375 lines
11 KiB
Python
375 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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# Licensed to PSF under a Contributor Agreement.
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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 . import process
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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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'close_all_fds_except', '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
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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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# 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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tempdir = process.current_process()._config.get('tempdir')
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if 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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process.current_process()._config['tempdir'] = tempdir
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return 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 as 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[(next(_afterfork_counter), 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) is int
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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, next(_finalizer_counter))
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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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# Need to bind these locally because the globals can have
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# been cleared at shutdown
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_finalizer_registry=_finalizer_registry,
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sub_debug=sub_debug, getpid=os.getpid):
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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 != 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 '<%s object, dead>' % self.__class__.__name__
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x = '<%s object, callback=%s' % (
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self.__class__.__name__,
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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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items = [x for x in list(_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=process.active_children,
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current_process=process.current_process):
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# 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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if not _exiting:
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_exiting = True
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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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# We check if the current process is None here because if
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# it's None, any call to ``active_children()`` will raise
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# an AttributeError (active_children winds up trying to
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# get attributes from util._current_process). One
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# situation where this can happen is if someone has
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# manipulated sys.modules, causing this module to be
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# garbage collected. The destructor for the module type
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# then replaces all values in the module dict with None.
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# For instance, after setuptools runs a test it replaces
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# sys.modules with a copy created earlier. See issues
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# #9775 and #15881. Also related: #4106, #9205, and
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# #9207.
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for p in active_children():
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if p.daemon:
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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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def __enter__(self):
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return self._lock.__enter__()
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def __exit__(self, *args):
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return self._lock.__exit__(*args)
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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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#
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# Close fds except those specified
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#
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try:
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MAXFD = os.sysconf("SC_OPEN_MAX")
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except Exception:
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MAXFD = 256
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def close_all_fds_except(fds):
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fds = list(fds) + [-1, MAXFD]
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fds.sort()
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assert fds[-1] == MAXFD, 'fd too large'
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for i in range(len(fds) - 1):
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os.closerange(fds[i]+1, fds[i+1])
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#
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# Start a program with only specified fds kept open
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#
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def spawnv_passfds(path, args, passfds):
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import _posixsubprocess
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passfds = sorted(passfds)
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errpipe_read, errpipe_write = os.pipe()
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try:
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return _posixsubprocess.fork_exec(
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args, [os.fsencode(path)], True, passfds, None, None,
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-1, -1, -1, -1, -1, -1, errpipe_read, errpipe_write,
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False, False, None)
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finally:
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os.close(errpipe_read)
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os.close(errpipe_write)
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