| # |
| # Module providing the `Process` class which emulates `threading.Thread` |
| # |
| # multiprocessing/process.py |
| # |
| # Copyright (c) 2006-2008, R Oudkerk |
| # All rights reserved. |
| # |
| # Redistribution and use in source and binary forms, with or without |
| # modification, are permitted provided that the following conditions |
| # are met: |
| # |
| # 1. Redistributions of source code must retain the above copyright |
| # notice, this list of conditions and the following disclaimer. |
| # 2. Redistributions in binary form must reproduce the above copyright |
| # notice, this list of conditions and the following disclaimer in the |
| # documentation and/or other materials provided with the distribution. |
| # 3. Neither the name of author nor the names of any contributors may be |
| # used to endorse or promote products derived from this software |
| # without specific prior written permission. |
| # |
| # THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND |
| # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| # ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| # SUCH DAMAGE. |
| # |
| |
| __all__ = ['Process', 'current_process', 'active_children'] |
| |
| # |
| # Imports |
| # |
| |
| import os |
| import sys |
| import signal |
| import itertools |
| |
| # |
| # |
| # |
| |
| try: |
| ORIGINAL_DIR = os.path.abspath(os.getcwd()) |
| except OSError: |
| ORIGINAL_DIR = None |
| |
| # |
| # Public functions |
| # |
| |
| def current_process(): |
| ''' |
| Return process object representing the current process |
| ''' |
| return _current_process |
| |
| def active_children(): |
| ''' |
| Return list of process objects corresponding to live child processes |
| ''' |
| _cleanup() |
| return list(_current_process._children) |
| |
| # |
| # |
| # |
| |
| def _cleanup(): |
| # check for processes which have finished |
| for p in list(_current_process._children): |
| if p._popen.poll() is not None: |
| _current_process._children.discard(p) |
| |
| # |
| # The `Process` class |
| # |
| |
| class Process(object): |
| ''' |
| Process objects represent activity that is run in a separate process |
| |
| The class is analagous to `threading.Thread` |
| ''' |
| _Popen = None |
| |
| def __init__(self, group=None, target=None, name=None, args=(), kwargs={}): |
| assert group is None, 'group argument must be None for now' |
| count = _current_process._counter.next() |
| self._identity = _current_process._identity + (count,) |
| self._authkey = _current_process._authkey |
| self._daemonic = _current_process._daemonic |
| self._tempdir = _current_process._tempdir |
| self._parent_pid = os.getpid() |
| self._popen = None |
| self._target = target |
| self._args = tuple(args) |
| self._kwargs = dict(kwargs) |
| self._name = name or type(self).__name__ + '-' + \ |
| ':'.join(str(i) for i in self._identity) |
| |
| def run(self): |
| ''' |
| Method to be run in sub-process; can be overridden in sub-class |
| ''' |
| if self._target: |
| self._target(*self._args, **self._kwargs) |
| |
| def start(self): |
| ''' |
| Start child process |
| ''' |
| assert self._popen is None, 'cannot start a process twice' |
| assert self._parent_pid == os.getpid(), \ |
| 'can only start a process object created by current process' |
| assert not _current_process._daemonic, \ |
| 'daemonic processes are not allowed to have children' |
| _cleanup() |
| if self._Popen is not None: |
| Popen = self._Popen |
| else: |
| from .forking import Popen |
| self._popen = Popen(self) |
| _current_process._children.add(self) |
| |
| def terminate(self): |
| ''' |
| Terminate process; sends SIGTERM signal or uses TerminateProcess() |
| ''' |
| self._popen.terminate() |
| |
| def join(self, timeout=None): |
| ''' |
| Wait until child process terminates |
| ''' |
| assert self._parent_pid == os.getpid(), 'can only join a child process' |
| assert self._popen is not None, 'can only join a started process' |
| res = self._popen.wait(timeout) |
| if res is not None: |
| _current_process._children.discard(self) |
| |
| def is_alive(self): |
| ''' |
| Return whether process is alive |
| ''' |
| if self is _current_process: |
| return True |
| assert self._parent_pid == os.getpid(), 'can only test a child process' |
| if self._popen is None: |
| return False |
| self._popen.poll() |
| return self._popen.returncode is None |
| |
| @property |
| def name(self): |
| return self._name |
| |
| @name.setter |
| def name(self, name): |
| assert isinstance(name, basestring), 'name must be a string' |
| self._name = name |
| |
| @property |
| def daemon(self): |
| ''' |
| Return whether process is a daemon |
| ''' |
| return self._daemonic |
| |
| @daemon.setter |
| def daemon(self, daemonic): |
| ''' |
| Set whether process is a daemon |
| ''' |
| assert self._popen is None, 'process has already started' |
| self._daemonic = daemonic |
| |
| @property |
| def authkey(self): |
| return self._authkey |
| |
| @authkey.setter |
| def authkey(self, authkey): |
| ''' |
| Set authorization key of process |
| ''' |
| self._authkey = AuthenticationString(authkey) |
| |
| @property |
| def exitcode(self): |
| ''' |
| Return exit code of process or `None` if it has yet to stop |
| ''' |
| if self._popen is None: |
| return self._popen |
| return self._popen.poll() |
| |
| @property |
| def ident(self): |
| ''' |
| Return identifier (PID) of process or `None` if it has yet to start |
| ''' |
| if self is _current_process: |
| return os.getpid() |
| else: |
| return self._popen and self._popen.pid |
| |
| pid = ident |
| |
| def __repr__(self): |
| if self is _current_process: |
| status = 'started' |
| elif self._parent_pid != os.getpid(): |
| status = 'unknown' |
| elif self._popen is None: |
| status = 'initial' |
| else: |
| if self._popen.poll() is not None: |
| status = self.exitcode |
| else: |
| status = 'started' |
| |
| if type(status) is int: |
| if status == 0: |
| status = 'stopped' |
| else: |
| status = 'stopped[%s]' % _exitcode_to_name.get(status, status) |
| |
| return '<%s(%s, %s%s)>' % (type(self).__name__, self._name, |
| status, self._daemonic and ' daemon' or '') |
| |
| ## |
| |
| def _bootstrap(self): |
| from . import util |
| global _current_process |
| |
| try: |
| self._children = set() |
| self._counter = itertools.count(1) |
| try: |
| sys.stdin.close() |
| sys.stdin = open(os.devnull) |
| except (OSError, ValueError): |
| pass |
| _current_process = self |
| util._finalizer_registry.clear() |
| util._run_after_forkers() |
| util.info('child process calling self.run()') |
| try: |
| self.run() |
| exitcode = 0 |
| finally: |
| util._exit_function() |
| except SystemExit, e: |
| if not e.args: |
| exitcode = 1 |
| elif isinstance(e.args[0], int): |
| exitcode = e.args[0] |
| else: |
| sys.stderr.write(str(e.args[0]) + '\n') |
| sys.stderr.flush() |
| exitcode = 0 if isinstance(e.args[0], str) else 1 |
| except: |
| exitcode = 1 |
| import traceback |
| sys.stderr.write('Process %s:\n' % self.name) |
| sys.stderr.flush() |
| traceback.print_exc() |
| |
| util.info('process exiting with exitcode %d' % exitcode) |
| return exitcode |
| |
| # |
| # We subclass bytes to avoid accidental transmission of auth keys over network |
| # |
| |
| class AuthenticationString(bytes): |
| def __reduce__(self): |
| from .forking import Popen |
| if not Popen.thread_is_spawning(): |
| raise TypeError( |
| 'Pickling an AuthenticationString object is ' |
| 'disallowed for security reasons' |
| ) |
| return AuthenticationString, (bytes(self),) |
| |
| # |
| # Create object representing the main process |
| # |
| |
| class _MainProcess(Process): |
| |
| def __init__(self): |
| self._identity = () |
| self._daemonic = False |
| self._name = 'MainProcess' |
| self._parent_pid = None |
| self._popen = None |
| self._counter = itertools.count(1) |
| self._children = set() |
| self._authkey = AuthenticationString(os.urandom(32)) |
| self._tempdir = None |
| |
| _current_process = _MainProcess() |
| del _MainProcess |
| |
| # |
| # Give names to some return codes |
| # |
| |
| _exitcode_to_name = {} |
| |
| for name, signum in signal.__dict__.items(): |
| if name[:3]=='SIG' and '_' not in name: |
| _exitcode_to_name[-signum] = name |
