twisted.internet.process.Process

class documentation

class Process(_BaseProcess): (source)

Implements interfaces: twisted.internet.interfaces.IProcessTransport

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	`childConnectionLost`	Undocumented
Method	`childDataReceived`	Undocumented
Method	`closeChildFD`	Close a file descriptor which is connected to the child process, identified by its FD in the child process.
Method	`closeStderr`	Close stderr.
Method	`closeStdin`	Call this to close standard input on this process.
Method	`closeStdout`	Close stdout.
Method	`getHost`	Similar to getPeer, but returns an address describing this side of the connection.
Method	`getPeer`	Get the remote address of this connection.
Method	`loseConnection`	Close stdin, stderr and stdout.
Method	`maybeCallProcessEnded`	Call processEnded on protocol after final cleanup.
Method	`pauseProducing`	Undocumented
Method	`registerProducer`	Call this to register producer for standard input.
Method	`resumeProducing`	Undocumented
Method	`unregisterProducer`	Call this to unregister producer for standard input.
Method	`write`	Call this to write to standard input on this process.
Method	`writeSequence`	Call this to write to standard input on this process.
Method	`writeToChild`	Similar to `ITransport.write` but also allows the file descriptor in the child process which will receive the bytes to be specified.
Class Variable	`debug`	Undocumented
Class Variable	`debug_child`	Undocumented
Class Variable	`pid`	From before `IProcessProtocol.makeConnection` is called to before `IProcessProtocol.processEnded` is called, `pid` is an `int` giving the platform process ID of this process. `pid` is `None` at all other times.
Class Variable	`status`	Undocumented
Instance Variable	`pipes`	Undocumented
Instance Variable	`proto`	Undocumented
Method	`_setupChild`	fdmap[childFD] = parentFD

Inherited from _BaseProcess:

Method	`__repr__`	String representation of a process.
Method	`reapProcess`	Try to reap a process (without blocking) via waitpid.
Method	`signalProcess`	No summary
Method	`_execChild`	The exec() which is done in the forked child.
Method	`_fork`	Fork and then exec sub-process.
Method	`_getReason`	Undocumented
Method	`_resetSignalDisposition`	Undocumented

Inherited from BaseProcess (via _BaseProcess):

Method	`processEnded`	This is called when the child terminates.
Class Variable	`lostProcess`	Undocumented
Method	`_callProcessExited`	Undocumented

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

overrides twisted.internet._baseprocess.BaseProcess.__init__

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 childConnectionLost(self, childFD, reason): (source)

Undocumented

def childDataReceived(self, name, data): (source)

Undocumented

def closeChildFD(self, childFD): (source)

from twisted.internet.interfaces.IProcessTransport

Close a file descriptor which is connected to the child process, identified by its FD in the child process.

def closeStderr(self): (source)

from twisted.internet.interfaces.IProcessTransport

Close stderr.

def closeStdin(self): (source)

from twisted.internet.interfaces.IProcessTransport

Call this to close standard input on this process.

def closeStdout(self): (source)

from twisted.internet.interfaces.IProcessTransport

Close stdout.

def getHost(self): (source)

from twisted.internet.interfaces.ITransport

Similar to getPeer, but returns an address describing this side of the connection.

Returns
An `IAddress` provider.

def getPeer(self): (source)

from twisted.internet.interfaces.ITransport

Get the remote address of this connection.

Treat this method with caution. It is the unfortunate result of the CGI and Jabber standards, but should not be considered reliable for the usual host of reasons; port forwarding, proxying, firewalls, IP masquerading, etc.

Returns
An `IAddress` provider.

def loseConnection(self): (source)

from twisted.internet.interfaces.IProcessTransport

Close stdin, stderr and stdout.

def maybeCallProcessEnded(self): (source)

overrides twisted.internet._baseprocess.BaseProcess.maybeCallProcessEnded

Call processEnded on protocol after final cleanup.

def pauseProducing(self): (source)

Undocumented

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.

def resumeProducing(self): (source)

Undocumented

def unregisterProducer(self): (source)

Call this to unregister producer for standard input.

def write(self, data): (source)

from twisted.internet.interfaces.ITransport

Call this to write to standard input on this process.

NOTE: This will silently lose data if there is no standard input.

def writeSequence(self, seq): (source)

from twisted.internet.interfaces.ITransport

Call this to write to standard input on this process.

NOTE: This will silently lose data if there is no standard input.

def writeToChild(self, childFD, data): (source)

from twisted.internet.interfaces.IProcessTransport

Similar to ITransport.write but also allows the file descriptor in the child process which will receive the bytes to be specified.

Parameters
childFD	The file descriptor to which to write.
data	The bytes to write.
Raises
`KeyError`	If `childFD` is not a file descriptor that was mapped in the child when `IReactorProcess.spawnProcess` was used to create it.

debug: bool = (source)

Undocumented

debug_child: bool = (source)

Undocumented

pid = (source)

from twisted.internet.interfaces.IProcessTransport

overrides twisted.internet.process._BaseProcess.pid

From before IProcessProtocol.makeConnection is called to before IProcessProtocol.processEnded is called, pid is an int giving the platform process ID of this process. pid is None at all other times.

status: int = (source)

overrides twisted.internet.process._BaseProcess.status

Undocumented

pipes: dict = (source)

Undocumented

proto = (source)

overrides twisted.internet._baseprocess.BaseProcess.proto

Undocumented

def _setupChild(self, fdmap): (source)

overrides twisted.internet.process._BaseProcess._setupChild

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 (or just the open fds within that range, if
       the platform supports '/proc/<pid>/fd').

    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.