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- #
- # Module providing the `Process` class which emulates `threading.Thread`
- #
- # processing/process.py
- #
- # Copyright (c) 2006-2008, R Oudkerk --- see COPYING.txt
- #
- __all__ = [
- 'Process', 'currentProcess', 'activeChildren'
- ]
- #
- # Imports
- #
- import os
- import sys
- import time
- import signal
- import atexit
- import weakref
- import copy_reg
- import itertools
- #
- # Public functions
- #
- def currentProcess():
- '''
- Return process object representing the current process
- '''
- return _current_process
- def activeChildren():
- '''
- Return list of process objects corresponding to live child processes
- '''
- _cleanup()
- return list(_current_process._children)
-
- #
- #
- #
- def _cleanup():
- '''
- Purge `_children` of dead processes
- '''
- 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`
- '''
- def __init__(self, group=None, target=None, name=None, args=(), kwargs={}):
- counter = _current_process._counter.next()
- self._identity = _current_process._identity + (counter,)
- self._authkey = _current_process._authkey
- self._daemonic = _current_process._daemonic
- self._parent_pid = os.getpid()
- self._popen = None
- self._exiting = False
- self._target = target
- self._args = tuple(args)
- self._kwargs = kwargs.copy()
- self._name = name or 'Process-' + ':'.join(map(str, 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
- '''
- from processing.forking import Popen
- 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'
- _cleanup()
- 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'
- if timeout == 0:
- res = self._popen.poll()
- elif timeout is None:
- res = self._popen.wait()
- else:
- res = self._popen.waitTimeout(timeout)
- if res is not None:
- _current_process._children.discard(self)
- def isAlive(self):
- '''
- Return whether child 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
- def getName(self):
- '''
- Return name of process
- '''
- return self._name
- def setName(self, name):
- '''
- Set name of process
- '''
- assert type(name) is str, 'name must be a string'
- self._name = name
- def isDaemon(self):
- '''
- Return whether process is a daemon
- '''
- return self._daemonic
- def setDaemon(self, daemonic):
- '''
- Set whether process is a daemon
- '''
- assert self._popen is None, 'process has already started'
- self._daemonic = daemonic
- def getAuthKey(self):
- '''
- Return authorization key of process
- '''
- return self._authkey
- def setAuthKey(self, authkey):
- '''
- Set authorization key of process
- '''
- assert type(authkey) is str, 'value must be a string'
- self._authkey = authkey
- def getExitCode(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()
- def getPid(self):
- '''
- Return PID of process or `None` if it has yet to start
- '''
- if self is _current_process:
- return os.getpid()
- else:
- assert self._parent_pid == os.getpid(), 'not a child process'
- return self._popen and self._popen.pid
- 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.getExitCode()
- 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 processing.finalize import _registry
- from processing.logger import info
-
- global _current_process
- try:
- self._children = set()
- self._counter = itertools.count(1)
- sys.stdin.close()
- _registry.clear()
- _current_process = self
- _runAfterForkers()
- info('child process calling self.run()')
- try:
- self.run()
- exitcode = 0
- finally:
- _exitFunction()
- except SystemExit, e:
- if not e.args:
- exitcode = 1
- elif type(e.args[0]) is int:
- exitcode = e.args[0]
- else:
- print >>sys.stderr, e.args[0]
- exitcode = 1
- except:
- exitcode = 1
- import traceback
- print >>sys.stderr, 'Process %s:' % self.getName()
- traceback.print_exc()
- info('process exiting with exitcode %d' % exitcode)
- return exitcode
- #
- # 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 = ''.join('%02x' % ord(c) for c in os.urandom(16))
- _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
- #
- # Make bound and unbound instance methods and class methods picklable
- #
- def _reduceMethod(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(_current_process.start), _reduceMethod)
- #
- # Support for reinitialization of objects when bootstrapping a child process
- #
- _afterfork_registry = weakref.WeakValueDictionary()
- _afterForkerId = itertools.count().next
- def _runAfterForkers():
- # execute in order of registration
- for (index, ident, func), obj in sorted(_afterfork_registry.items()):
- func(obj)
-
- def _registerAfterFork(obj, func):
- _afterfork_registry[(_afterForkerId(), id(obj), func)] = obj
-
- #
- # Clean up on exit
- #
- def _exitFunction():
- from processing.finalize import _runFinalizers
- from processing.logger import info
-
- _current_process._exiting = True
- info('running all "atexit" finalizers with priority >= 0')
- _runFinalizers(0)
- for p in activeChildren():
- if p._daemonic:
- info('calling `terminate()` for daemon %s', p.getName())
- p._popen.terminate()
- for p in activeChildren():
- info('calling `join()` for process %s', p.getName())
- p.join()
- info('running the remaining "atexit" finalizers')
- _runFinalizers()
- atexit.register(_exitFunction)
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