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Unified Diff: Lib/multiprocessing/util.py

Issue 2061: Review PEP 371 patch 1 Base URL: http://svn.python.org/view/*checkout*/python/trunk/
Patch Set: Created 15 years, 9 months ago
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Index: Lib/multiprocessing/util.py
===================================================================
--- Lib/multiprocessing/util.py (revision 0)
+++ Lib/multiprocessing/util.py (revision 0)
@@ -0,0 +1,336 @@
+#
+# Module providing various facilities to other parts of the package
+#
+# multiprocessing/util.py
+#
+# Copyright (c) 2006-2008, R Oudkerk --- see COPYING.txt
+#
+
+import itertools
+import weakref
+import copy_reg
+import atexit
+import threading # we want threading to install it's
+ # cleanup function before multiprocessing does
+
+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'
+ ]
+
+#
+# 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
+
+ if not _logger:
+ import logging, atexit
+
+ # 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, (), {}))
+
+ _check_logger_class()
+ _logger = logging.getLogger(LOGGER_NAME)
+
+ return _logger
+
+def _check_logger_class():
+ '''
+ Make sure process name is recorded when loggers are used
+ '''
+ # XXX This function is unnecessary once logging is patched
+ import logging
+ if hasattr(logging, 'multiprocessing'):
+ return
+
+ logging._acquireLock()
+ try:
+ OldLoggerClass = logging.getLoggerClass()
+ if not getattr(OldLoggerClass, '_process_aware', False):
+ class ProcessAwareLogger(OldLoggerClass):
+ _process_aware = True
+ def makeRecord(self, *args, **kwds):
+ record = OldLoggerClass.makeRecord(self, *args, **kwds)
+ record.processName = current_process()._name
+ return record
+ logging.setLoggerClass(ProcessAwareLogger)
+ finally:
+ logging._releaseLock()
+
+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 is not None:
+ logger.setLevel(level)
+ _log_to_stderr = True
+
+#
+# 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 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():
+ global _exiting
+
+ info('process shutting down')
+ debug('running all "atexit" finalizers with priority >= 0')
+ _run_finalizers(0)
+
+ for p in active_children():
+ if p._daemonic:
+ info('calling terminate() for daemon %s', p.get_name())
+ p._popen.terminate()
+
+ for p in active_children():
+ info('calling join() for process %s', p.get_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._lock = threading.Lock()
+ self.acquire = self._lock.acquire
+ self.release = self._lock.release
+ register_after_fork(self, ForkAwareThreadLock.__init__)
+
+class ForkAwareLocal(threading.local):
+ def __init__(self):
+ register_after_fork(self, lambda obj : obj.__dict__.clear())
+ def __reduce__(self):
+ return type(self), ()
+
+#
+# Try making some callable types picklable
+#
+
+def _reduce_method(m):
+ if m.im_self is None:
+ return getattr, (m.im_class, m.im_func.func_name)
+ else:
+ return getattr, (m.im_self, m.im_func.func_name)
+copy_reg.pickle(type(Finalize.__init__), _reduce_method)
+
+def _reduce_method_descriptor(m):
+ return getattr, (m.__objclass__, m.__name__)
+copy_reg.pickle(type(list.append), _reduce_method_descriptor)
+copy_reg.pickle(type(int.__add__), _reduce_method_descriptor)
+
+def _reduce_builtin_function_or_method(m):
+ return getattr, (m.__self__, m.__name__)
+copy_reg.pickle(type(list().append), _reduce_builtin_function_or_method)
+copy_reg.pickle(type(int().__add__), _reduce_builtin_function_or_method)
+
+try:
+ from functools import partial
+except ImportError:
+ pass
+else:
+ def _reduce_partial(p):
+ return _rebuild_partial, (p.func, p.args, p.keywords or {})
+ def _rebuild_partial(func, args, keywords):
+ return partial(func, *args, **keywords)
+ copy_reg.pickle(partial, _reduce_partial)

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