# ``twisted`.`internet`.`interfaces`.`IReactorProcess``

interface documentation

`class IReactorProcess(Interface): (source)`

Known implementations: `twisted.internet.iocpreactor.reactor.IOCPReactor`, `twisted.internet.posixbase.PosixReactorBase`

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Undocumented

Method | `spawnProcess` | Spawn a process, with a process protocol.

def spawnProcess(processProtocol, executable, args, env, path, uid, gid, usePTY, childFDs): (source)

Spawn a process, with a process protocol.

Arguments given to this function that are listed as `bytes` or `unicode` may be encoded or decoded depending on the platform and the argument type given. On UNIX systems (Linux, FreeBSD, macOS) and Python 2 on Windows, `unicode` arguments will be encoded down to `bytes` using the encoding given by `sys.getfilesystemencoding`, to be used with the "narrow" OS APIs. On Python 3 on Windows, `bytes` arguments will be decoded up to `unicode` using the encoding given by `sys.getfilesystemencoding` (`mbcs` before Python 3.6, `utf8` thereafter) and given to Windows's native "wide" APIs.

Parameters
processProtocol:`IProcessProtocol` | An object which will be notified of all events related to the created process.
executable:`Union[bytes, str]` | the file name to spawn - the full path should be used.
args:`Sequence[Union[bytes, str]]` | the command line arguments to pass to the process; a sequence of strings. The first string should be the executable's name.

env:`Optional[Mapping[AnyStr, AnyStr]]`

the environment variables to pass to the child process. The resulting behavior varies between platforms. If:

- `env` is not set:
  - On POSIX: pass an empty environment.
  - On Windows: pass `os.environ`.
- `env` is `None`:
  - On POSIX: pass `os.environ`.
  - On Windows: pass `os.environ`.
- `env` is a `dict`:
  - On POSIX: pass the key/value pairs in `env` as the complete environment.
  - On Windows: update `os.environ` with the key/value pairs in the `dict` before passing it. As a consequence of bug #1640, passing keys with empty values in an effort to unset environment variables won't unset them.

path:`Union[bytes, str]` | the path to run the subprocess in - defaults to the current directory.
uid:`int` | user ID to run the subprocess as. (Only available on POSIX systems.)
gid:`int` | group ID to run the subprocess as. (Only available on POSIX systems.)
usePTY:`bool` | if true, run this process in a pseudo-terminal. optionally a tuple of `(masterfd, slavefd, ttyname)`, in which case use those file descriptors. (Not available on all systems.)

childFDs:`Mapping[int, Union[int, str]]`

A dictionary mapping file descriptors in the new child process to an integer or to the string 'r' or 'w'.

If the value is an integer, it specifies a file descriptor in the parent process which will be mapped to a file descriptor (specified by the key) in the child process. This is useful for things like inetd and shell-like file redirection.

If it is the string 'r', a pipe will be created and attached to the child at that file descriptor: the child will be able to write to that file descriptor and the parent will receive read notification via the `IProcessProtocol.childDataReceived` callback. This is useful for the child's stdout and stderr.

If it is the string 'w', similar setup to the previous case will occur, with the pipe being readable by the child instead of writeable. The parent process can write to that file descriptor using `IProcessTransport.writeToChild`. This is useful for the child's stdin.

If childFDs is not passed, the default behaviour is to use a mapping that opens the usual stdin/stdout/stderr pipes.

Returns
`IProcessTransport` | An object which provides `IProcessTransport`.
Raises
`OSError` | Raised with errno `EAGAIN` or `ENOMEM` if there are insufficient system resources to create a new process.
See Also
`twisted.internet.protocol.ProcessProtocol`