[feat] refactor events to use ZMQ

Before this commit, protobuf and protobuf.socketrpc were used to serialize and
transmit messages between events clients. This change implements a simpler ZMQ
client/server events mechanism that uses ZMQ sockets for transmitting messages
from clients to server and to redistribute such messages to subscribed
clients.

Closes: #6359

1 files changed, 0 insertions, 208 deletions

diff --git a/src/leap/common/events/daemon.py b/src/leap/common/events/daemon.py
deleted file mode 100644
index c4a4189..0000000
--- a/src/leap/common/events/daemon.py
+++ /dev/null
@@ -1,208 +0,0 @@
-# -*- coding: utf-8 -*-
-# daemon.py
-# Copyright (C) 2013 LEAP
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program. If not, see <http://www.gnu.org/licenses/>.
-
-"""
-A singleton daemon for running RPC services using protobuf.socketrpc.
-"""
-
-
-import logging
-import threading
-
-
-from protobuf.socketrpc.server import (
-    SocketRpcServer,
-    ThreadedTCPServer,
-    SocketHandler,
-)
-
-
-logger = logging.getLogger(__name__)
-
-
-class ServiceAlreadyRunningException(Exception):
-    """
-    Raised whenever a service is already running in this process but someone
-    attemped to start it in a different port.
-    """
-
-
-class EventsRpcServer(SocketRpcServer):
-    """
-    RPC server used in server and client interfaces to receive messages.
-    """
-
-    def __init__(self, port, host='localhost'):
-        """
-        Initialize a RPC server.
-
-        :param port: the port in which to listen for incoming messages
-        :type port: int
-        :param host: the address to bind to
-        :type host: str
-        """
-        SocketRpcServer.__init__(self, port, host)
-        self._server = None
-
-    def run(self):
-        """
-        Run the server.
-        """
-        logger.info('Running server on port %d.' % self.port)
-        # parent implementation does not hold the server instance, so we do it
-        # here.
-        self._server = ThreadedTCPServer((self.host, self.port),
-                                         SocketHandler, self)
-        # if we chose to use a random port, fetch the port number info.
-        if self.port is 0:
-            self.port = self._server.socket.getsockname()[1]
-        self._server.serve_forever()
-
-    def stop(self):
-        """
-        Stop the server.
-        """
-        self._server.shutdown()
-
-
-class EventsSingletonDaemon(threading.Thread):
-    """
-    Singleton class for for launching and terminating a daemon.
-
-    This class is used so every part of the mechanism that needs to listen for
-    messages can launch its own daemon (thread) to do the job.
-    """
-
-    # Singleton instance
-    __instance = None
-
-    def __new__(cls, *args, **kwargs):
-        """
-        Return a singleton instance if it exists or create and initialize one.
-        """
-        if len(args) is not 2:
-            raise TypeError("__init__() takes exactly 2 arguments (%d given)"
-                            % len(args))
-        if cls.__instance is None:
-            cls.__instance = object.__new__(
-                EventsSingletonDaemon)
-            cls.__initialize(cls.__instance, args[0], args[1])
-        return cls.__instance
-
-    @staticmethod
-    def __initialize(self, port, service):
-        """
-        Initialize a singleton daemon.
-
-        This is a static method disguised as instance method that actually
-        does the initialization of the daemon instance.
-
-        :param port: the port in which to listen for incoming messages
-        :type port: int
-        :param service: the service to provide in this daemon
-        :type service: google.protobuf.service.Service
-        """
-        threading.Thread.__init__(self)
-        self._port = port
-        self._service = service
-        self._server = EventsRpcServer(self._port)
-        self._server.registerService(self._service)
-        self.daemon = True
-
-    def __init__(self):
-        """
-        Singleton placeholder initialization method.
-
-        Initialization is made in __new__ so we can always return the same
-        instance upon object creation.
-        """
-        pass
-
-    @classmethod
-    def ensure(cls, port):
-        """
-        Make sure the daemon instance is running.
-
-        Each implementation of this method should call `self.ensure_service`
-        with the appropriate service from the `events.proto` definitions, and
-        return the daemon instance.
-
-        :param port: the port in which the daemon should be listening
-        :type port: int
-
-        :return: a daemon instance
-        :rtype: EventsSingletonDaemon
-        """
-        raise NotImplementedError(self.ensure)
-
-    @classmethod
-    def ensure_service(cls, port, service):
-        """
-        Start the singleton instance if not already running.
-
-        Might return ServiceAlreadyRunningException
-
-        :param port: the port in which the daemon should be listening
-        :type port: int
-
-        :return: a daemon instance
-        :rtype: EventsSingletonDaemon
-        """
-        daemon = cls(port, service)
-        if not daemon.is_alive():
-            daemon.start()
-        elif port and port != cls.__instance._port:
-            # service is running in this process but someone is trying to
-            # start it in another port
-            raise ServiceAlreadyRunningException(
-                "Service is already running in this process on port %d."
-                % self.__instance._port)
-        return daemon
-
-    @classmethod
-    def get_instance(cls):
-        """
-        Retrieve singleton instance of this daemon.
-
-        :return: a daemon instance
-        :rtype: EventsSingletonDaemon
-        """
-        return cls.__instance
-
-    def run(self):
-        """
-        Run the server.
-        """
-        self._server.run()
-
-    def stop(self):
-        """
-        Stop the daemon.
-        """
-        self._server.stop()
-
-    def get_port(self):
-        """
-        Retrieve the value of the port to which the service running in this
-        daemon is binded to.
-
-        :return: the port to which the daemon is binded to
-        :rtype: int
-        """
-        if self._port is 0:
-            self._port = self._server.port
-        return self._port