354 lines
11 KiB
Python
354 lines
11 KiB
Python
#
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# Module providing various facilities to other parts of the package
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#
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# multiprocessing/util.py
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#
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# Copyright (c) 2006-2008, R Oudkerk
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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#
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution.
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# 3. Neither the name of author nor the names of any contributors may be
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# used to endorse or promote products derived from this software
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# without specific prior written permission.
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#
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# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
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# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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# SUCH DAMAGE.
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#
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import os
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import itertools
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import weakref
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import atexit
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import threading # we want threading to install it's
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# cleanup function before multiprocessing does
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from subprocess import _args_from_interpreter_flags
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from multiprocessing.process import current_process, active_children
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__all__ = [
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'sub_debug', 'debug', 'info', 'sub_warning', 'get_logger',
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'log_to_stderr', 'get_temp_dir', 'register_after_fork',
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'is_exiting', 'Finalize', 'ForkAwareThreadLock', 'ForkAwareLocal',
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'SUBDEBUG', 'SUBWARNING',
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]
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#
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# Logging
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#
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NOTSET = 0
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SUBDEBUG = 5
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DEBUG = 10
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INFO = 20
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SUBWARNING = 25
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LOGGER_NAME = 'multiprocessing'
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DEFAULT_LOGGING_FORMAT = '[%(levelname)s/%(processName)s] %(message)s'
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_logger = None
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_log_to_stderr = False
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def sub_debug(msg, *args):
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if _logger:
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_logger.log(SUBDEBUG, msg, *args)
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def debug(msg, *args):
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if _logger:
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_logger.log(DEBUG, msg, *args)
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def info(msg, *args):
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if _logger:
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_logger.log(INFO, msg, *args)
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def sub_warning(msg, *args):
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if _logger:
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_logger.log(SUBWARNING, msg, *args)
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def get_logger():
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'''
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Returns logger used by multiprocessing
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'''
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global _logger
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import logging, atexit
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logging._acquireLock()
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try:
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if not _logger:
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_logger = logging.getLogger(LOGGER_NAME)
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_logger.propagate = 0
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logging.addLevelName(SUBDEBUG, 'SUBDEBUG')
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logging.addLevelName(SUBWARNING, 'SUBWARNING')
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# XXX multiprocessing should cleanup before logging
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if hasattr(atexit, 'unregister'):
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atexit.unregister(_exit_function)
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atexit.register(_exit_function)
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else:
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atexit._exithandlers.remove((_exit_function, (), {}))
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atexit._exithandlers.append((_exit_function, (), {}))
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finally:
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logging._releaseLock()
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return _logger
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def log_to_stderr(level=None):
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'''
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Turn on logging and add a handler which prints to stderr
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'''
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global _log_to_stderr
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import logging
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logger = get_logger()
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formatter = logging.Formatter(DEFAULT_LOGGING_FORMAT)
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handler = logging.StreamHandler()
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handler.setFormatter(formatter)
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logger.addHandler(handler)
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if level:
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logger.setLevel(level)
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_log_to_stderr = True
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return _logger
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#
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# Function returning a temp directory which will be removed on exit
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#
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def get_temp_dir():
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# get name of a temp directory which will be automatically cleaned up
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if current_process()._tempdir is None:
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import shutil, tempfile
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tempdir = tempfile.mkdtemp(prefix='pymp-')
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info('created temp directory %s', tempdir)
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Finalize(None, shutil.rmtree, args=[tempdir], exitpriority=-100)
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current_process()._tempdir = tempdir
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return current_process()._tempdir
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#
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# Support for reinitialization of objects when bootstrapping a child process
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#
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_afterfork_registry = weakref.WeakValueDictionary()
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_afterfork_counter = itertools.count()
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def _run_after_forkers():
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items = list(_afterfork_registry.items())
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items.sort()
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for (index, ident, func), obj in items:
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try:
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func(obj)
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except Exception, e:
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info('after forker raised exception %s', e)
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def register_after_fork(obj, func):
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_afterfork_registry[(_afterfork_counter.next(), id(obj), func)] = obj
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#
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# Finalization using weakrefs
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#
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_finalizer_registry = {}
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_finalizer_counter = itertools.count()
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class Finalize(object):
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'''
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Class which supports object finalization using weakrefs
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'''
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def __init__(self, obj, callback, args=(), kwargs=None, exitpriority=None):
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assert exitpriority is None or type(exitpriority) in (int, long)
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if obj is not None:
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self._weakref = weakref.ref(obj, self)
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else:
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assert exitpriority is not None
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self._callback = callback
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self._args = args
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self._kwargs = kwargs or {}
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self._key = (exitpriority, _finalizer_counter.next())
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self._pid = os.getpid()
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_finalizer_registry[self._key] = self
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def __call__(self, wr=None):
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'''
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Run the callback unless it has already been called or cancelled
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'''
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try:
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del _finalizer_registry[self._key]
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except KeyError:
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sub_debug('finalizer no longer registered')
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else:
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if self._pid != os.getpid():
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sub_debug('finalizer ignored because different process')
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res = None
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else:
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sub_debug('finalizer calling %s with args %s and kwargs %s',
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self._callback, self._args, self._kwargs)
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res = self._callback(*self._args, **self._kwargs)
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self._weakref = self._callback = self._args = \
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self._kwargs = self._key = None
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return res
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def cancel(self):
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'''
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Cancel finalization of the object
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'''
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try:
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del _finalizer_registry[self._key]
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except KeyError:
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pass
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else:
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self._weakref = self._callback = self._args = \
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self._kwargs = self._key = None
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def still_active(self):
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'''
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Return whether this finalizer is still waiting to invoke callback
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'''
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return self._key in _finalizer_registry
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def __repr__(self):
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try:
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obj = self._weakref()
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except (AttributeError, TypeError):
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obj = None
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if obj is None:
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return '<Finalize object, dead>'
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x = '<Finalize object, callback=%s' % \
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getattr(self._callback, '__name__', self._callback)
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if self._args:
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x += ', args=' + str(self._args)
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if self._kwargs:
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x += ', kwargs=' + str(self._kwargs)
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if self._key[0] is not None:
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x += ', exitprority=' + str(self._key[0])
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return x + '>'
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def _run_finalizers(minpriority=None):
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'''
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Run all finalizers whose exit priority is not None and at least minpriority
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Finalizers with highest priority are called first; finalizers with
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the same priority will be called in reverse order of creation.
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'''
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if _finalizer_registry is None:
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# This function may be called after this module's globals are
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# destroyed. See the _exit_function function in this module for more
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# notes.
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return
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if minpriority is None:
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f = lambda p : p[0][0] is not None
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else:
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f = lambda p : p[0][0] is not None and p[0][0] >= minpriority
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# Careful: _finalizer_registry may be mutated while this function
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# is running (either by a GC run or by another thread).
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items = [x for x in _finalizer_registry.items() if f(x)]
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items.sort(reverse=True)
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for key, finalizer in items:
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sub_debug('calling %s', finalizer)
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try:
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finalizer()
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except Exception:
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import traceback
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traceback.print_exc()
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if minpriority is None:
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_finalizer_registry.clear()
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#
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# Clean up on exit
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#
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def is_exiting():
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'''
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Returns true if the process is shutting down
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'''
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return _exiting or _exiting is None
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_exiting = False
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def _exit_function(info=info, debug=debug, _run_finalizers=_run_finalizers,
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active_children=active_children,
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current_process=current_process):
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# NB: we hold on to references to functions in the arglist due to the
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# situation described below, where this function is called after this
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# module's globals are destroyed.
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global _exiting
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info('process shutting down')
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debug('running all "atexit" finalizers with priority >= 0')
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_run_finalizers(0)
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if current_process() is not None:
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# NB: we check if the current process is None here because if
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# it's None, any call to ``active_children()`` will throw an
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# AttributeError (active_children winds up trying to get
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# attributes from util._current_process). This happens in a
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# variety of shutdown circumstances that are not well-understood
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# because module-scope variables are not apparently supposed to
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# be destroyed until after this function is called. However,
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# they are indeed destroyed before this function is called. See
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# issues 9775 and 15881. Also related: 4106, 9205, and 9207.
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for p in active_children():
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if p._daemonic:
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info('calling terminate() for daemon %s', p.name)
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p._popen.terminate()
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for p in active_children():
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info('calling join() for process %s', p.name)
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p.join()
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debug('running the remaining "atexit" finalizers')
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_run_finalizers()
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atexit.register(_exit_function)
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#
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# Some fork aware types
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#
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class ForkAwareThreadLock(object):
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def __init__(self):
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self._reset()
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register_after_fork(self, ForkAwareThreadLock._reset)
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def _reset(self):
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self._lock = threading.Lock()
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self.acquire = self._lock.acquire
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self.release = self._lock.release
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class ForkAwareLocal(threading.local):
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def __init__(self):
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register_after_fork(self, lambda obj : obj.__dict__.clear())
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def __reduce__(self):
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return type(self), ()
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