API docs for “twisted.internet.process.Process”

An operating-system Process.

This represents an operating-system process with arbitrary input/output pipes connected to it. Those pipes may represent standard input, standard output, and standard error, or any other file descriptor.

On UNIX, this is implemented using fork(), exec(), pipe() and fcntl(). These calls may not exist elsewhere so this code is not cross-platform. (also, windows can only select on sockets...)

Method	__init__	Spawn an operating-system process.
Method	_setupChild	fdmap[childFD] = parentFD
Method	_execChild	Undocumented
Method	reapProcess	Try to reap a process (without blocking) via waitpid.
Method	writeToChild	Undocumented
Method	closeChildFD	Undocumented
Method	pauseProducing	Undocumented
Method	resumeProducing	Undocumented
Method	closeStdin	Call this to close standard input on this process.
Method	closeStdout	Undocumented
Method	closeStderr	Undocumented
Method	loseConnection	Undocumented
Method	write	Call this to write to standard input on this process.
Method	registerProducer	Call this to register producer for standard input.
Method	unregisterProducer	Call this to unregister producer for standard input.
Method	writeSequence	Call this to write to standard input on this process.
Method	childDataReceived	Undocumented
Method	signalProcess	Undocumented
Method	processEnded	Undocumented
Method	childConnectionLost	Undocumented
Method	maybeCallProcessEnded	Undocumented
Method	__repr__	Undocumented

Inherited from Ephemeral:

Method	__getstate__	Undocumented
Method	__setstate__	Undocumented

def __init__(self, reactor, command, args, environment, path, proto, uid=None, gid=None, childFDs=None): (source)

Spawn an operating-system process.

This is where the hard work of disconnecting all currently open files / forking / executing the new process happens. (This is executed automatically when a Process is instantiated.)

This will also run the subprocess as a given user ID and group ID, if specified. (Implementation Note: this doesn't support all the arcane nuances of setXXuid on UNIX: it will assume that either your effective or real UID is 0.)

def _setupChild(self, fdmap): (source)

fdmap[childFD] = parentFD

The child wants to end up with 'childFD' attached to what used to be the parent's parentFD. As an example, a bash command run like 'command 2>&1' would correspond to an fdmap of {0:0, 1:1, 2:1}. 'command >foo.txt' would be {0:0, 1:os.open('foo.txt'), 2:2}.

This is accomplished in two steps:

   1. close all file descriptors that aren't values of fdmap.  This means
      0 .. maxfds.

   2. for each childFD::

        - if fdmap[childFD] == childFD, the descriptor is already in
          place.  Make sure the CLOEXEC flag is not set, then delete the
          entry from fdmap.

        - if childFD is in fdmap.values(), then the target descriptor is
          busy. Use os.dup() to move it elsewhere, update all
          fdmap[childFD] items that point to it, then close the
          original. Then fall through to the next case.

        - now fdmap[childFD] is not in fdmap.values(), and is free. Use
          os.dup2() to move it to the right place, then close the
          original.

def reapProcess(self): (source)

Try to reap a process (without blocking) via waitpid.

This is called when sigchild is caught or a Process object loses its "connection" (stdout is closed) This ought to result in reaping all zombie processes, since it will be called twice as often as it needs to be.

(Unfortunately, this is a slightly experimental approach, since UNIX has no way to be really sure that your process is going to go away w/o blocking. I don't want to block.)

def registerProducer(self, producer, streaming): (source)

Call this to register producer for standard input.

If there is no standard input producer.stopProducing() will be called immediately.

Class t.i.p.Process(styles.Ephemeral):