"""Python multiprocessing fork with improvements and bugfixes"""
#
# Package analogous to 'threading.py' but using processes
#
# multiprocessing/__init__.py
#
# This package is intended to duplicate the functionality (and much of
# the API) of threading.py but uses processes instead of threads. A
# subpackage 'multiprocessing.dummy' has the same API but is a simple
# wrapper for 'threading'.
#
# Try calling `multiprocessing.doc.main()` to read the html
# documentation in a webbrowser.
#
#
# Copyright (c) 2006-2008, R Oudkerk
# Licensed to PSF under a Contributor Agreement.
#
from __future__ import absolute_import
import os
import sys
import warnings
from .exceptions import ( # noqa
ProcessError,
BufferTooShort,
TimeoutError,
AuthenticationError,
TimeLimitExceeded,
SoftTimeLimitExceeded,
WorkerLostError,
)
from .process import Process, current_process, active_children
from .util import SUBDEBUG, SUBWARNING
VERSION = (3, 3, 0, 23)
__version__ = '.'.join(map(str, VERSION[0:4])) + "".join(VERSION[4:])
__author__ = 'R Oudkerk / Python Software Foundation'
__author_email__ = 'python-dev@python.org'
__maintainer__ = 'Ask Solem'
__contact__ = "ask@celeryproject.org"
__homepage__ = "http://github.com/celery/billiard"
__docformat__ = "restructuredtext"
# -eof meta-
__all__ = [
'Process', 'current_process', 'active_children', 'freeze_support',
'Manager', 'Pipe', 'cpu_count', 'log_to_stderr', 'get_logger',
'allow_connection_pickling', 'BufferTooShort', 'TimeoutError',
'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Condition',
'Event', 'Queue', 'JoinableQueue', 'Pool', 'Value', 'Array',
'RawValue', 'RawArray', 'SUBDEBUG', 'SUBWARNING', 'set_executable',
'forking_enable', 'forking_is_enabled'
]
def ensure_multiprocessing():
from ._ext import ensure_multiprocessing
return ensure_multiprocessing()
W_NO_EXECV = """\
force_execv is not supported as the billiard C extension \
is not installed\
"""
#
# Definitions not depending on native semaphores
#
def Manager():
'''
Returns a manager associated with a running server process
The managers methods such as `Lock()`, `Condition()` and `Queue()`
can be used to create shared objects.
'''
from .managers import SyncManager
m = SyncManager()
m.start()
return m
def Pipe(duplex=True, rnonblock=False, wnonblock=False):
'''
Returns two connection object connected by a pipe
'''
from billiard.connection import Pipe
return Pipe(duplex, rnonblock, wnonblock)
def cpu_count():
'''
Returns the number of CPUs in the system
'''
if sys.platform == 'win32':
try:
num = int(os.environ['NUMBER_OF_PROCESSORS'])
except (ValueError, KeyError):
num = 0
elif 'bsd' in sys.platform or sys.platform == 'darwin':
comm = '/sbin/sysctl -n hw.ncpu'
if sys.platform == 'darwin':
comm = '/usr' + comm
try:
with os.popen(comm) as p:
num = int(p.read())
except ValueError:
num = 0
else:
try:
num = os.sysconf('SC_NPROCESSORS_ONLN')
except (ValueError, OSError, AttributeError):
num = 0
if num >= 1:
return num
else:
raise NotImplementedError('cannot determine number of cpus')
def freeze_support():
'''
Check whether this is a fake forked process in a frozen executable.
If so then run code specified by commandline and exit.
'''
if sys.platform == 'win32' and getattr(sys, 'frozen', False):
from .forking import freeze_support
freeze_support()
def get_logger():
'''
Return package logger -- if it does not already exist then it is created
'''
from .util import get_logger
return get_logger()
def log_to_stderr(level=None):
'''
Turn on logging and add a handler which prints to stderr
'''
from .util import log_to_stderr
return log_to_stderr(level)
def allow_connection_pickling():
'''
Install support for sending connections and sockets between processes
'''
from . import reduction # noqa
#
# Definitions depending on native semaphores
#
def Lock():
'''
Returns a non-recursive lock object
'''
from .synchronize import Lock
return Lock()
def RLock():
'''
Returns a recursive lock object
'''
from .synchronize import RLock
return RLock()
def Condition(lock=None):
'''
Returns a condition object
'''
from .synchronize import Condition
return Condition(lock)
def Semaphore(value=1):
'''
Returns a semaphore object
'''
from .synchronize import Semaphore
return Semaphore(value)
def BoundedSemaphore(value=1):
'''
Returns a bounded semaphore object
'''
from .synchronize import BoundedSemaphore
return BoundedSemaphore(value)
def Event():
'''
Returns an event object
'''
from .synchronize import Event
return Event()
def Queue(maxsize=0):
'''
Returns a queue object
'''
from .queues import Queue
return Queue(maxsize)
def JoinableQueue(maxsize=0):
'''
Returns a queue object
'''
from .queues import JoinableQueue
return JoinableQueue(maxsize)
def Pool(processes=None, initializer=None, initargs=(), maxtasksperchild=None,
timeout=None, soft_timeout=None, lost_worker_timeout=None,
max_restarts=None, max_restart_freq=1, on_process_up=None,
on_process_down=None, on_timeout_set=None, on_timeout_cancel=None,
threads=True, semaphore=None, putlocks=False, allow_restart=False):
'''
Returns a process pool object
'''
from .pool import Pool
return Pool(processes, initializer, initargs, maxtasksperchild,
timeout, soft_timeout, lost_worker_timeout,
max_restarts, max_restart_freq, on_process_up,
on_process_down, on_timeout_set, on_timeout_cancel,
threads, semaphore, putlocks, allow_restart)
def RawValue(typecode_or_type, *args):
'''
Returns a shared object
'''
from .sharedctypes import RawValue
return RawValue(typecode_or_type, *args)
def RawArray(typecode_or_type, size_or_initializer):
'''
Returns a shared array
'''
from .sharedctypes import RawArray
return RawArray(typecode_or_type, size_or_initializer)
def Value(typecode_or_type, *args, **kwds):
'''
Returns a synchronized shared object
'''
from .sharedctypes import Value
return Value(typecode_or_type, *args, **kwds)
def Array(typecode_or_type, size_or_initializer, **kwds):
'''
Returns a synchronized shared array
'''
from .sharedctypes import Array
return Array(typecode_or_type, size_or_initializer, **kwds)
#
#
#
def set_executable(executable):
'''
Sets the path to a python.exe or pythonw.exe binary used to run
child processes on Windows instead of sys.executable.
Useful for people embedding Python.
'''
from .forking import set_executable
set_executable(executable)
def forking_is_enabled():
'''
Returns a boolean value indicating whether billiard is
currently set to create child processes by forking the current
python process rather than by starting a new instances of python.
On Windows this always returns `False`. On Unix it returns `True` by
default.
'''
from . import forking
return forking._forking_is_enabled
def forking_enable(value):
'''
Enable/disable creation of child process by forking the current process.
`value` should be a boolean value. If `value` is true then
forking is enabled. If `value` is false then forking is disabled.
On systems with `os.fork()` forking is enabled by default, and on
other systems it is always disabled.
'''
if not value:
from ._ext import supports_exec
if supports_exec:
from . import forking
if value and not hasattr(os, 'fork'):
raise ValueError('os.fork() not found')
forking._forking_is_enabled = bool(value)
if not value:
os.environ["MULTIPROCESSING_FORKING_DISABLE"] = "1"
else:
warnings.warn(RuntimeWarning(W_NO_EXECV))
if os.environ.get("MULTIPROCESSING_FORKING_DISABLE"):
forking_enable(False)