t.i.p.Process(_BaseProcess) : class documentation

Part of twisted.internet.process View Source View In Hierarchy

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 writeToChild Similar to ITransport.write but also allows the file descriptor in the child process which will receive the bytes to be specified.
Method closeChildFD Close a file descriptor which is connected to the child process, identified by its FD in the child process.
Method pauseProducing Undocumented
Method resumeProducing Undocumented
Method closeStdin Call this to close standard input on this process.
Method closeStdout Close stdout.
Method closeStderr Close stderr.
Method loseConnection Close stdin, stderr and stdout.
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 childConnectionLost Undocumented
Method maybeCallProcessEnded Call processEnded on protocol after final cleanup.
Method _setupChild fdmap[childFD] = parentFD

Inherited from _BaseProcess:

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

Inherited from BaseProcess (via _BaseProcess):

Method processEnded This is called when the child terminates.
Method _callProcessExited Undocumented

Inherited from Ephemeral (via _BaseProcess, BaseProcess):

Method __getstate__ Undocumented
Method __setstate__ Undocumented
def __init__(self, reactor, executable, 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 (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.
def writeToChild(self, childFD, data): (source)
Similar to ITransport.write but also allows the file descriptor in the child process which will receive the bytes to be specified.
ParameterschildFDThe file descriptor to which to write. (type: int)
dataThe bytes to write. (type: str)
ReturnsNone
RaisesKeyErrorIf childFD is not a file descriptor that was mapped in the child when IReactorProcess.spawnProcess was used to create it.
def closeChildFD(self, childFD): (source)
Close a file descriptor which is connected to the child process, identified by its FD in the child process.
def pauseProducing(self): (source)
Undocumented
def resumeProducing(self): (source)
Undocumented
def closeStdin(self): (source)
Call this to close standard input on this process.
def closeStdout(self): (source)
Close stdout.
def closeStderr(self): (source)
Close stderr.
def loseConnection(self): (source)
Close stdin, stderr and stdout.
def write(self, data): (source)
Call this to write to standard input on this process.

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

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 unregisterProducer(self): (source)
Call this to unregister producer for standard input.
def writeSequence(self, seq): (source)
Call this to write to standard input on this process.

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

def childDataReceived(self, name, data): (source)
Undocumented
def childConnectionLost(self, childFD, reason): (source)
Undocumented
def maybeCallProcessEnded(self): (source)
Call processEnded on protocol after final cleanup.
API Documentation for Twisted, generated by pydoctor at 2012-09-01 11:44:56.