Richard Oudkerk | b1694cf | 2013-10-16 16:41:56 +0100 | [diff] [blame] | 1 | import os |
| 2 | import sys |
| 3 | import threading |
| 4 | |
| 5 | from . import process |
Davin Potts | 5458647 | 2016-09-09 18:03:10 -0500 | [diff] [blame] | 6 | from . import reduction |
Richard Oudkerk | b1694cf | 2013-10-16 16:41:56 +0100 | [diff] [blame] | 7 | |
| 8 | __all__ = [] # things are copied from here to __init__.py |
| 9 | |
| 10 | # |
| 11 | # Exceptions |
| 12 | # |
| 13 | |
| 14 | class ProcessError(Exception): |
| 15 | pass |
| 16 | |
| 17 | class BufferTooShort(ProcessError): |
| 18 | pass |
| 19 | |
| 20 | class TimeoutError(ProcessError): |
| 21 | pass |
| 22 | |
| 23 | class AuthenticationError(ProcessError): |
| 24 | pass |
| 25 | |
| 26 | # |
| 27 | # Base type for contexts |
| 28 | # |
| 29 | |
| 30 | class BaseContext(object): |
| 31 | |
| 32 | ProcessError = ProcessError |
| 33 | BufferTooShort = BufferTooShort |
| 34 | TimeoutError = TimeoutError |
| 35 | AuthenticationError = AuthenticationError |
| 36 | |
| 37 | current_process = staticmethod(process.current_process) |
| 38 | active_children = staticmethod(process.active_children) |
| 39 | |
| 40 | def cpu_count(self): |
| 41 | '''Returns the number of CPUs in the system''' |
| 42 | num = os.cpu_count() |
| 43 | if num is None: |
| 44 | raise NotImplementedError('cannot determine number of cpus') |
| 45 | else: |
| 46 | return num |
| 47 | |
| 48 | def Manager(self): |
| 49 | '''Returns a manager associated with a running server process |
| 50 | |
| 51 | The managers methods such as `Lock()`, `Condition()` and `Queue()` |
| 52 | can be used to create shared objects. |
| 53 | ''' |
| 54 | from .managers import SyncManager |
| 55 | m = SyncManager(ctx=self.get_context()) |
| 56 | m.start() |
| 57 | return m |
| 58 | |
| 59 | def Pipe(self, duplex=True): |
| 60 | '''Returns two connection object connected by a pipe''' |
| 61 | from .connection import Pipe |
| 62 | return Pipe(duplex) |
| 63 | |
| 64 | def Lock(self): |
| 65 | '''Returns a non-recursive lock object''' |
| 66 | from .synchronize import Lock |
| 67 | return Lock(ctx=self.get_context()) |
| 68 | |
| 69 | def RLock(self): |
| 70 | '''Returns a recursive lock object''' |
| 71 | from .synchronize import RLock |
| 72 | return RLock(ctx=self.get_context()) |
| 73 | |
| 74 | def Condition(self, lock=None): |
| 75 | '''Returns a condition object''' |
| 76 | from .synchronize import Condition |
| 77 | return Condition(lock, ctx=self.get_context()) |
| 78 | |
| 79 | def Semaphore(self, value=1): |
| 80 | '''Returns a semaphore object''' |
| 81 | from .synchronize import Semaphore |
| 82 | return Semaphore(value, ctx=self.get_context()) |
| 83 | |
| 84 | def BoundedSemaphore(self, value=1): |
| 85 | '''Returns a bounded semaphore object''' |
| 86 | from .synchronize import BoundedSemaphore |
| 87 | return BoundedSemaphore(value, ctx=self.get_context()) |
| 88 | |
| 89 | def Event(self): |
| 90 | '''Returns an event object''' |
| 91 | from .synchronize import Event |
| 92 | return Event(ctx=self.get_context()) |
| 93 | |
| 94 | def Barrier(self, parties, action=None, timeout=None): |
| 95 | '''Returns a barrier object''' |
| 96 | from .synchronize import Barrier |
| 97 | return Barrier(parties, action, timeout, ctx=self.get_context()) |
| 98 | |
| 99 | def Queue(self, maxsize=0): |
| 100 | '''Returns a queue object''' |
| 101 | from .queues import Queue |
| 102 | return Queue(maxsize, ctx=self.get_context()) |
| 103 | |
| 104 | def JoinableQueue(self, maxsize=0): |
| 105 | '''Returns a queue object''' |
| 106 | from .queues import JoinableQueue |
| 107 | return JoinableQueue(maxsize, ctx=self.get_context()) |
| 108 | |
| 109 | def SimpleQueue(self): |
| 110 | '''Returns a queue object''' |
| 111 | from .queues import SimpleQueue |
| 112 | return SimpleQueue(ctx=self.get_context()) |
| 113 | |
| 114 | def Pool(self, processes=None, initializer=None, initargs=(), |
| 115 | maxtasksperchild=None): |
| 116 | '''Returns a process pool object''' |
| 117 | from .pool import Pool |
| 118 | return Pool(processes, initializer, initargs, maxtasksperchild, |
| 119 | context=self.get_context()) |
| 120 | |
| 121 | def RawValue(self, typecode_or_type, *args): |
| 122 | '''Returns a shared object''' |
| 123 | from .sharedctypes import RawValue |
| 124 | return RawValue(typecode_or_type, *args) |
| 125 | |
| 126 | def RawArray(self, typecode_or_type, size_or_initializer): |
| 127 | '''Returns a shared array''' |
| 128 | from .sharedctypes import RawArray |
| 129 | return RawArray(typecode_or_type, size_or_initializer) |
| 130 | |
| 131 | def Value(self, typecode_or_type, *args, lock=True): |
| 132 | '''Returns a synchronized shared object''' |
| 133 | from .sharedctypes import Value |
| 134 | return Value(typecode_or_type, *args, lock=lock, |
| 135 | ctx=self.get_context()) |
| 136 | |
| 137 | def Array(self, typecode_or_type, size_or_initializer, *, lock=True): |
| 138 | '''Returns a synchronized shared array''' |
| 139 | from .sharedctypes import Array |
| 140 | return Array(typecode_or_type, size_or_initializer, lock=lock, |
| 141 | ctx=self.get_context()) |
| 142 | |
| 143 | def freeze_support(self): |
| 144 | '''Check whether this is a fake forked process in a frozen executable. |
| 145 | If so then run code specified by commandline and exit. |
| 146 | ''' |
| 147 | if sys.platform == 'win32' and getattr(sys, 'frozen', False): |
| 148 | from .spawn import freeze_support |
| 149 | freeze_support() |
| 150 | |
| 151 | def get_logger(self): |
| 152 | '''Return package logger -- if it does not already exist then |
| 153 | it is created. |
| 154 | ''' |
| 155 | from .util import get_logger |
| 156 | return get_logger() |
| 157 | |
| 158 | def log_to_stderr(self, level=None): |
| 159 | '''Turn on logging and add a handler which prints to stderr''' |
| 160 | from .util import log_to_stderr |
| 161 | return log_to_stderr(level) |
| 162 | |
| 163 | def allow_connection_pickling(self): |
| 164 | '''Install support for sending connections and sockets |
| 165 | between processes |
| 166 | ''' |
| 167 | # This is undocumented. In previous versions of multiprocessing |
| 168 | # its only effect was to make socket objects inheritable on Windows. |
| 169 | from . import connection |
| 170 | |
| 171 | def set_executable(self, executable): |
| 172 | '''Sets the path to a python.exe or pythonw.exe binary used to run |
| 173 | child processes instead of sys.executable when using the 'spawn' |
| 174 | start method. Useful for people embedding Python. |
| 175 | ''' |
| 176 | from .spawn import set_executable |
| 177 | set_executable(executable) |
| 178 | |
| 179 | def set_forkserver_preload(self, module_names): |
| 180 | '''Set list of module names to try to load in forkserver process. |
| 181 | This is really just a hint. |
| 182 | ''' |
| 183 | from .forkserver import set_forkserver_preload |
| 184 | set_forkserver_preload(module_names) |
| 185 | |
| 186 | def get_context(self, method=None): |
| 187 | if method is None: |
| 188 | return self |
| 189 | try: |
| 190 | ctx = _concrete_contexts[method] |
| 191 | except KeyError: |
| 192 | raise ValueError('cannot find context for %r' % method) |
| 193 | ctx._check_available() |
| 194 | return ctx |
| 195 | |
| 196 | def get_start_method(self, allow_none=False): |
| 197 | return self._name |
| 198 | |
Antoine Pitrou | cd2a201 | 2016-12-10 17:13:16 +0100 | [diff] [blame] | 199 | def set_start_method(self, method, force=False): |
Richard Oudkerk | b1694cf | 2013-10-16 16:41:56 +0100 | [diff] [blame] | 200 | raise ValueError('cannot set start method of concrete context') |
| 201 | |
Davin Potts | 5458647 | 2016-09-09 18:03:10 -0500 | [diff] [blame] | 202 | @property |
| 203 | def reducer(self): |
| 204 | '''Controls how objects will be reduced to a form that can be |
| 205 | shared with other processes.''' |
| 206 | return globals().get('reduction') |
| 207 | |
| 208 | @reducer.setter |
| 209 | def reducer(self, reduction): |
| 210 | globals()['reduction'] = reduction |
| 211 | |
Richard Oudkerk | b1694cf | 2013-10-16 16:41:56 +0100 | [diff] [blame] | 212 | def _check_available(self): |
| 213 | pass |
| 214 | |
| 215 | # |
| 216 | # Type of default context -- underlying context can be set at most once |
| 217 | # |
| 218 | |
| 219 | class Process(process.BaseProcess): |
| 220 | _start_method = None |
| 221 | @staticmethod |
| 222 | def _Popen(process_obj): |
| 223 | return _default_context.get_context().Process._Popen(process_obj) |
| 224 | |
| 225 | class DefaultContext(BaseContext): |
| 226 | Process = Process |
| 227 | |
| 228 | def __init__(self, context): |
| 229 | self._default_context = context |
| 230 | self._actual_context = None |
| 231 | |
| 232 | def get_context(self, method=None): |
| 233 | if method is None: |
| 234 | if self._actual_context is None: |
| 235 | self._actual_context = self._default_context |
| 236 | return self._actual_context |
| 237 | else: |
| 238 | return super().get_context(method) |
| 239 | |
| 240 | def set_start_method(self, method, force=False): |
| 241 | if self._actual_context is not None and not force: |
| 242 | raise RuntimeError('context has already been set') |
| 243 | if method is None and force: |
| 244 | self._actual_context = None |
| 245 | return |
| 246 | self._actual_context = self.get_context(method) |
| 247 | |
| 248 | def get_start_method(self, allow_none=False): |
| 249 | if self._actual_context is None: |
| 250 | if allow_none: |
| 251 | return None |
| 252 | self._actual_context = self._default_context |
| 253 | return self._actual_context._name |
| 254 | |
| 255 | def get_all_start_methods(self): |
| 256 | if sys.platform == 'win32': |
| 257 | return ['spawn'] |
| 258 | else: |
Richard Oudkerk | b1694cf | 2013-10-16 16:41:56 +0100 | [diff] [blame] | 259 | if reduction.HAVE_SEND_HANDLE: |
| 260 | return ['fork', 'spawn', 'forkserver'] |
| 261 | else: |
| 262 | return ['fork', 'spawn'] |
| 263 | |
| 264 | DefaultContext.__all__ = list(x for x in dir(DefaultContext) if x[0] != '_') |
| 265 | |
| 266 | # |
| 267 | # Context types for fixed start method |
| 268 | # |
| 269 | |
| 270 | if sys.platform != 'win32': |
| 271 | |
| 272 | class ForkProcess(process.BaseProcess): |
| 273 | _start_method = 'fork' |
| 274 | @staticmethod |
| 275 | def _Popen(process_obj): |
| 276 | from .popen_fork import Popen |
| 277 | return Popen(process_obj) |
| 278 | |
| 279 | class SpawnProcess(process.BaseProcess): |
| 280 | _start_method = 'spawn' |
| 281 | @staticmethod |
| 282 | def _Popen(process_obj): |
| 283 | from .popen_spawn_posix import Popen |
| 284 | return Popen(process_obj) |
| 285 | |
| 286 | class ForkServerProcess(process.BaseProcess): |
| 287 | _start_method = 'forkserver' |
| 288 | @staticmethod |
| 289 | def _Popen(process_obj): |
| 290 | from .popen_forkserver import Popen |
| 291 | return Popen(process_obj) |
| 292 | |
| 293 | class ForkContext(BaseContext): |
| 294 | _name = 'fork' |
| 295 | Process = ForkProcess |
| 296 | |
| 297 | class SpawnContext(BaseContext): |
| 298 | _name = 'spawn' |
| 299 | Process = SpawnProcess |
| 300 | |
| 301 | class ForkServerContext(BaseContext): |
| 302 | _name = 'forkserver' |
| 303 | Process = ForkServerProcess |
| 304 | def _check_available(self): |
Richard Oudkerk | b1694cf | 2013-10-16 16:41:56 +0100 | [diff] [blame] | 305 | if not reduction.HAVE_SEND_HANDLE: |
| 306 | raise ValueError('forkserver start method not available') |
| 307 | |
| 308 | _concrete_contexts = { |
| 309 | 'fork': ForkContext(), |
| 310 | 'spawn': SpawnContext(), |
| 311 | 'forkserver': ForkServerContext(), |
| 312 | } |
| 313 | _default_context = DefaultContext(_concrete_contexts['fork']) |
| 314 | |
| 315 | else: |
| 316 | |
| 317 | class SpawnProcess(process.BaseProcess): |
| 318 | _start_method = 'spawn' |
| 319 | @staticmethod |
| 320 | def _Popen(process_obj): |
| 321 | from .popen_spawn_win32 import Popen |
| 322 | return Popen(process_obj) |
| 323 | |
| 324 | class SpawnContext(BaseContext): |
| 325 | _name = 'spawn' |
| 326 | Process = SpawnProcess |
| 327 | |
| 328 | _concrete_contexts = { |
| 329 | 'spawn': SpawnContext(), |
| 330 | } |
| 331 | _default_context = DefaultContext(_concrete_contexts['spawn']) |
| 332 | |
| 333 | # |
| 334 | # Force the start method |
| 335 | # |
| 336 | |
| 337 | def _force_start_method(method): |
| 338 | _default_context._actual_context = _concrete_contexts[method] |
| 339 | |
| 340 | # |
| 341 | # Check that the current thread is spawning a child process |
| 342 | # |
| 343 | |
| 344 | _tls = threading.local() |
| 345 | |
| 346 | def get_spawning_popen(): |
| 347 | return getattr(_tls, 'spawning_popen', None) |
| 348 | |
| 349 | def set_spawning_popen(popen): |
| 350 | _tls.spawning_popen = popen |
| 351 | |
| 352 | def assert_spawning(obj): |
| 353 | if get_spawning_popen() is None: |
| 354 | raise RuntimeError( |
| 355 | '%s objects should only be shared between processes' |
| 356 | ' through inheritance' % type(obj).__name__ |
| 357 | ) |