baseimage-tutorial-framework/lib/tfw/networking/event_handlers/server_connector.py

# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
# All Rights Reserved. See LICENSE file for details.

from functools import partial

import zmq
from zmq.eventloop.zmqstream import ZMQStream

from tfw.networking.zmq_connector_base import ZMQConnectorBase
from tfw.networking.serialization import serialize_tfw_msg, with_deserialize_tfw_msg
from tfw.config import TFWENV
from tfw.config.logs import logging

LOG = logging.getLogger(__name__)


class ServerDownlinkConnector(ZMQConnectorBase):
    def __init__(self, zmq_context=None):
        super(ServerDownlinkConnector, self).__init__(zmq_context)
        self._zmq_sub_socket = self._zmq_context.socket(zmq.SUB)
        self._zmq_sub_socket.connect(f'tcp://localhost:{TFWENV.PUBLISHER_PORT}')
        self._zmq_sub_socket.setsockopt(zmq.RCVHWM,0)
        self._zmq_sub_stream = ZMQStream(self._zmq_sub_socket)

        self.subscribe = partial(self._zmq_sub_socket.setsockopt_string, zmq.SUBSCRIBE)
        self.unsubscribe = partial(self._zmq_sub_socket.setsockopt_string, zmq.UNSUBSCRIBE)

    def register_callback(self, callback):
        callback = with_deserialize_tfw_msg(callback)
        self._zmq_sub_stream.on_recv(callback)

    def close(self):
        self._zmq_sub_stream.close()


class ServerUplinkConnector(ZMQConnectorBase):
    """
    Class capable of sending messages to the TFW server and event handlers.
    """
    def __init__(self, zmq_context=None):
        super(ServerUplinkConnector, self).__init__(zmq_context)
        self._zmq_push_socket = self._zmq_context.socket(zmq.PUSH)
        self._zmq_push_socket.connect(f'tcp://localhost:{TFWENV.RECEIVER_PORT}')
        self._zmq_push_socket.setsockopt(zmq.SNDHWM,0)

    def send_to_eventhandler(self, message):
        """
        Send a message to an event handler through the TFW server.

        This envelopes the desired message in the 'data' field of the message to
        TFWServer, which will mirror it to event handlers.

        :param message: JSON message you want to send
        """
        self.send({
            'key': 'mirror',
            'data': message
        })

    def send(self, message):
        """
        Send a message to the frontend through the TFW server.

        :param message: JSON message you want to send
        """
        self._zmq_push_socket.send_multipart(serialize_tfw_msg(message))

    def broadcast(self, message):
        """
        Broadast a message through the TFW server.

        This envelopes the desired message in the 'data' field of the message to
        TFWServer, which will broadast it.

        :param message: JSON message you want to send
        """
        self.send({
            'key': 'broadcast',
            'data': message
        })

    def close(self):
        self._zmq_push_socket.close()


class ServerConnector(ServerUplinkConnector, ServerDownlinkConnector):
    def close(self):
        ServerUplinkConnector.close(self)
        ServerDownlinkConnector.close(self)