##########################################################################
# 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
"""
import logging
import multiprocessing
import queue
from typing import Dict, Union
from pykiso import Message
from pykiso.connector import CChannel
log = logging.getLogger(__name__)
ProxyReturn = Union[
Dict[str, Union[bytes, int]],
Dict[str, Union[bytes, None]],
Dict[str, Union[Message, None]],
Dict[str, Union[None, None]],
]
[docs]class CCMpProxy(CChannel):
"""Multiprocessing Proxy CChannel for multi auxiliary usage."""
def __init__(self, **kwargs):
"""Initialize attributes."""
super().__init__(**kwargs)
# instantiate directly both queue_in and queue_out
self.queue_in = multiprocessing.Queue()
self.queue_out = multiprocessing.Queue()
self.timeout = 1
[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, raw: bool = False) -> ProxyReturn:
"""Depopulate the queue out of the proxy connector.
:param timeout: not used
:param raw: not used
:return: raw 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}