##########################################################################
# Copyright (c) 2010-2022 Robert Bosch GmbH
# This program and the accompanying materials are made available under the
# terms of the Eclipse Public License 2.0 which is available at
# http://www.eclipse.org/legal/epl-2.0.
#
# SPDX-License-Identifier: EPL-2.0
##########################################################################
"""
Multiprocessing Proxy Channel
*****************************
:module: cc_mp_proxy
:synopsis: concrete implementation of a multiprocessing proxy channel
CCProxy channel was created, in order to enable the connection of
multiple auxiliaries on one and only one CChannel. This CChannel
has to be used with a so called proxy auxiliary.
.. currentmodule:: cc_mp_proxy
"""
from __future__ import annotations
import logging
import multiprocessing
import queue
from typing import TYPE_CHECKING, Any
from pykiso.connector import CChannel
if TYPE_CHECKING:
from pykiso.lib.auxiliaries.mp_proxy_auxiliary import MpProxyAuxiliary
from pykiso.types import ProxyReturn
log = logging.getLogger(__name__)
[docs]class CCMpProxy(CChannel):
"""Multiprocessing Proxy CChannel for multi auxiliary usage."""
def __init__(self, **kwargs):
"""Initialize attributes."""
kwargs.update(processing=True)
super().__init__(**kwargs)
# instantiate directly both queue_in and queue_out
self.queue_in = multiprocessing.Queue()
self.queue_out = multiprocessing.Queue()
self.timeout = 1
# used for physical channel attributes access from main auxiliary
self._proxy = None
self._physical_channel = None
[docs] def _bind_channel_info(self, proxy_aux: MpProxyAuxiliary):
"""Bind a :py:class:`~pykiso.lib.auxiliaries.mp_proxy_auxiliary.MpProxyAuxiliary`
instance that is instanciated in order to handle the connection of
multiple auxiliaries to a single communication channel in order to
hide the underlying proxy setup.
:param proxy_aux: the proxy auxiliary instance that is holding the
real communication channel.
"""
self._proxy = proxy_aux
self._physical_channel = proxy_aux.channel
def __getattr__(self, name: str) -> Any:
"""Implement getattr to retrieve attributes from the real channel attached
to the underlying :py:class:`~pykiso.lib.auxiliaries.mp_proxy_auxiliary.MpProxyAuxiliary`.
:param name: name of the attribute to get.
:raises AttributeError: if the attribute is not part of the real
channel instance or if the real channel hasn't been bound to
this proxy channel yet.
:return: the found attribute value.
"""
if self._physical_channel is not None:
with self._proxy.lock:
return getattr(self._physical_channel, name)
raise AttributeError(
f"{self.__class__.__name__} object has no attribute '{name}'"
)
def __getstate__(self):
"""Avoid getattr to be called on pickling before instanciation,
which would cause infinite recursion.
"""
return self.__dict__
def __setstate__(self, state):
self.__dict__ = state
[docs] def _cc_open(self) -> None:
"""Open proxy channel.
Due to usage of multiprocessing the queue_in and queue_out state
doesn't have to change in order to ensure that ProxyAuxiliary
works even if suspend or resume is called.
"""
log.internal_debug("Open proxy channel")
[docs] def _cc_close(self) -> None:
"""Close proxy channel.
Due to usage of multiprocessing the queue_in and queue_out state
doesn't have to change in order to ensure that ProxyAuxiliary
works even if suspend or resume is called.
"""
log.internal_debug("Close proxy channel")
[docs] def _cc_send(self, *args: tuple, **kwargs: dict) -> None:
"""Populate the queue in of the proxy connector.
:param args: tuple containing positionnal arguments
:param kwargs: dictionary containing named arguments
"""
log.internal_debug(f"put at proxy level: {args} {kwargs}")
self.queue_in.put((args, kwargs))
[docs] def _cc_receive(self, timeout: float = 0.1) -> ProxyReturn:
"""Depopulate the queue out of the proxy connector.
:param timeout: not used
:return: bytes and source when it exist. if queue timeout
is reached return None
"""
try:
return_response = self.queue_out.get(True, self.timeout)
log.internal_debug(f"received at proxy level : {return_response}")
return return_response
except queue.Empty:
return {"msg": None}