def patch_thread(threading=True, _threading_local=True, Event=True, logging=True,
existing_locks=True,
_warnings=None):
"""
patch_thread(threading=True, _threading_local=True, Event=True, logging=True, existing_locks=True) -> None
Replace the standard :mod:`thread` module to make it greenlet-based.
:keyword bool threading: When True (the default),
also patch :mod:`threading`.
:keyword bool _threading_local: When True (the default),
also patch :class:`_threading_local.local`.
:keyword bool logging: When True (the default), also patch locks
taken if the logging module has been configured.
:keyword bool existing_locks: When True (the default), and the
process is still single threaded, make sure that any
:class:`threading.RLock` (and, under Python 3, :class:`importlib._bootstrap._ModuleLock`)
instances that are currently locked can be properly unlocked. **Important**: This is a
best-effort attempt and, on certain implementations, may not detect all
locks. It is important to monkey-patch extremely early in the startup process.
.. caution::
Monkey-patching :mod:`thread` and using
:class:`multiprocessing.Queue` or
:class:`concurrent.futures.ProcessPoolExecutor` (which uses a
``Queue``) will hang the process.
.. versionchanged:: 1.1b1
Add *logging* and *existing_locks* params.
.. versionchanged:: 1.3a2
``Event`` defaults to True.
"""
# XXX: Simplify
# pylint:disable=too-many-branches,too-many-locals,too-many-statements
# Description of the hang:
# There is an incompatibility with patching 'thread' and the 'multiprocessing' module:
# The problem is that multiprocessing.queues.Queue uses a half-duplex multiprocessing.Pipe,
# which is implemented with os.pipe() and _multiprocessing.Connection. os.pipe isn't patched
# by gevent, as it returns just a fileno. _multiprocessing.Connection is an internal implementation
# class implemented in C, which exposes a 'poll(timeout)' method; under the covers, this issues a
# (blocking) select() call: hence the need for a real thread. Except for that method, we could
# almost replace Connection with gevent.fileobject.SocketAdapter, plus a trivial
# patch to os.pipe (below). Sigh, so close. (With a little work, we could replicate that method)
# import os
# import fcntl
# os_pipe = os.pipe
# def _pipe():
# r, w = os_pipe()
# fcntl.fcntl(r, fcntl.F_SETFL, os.O_NONBLOCK)
# fcntl.fcntl(w, fcntl.F_SETFL, os.O_NONBLOCK)
# return r, w
# os.pipe = _pipe
# The 'threading' module copies some attributes from the
# thread module the first time it is imported. If we patch 'thread'
# before that happens, then we store the wrong values in 'saved',
# So if we're going to patch threading, we either need to import it
# before we patch thread, or manually clean up the attributes that
# are in trouble. The latter is tricky because of the different names
# on different versions.
if threading:
threading_mod = __import__('threading')
# Capture the *real* current thread object before
# we start returning DummyThread objects, for comparison
# to the main thread.
orig_current_thread = threading_mod.current_thread()
else:
threading_mod = None
gevent_threading_mod = None
orig_current_thread = None
gevent_thread_mod, thread_mod = _patch_module('thread',
_warnings=_warnings,
_notify_did_subscribers=False)
if threading:
gevent_threading_mod, _ = _patch_module('threading',
_warnings=_warnings,
_notify_did_subscribers=False)
if Event:
from gevent.event import Event
patch_item(threading_mod, 'Event', Event)
# Python 2 had `Event` as a function returning
# the private class `_Event`. Some code may be relying
# on that.
if hasattr(threading_mod, '_Event'):
patch_item(threading_mod, '_Event', Event)
if existing_locks:
_patch_existing_locks(threading_mod)
if logging and 'logging' in sys.modules:
logging = __import__('logging')
patch_item(logging, '_lock', threading_mod.RLock())
for wr in logging._handlerList:
# In py26, these are actual handlers, not weakrefs
handler = wr() if callable(wr) else wr
if handler is None:
continue
if not hasattr(handler, 'lock'):
raise TypeError("Unknown/unsupported handler %r" % handler)
handler.lock = threading_mod.RLock()
if _threading_local:
_threading_local = __import__('_threading_local')
from gevent.local import local
patch_item(_threading_local, 'local', local)
def make_join_func(thread, thread_greenlet):
from gevent.hub import sleep
from time import time
def join(timeout=None):
end = None
if threading_mod.current_thread() is thread:
raise RuntimeError("Cannot join current thread")
if thread_greenlet is not None and thread_greenlet.dead:
return
# You may ask: Why not call thread_greenlet.join()?
# Well, in the one case we actually have a greenlet, it's the
# low-level greenlet.greenlet object for the main thread, which
# doesn't have a join method.
#
# You may ask: Why not become the main greenlet's *parent*
# so you can get notified when it finishes? Because you can't
# create a greenlet cycle (the current greenlet is a descendent
# of the parent), and nor can you set a greenlet's parent to None,
# so there can only ever be one greenlet with a parent of None: the main
# greenlet, the one we need to watch.
#
# You may ask: why not swizzle out the problematic lock on the main thread
# into a gevent friendly lock? Well, the interpreter actually depends on that
# for the main thread in threading._shutdown; see below.
if not thread.is_alive():
return
if timeout:
end = time() + timeout
while thread.is_alive():
if end is not None and time() > end:
return
sleep(0.01)
return join
if threading:
from gevent.threading import main_native_thread
for thread in threading_mod._active.values():
if thread == main_native_thread():
continue
thread.join = make_join_func(thread, None)
if PY3:
# Issue 18808 changes the nature of Thread.join() to use
# locks. This means that a greenlet spawned in the main thread
# (which is already running) cannot wait for the main thread---it
# hangs forever. We patch around this if possible. See also
# gevent.threading.
greenlet = __import__('greenlet')
already_patched = is_object_patched('threading', '_shutdown')
if orig_current_thread == threading_mod.main_thread() and not already_patched:
main_thread = threading_mod.main_thread()
_greenlet = main_thread._greenlet = greenlet.getcurrent()
main_thread.__real_tstate_lock = main_thread._tstate_lock
assert main_thread.__real_tstate_lock is not None
# The interpreter will call threading._shutdown
# when the main thread exits and is about to
# go away. It is called *in* the main thread. This
# is a perfect place to notify other greenlets that
# the main thread is done. We do this by overriding the
# lock of the main thread during operation, and only restoring
# it to the native blocking version at shutdown time
# (the interpreter also has a reference to this lock in a
# C data structure).
main_thread._tstate_lock = threading_mod.Lock()
main_thread._tstate_lock.acquire()
orig_shutdown = threading_mod._shutdown
def _shutdown():
# Release anyone trying to join() me,
# and let us switch to them.
if not main_thread._tstate_lock:
return
main_thread._tstate_lock.release()
from gevent import sleep
try:
sleep()
except: # pylint:disable=bare-except
# A greenlet could have .kill() us
# or .throw() to us. I'm the main greenlet,
# there's no where else for this to go.
from gevent import get_hub
get_hub().print_exception(_greenlet, *sys.exc_info())
# Now, this may have resulted in us getting stopped
# if some other greenlet actually just ran there.
# That's not good, we're not supposed to be stopped
# when we enter _shutdown.
main_thread._is_stopped = False
main_thread._tstate_lock = main_thread.__real_tstate_lock
main_thread.__real_tstate_lock = None
# The only truly blocking native shutdown lock to
# acquire should be our own (hopefully), and the call to
# _stop that orig_shutdown makes will discard it.
orig_shutdown()
patch_item(threading_mod, '_shutdown', orig_shutdown)
patch_item(threading_mod, '_shutdown', _shutdown)
# We create a bit of a reference cycle here,
# so main_thread doesn't get to be collected in a timely way.
# Not good. Take it out of dangling so we don't get
# warned about it.
threading_mod._dangling.remove(main_thread)
# Patch up the ident of the main thread to match. This
# matters if threading was imported before monkey-patching
# thread
oldid = main_thread.ident
main_thread._ident = threading_mod.get_ident()
if oldid in threading_mod._active:
threading_mod._active[main_thread.ident] = threading_mod._active[oldid]
if oldid != main_thread.ident:
del threading_mod._active[oldid]
elif not already_patched:
_queue_warning("Monkey-patching not on the main thread; "
"threading.main_thread().join() will hang from a greenlet",
_warnings)
from gevent import events
_notify_patch(events.GeventDidPatchModuleEvent('thread', gevent_thread_mod, thread_mod))
_notify_patch(events.GeventDidPatchModuleEvent('threading', gevent_threading_mod, threading_mod))
def patch_thread(threading=True, _threading_local=True, Event=False, logging=True,
existing_locks=True,
_warnings=None):
"""
Replace the standard :mod:`thread` module to make it greenlet-based.
- If *threading* is true (the default), also patch ``threading``.
- If *_threading_local* is true (the default), also patch ``_threading_local.local``.
- If *logging* is True (the default), also patch locks taken if the logging module has
been configured.
- If *existing_locks* is True (the default), and the process is still single threaded,
make sure than any :class:`threading.RLock` (and, under Python 3, :class:`importlib._bootstrap._ModuleLock`)
instances that are currently locked can be properly unlocked.
.. caution::
Monkey-patching :mod:`thread` and using
:class:`multiprocessing.Queue` or
:class:`concurrent.futures.ProcessPoolExecutor` (which uses a
``Queue``) will hang the process.
.. versionchanged:: 1.1b1
Add *logging* and *existing_locks* params.
"""
# XXX: Simplify
# pylint:disable=too-many-branches,too-many-locals
# Description of the hang:
# There is an incompatibility with patching 'thread' and the 'multiprocessing' module:
# The problem is that multiprocessing.queues.Queue uses a half-duplex multiprocessing.Pipe,
# which is implemented with os.pipe() and _multiprocessing.Connection. os.pipe isn't patched
# by gevent, as it returns just a fileno. _multiprocessing.Connection is an internal implementation
# class implemented in C, which exposes a 'poll(timeout)' method; under the covers, this issues a
# (blocking) select() call: hence the need for a real thread. Except for that method, we could
# almost replace Connection with gevent.fileobject.SocketAdapter, plus a trivial
# patch to os.pipe (below). Sigh, so close. (With a little work, we could replicate that method)
# import os
# import fcntl
# os_pipe = os.pipe
# def _pipe():
# r, w = os_pipe()
# fcntl.fcntl(r, fcntl.F_SETFL, os.O_NONBLOCK)
# fcntl.fcntl(w, fcntl.F_SETFL, os.O_NONBLOCK)
# return r, w
# os.pipe = _pipe
# The 'threading' module copies some attributes from the
# thread module the first time it is imported. If we patch 'thread'
# before that happens, then we store the wrong values in 'saved',
# So if we're going to patch threading, we either need to import it
# before we patch thread, or manually clean up the attributes that
# are in trouble. The latter is tricky because of the different names
# on different versions.
if threading:
threading_mod = __import__('threading')
# Capture the *real* current thread object before
# we start returning DummyThread objects, for comparison
# to the main thread.
orig_current_thread = threading_mod.current_thread()
else:
threading_mod = None
orig_current_thread = None
patch_module('thread')
if threading:
if existing_locks:
_patch_existing_locks(threading_mod)
patch_module('threading')
if Event:
from gevent.event import Event
patch_item(threading_mod, 'Event', Event)
if logging and 'logging' in sys.modules:
logging = __import__('logging')
patch_item(logging, '_lock', threading_mod.RLock())
for wr in logging._handlerList:
# In py26, these are actual handlers, not weakrefs
handler = wr() if callable(wr) else wr
if handler is None:
continue
if not hasattr(handler, 'lock'):
raise TypeError("Unknown/unsupported handler %r" % handler)
handler.lock = threading_mod.RLock()
if _threading_local:
_threading_local = __import__('_threading_local')
from gevent.local import local
patch_item(_threading_local, 'local', local)
def make_join_func(thread, thread_greenlet):
from gevent.hub import sleep
from time import time
def join(timeout=None):
end = None
if threading_mod.current_thread() is thread:
raise RuntimeError("Cannot join current thread")
if thread_greenlet is not None and thread_greenlet.dead:
return
if not thread.is_alive():
return
if timeout:
end = time() + timeout
while thread.is_alive():
if end is not None and time() > end:
return
sleep(0.01)
return join
if threading:
from gevent.threading import main_native_thread
for thread in threading_mod._active.values():
if thread == main_native_thread():
continue
thread.join = make_join_func(thread, None)
if sys.version_info[:2] >= (3, 4):
# Issue 18808 changes the nature of Thread.join() to use
# locks. This means that a greenlet spawned in the main thread
# (which is already running) cannot wait for the main thread---it
# hangs forever. We patch around this if possible. See also
# gevent.threading.
greenlet = __import__('greenlet')
if orig_current_thread == threading_mod.main_thread():
main_thread = threading_mod.main_thread()
_greenlet = main_thread._greenlet = greenlet.getcurrent()
from gevent.hub import sleep
main_thread.join = make_join_func(main_thread, _greenlet)
# Patch up the ident of the main thread to match. This
# matters if threading was imported before monkey-patching
# thread
oldid = main_thread.ident
main_thread._ident = threading_mod.get_ident()
if oldid in threading_mod._active:
threading_mod._active[main_thread.ident] = threading_mod._active[oldid]
if oldid != main_thread.ident:
del threading_mod._active[oldid]
else:
_queue_warning("Monkey-patching not on the main thread; "
"threading.main_thread().join() will hang from a greenlet",
_warnings)
def patch_thread(threading=True, _threading_local=True, Event=True, logging=True,
existing_locks=True,
_warnings=None):
"""
patch_thread(threading=True, _threading_local=True, Event=True, logging=True, existing_locks=True) -> None
Replace the standard :mod:`thread` module to make it greenlet-based.
:keyword bool threading: When True (the default),
also patch :mod:`threading`.
:keyword bool _threading_local: When True (the default),
also patch :class:`_threading_local.local`.
:keyword bool logging: When True (the default), also patch locks
taken if the logging module has been configured.
:keyword bool existing_locks: When True (the default), and the
process is still single threaded, make sure that any
:class:`threading.RLock` (and, under Python 3, :class:`importlib._bootstrap._ModuleLock`)
instances that are currently locked can be properly unlocked.
.. caution::
Monkey-patching :mod:`thread` and using
:class:`multiprocessing.Queue` or
:class:`concurrent.futures.ProcessPoolExecutor` (which uses a
``Queue``) will hang the process.
.. versionchanged:: 1.1b1
Add *logging* and *existing_locks* params.
.. versionchanged:: 1.3a2
``Event`` defaults to True.
"""
# XXX: Simplify
# pylint:disable=too-many-branches,too-many-locals,too-many-statements
# Description of the hang:
# There is an incompatibility with patching 'thread' and the 'multiprocessing' module:
# The problem is that multiprocessing.queues.Queue uses a half-duplex multiprocessing.Pipe,
# which is implemented with os.pipe() and _multiprocessing.Connection. os.pipe isn't patched
# by gevent, as it returns just a fileno. _multiprocessing.Connection is an internal implementation
# class implemented in C, which exposes a 'poll(timeout)' method; under the covers, this issues a
# (blocking) select() call: hence the need for a real thread. Except for that method, we could
# almost replace Connection with gevent.fileobject.SocketAdapter, plus a trivial
# patch to os.pipe (below). Sigh, so close. (With a little work, we could replicate that method)
# import os
# import fcntl
# os_pipe = os.pipe
# def _pipe():
# r, w = os_pipe()
# fcntl.fcntl(r, fcntl.F_SETFL, os.O_NONBLOCK)
# fcntl.fcntl(w, fcntl.F_SETFL, os.O_NONBLOCK)
# return r, w
# os.pipe = _pipe
# The 'threading' module copies some attributes from the
# thread module the first time it is imported. If we patch 'thread'
# before that happens, then we store the wrong values in 'saved',
# So if we're going to patch threading, we either need to import it
# before we patch thread, or manually clean up the attributes that
# are in trouble. The latter is tricky because of the different names
# on different versions.
if threading:
threading_mod = __import__('threading')
# Capture the *real* current thread object before
# we start returning DummyThread objects, for comparison
# to the main thread.
orig_current_thread = threading_mod.current_thread()
else:
threading_mod = None
gevent_threading_mod = None
orig_current_thread = None
gevent_thread_mod, thread_mod = _patch_module('thread',
_warnings=_warnings, _notify_did_subscribers=False)
if threading:
gevent_threading_mod, _ = _patch_module('threading',
_warnings=_warnings, _notify_did_subscribers=False)
if Event:
from gevent.event import Event
patch_item(threading_mod, 'Event', Event)
# Python 2 had `Event` as a function returning
# the private class `_Event`. Some code may be relying
# on that.
if hasattr(threading_mod, '_Event'):
patch_item(threading_mod, '_Event', Event)
if existing_locks:
_patch_existing_locks(threading_mod)
if logging and 'logging' in sys.modules:
logging = __import__('logging')
patch_item(logging, '_lock', threading_mod.RLock())
for wr in logging._handlerList:
# In py26, these are actual handlers, not weakrefs
handler = wr() if callable(wr) else wr
if handler is None:
continue
if not hasattr(handler, 'lock'):
raise TypeError("Unknown/unsupported handler %r" % handler)
handler.lock = threading_mod.RLock()
if _threading_local:
_threading_local = __import__('_threading_local')
from gevent.local import local
patch_item(_threading_local, 'local', local)
def make_join_func(thread, thread_greenlet):
from gevent.hub import sleep
from time import time
def join(timeout=None):
end = None
if threading_mod.current_thread() is thread:
raise RuntimeError("Cannot join current thread")
if thread_greenlet is not None and thread_greenlet.dead:
return
if not thread.is_alive():
return
if timeout:
end = time() + timeout
while thread.is_alive():
if end is not None and time() > end:
return
sleep(0.01)
return join
if threading:
from gevent.threading import main_native_thread
for thread in threading_mod._active.values():
if thread == main_native_thread():
continue
thread.join = make_join_func(thread, None)
if sys.version_info[:2] >= (3, 4):
# Issue 18808 changes the nature of Thread.join() to use
# locks. This means that a greenlet spawned in the main thread
# (which is already running) cannot wait for the main thread---it
# hangs forever. We patch around this if possible. See also
# gevent.threading.
greenlet = __import__('greenlet')
if orig_current_thread == threading_mod.main_thread():
main_thread = threading_mod.main_thread()
_greenlet = main_thread._greenlet = greenlet.getcurrent()
main_thread.join = make_join_func(main_thread, _greenlet)
# Patch up the ident of the main thread to match. This
# matters if threading was imported before monkey-patching
# thread
oldid = main_thread.ident
main_thread._ident = threading_mod.get_ident()
if oldid in threading_mod._active:
threading_mod._active[main_thread.ident] = threading_mod._active[oldid]
if oldid != main_thread.ident:
del threading_mod._active[oldid]
else:
_queue_warning("Monkey-patching not on the main thread; "
"threading.main_thread().join() will hang from a greenlet",
_warnings)
from gevent import events
_notify_patch(events.GeventDidPatchModuleEvent('thread', gevent_thread_mod, thread_mod))
_notify_patch(events.GeventDidPatchModuleEvent('threading', gevent_threading_mod, threading_mod))
