Source code for labgrid.driver.externalconsoledriver

import fcntl
import logging
import os
import select
import shlex
import subprocess

import attr

from ..factory import target_factory
from ..protocol import ConsoleProtocol
from .common import Driver
from .consoleexpectmixin import ConsoleExpectMixin
from .exception import ExecutionError


[docs]@target_factory.reg_driver @attr.s(eq=False) class ExternalConsoleDriver(ConsoleExpectMixin, Driver, ConsoleProtocol): """ Driver implementing the ConsoleProtocol interface using a subprocess """ cmd = attr.ib(validator=attr.validators.instance_of(str)) txdelay = attr.ib(default=0.0, validator=attr.validators.instance_of(float))
[docs] def __attrs_post_init__(self): super().__attrs_post_init__() self.logger = logging.getLogger(f"{self}({self.target})") self.status = 0 #pylint: disable=attribute-defined-outside-init self._child = None self.open()
[docs] def open(self): """Starts the subprocess, does nothing if it is already closed""" if self.status: return cmd = shlex.split(self.cmd) self._child = subprocess.Popen( cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=None ) # make stdout non-blocking stdout_fd = self._child.stdout.fileno() stdout_fl = fcntl.fcntl(stdout_fd, fcntl.F_GETFL) | os.O_NONBLOCK fcntl.fcntl(stdout_fd, fcntl.F_SETFL, stdout_fl) # prepare for timeout handing self._poll = select.poll() self._poll.register(self._child.stdout.fileno()) self.status = 1
[docs] def close(self): """Stops the subprocess, does nothing if it is already closed""" if not self.status: return if self._child.poll() is not None: raise ExecutionError("child has vanished") self._child.terminate() try: outs, errs = self._child.communicate(timeout=1) except subprocess.TimeoutExpired: self._child.kill() outs, errs = self._child.communicate() if outs: self.logger.info("child stdout while closing: %s", outs) if errs: self.logger.warning("child error while closing: %s", errs) self._child = None self.status = 0
def _read(self, size: int = 1024, timeout: int = 0, max_size: int = None): """ Reads 'size' bytes from the serialport Keyword Arguments: size -- amount of bytes to read, defaults to 1024 max_size -- maximal amount of bytes to read """ if max_size: read_size = min(size, max_size) else: read_size = size if self._child.poll() is not None: raise ExecutionError("child has vanished") if self._poll.poll(timeout): return self._child.stdout.read(read_size) return b'' def _write(self, data: bytes): """ Writes 'data' to the serialport Arguments: data -- data to write, must be bytes """ if self._child.poll() is not None: raise ExecutionError("child has vanished") result = self._child.stdin.write(data) self._child.stdin.flush() return result
[docs] def on_deactivate(self): self.close()