337 lines
10 KiB
Python
337 lines
10 KiB
Python
# Copyright (c) 2007-2009, Linden Research, Inc.
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# Copyright (c) 2007, IBM Corp.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import atexit
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try:
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import _imp as imp
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except ImportError:
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import imp
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import os
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import sys
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import traceback
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import eventlet
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from eventlet import event, greenio, greenthread, patcher, timeout
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__all__ = ['execute', 'Proxy', 'killall', 'set_num_threads']
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EXC_CLASSES = (Exception, timeout.Timeout)
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SYS_EXCS = (GeneratorExit, KeyboardInterrupt, SystemExit)
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QUIET = True
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socket = patcher.original('socket')
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threading = patcher.original('threading')
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Queue_module = patcher.original('queue')
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Empty = Queue_module.Empty
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Queue = Queue_module.Queue
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_bytetosend = b' '
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_coro = None
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_nthreads = int(os.environ.get('EVENTLET_THREADPOOL_SIZE', 20))
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_reqq = _rspq = None
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_rsock = _wsock = None
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_setup_already = False
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_threads = []
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def tpool_trampoline():
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global _rspq
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while True:
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try:
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_c = _rsock.recv(1)
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assert _c
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# FIXME: this is probably redundant since using sockets instead of pipe now
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except ValueError:
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break # will be raised when pipe is closed
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while not _rspq.empty():
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try:
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(e, rv) = _rspq.get(block=False)
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e.send(rv)
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e = rv = None
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except Empty:
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pass
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def tworker():
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global _rspq
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while True:
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try:
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msg = _reqq.get()
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except AttributeError:
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return # can't get anything off of a dud queue
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if msg is None:
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return
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(e, meth, args, kwargs) = msg
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rv = None
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try:
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rv = meth(*args, **kwargs)
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except SYS_EXCS:
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raise
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except EXC_CLASSES:
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rv = sys.exc_info()
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traceback.clear_frames(rv[1].__traceback__)
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# test_leakage_from_tracebacks verifies that the use of
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# exc_info does not lead to memory leaks
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_rspq.put((e, rv))
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msg = meth = args = kwargs = e = rv = None
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_wsock.sendall(_bytetosend)
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def execute(meth, *args, **kwargs):
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"""
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Execute *meth* in a Python thread, blocking the current coroutine/
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greenthread until the method completes.
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The primary use case for this is to wrap an object or module that is not
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amenable to monkeypatching or any of the other tricks that Eventlet uses
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to achieve cooperative yielding. With tpool, you can force such objects to
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cooperate with green threads by sticking them in native threads, at the cost
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of some overhead.
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"""
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setup()
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# if already in tpool, don't recurse into the tpool
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# also, call functions directly if we're inside an import lock, because
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# if meth does any importing (sadly common), it will hang
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my_thread = threading.current_thread()
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if my_thread in _threads or imp.lock_held() or _nthreads == 0:
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return meth(*args, **kwargs)
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e = event.Event()
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_reqq.put((e, meth, args, kwargs))
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rv = e.wait()
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if isinstance(rv, tuple) \
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and len(rv) == 3 \
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and isinstance(rv[1], EXC_CLASSES):
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(c, e, tb) = rv
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if not QUIET:
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traceback.print_exception(c, e, tb)
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traceback.print_stack()
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raise e.with_traceback(tb)
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return rv
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def proxy_call(autowrap, f, *args, **kwargs):
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"""
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Call a function *f* and returns the value. If the type of the return value
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is in the *autowrap* collection, then it is wrapped in a :class:`Proxy`
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object before return.
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Normally *f* will be called in the threadpool with :func:`execute`; if the
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keyword argument "nonblocking" is set to ``True``, it will simply be
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executed directly. This is useful if you have an object which has methods
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that don't need to be called in a separate thread, but which return objects
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that should be Proxy wrapped.
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"""
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if kwargs.pop('nonblocking', False):
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rv = f(*args, **kwargs)
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else:
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rv = execute(f, *args, **kwargs)
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if isinstance(rv, autowrap):
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return Proxy(rv, autowrap)
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else:
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return rv
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class Proxy:
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"""
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a simple proxy-wrapper of any object that comes with a
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methods-only interface, in order to forward every method
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invocation onto a thread in the native-thread pool. A key
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restriction is that the object's methods should not switch
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greenlets or use Eventlet primitives, since they are in a
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different thread from the main hub, and therefore might behave
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unexpectedly. This is for running native-threaded code
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only.
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It's common to want to have some of the attributes or return
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values also wrapped in Proxy objects (for example, database
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connection objects produce cursor objects which also should be
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wrapped in Proxy objects to remain nonblocking). *autowrap*, if
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supplied, is a collection of types; if an attribute or return
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value matches one of those types (via isinstance), it will be
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wrapped in a Proxy. *autowrap_names* is a collection
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of strings, which represent the names of attributes that should be
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wrapped in Proxy objects when accessed.
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"""
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def __init__(self, obj, autowrap=(), autowrap_names=()):
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self._obj = obj
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self._autowrap = autowrap
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self._autowrap_names = autowrap_names
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def __getattr__(self, attr_name):
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f = getattr(self._obj, attr_name)
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if not hasattr(f, '__call__'):
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if isinstance(f, self._autowrap) or attr_name in self._autowrap_names:
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return Proxy(f, self._autowrap)
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return f
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def doit(*args, **kwargs):
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result = proxy_call(self._autowrap, f, *args, **kwargs)
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if attr_name in self._autowrap_names and not isinstance(result, Proxy):
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return Proxy(result)
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return result
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return doit
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# the following are a buncha methods that the python interpeter
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# doesn't use getattr to retrieve and therefore have to be defined
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# explicitly
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def __getitem__(self, key):
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return proxy_call(self._autowrap, self._obj.__getitem__, key)
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def __setitem__(self, key, value):
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return proxy_call(self._autowrap, self._obj.__setitem__, key, value)
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def __deepcopy__(self, memo=None):
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return proxy_call(self._autowrap, self._obj.__deepcopy__, memo)
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def __copy__(self, memo=None):
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return proxy_call(self._autowrap, self._obj.__copy__, memo)
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def __call__(self, *a, **kw):
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if '__call__' in self._autowrap_names:
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return Proxy(proxy_call(self._autowrap, self._obj, *a, **kw))
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else:
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return proxy_call(self._autowrap, self._obj, *a, **kw)
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def __enter__(self):
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return proxy_call(self._autowrap, self._obj.__enter__)
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def __exit__(self, *exc):
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return proxy_call(self._autowrap, self._obj.__exit__, *exc)
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# these don't go through a proxy call, because they're likely to
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# be called often, and are unlikely to be implemented on the
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# wrapped object in such a way that they would block
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def __eq__(self, rhs):
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return self._obj == rhs
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def __hash__(self):
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return self._obj.__hash__()
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def __repr__(self):
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return self._obj.__repr__()
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def __str__(self):
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return self._obj.__str__()
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def __len__(self):
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return len(self._obj)
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def __nonzero__(self):
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return bool(self._obj)
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# Python3
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__bool__ = __nonzero__
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def __iter__(self):
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it = iter(self._obj)
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if it == self._obj:
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return self
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else:
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return Proxy(it)
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def next(self):
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return proxy_call(self._autowrap, next, self._obj)
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# Python3
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__next__ = next
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def setup():
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global _rsock, _wsock, _coro, _setup_already, _rspq, _reqq
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if _setup_already:
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return
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else:
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_setup_already = True
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assert _nthreads >= 0, "Can't specify negative number of threads"
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if _nthreads == 0:
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import warnings
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warnings.warn("Zero threads in tpool. All tpool.execute calls will\
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execute in main thread. Check the value of the environment \
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variable EVENTLET_THREADPOOL_SIZE.", RuntimeWarning)
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_reqq = Queue(maxsize=-1)
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_rspq = Queue(maxsize=-1)
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# connected socket pair
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sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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sock.bind(('127.0.0.1', 0))
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sock.listen(1)
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csock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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csock.connect(sock.getsockname())
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csock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, True)
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_wsock, _addr = sock.accept()
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_wsock.settimeout(None)
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_wsock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, True)
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sock.close()
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_rsock = greenio.GreenSocket(csock)
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_rsock.settimeout(None)
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for i in range(_nthreads):
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t = threading.Thread(target=tworker,
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name="tpool_thread_%s" % i)
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t.daemon = True
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t.start()
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_threads.append(t)
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_coro = greenthread.spawn_n(tpool_trampoline)
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# This yield fixes subtle error with GreenSocket.__del__
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eventlet.sleep(0)
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# Avoid ResourceWarning unclosed socket on Python3.2+
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@atexit.register
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def killall():
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global _setup_already, _rspq, _rsock, _wsock
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if not _setup_already:
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return
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# This yield fixes freeze in some scenarios
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eventlet.sleep(0)
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for thr in _threads:
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_reqq.put(None)
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for thr in _threads:
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thr.join()
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del _threads[:]
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# return any remaining results
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while (_rspq is not None) and not _rspq.empty():
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try:
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(e, rv) = _rspq.get(block=False)
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e.send(rv)
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e = rv = None
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except Empty:
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pass
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if _coro is not None:
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greenthread.kill(_coro)
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if _rsock is not None:
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_rsock.close()
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_rsock = None
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if _wsock is not None:
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_wsock.close()
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_wsock = None
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_rspq = None
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_setup_already = False
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def set_num_threads(nthreads):
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global _nthreads
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_nthreads = nthreads
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