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