class twisted.internet.process.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...)
| Class Variable | debug | Undocumented |
| Class Variable | debug_child | Undocumented |
| Class Variable | status | 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. |
| Method | __init__ | Spawn an operating-system process. |
| Instance Variable | pipes | Undocumented |
| Instance Variable | proto | Undocumented |
| 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 | getHost | Similar to getPeer, but returns an address describing this side of the connection. |
| Method | getPeer | Get the remote address of this connection. |
| 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):
| Class Variable | lostProcess | Undocumented |
| Method | processEnded | This is called when the child terminates. |
| Method | _callProcessExited | Undocumented |
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.
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.)
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.
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. |
Close a file descriptor which is connected to the child process, identified by its FD in the child process.
Call this to write to standard input on this process.
NOTE: This will silently lose data if there is no standard input.
Call this to register producer for standard input.
If there is no standard input producer.stopProducing() will be called immediately.
Call this to write to standard input on this process.
NOTE: This will silently lose data if there is no standard input.
Similar to getPeer, but returns an address describing this side of the connection.
| Returns | An IAddress provider. | |
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. | |