377 lines
11 KiB
Python
377 lines
11 KiB
Python
import os
|
|
import sys
|
|
import threading
|
|
|
|
from . import process
|
|
from . import reduction
|
|
|
|
__all__ = ()
|
|
|
|
#
|
|
# Exceptions
|
|
#
|
|
|
|
class ProcessError(Exception):
|
|
pass
|
|
|
|
class BufferTooShort(ProcessError):
|
|
pass
|
|
|
|
class TimeoutError(ProcessError):
|
|
pass
|
|
|
|
class AuthenticationError(ProcessError):
|
|
pass
|
|
|
|
#
|
|
# Base type for contexts. Bound methods of an instance of this type are included in __all__ of __init__.py
|
|
#
|
|
|
|
class BaseContext(object):
|
|
|
|
ProcessError = ProcessError
|
|
BufferTooShort = BufferTooShort
|
|
TimeoutError = TimeoutError
|
|
AuthenticationError = AuthenticationError
|
|
|
|
current_process = staticmethod(process.current_process)
|
|
parent_process = staticmethod(process.parent_process)
|
|
active_children = staticmethod(process.active_children)
|
|
|
|
def cpu_count(self):
|
|
'''Returns the number of CPUs in the system'''
|
|
num = os.cpu_count()
|
|
if num is None:
|
|
raise NotImplementedError('cannot determine number of cpus')
|
|
else:
|
|
return num
|
|
|
|
def Manager(self):
|
|
'''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(ctx=self.get_context())
|
|
m.start()
|
|
return m
|
|
|
|
def Pipe(self, duplex=True):
|
|
'''Returns two connection object connected by a pipe'''
|
|
from .connection import Pipe
|
|
return Pipe(duplex)
|
|
|
|
def Lock(self):
|
|
'''Returns a non-recursive lock object'''
|
|
from .synchronize import Lock
|
|
return Lock(ctx=self.get_context())
|
|
|
|
def RLock(self):
|
|
'''Returns a recursive lock object'''
|
|
from .synchronize import RLock
|
|
return RLock(ctx=self.get_context())
|
|
|
|
def Condition(self, lock=None):
|
|
'''Returns a condition object'''
|
|
from .synchronize import Condition
|
|
return Condition(lock, ctx=self.get_context())
|
|
|
|
def Semaphore(self, value=1):
|
|
'''Returns a semaphore object'''
|
|
from .synchronize import Semaphore
|
|
return Semaphore(value, ctx=self.get_context())
|
|
|
|
def BoundedSemaphore(self, value=1):
|
|
'''Returns a bounded semaphore object'''
|
|
from .synchronize import BoundedSemaphore
|
|
return BoundedSemaphore(value, ctx=self.get_context())
|
|
|
|
def Event(self):
|
|
'''Returns an event object'''
|
|
from .synchronize import Event
|
|
return Event(ctx=self.get_context())
|
|
|
|
def Barrier(self, parties, action=None, timeout=None):
|
|
'''Returns a barrier object'''
|
|
from .synchronize import Barrier
|
|
return Barrier(parties, action, timeout, ctx=self.get_context())
|
|
|
|
def Queue(self, maxsize=0):
|
|
'''Returns a queue object'''
|
|
from .queues import Queue
|
|
return Queue(maxsize, ctx=self.get_context())
|
|
|
|
def JoinableQueue(self, maxsize=0):
|
|
'''Returns a queue object'''
|
|
from .queues import JoinableQueue
|
|
return JoinableQueue(maxsize, ctx=self.get_context())
|
|
|
|
def SimpleQueue(self):
|
|
'''Returns a queue object'''
|
|
from .queues import SimpleQueue
|
|
return SimpleQueue(ctx=self.get_context())
|
|
|
|
def Pool(self, processes=None, initializer=None, initargs=(),
|
|
maxtasksperchild=None):
|
|
'''Returns a process pool object'''
|
|
from .pool import Pool
|
|
return Pool(processes, initializer, initargs, maxtasksperchild,
|
|
context=self.get_context())
|
|
|
|
def RawValue(self, typecode_or_type, *args):
|
|
'''Returns a shared object'''
|
|
from .sharedctypes import RawValue
|
|
return RawValue(typecode_or_type, *args)
|
|
|
|
def RawArray(self, typecode_or_type, size_or_initializer):
|
|
'''Returns a shared array'''
|
|
from .sharedctypes import RawArray
|
|
return RawArray(typecode_or_type, size_or_initializer)
|
|
|
|
def Value(self, typecode_or_type, *args, lock=True):
|
|
'''Returns a synchronized shared object'''
|
|
from .sharedctypes import Value
|
|
return Value(typecode_or_type, *args, lock=lock,
|
|
ctx=self.get_context())
|
|
|
|
def Array(self, typecode_or_type, size_or_initializer, *, lock=True):
|
|
'''Returns a synchronized shared array'''
|
|
from .sharedctypes import Array
|
|
return Array(typecode_or_type, size_or_initializer, lock=lock,
|
|
ctx=self.get_context())
|
|
|
|
def freeze_support(self):
|
|
'''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 .spawn import freeze_support
|
|
freeze_support()
|
|
|
|
def get_logger(self):
|
|
'''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(self, 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(self):
|
|
'''Install support for sending connections and sockets
|
|
between processes
|
|
'''
|
|
# This is undocumented. In previous versions of multiprocessing
|
|
# its only effect was to make socket objects inheritable on Windows.
|
|
from . import connection
|
|
|
|
def set_executable(self, executable):
|
|
'''Sets the path to a python.exe or pythonw.exe binary used to run
|
|
child processes instead of sys.executable when using the 'spawn'
|
|
start method. Useful for people embedding Python.
|
|
'''
|
|
from .spawn import set_executable
|
|
set_executable(executable)
|
|
|
|
def set_forkserver_preload(self, module_names):
|
|
'''Set list of module names to try to load in forkserver process.
|
|
This is really just a hint.
|
|
'''
|
|
from .forkserver import set_forkserver_preload
|
|
set_forkserver_preload(module_names)
|
|
|
|
def get_context(self, method=None):
|
|
if method is None:
|
|
return self
|
|
try:
|
|
ctx = _concrete_contexts[method]
|
|
except KeyError:
|
|
raise ValueError('cannot find context for %r' % method) from None
|
|
ctx._check_available()
|
|
return ctx
|
|
|
|
def get_start_method(self, allow_none=False):
|
|
return self._name
|
|
|
|
def set_start_method(self, method, force=False):
|
|
raise ValueError('cannot set start method of concrete context')
|
|
|
|
@property
|
|
def reducer(self):
|
|
'''Controls how objects will be reduced to a form that can be
|
|
shared with other processes.'''
|
|
return globals().get('reduction')
|
|
|
|
@reducer.setter
|
|
def reducer(self, reduction):
|
|
globals()['reduction'] = reduction
|
|
|
|
def _check_available(self):
|
|
pass
|
|
|
|
#
|
|
# Type of default context -- underlying context can be set at most once
|
|
#
|
|
|
|
class Process(process.BaseProcess):
|
|
_start_method = None
|
|
@staticmethod
|
|
def _Popen(process_obj):
|
|
return _default_context.get_context().Process._Popen(process_obj)
|
|
|
|
@staticmethod
|
|
def _after_fork():
|
|
return _default_context.get_context().Process._after_fork()
|
|
|
|
class DefaultContext(BaseContext):
|
|
Process = Process
|
|
|
|
def __init__(self, context):
|
|
self._default_context = context
|
|
self._actual_context = None
|
|
|
|
def get_context(self, method=None):
|
|
if method is None:
|
|
if self._actual_context is None:
|
|
self._actual_context = self._default_context
|
|
return self._actual_context
|
|
else:
|
|
return super().get_context(method)
|
|
|
|
def set_start_method(self, method, force=False):
|
|
if self._actual_context is not None and not force:
|
|
raise RuntimeError('context has already been set')
|
|
if method is None and force:
|
|
self._actual_context = None
|
|
return
|
|
self._actual_context = self.get_context(method)
|
|
|
|
def get_start_method(self, allow_none=False):
|
|
if self._actual_context is None:
|
|
if allow_none:
|
|
return None
|
|
self._actual_context = self._default_context
|
|
return self._actual_context._name
|
|
|
|
def get_all_start_methods(self):
|
|
if sys.platform == 'win32':
|
|
return ['spawn']
|
|
else:
|
|
methods = ['spawn', 'fork'] if sys.platform == 'darwin' else ['fork', 'spawn']
|
|
if reduction.HAVE_SEND_HANDLE:
|
|
methods.append('forkserver')
|
|
return methods
|
|
|
|
|
|
#
|
|
# Context types for fixed start method
|
|
#
|
|
|
|
if sys.platform != 'win32':
|
|
|
|
class ForkProcess(process.BaseProcess):
|
|
_start_method = 'fork'
|
|
@staticmethod
|
|
def _Popen(process_obj):
|
|
from .popen_fork import Popen
|
|
return Popen(process_obj)
|
|
|
|
class SpawnProcess(process.BaseProcess):
|
|
_start_method = 'spawn'
|
|
@staticmethod
|
|
def _Popen(process_obj):
|
|
from .popen_spawn_posix import Popen
|
|
return Popen(process_obj)
|
|
|
|
@staticmethod
|
|
def _after_fork():
|
|
# process is spawned, nothing to do
|
|
pass
|
|
|
|
class ForkServerProcess(process.BaseProcess):
|
|
_start_method = 'forkserver'
|
|
@staticmethod
|
|
def _Popen(process_obj):
|
|
from .popen_forkserver import Popen
|
|
return Popen(process_obj)
|
|
|
|
class ForkContext(BaseContext):
|
|
_name = 'fork'
|
|
Process = ForkProcess
|
|
|
|
class SpawnContext(BaseContext):
|
|
_name = 'spawn'
|
|
Process = SpawnProcess
|
|
|
|
class ForkServerContext(BaseContext):
|
|
_name = 'forkserver'
|
|
Process = ForkServerProcess
|
|
def _check_available(self):
|
|
if not reduction.HAVE_SEND_HANDLE:
|
|
raise ValueError('forkserver start method not available')
|
|
|
|
_concrete_contexts = {
|
|
'fork': ForkContext(),
|
|
'spawn': SpawnContext(),
|
|
'forkserver': ForkServerContext(),
|
|
}
|
|
if sys.platform == 'darwin':
|
|
# bpo-33725: running arbitrary code after fork() is no longer reliable
|
|
# on macOS since macOS 10.14 (Mojave). Use spawn by default instead.
|
|
_default_context = DefaultContext(_concrete_contexts['spawn'])
|
|
else:
|
|
_default_context = DefaultContext(_concrete_contexts['fork'])
|
|
|
|
else:
|
|
|
|
class SpawnProcess(process.BaseProcess):
|
|
_start_method = 'spawn'
|
|
@staticmethod
|
|
def _Popen(process_obj):
|
|
from .popen_spawn_win32 import Popen
|
|
return Popen(process_obj)
|
|
|
|
@staticmethod
|
|
def _after_fork():
|
|
# process is spawned, nothing to do
|
|
pass
|
|
|
|
class SpawnContext(BaseContext):
|
|
_name = 'spawn'
|
|
Process = SpawnProcess
|
|
|
|
_concrete_contexts = {
|
|
'spawn': SpawnContext(),
|
|
}
|
|
_default_context = DefaultContext(_concrete_contexts['spawn'])
|
|
|
|
#
|
|
# Force the start method
|
|
#
|
|
|
|
def _force_start_method(method):
|
|
_default_context._actual_context = _concrete_contexts[method]
|
|
|
|
#
|
|
# Check that the current thread is spawning a child process
|
|
#
|
|
|
|
_tls = threading.local()
|
|
|
|
def get_spawning_popen():
|
|
return getattr(_tls, 'spawning_popen', None)
|
|
|
|
def set_spawning_popen(popen):
|
|
_tls.spawning_popen = popen
|
|
|
|
def assert_spawning(obj):
|
|
if get_spawning_popen() is None:
|
|
raise RuntimeError(
|
|
'%s objects should only be shared between processes'
|
|
' through inheritance' % type(obj).__name__
|
|
)
|