_additional_modules)
Imports a module in a way that ensures that the module uses "green" versions of the standard library modules, so that everything works nonblockingly. The only required argument is the name of the module to be imported. For more information see :ref:`import-green`.
.. function:: eventlet.monkey_patch(all=True, os=False, select=False, socket=False, thread=False, time=False)
Globally patches certain system modules to be greenthread-friendly. The keyword arguments afford some control over which modules are patched. If *all* is True, then all modules are patched regardless of the other arguments. If it's False, then the rest of the keyword arguments control patching of specific subsections of the standard library. Most patch the single module of the same name (os, time, select). The exceptions are socket, which also patches the ssl module if present; and thread, which patches thread, threading, and Queue. It's safe to call monkey_patch multiple times. For more information see :ref:`monkey-patch`.
These are the basic primitives of Eventlet; there are a lot more out there in the other Eventlet modules; check out the :doc:`modules`.

2
doc/conf.py
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@@ -43,7 +43,7 @@ master_doc = 'index'
# General information about the project.
project = u'Eventlet'
copyright = u'2009, Eventlet Contributors'
copyright = u'2005-2010, Eventlet Contributors'
# The version info for the project you're documenting, acts as replacement for
# |version| and |release|, also used in various other places throughout the

3
doc/design_patterns.rst
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@@ -76,8 +76,7 @@ One common use case that Linden Lab runs into all the time is a "dispatch" desig
Here's a somewhat contrived example: a server that receives POSTs from clients that contain a list of urls of RSS feeds. The server fetches all the feeds concurrently and responds with a list of their titles to the client. It's easy to imagine it doing something more complex than this, and this could be easily modified to become a Reader-style application::
import eventlet
from eventlet import patcher
feedparser = patcher.import_patched('feedparser')
feedparser = eventlet.import_patched('feedparser')
pool = eventlet.GreenPool()

9
doc/modules/semaphore.rst
View File

@@ -1,6 +1,11 @@
:mod:`semaphore` -- Semaphore classes
==================================================
.. automodule:: eventlet.semaphore
.. autoclass:: eventlet.semaphore.Semaphore
:members:
:undoc-members:
.. autoclass:: eventlet.semaphore.BoundedSemaphore
:members:
.. autoclass:: eventlet.semaphore.CappedSemaphore
:members:

17
doc/patching.rst
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@@ -16,14 +16,14 @@ The first way of greening an application is to import networking-related librari
from eventlet.green import threading
from eventlet.green import asyncore
This works best if every library can be imported green in this manner. If ``eventlet.green`` lacks a module (for example, non-python-standard modules), then the :mod:`eventlet.patcher` module can come to the rescue. It provides a function, :func:`eventlet.patcher.import_patched`, that greens any module on import.
This works best if every library can be imported green in this manner. If ``eventlet.green`` lacks a module (for example, non-python-standard modules), then :func:`~eventlet.patcher.import_patched` function can come to the rescue. It is a replacement for the builtin import statement that greens any module on import.
.. function:: eventlet.patcher.import_patched(module_name, *additional_modules, **kw_additional_modules)
Imports a module in a greened manner, so that the module's use of networking libraries like socket will use Eventlet's green versions instead. The only required argument is the name of the module to be imported::
from eventlet import patcher
httplib2 = patcher.import_patched('httplib2')
import eventlet
httplib2 = eventlet.import_patched('httplib2')
Under the hood, it works by temporarily swapping out the "normal" versions of the libraries in sys.modules for an eventlet.green equivalent. When the import of the to-be-patched module completes, the state of sys.modules is restored. Therefore, if the patched module contains the statement 'import socket', import_patched will have it reference eventlet.green.socket. One weakness of this approach is that it doesn't work for late binding (i.e. imports that happen during runtime). Late binding of imports is fortunately rarely done (it's slow and against `PEP-8 <http://www.python.org/dev/peps/pep-0008/>`_), so in most cases import_patched will work just fine.
@@ -31,12 +31,13 @@ This works best if every library can be imported green in this manner. If ``eve
from eventlet.green import socket
from eventlet.green import SocketServer
BaseHTTPServer = patcher.import_patched('BaseHTTPServer',
BaseHTTPServer = eventlet.import_patched('BaseHTTPServer',
('socket', socket),
('SocketServer', SocketServer))
BaseHTTPServer = patcher.import_patched('BaseHTTPServer',
BaseHTTPServer = eventlet.import_patched('BaseHTTPServer',
socket=socket, SocketServer=SocketServer)
.. _monkey-patch:
Monkeypatching the Standard Library
----------------------------------------
@@ -50,7 +51,7 @@ library. This has the disadvantage of appearing quite magical, but the advantag
Here's an example of using monkey_patch to patch only a few modules::
from eventlet import patcher
patcher.monkey_patch(all=False, socket=True, select=True)
import eventlet
eventlet.monkey_patch(all=False, socket=True, select=True)
It is important to call :func:`eventlet.patcher.monkey_patch` as early in the lifetime of the application as possible. Try to do it as one of the first lines in the main module. The reason for this is that sometimes there is a class that inherits from a class that needs to be greened -- e.g. a class that inherits from socket.socket -- and inheritance is done at import time, so therefore the monkeypatching should happen before the derived class is defined. It's safe to call monkey_patch multiple times.
It is important to call :func:`~eventlet.patcher.monkey_patch` as early in the lifetime of the application as possible. Try to do it as one of the first lines in the main module. The reason for this is that sometimes there is a class that inherits from a class that needs to be greened -- e.g. a class that inherits from socket.socket -- and inheritance is done at import time, so therefore the monkeypatching should happen before the derived class is defined. It's safe to call monkey_patch multiple times.

3
eventlet/api.py
View File

@@ -17,6 +17,9 @@ __all__ = [
'ssl_listener', 'tcp_listener', 'trampoline',
'unspew', 'use_hub', 'with_timeout', 'timeout']
warnings.warn("eventlet.api is deprecated! Nearly everything in it has moved "
"to the eventlet module.", DeprecationWarning, stacklevel=2)
def get_hub(*a, **kw):
warnings.warn("eventlet.api.get_hub has moved to eventlet.hubs.get_hub",
DeprecationWarning, stacklevel=2)

4
eventlet/corolocal.py
View File

@@ -1,8 +1,8 @@
from eventlet import api
from eventlet import greenthread
def get_ident():
""" Returns ``id()`` of current greenlet. Useful for debugging."""
return id(api.getcurrent())
return id(greenthread.getcurrent())
# TODO: The base threadlocal class wants to call __init__ on itself for every new thread that associates with it; our corolocal doesn't do this, but should for 100% compatibility. The implementation in _threading_local.py is so janky....
class local(object):

4
eventlet/green/select.py
View File

@@ -1,8 +1,6 @@
__select = __import__('select')
error = __select.error
from eventlet.api import getcurrent
from eventlet.greenthread import getcurrent
from eventlet.hubs import get_hub
__patched__ = ['select']

2
eventlet/green/time.py
View File

@@ -2,4 +2,4 @@ __time = __import__('time')
for var in dir(__time):
exec "%s = __time.%s" % (var, var)
__patched__ = ['sleep']
from eventlet.api import sleep
from eventlet.greenthread import sleep

56
eventlet/greenthread.py
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@@ -7,7 +7,7 @@ from eventlet.hubs import timer
from eventlet.support import greenlets as greenlet
import warnings
__all__ = ['getcurrent', 'sleep', 'spawn', 'spawn_n', 'call_after_global', 'call_after_local', 'GreenThread']
__all__ = ['getcurrent', 'sleep', 'spawn', 'spawn_n', 'spawn_after', 'spawn_after_local', 'GreenThread']
getcurrent = greenlet.getcurrent
@@ -16,7 +16,7 @@ def sleep(seconds=0):
elapsed.
*seconds* may be specified as an integer, or a float if fractional seconds
are desired. Calling :func:`~eventlet.api.sleep` with *seconds* of 0 is the
are desired. Calling :func:`~greenthread.sleep` with *seconds* of 0 is the
canonical way of expressing a cooperative yield. For example, if one is
looping over a large list performing an expensive calculation without
calling any socket methods, it's a good idea to call ``sleep(0)``
@@ -73,9 +73,9 @@ def spawn_after(seconds, func, *args, **kwargs):
To cancel the spawn and prevent *func* from being called,
call :meth:`GreenThread.cancel` on the return value of :func:`spawn_after`.
This will not abort the function if it's already started running. If
terminating *func* regardless of whether it's started or not is the desired
behavior, call :meth:`GreenThread.kill`.
This will not abort the function if it's already started running, which is
generally the desired behavior. If terminating *func* regardless of whether
it's started or not is the desired behavior, call :meth:`GreenThread.kill`.
"""
hub = hubs.get_hub()
g = GreenThread(hub.greenlet)
@@ -107,14 +107,6 @@ def spawn_after_local(seconds, func, *args, **kwargs):
def call_after_global(seconds, func, *args, **kwargs):
"""Schedule *function* to be called after *seconds* have elapsed.
The function will be scheduled even if the current greenlet has exited.
*seconds* may be specified as an integer, or a float if fractional seconds
are desired. The *function* will be called with the given *args* and
keyword arguments *kwargs*, and will be executed within its own greenthread.
Its return value is discarded."""
warnings.warn("call_after_global is renamed to spawn_after, which"
"has the same signature and semantics (plus a bit extra). Please do a"
" quick search-and-replace on your codebase, thanks!",
@@ -123,15 +115,6 @@ def call_after_global(seconds, func, *args, **kwargs):
def call_after_local(seconds, function, *args, **kwargs):
"""Schedule *function* to be called after *seconds* have elapsed.
The function will NOT be called if the current greenthread has exited.
*seconds* may be specified as an integer, or a float if fractional seconds
are desired. The *function* will be called with the given *args* and
keyword arguments *kwargs*, and will be executed within its own greenthread.
Its return value is discarded.
"""
warnings.warn("call_after_local is renamed to spawn_after_local, which"
"has the same signature and semantics (plus a bit extra).",
DeprecationWarning, stacklevel=2)
@@ -145,30 +128,6 @@ call_after = call_after_local
def exc_after(seconds, *throw_args):
"""Schedule an exception to be raised into the current coroutine
after *seconds* have elapsed.
This only works if the current coroutine is yielding, and is generally
used to set timeouts after which a network operation or series of
operations will be canceled.
Returns a :class:`~eventlet.timer.Timer` object with a
:meth:`~eventlet.timer.Timer.cancel` method which should be used to
prevent the exception if the operation completes successfully.
See also :func:`~eventlet.api.with_timeout` that encapsulates the idiom below.
Example::
def read_with_timeout():
timer = api.exc_after(30, RuntimeError())
try:
httpc.get('http://www.google.com/')
except RuntimeError:
print "Timed out!"
else:
timer.cancel()
"""
warnings.warn("Instead of exc_after, which is deprecated, use "
"Timeout(seconds, exception)",
DeprecationWarning, stacklevel=2)
@@ -270,9 +229,14 @@ def cancel(g, *throw_args):
def kill(g, *throw_args):
"""Terminates the target greenthread by raising an exception into it.
Whatever that greenthread might be doing; be it waiting for I/O or another
primitive, it sees an exception right away.
By default, this exception is GreenletExit, but a specific exception
may be specified. *throw_args* should be the same as the arguments to
raise; either an exception instance or an exc_info tuple.
Calling :func:`kill` causes the calling greenthread to cooperatively yield.
"""
if g.dead:
return

1
eventlet/pools.py
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@@ -1,6 +1,5 @@
import collections
from eventlet import api
from eventlet import queue
__all__ = ['Pool', 'TokenPool']

52
eventlet/saranwrap.py
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@@ -4,7 +4,12 @@ import struct
import sys
from eventlet.processes import Process, DeadProcess
from eventlet import api, pools
from eventlet import pools
import warnings
warnings.warn("eventlet.saranwrap is deprecated due to underuse. If you love "
"it, let us know by emailing eventletdev@lists.secondlife.com",
DeprecationWarning, stacklevel=2)
# debugging hooks
_g_debug_mode = False
@@ -31,9 +36,9 @@ def wrap(obj, dead_callback = None):
return wrap_module(obj.__name__, dead_callback)
pythonpath_sync()
if _g_debug_mode:
p = Process(sys.executable, [__file__, '--child', '--logfile', os.path.join(tempfile.gettempdir(), 'saranwrap.log')], dead_callback)
p = Process(sys.executable, ["-W", "ignore", __file__, '--child', '--logfile', os.path.join(tempfile.gettempdir(), 'saranwrap.log')], dead_callback)
else:
p = Process(sys.executable, [__file__, '--child'], dead_callback)
p = Process(sys.executable, ["-W", "ignore", __file__, '--child'], dead_callback)
prox = Proxy(ChildProcess(p, p))
prox.obj = obj
return prox.obj
@@ -48,9 +53,9 @@ def wrap_module(fqname, dead_callback = None):
pythonpath_sync()
global _g_debug_mode
if _g_debug_mode:
p = Process(sys.executable, [__file__, '--module', fqname, '--logfile', os.path.join(tempfile.gettempdir(), 'saranwrap.log')], dead_callback)
p = Process(sys.executable, ["-W", "ignore", __file__, '--module', fqname, '--logfile', os.path.join(tempfile.gettempdir(), 'saranwrap.log')], dead_callback)
else:
p = Process(sys.executable, [__file__, '--module', fqname,], dead_callback)
p = Process(sys.executable, ["-W", "ignore", __file__, '--module', fqname,], dead_callback)
prox = Proxy(ChildProcess(p,p))
return prox
@@ -593,6 +598,41 @@ def print_string(str):
def err_string(str):
print >>sys.stderr, str
def named(name):
"""Return an object given its name.
The name uses a module-like syntax, eg::
os.path.join
or::
mulib.mu.Resource
"""
toimport = name
obj = None
import_err_strings = []
while toimport:
try:
obj = __import__(toimport)
break
except ImportError, err:
# print 'Import error on %s: %s' % (toimport, err) # debugging spam
import_err_strings.append(err.__str__())
toimport = '.'.join(toimport.split('.')[:-1])
if obj is None:
raise ImportError('%s could not be imported. Import errors: %r' % (name, import_err_strings))
for seg in name.split('.')[1:]:
try:
obj = getattr(obj, seg)
except AttributeError:
dirobj = dir(obj)
dirobj.sort()
raise AttributeError('attribute %r missing from %r (%r) %r. Import errors: %r' % (
seg, obj, dirobj, name, import_err_strings))
return obj
def main():
import optparse
parser = optparse.OptionParser(
@@ -617,7 +657,7 @@ def main():
if options.module:
def get_module():
if base_obj[0] is None:
base_obj[0] = api.named(options.module)
base_obj[0] = named(options.module)
return base_obj[0]
server = Server(tpool.Proxy(sys.stdin),
tpool.Proxy(sys.stdout),

136
eventlet/semaphore.py
View File

@@ -5,12 +5,25 @@ class Semaphore(object):
"""An unbounded semaphore.
Optionally initialize with a resource *count*, then :meth:`acquire` and
:meth:`release` resources as needed. Attempting to :meth:`acquire` when
*count* is zero suspends the calling coroutine until *count* becomes
*count* is zero suspends the calling greenthread until *count* becomes
nonzero again.
This is API-compatible with :class:`threading.Semaphore`.
It is a context manager, and thus can be used in a with block::
sem = Semaphore(2)
with sem:
do_some_stuff()
If not specified, *value* defaults to 1.
"""
def __init__(self, count=0):
self.counter = count
def __init__(self, value=1):
self.counter = value
if value < 0:
raise ValueError("Semaphore must be initialized with a positive "
"number, got %s" % value)
self._waiters = set()
def __repr__(self):
@@ -22,13 +35,31 @@ class Semaphore(object):
return '<%s c=%s _w[%s]>' % params
def locked(self):
""" Returns true if a call to acquire would block."""
return self.counter <= 0
def bounded(self):
# for consistency with BoundedSemaphore
""" Returns False; for consistency with :class:`~eventlet.semaphore.CappedSemaphore`."""
return False
def acquire(self, blocking=True):
"""Acquire a semaphore.
When invoked without arguments: if the internal counter is larger than
zero on entry, decrement it by one and return immediately. If it is zero
on entry, block, waiting until some other thread has called release() to
make it larger than zero. This is done with proper interlocking so that
if multiple acquire() calls are blocked, release() will wake exactly one
of them up. The implementation may pick one at random, so the order in
which blocked threads are awakened should not be relied on. There is no
return value in this case.
When invoked with blocking set to true, do the same thing as when called
without arguments, and return true.
When invoked with blocking set to false, do not block. If a call without
an argument would block, return false immediately; otherwise, do the
same thing as when called without arguments, and return true."""
if not blocking and self.locked():
return False
if self.counter <= 0:
@@ -45,7 +76,12 @@ class Semaphore(object):
self.acquire()
def release(self, blocking=True):
# `blocking' parameter is for consistency with BoundedSemaphore and is ignored
"""Release a semaphore, incrementing the internal counter by one. When
it was zero on entry and another thread is waiting for it to become
larger than zero again, wake up that thread.
The *blocking* argument is for consistency with CappedSemaphore and is
ignored"""
self.counter += 1
if self._waiters:
hubs.get_hub().schedule_call_global(0, self._do_acquire)
@@ -61,22 +97,69 @@ class Semaphore(object):
@property
def balance(self):
"""An integer value that represents how many new calls to
:meth:`acquire` or :meth:`release` would be needed to get the counter to
0. If it is positive, then its value is the number of acquires that can
happen before the next acquire would block. If it is negative, it is
the negative of the number of releases that would be required in order
to make the counter 0 again (one more release would push the counter to
1 and unblock acquirers). It takes into account how many greenthreads
are currently blocking in :meth:`acquire`.
"""
# positive means there are free items
# zero means there are no free items but nobody has requested one
# negative means there are requests for items, but no items
return self.counter - len(self._waiters)
class BoundedSemaphore(object):
"""A bounded semaphore.
class BoundedSemaphore(Semaphore):
"""A bounded semaphore checks to make sure its current value doesn't exceed
its initial value. If it does, ValueError is raised. In most situations
semaphores are used to guard resources with limited capacity. If the
semaphore is released too many times it's a sign of a bug. If not given,
*value* defaults to 1."""
def __init__(self, value=1):
super(BoundedSemaphore, self).__init__(value)
self.original_counter = value
def release(self, blocking=True):
"""Release a semaphore, incrementing the internal counter by one. If
the counter would exceed the initial value, raises ValueError. When
it was zero on entry and another thread is waiting for it to become
larger than zero again, wake up that thread.
The *blocking* argument is for consistency with :class:`CappedSemaphore`
and is ignored"""
if self.counter >= self.original_counter:
raise ValueError, "Semaphore released too many times"
return super(BoundedSemaphore, self).release(blocking)
class CappedSemaphore(object):
"""A blockingly bounded semaphore.
Optionally initialize with a resource *count*, then :meth:`acquire` and
:meth:`release` resources as needed. Attempting to :meth:`acquire` when
*count* is zero suspends the calling coroutine until count becomes nonzero
*count* is zero suspends the calling greenthread until count becomes nonzero
again. Attempting to :meth:`release` after *count* has reached *limit*
suspends the calling coroutine until *count* becomes less than *limit*
suspends the calling greenthread until *count* becomes less than *limit*
again.
This has the same API as :class:`threading.Semaphore`, though its
semantics and behavior differ subtly due to the upper limit on calls
to :meth:`release`. It is **not** compatible with
:class:`threading.BoundedSemaphore` because it blocks when reaching *limit*
instead of raising a ValueError.
It is a context manager, and thus can be used in a with block::
sem = CappedSemaphore(2)
with sem:
do_some_stuff()
"""
def __init__(self, count, limit):
if count < 0:
raise ValueError("CappedSemaphore must be initialized with a "
"positive number, got %s" % count)
if count > limit:
# accidentally, this also catches the case when limit is None
raise ValueError("'count' cannot be more than 'limit'")
@@ -92,12 +175,31 @@ class BoundedSemaphore(object):
return '<%s b=%s l=%s u=%s>' % params
def locked(self):
"""Returns true if a call to acquire would block."""
return self.lower_bound.locked()
def bounded(self):
def bounded(self):
"""Returns true if a call to release would block."""
return self.upper_bound.locked()
def acquire(self, blocking=True):
"""Acquire a semaphore.
When invoked without arguments: if the internal counter is larger than
zero on entry, decrement it by one and return immediately. If it is zero
on entry, block, waiting until some other thread has called release() to
make it larger than zero. This is done with proper interlocking so that
if multiple acquire() calls are blocked, release() will wake exactly one
of them up. The implementation may pick one at random, so the order in
which blocked threads are awakened should not be relied on. There is no
return value in this case.
When invoked with blocking set to true, do the same thing as when called
without arguments, and return true.
When invoked with blocking set to false, do not block. If a call without
an argument would block, return false immediately; otherwise, do the
same thing as when called without arguments, and return true."""
if not blocking and self.locked():
return False
self.upper_bound.release()
@@ -114,6 +216,12 @@ class BoundedSemaphore(object):
self.acquire()
def release(self, blocking=True):
"""Release a semaphore. In this class, this behaves very much like
an :meth:`acquire` but in the opposite direction.
Imagine the docs of :meth:`acquire` here, but with every direction
reversed. When calling this method, it will block if the internal
counter is greater than or equal to *limit*."""
if not blocking and self.bounded():
return False
self.lower_bound.release()
@@ -128,4 +236,12 @@ class BoundedSemaphore(object):
@property
def balance(self):
"""An integer value that represents how many new calls to
:meth:`acquire` or :meth:`release` would be needed to get the counter to
0. If it is positive, then its value is the number of acquires that can
happen before the next acquire would block. If it is negative, it is
the negative of the number of releases that would be required in order
to make the counter 0 again (one more release would push the counter to
1 and unblock acquirers). It takes into account how many greenthreads
are currently blocking in :meth:`acquire` and :meth:`release`."""
return self.lower_bound.balance - self.upper_bound.balance

3
examples/feedscraper.py
View File

@@ -2,8 +2,7 @@
and returns the titles of those feeds.
"""
import eventlet
from eventlet import patcher
feedparser = patcher.import_patched('feedparser')
feedparser = eventlet.import_patched('feedparser')
# the pool provides a safety limit on our concurrency
pool = eventlet.GreenPool()

4
tests/semaphore_test.py
View File

@@ -5,7 +5,7 @@ from tests import LimitedTestCase
class TestSemaphore(LimitedTestCase):
def test_bounded(self):
sem = semaphore.BoundedSemaphore(2, limit=3)
sem = semaphore.CappedSemaphore(2, limit=3)
self.assertEqual(sem.acquire(), True)
self.assertEqual(sem.acquire(), True)
gt1 = eventlet.spawn(sem.release)
@@ -21,7 +21,7 @@ class TestSemaphore(LimitedTestCase):
gt2.wait()
def test_bounded_with_zero_limit(self):
sem = semaphore.BoundedSemaphore(0, 0)
sem = semaphore.CappedSemaphore(0, 0)
gt = eventlet.spawn(sem.acquire)
sem.release()
gt.wait()

2
tests/stdlib/test_thread__boundedsem.py
View File

@@ -8,7 +8,7 @@ def allocate_lock():
original_allocate_lock = thread.allocate_lock
thread.allocate_lock = allocate_lock
original_LockType = thread.LockType
thread.LockType = coros.BoundedSemaphore
thread.LockType = coros.CappedSemaphore
try:
import os.path