Merge remote-tracking branch 'drebs/feature/events-signals' into develop

Conflicts:
	.gitignore
	src/leap/common/__init__.py

9 files changed, 1231 insertions, 0 deletions

diff --git a/src/leap/common/events/Makefile b/src/leap/common/events/Makefile
new file mode 100644
index 0000000..4f73dea
--- /dev/null
+++ b/src/leap/common/events/Makefile
@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+# Makefile
+# 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/>.
+
+# This file is used to generate protobuf python files that are used for IPC:
+#
+#   https://developers.google.com/protocol-buffers/docs/pythontutorial
+
+PROTOC = protoc
+
+all: events_pb2.py
+
+%_pb2.py: %.proto
+	$(PROTOC) --python_out=./ $<
+	autopep8 --in-place --aggressive $@
+
+clean:
+	rm -f *_pb2.py
diff --git a/src/leap/common/events/README b/src/leap/common/events/README
new file mode 100644
index 0000000..61b320d
--- /dev/null
+++ b/src/leap/common/events/README
@@ -0,0 +1,45 @@
+Events mechanism
+================
+
+The events mechanism allows for "components" to send signal events to each
+other by means of a centralized server. Components can register with the
+server to receive signals of certain types, and they can also send signals to
+the server that will then redistribute these signals to registered components.
+
+
+Listening daemons
+-----------------
+
+Both components and the server listen for incoming messages by using a
+listening daemon that runs in its own thread. The server daemon has to be
+started explicitly, while components daemon will be started whenever a
+component registers with the server to receive messages.
+
+
+How to use it
+-------------
+
+To start the events server:
+
+>>> from leap.common.events import server
+>>> server.ensure_server(port=8090)
+
+To register a callback to be called when a given signal is raised:
+
+>>> from leap.common.events import (
+>>>     register,
+>>>     events_pb2 as proto,
+>>> )
+>>>
+>>> def mycallback(sigreq):
+>>>     print str(sigreq)
+>>>
+>>> events.register(signal=proto.CLIENT_UID, callback=mycallback)
+
+To signal an event:
+
+>>> from leap.common.events import (
+>>>     signal,
+>>>     events_pb2 as proto,
+>>> )
+>>> signal(proto.CLIENT_UID)
diff --git a/src/leap/common/events/__init__.py b/src/leap/common/events/__init__.py
new file mode 100644
index 0000000..b8441bd
--- /dev/null
+++ b/src/leap/common/events/__init__.py
@@ -0,0 +1,100 @@
+# -*- coding: utf-8 -*-
+# __init__.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/>.
+
+"""
+An events mechanism that allows for signaling of events between components.
+"""
+
+import logging
+import socket
+
+
+from leap.common.events import (
+    events_pb2,
+    server,
+    component,
+    daemon,
+)
+
+
+logger = logging.getLogger(__name__)
+
+
+def register(signal, callback, uid=None, replace=False, reqcbk=None,
+             timeout=1000):
+    """
+    Register a callback to be called when the given signal is received.
+
+    Will timeout after timeout ms if response has not been received. The
+    timeout arg is only used for asynch requests. If a reqcbk callback has
+    been supplied the timeout arg is not used. The response value will be
+    returned for a synch request but nothing will be returned for an asynch
+    request.
+
+    @param signal: the signal that causes the callback to be launched
+    @type signal: int (see the `events.proto` file)
+    @param callback: the callback to be called when the signal is received
+    @type callback: function
+    @param uid: a unique id for the callback
+    @type uid: int
+    @param replace: should an existent callback with same uid be replaced?
+    @type replace: bool
+    @param reqcbk: a callback to be called when a response from server is
+        received
+    @type reqcbk: function
+        callback(leap.common.events.events_pb2.EventResponse)
+    @param timeout: the timeout for synch calls
+    @type timeout: int
+
+    @return: the response from server for synch calls or nothing for asynch
+        calls
+    @rtype: leap.common.events.events_pb2.EventsResponse or None
+    """
+    return component.register(signal, callback, uid, replace, reqcbk, timeout)
+
+
+def signal(signal, content="", mac_method="", mac="", reqcbk=None,
+           timeout=1000):
+    """
+    Send `signal` event to events server.
+
+    Will timeout after timeout ms if response has not been received. The
+    timeout arg is only used for asynch requests.  If a reqcbk callback has
+    been supplied the timeout arg is not used. The response value will be
+    returned for a synch request but nothing will be returned for an asynch
+    request.
+
+    @param signal: the signal that causes the callback to be launched
+    @type signal: int (see the `events.proto` file)
+    @param content: the contents of the event signal
+    @type content: str
+    @param mac_method: the method used to auth mac
+    @type mac_method: str
+    @param mac: the content of the auth mac
+    @type mac: str
+    @param reqcbk: a callback to be called when a response from server is
+        received
+    @type reqcbk: function
+        callback(leap.common.events.events_pb2.EventResponse)
+    @param timeout: the timeout for synch calls
+    @type timeout: int
+
+    @return: the response from server for synch calls or nothing for asynch
+        calls
+    @rtype: leap.common.events.events_pb2.EventsResponse or None
+    """
+    return component.signal(signal)
diff --git a/src/leap/common/events/component.py b/src/leap/common/events/component.py
new file mode 100644
index 0000000..4fcd6e7
--- /dev/null
+++ b/src/leap/common/events/component.py
@@ -0,0 +1,233 @@
+# -*- coding: utf-8 -*-
+# component.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/>.
+
+"""
+The component end point of the events mechanism.
+
+Components are the communicating parties of the events mechanism. They
+communicate by sending messages to a server, which in turn redistributes
+messages to other components.
+
+When a component registers a callback for a given signal, it also tells the
+server that it wants to be notified whenever signals of that type are sent by
+some other component.
+"""
+
+
+import logging
+import threading
+
+
+from protobuf.socketrpc import RpcService
+from leap.common.events import (
+    events_pb2 as proto,
+    server,
+    daemon,
+    mac_auth,
+)
+
+
+logger = logging.getLogger(__name__)
+
+
+# the `registered_callbacks` dictionary below should have the following
+# format:
+#
+#     { event_signal: [ (uid, callback), ... ], ... }
+#
+registered_callbacks = {}
+
+
+class CallbackAlreadyRegistered(Exception):
+    """
+    Raised when trying to register an already registered callback.
+    """
+
+
+def ensure_component_daemon():
+    """
+    Ensure the component daemon is running and listening for incoming
+    messages.
+
+    @return: the daemon instance
+    @rtype: EventsComponentDaemon
+    """
+    daemon = EventsComponentDaemon.ensure(0)
+    import time
+    # Because we use a random port we want to wait until a port is assigned to
+    # local component daemon.
+    while not (EventsComponentDaemon.get_instance() and
+               EventsComponentDaemon.get_instance().get_port()):
+        time.sleep(0.1)
+    return daemon
+
+
+def register(signal, callback, uid=None, replace=False, reqcbk=None,
+             timeout=1000):
+    """
+    Registers a callback to be called when a specific signal event is
+    received.
+
+    Will timeout after timeout ms if response has not been received. The
+    timeout arg is only used for asynch requests. If a reqcbk callback has
+    been supplied the timeout arg is not used. The response value will be
+    returned for a synch request but nothing will be returned for an asynch
+    request.
+
+    @param signal: the signal that causes the callback to be launched
+    @type signal: int (see the `events.proto` file)
+    @param callback: the callback to be called when the signal is received
+    @type callback: function
+        callback(leap.common.events.events_pb2.SignalRequest)
+    @param uid: a unique id for the callback
+    @type uid: int
+    @param replace: should an existent callback with same uid be replaced?
+    @type replace: bool
+    @param reqcbk: a callback to be called when a response from server is
+        received
+    @type reqcbk: function
+        callback(leap.common.events.events_pb2.EventResponse)
+    @param timeout: the timeout for synch calls
+    @type timeout: int
+
+    Might raise a CallbackAlreadyRegistered exception if there's already a
+    callback identified by the given uid and replace is False.
+
+    @return: the response from server for synch calls or nothing for asynch
+        calls
+    @rtype: leap.common.events.events_pb2.EventsResponse or None
+    """
+    ensure_component_daemon()  # so we can receive registered signals
+    # register callback locally
+    if signal not in registered_callbacks:
+        registered_callbacks[signal] = []
+    cbklist = registered_callbacks[signal]
+    if uid and filter(lambda (x, y): x == uid, cbklist):
+        if not replace:
+            raise CallbackAlreadyRegisteredException()
+        else:
+            registered_callbacks[signal] = filter(lambda(x, y): x != uid,
+                                                  cbklist)
+    registered_callbacks[signal].append((uid, callback))
+    # register callback on server
+    request = proto.RegisterRequest()
+    request.event = signal
+    request.port = EventsComponentDaemon.get_instance().get_port()
+    request.mac_method = mac_auth.MacMethod.MAC_NONE
+    request.mac = ""
+    service = RpcService(proto.EventsServerService_Stub,
+                         server.SERVER_PORT, 'localhost')
+    logger.info("Sending registration request to server: %s", str(request))
+    return service.register(request, callback=reqcbk, timeout=timeout)
+
+
+def signal(signal, content="", mac_method="", mac="", reqcbk=None,
+           timeout=1000):
+    """
+    Send `signal` event to events server.
+
+    Will timeout after timeout ms if response has not been received. The
+    timeout arg is only used for asynch requests.  If a reqcbk callback has
+    been supplied the timeout arg is not used. The response value will be
+    returned for a synch request but nothing will be returned for an asynch
+    request.
+
+    @param signal: the signal that causes the callback to be launched
+    @type signal: int (see the `events.proto` file)
+    @param content: the contents of the event signal
+    @type content: str
+    @param mac_method: the method used for auth mac
+    @type mac_method: str
+    @param mac: the content of the auth mac
+    @type mac: str
+    @param reqcbk: a callback to be called when a response from server is
+        received
+    @type reqcbk: function
+        callback(leap.common.events.events_pb2.EventResponse)
+    @param timeout: the timeout for synch calls
+    @type timeout: int
+
+    @return: the response from server for synch calls or nothing for asynch
+        calls
+    @rtype: leap.common.events.events_pb2.EventsResponse or None
+    """
+    request = proto.SignalRequest()
+    request.event = signal
+    request.content = content
+    request.mac_method = mac_method
+    request.mac = mac
+    service = RpcService(proto.EventsServerService_Stub, server.SERVER_PORT,
+                         'localhost')
+    logger.info("Sending signal to server: %s", str(request))
+    return service.signal(request, callback=reqcbk, timeout=timeout)
+
+
+class EventsComponentService(proto.EventsComponentService):
+    """
+    Service for receiving signal events in components.
+    """
+
+    def __init__(self):
+        proto.EventsComponentService.__init__(self)
+
+    def signal(self, controller, request, done):
+        """
+        Receive a signal and run callbacks registered for that signal.
+
+        This method is called whenever a signal request is received from
+        server.
+
+        @param controller: used to mediate a single method call
+        @type controller: protobuf.socketrpc.controller.SocketRpcController
+        @param request: the request received from the component
+        @type request: leap.common.events.events_pb2.SignalRequest
+        @param done: callback to be called when done
+        @type done: protobuf.socketrpc.server.Callback
+        """
+        logger.info('Received signal from server: %s' % str(request))
+
+        # run registered callbacks
+        # TODO: verify authentication using mac in incoming message
+        if request.event in registered_callbacks:
+            for (_, cbk) in registered_callbacks[request.event]:
+                # callbacks should be prepared to receive a
+                # events_pb2.SignalRequest.
+                cbk(request)
+
+        # send response back to server
+        response = proto.EventResponse()
+        response.status = proto.EventResponse.OK
+        done.run(response)
+
+
+class EventsComponentDaemon(daemon.EventsSingletonDaemon):
+    """
+    A daemon that listens for incoming events from server.
+    """
+
+    @classmethod
+    def ensure(cls, port):
+        """
+        Make sure the daemon is running on the given port.
+
+        @param port: the port in which the daemon should listen
+        @type port: int
+
+        @return: a daemon instance
+        @rtype: EventsComponentDaemon
+        """
+        return cls.ensure_service(port, EventsComponentService())
diff --git a/src/leap/common/events/daemon.py b/src/leap/common/events/daemon.py
new file mode 100644
index 0000000..09f3c2f
--- /dev/null
+++ b/src/leap/common/events/daemon.py
@@ -0,0 +1,208 @@
+# -*- 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 component 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, *args, **kwargs)
+            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
diff --git a/src/leap/common/events/events.proto b/src/leap/common/events/events.proto
new file mode 100644
index 0000000..29388b8
--- /dev/null
+++ b/src/leap/common/events/events.proto
@@ -0,0 +1,69 @@
+// signal.proto
+// Copyright (C) 2013 LEA
+//
+// 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/>.
+
+package leap.common.events;
+
+enum Event {
+  CLIENT_SESSION_ID = 1;
+  CLIENT_UID = 2;
+  SOLEDAD_CREATING_KEYS = 3;
+  SOLEDAD_DONE_CREATING_KEYS = 4;
+  SOLEDAD_UPLOADING_KEYS = 5;
+  SOLEDAD_DONE_UPLOADING_KEYS = 6;
+  SOLEDAD_DOWNLOADING_KEYS = 7;
+  SOLEDAD_DONE_DOWNLOADING_KEYS = 8;
+  SOLEDAD_NEW_DATA_TO_SYNC = 9;
+  SOLEDAD_DONE_DATA_SYNC = 10;
+  UPDATER_NEW_UPDATES = 11;
+  UPDATER_DONE_UPDATING = 12;
+}
+
+message SignalRequest {
+  required Event event = 1;
+  required string content = 2;
+  required string mac_method = 3;
+  required bytes mac = 4;
+  optional string enc_method = 5;
+  optional bool error_occurred = 6;
+}
+
+message RegisterRequest {
+  required Event event = 1;
+  required int32 port = 2;
+  required string mac_method = 3;
+  required bytes mac = 4;
+}
+
+message EventResponse {
+
+  enum Status {
+    OK = 1;
+    UNAUTH = 2;
+    ERROR = 3;
+  }
+
+  required Status status = 1;
+  optional string result = 2;
+}
+
+service EventsServerService {
+  rpc register(RegisterRequest) returns (EventResponse);
+  rpc signal(SignalRequest) returns (EventResponse);
+}
+
+service EventsComponentService {
+  rpc signal(SignalRequest) returns (EventResponse);
+}
diff --git a/src/leap/common/events/events_pb2.py b/src/leap/common/events/events_pb2.py
new file mode 100644
index 0000000..1d278cc
--- /dev/null
+++ b/src/leap/common/events/events_pb2.py
@@ -0,0 +1,364 @@
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+
+from google.protobuf import descriptor
+from google.protobuf import message
+from google.protobuf import reflection
+from google.protobuf import service
+from google.protobuf import service_reflection
+from google.protobuf import descriptor_pb2
+# @@protoc_insertion_point(imports)
+
+
+DESCRIPTOR = descriptor.FileDescriptor(
+    name='events.proto',
+    package='leap.common.events',
+    serialized_pb='\n\x0c\x65vents.proto\x12\x12leap.common.events\"\x97\x01\n\rSignalRequest\x12(\n\x05\x65vent\x18\x01 \x02(\x0e\x32\x19.leap.common.events.Event\x12\x0f\n\x07\x63ontent\x18\x02 \x02(\t\x12\x12\n\nmac_method\x18\x03 \x02(\t\x12\x0b\n\x03mac\x18\x04 \x02(\x0c\x12\x12\n\nenc_method\x18\x05 \x01(\t\x12\x16\n\x0e\x65rror_occurred\x18\x06 \x01(\x08\"j\n\x0fRegisterRequest\x12(\n\x05\x65vent\x18\x01 \x02(\x0e\x32\x19.leap.common.events.Event\x12\x0c\n\x04port\x18\x02 \x02(\x05\x12\x12\n\nmac_method\x18\x03 \x02(\t\x12\x0b\n\x03mac\x18\x04 \x02(\x0c\"\x82\x01\n\rEventResponse\x12\x38\n\x06status\x18\x01 \x02(\x0e\x32(.leap.common.events.EventResponse.Status\x12\x0e\n\x06result\x18\x02 \x01(\t\"\'\n\x06Status\x12\x06\n\x02OK\x10\x01\x12\n\n\x06UNAUTH\x10\x02\x12\t\n\x05\x45RROR\x10\x03*\xd5\x02\n\x05\x45vent\x12\x15\n\x11\x43LIENT_SESSION_ID\x10\x01\x12\x0e\n\nCLIENT_UID\x10\x02\x12\x19\n\x15SOLEDAD_CREATING_KEYS\x10\x03\x12\x1e\n\x1aSOLEDAD_DONE_CREATING_KEYS\x10\x04\x12\x1a\n\x16SOLEDAD_UPLOADING_KEYS\x10\x05\x12\x1f\n\x1bSOLEDAD_DONE_UPLOADING_KEYS\x10\x06\x12\x1c\n\x18SOLEDAD_DOWNLOADING_KEYS\x10\x07\x12!\n\x1dSOLEDAD_DONE_DOWNLOADING_KEYS\x10\x08\x12\x1c\n\x18SOLEDAD_NEW_DATA_TO_SYNC\x10\t\x12\x1a\n\x16SOLEDAD_DONE_DATA_SYNC\x10\n\x12\x17\n\x13UPDATER_NEW_UPDATES\x10\x0b\x12\x19\n\x15UPDATER_DONE_UPDATING\x10\x0c\x32\xb9\x01\n\x13\x45ventsServerService\x12R\n\x08register\x12#.leap.common.events.RegisterRequest\x1a!.leap.common.events.EventResponse\x12N\n\x06signal\x12!.leap.common.events.SignalRequest\x1a!.leap.common.events.EventResponse2h\n\x16\x45ventsComponentService\x12N\n\x06signal\x12!.leap.common.events.SignalRequest\x1a!.leap.common.events.EventResponse')
+
+_EVENT = descriptor.EnumDescriptor(
+    name='Event',
+    full_name='leap.common.events.Event',
+    filename=None,
+    file=DESCRIPTOR,
+    values=[
+        descriptor.EnumValueDescriptor(
+            name='CLIENT_SESSION_ID', index=0, number=1,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='CLIENT_UID', index=1, number=2,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='SOLEDAD_CREATING_KEYS', index=2, number=3,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='SOLEDAD_DONE_CREATING_KEYS', index=3, number=4,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='SOLEDAD_UPLOADING_KEYS', index=4, number=5,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='SOLEDAD_DONE_UPLOADING_KEYS', index=5, number=6,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='SOLEDAD_DOWNLOADING_KEYS', index=6, number=7,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='SOLEDAD_DONE_DOWNLOADING_KEYS', index=7, number=8,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='SOLEDAD_NEW_DATA_TO_SYNC', index=8, number=9,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='SOLEDAD_DONE_DATA_SYNC', index=9, number=10,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='UPDATER_NEW_UPDATES', index=10, number=11,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='UPDATER_DONE_UPDATING', index=11, number=12,
+            options=None,
+            type=None),
+    ],
+    containing_type=None,
+    options=None,
+    serialized_start=432,
+    serialized_end=773,
+)
+
+
+CLIENT_SESSION_ID = 1
+CLIENT_UID = 2
+SOLEDAD_CREATING_KEYS = 3
+SOLEDAD_DONE_CREATING_KEYS = 4
+SOLEDAD_UPLOADING_KEYS = 5
+SOLEDAD_DONE_UPLOADING_KEYS = 6
+SOLEDAD_DOWNLOADING_KEYS = 7
+SOLEDAD_DONE_DOWNLOADING_KEYS = 8
+SOLEDAD_NEW_DATA_TO_SYNC = 9
+SOLEDAD_DONE_DATA_SYNC = 10
+UPDATER_NEW_UPDATES = 11
+UPDATER_DONE_UPDATING = 12
+
+
+_EVENTRESPONSE_STATUS = descriptor.EnumDescriptor(
+    name='Status',
+    full_name='leap.common.events.EventResponse.Status',
+    filename=None,
+    file=DESCRIPTOR,
+    values=[
+        descriptor.EnumValueDescriptor(
+            name='OK', index=0, number=1,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='UNAUTH', index=1, number=2,
+            options=None,
+            type=None),
+        descriptor.EnumValueDescriptor(
+            name='ERROR', index=2, number=3,
+            options=None,
+            type=None),
+    ],
+    containing_type=None,
+    options=None,
+    serialized_start=390,
+    serialized_end=429,
+)
+
+
+_SIGNALREQUEST = descriptor.Descriptor(
+    name='SignalRequest',
+    full_name='leap.common.events.SignalRequest',
+    filename=None,
+    file=DESCRIPTOR,
+    containing_type=None,
+    fields=[
+        descriptor.FieldDescriptor(
+            name='event', full_name='leap.common.events.SignalRequest.event', index=0,
+            number=1, type=14, cpp_type=8, label=2,
+            has_default_value=False, default_value=1,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        descriptor.FieldDescriptor(
+            name='content', full_name='leap.common.events.SignalRequest.content', index=1,
+            number=2, type=9, cpp_type=9, label=2,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        descriptor.FieldDescriptor(
+            name='mac_method', full_name='leap.common.events.SignalRequest.mac_method', index=2,
+            number=3, type=9, cpp_type=9, label=2,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        descriptor.FieldDescriptor(
+            name='mac', full_name='leap.common.events.SignalRequest.mac', index=3,
+            number=4, type=12, cpp_type=9, label=2,
+            has_default_value=False, default_value="",
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        descriptor.FieldDescriptor(
+            name='enc_method', full_name='leap.common.events.SignalRequest.enc_method', index=4,
+            number=5, type=9, cpp_type=9, label=1,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        descriptor.FieldDescriptor(
+            name='error_occurred', full_name='leap.common.events.SignalRequest.error_occurred', index=5,
+            number=6, type=8, cpp_type=7, label=1,
+            has_default_value=False, default_value=False,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+    ],
+    extensions=[
+    ],
+    nested_types=[],
+    enum_types=[
+    ],
+    options=None,
+    is_extendable=False,
+    extension_ranges=[],
+    serialized_start=37,
+    serialized_end=188,
+)
+
+
+_REGISTERREQUEST = descriptor.Descriptor(
+    name='RegisterRequest',
+    full_name='leap.common.events.RegisterRequest',
+    filename=None,
+    file=DESCRIPTOR,
+    containing_type=None,
+    fields=[
+        descriptor.FieldDescriptor(
+            name='event', full_name='leap.common.events.RegisterRequest.event', index=0,
+            number=1, type=14, cpp_type=8, label=2,
+            has_default_value=False, default_value=1,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        descriptor.FieldDescriptor(
+            name='port', full_name='leap.common.events.RegisterRequest.port', index=1,
+            number=2, type=5, cpp_type=1, label=2,
+            has_default_value=False, default_value=0,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        descriptor.FieldDescriptor(
+            name='mac_method', full_name='leap.common.events.RegisterRequest.mac_method', index=2,
+            number=3, type=9, cpp_type=9, label=2,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        descriptor.FieldDescriptor(
+            name='mac', full_name='leap.common.events.RegisterRequest.mac', index=3,
+            number=4, type=12, cpp_type=9, label=2,
+            has_default_value=False, default_value="",
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+    ],
+    extensions=[
+    ],
+    nested_types=[],
+    enum_types=[
+    ],
+    options=None,
+    is_extendable=False,
+    extension_ranges=[],
+    serialized_start=190,
+    serialized_end=296,
+)
+
+
+_EVENTRESPONSE = descriptor.Descriptor(
+    name='EventResponse',
+    full_name='leap.common.events.EventResponse',
+    filename=None,
+    file=DESCRIPTOR,
+    containing_type=None,
+    fields=[
+        descriptor.FieldDescriptor(
+            name='status', full_name='leap.common.events.EventResponse.status', index=0,
+            number=1, type=14, cpp_type=8, label=2,
+            has_default_value=False, default_value=1,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        descriptor.FieldDescriptor(
+            name='result', full_name='leap.common.events.EventResponse.result', index=1,
+            number=2, type=9, cpp_type=9, label=1,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+    ],
+    extensions=[
+    ],
+    nested_types=[],
+    enum_types=[
+        _EVENTRESPONSE_STATUS,
+    ],
+    options=None,
+    is_extendable=False,
+    extension_ranges=[],
+    serialized_start=299,
+    serialized_end=429,
+)
+
+
+_SIGNALREQUEST.fields_by_name['event'].enum_type = _EVENT
+_REGISTERREQUEST.fields_by_name['event'].enum_type = _EVENT
+_EVENTRESPONSE.fields_by_name['status'].enum_type = _EVENTRESPONSE_STATUS
+_EVENTRESPONSE_STATUS.containing_type = _EVENTRESPONSE
+
+
+class SignalRequest(message.Message):
+    __metaclass__ = reflection.GeneratedProtocolMessageType
+    DESCRIPTOR = _SIGNALREQUEST
+
+    # @@protoc_insertion_point(class_scope:leap.common.events.SignalRequest)
+
+
+class RegisterRequest(message.Message):
+    __metaclass__ = reflection.GeneratedProtocolMessageType
+    DESCRIPTOR = _REGISTERREQUEST
+
+    # @@protoc_insertion_point(class_scope:leap.common.events.RegisterRequest)
+
+
+class EventResponse(message.Message):
+    __metaclass__ = reflection.GeneratedProtocolMessageType
+    DESCRIPTOR = _EVENTRESPONSE
+
+    # @@protoc_insertion_point(class_scope:leap.common.events.EventResponse)
+
+
+_EVENTSSERVERSERVICE = descriptor.ServiceDescriptor(
+    name='EventsServerService',
+    full_name='leap.common.events.EventsServerService',
+    file=DESCRIPTOR,
+    index=0,
+    options=None,
+    serialized_start=776,
+    serialized_end=961,
+    methods=[
+        descriptor.MethodDescriptor(
+            name='register',
+            full_name='leap.common.events.EventsServerService.register',
+            index=0,
+            containing_service=None,
+            input_type=_REGISTERREQUEST,
+            output_type=_EVENTRESPONSE,
+            options=None,
+        ),
+        descriptor.MethodDescriptor(
+            name='signal',
+            full_name='leap.common.events.EventsServerService.signal',
+            index=1,
+            containing_service=None,
+            input_type=_SIGNALREQUEST,
+            output_type=_EVENTRESPONSE,
+            options=None,
+        ),
+    ])
+
+
+class EventsServerService(service.Service):
+    __metaclass__ = service_reflection.GeneratedServiceType
+    DESCRIPTOR = _EVENTSSERVERSERVICE
+
+
+class EventsServerService_Stub(EventsServerService):
+    __metaclass__ = service_reflection.GeneratedServiceStubType
+    DESCRIPTOR = _EVENTSSERVERSERVICE
+
+
+_EVENTSCOMPONENTSERVICE = descriptor.ServiceDescriptor(
+    name='EventsComponentService',
+    full_name='leap.common.events.EventsComponentService',
+    file=DESCRIPTOR,
+    index=1,
+    options=None,
+    serialized_start=963,
+    serialized_end=1067,
+    methods=[
+        descriptor.MethodDescriptor(
+            name='signal',
+            full_name='leap.common.events.EventsComponentService.signal',
+            index=0,
+            containing_service=None,
+            input_type=_SIGNALREQUEST,
+            output_type=_EVENTRESPONSE,
+            options=None,
+        ),
+    ])
+
+
+class EventsComponentService(service.Service):
+    __metaclass__ = service_reflection.GeneratedServiceType
+    DESCRIPTOR = _EVENTSCOMPONENTSERVICE
+
+
+class EventsComponentService_Stub(EventsComponentService):
+    __metaclass__ = service_reflection.GeneratedServiceStubType
+    DESCRIPTOR = _EVENTSCOMPONENTSERVICE
+
+# @@protoc_insertion_point(module_scope)
diff --git a/src/leap/common/events/mac_auth.py b/src/leap/common/events/mac_auth.py
new file mode 100644
index 0000000..49d48f7
--- /dev/null
+++ b/src/leap/common/events/mac_auth.py
@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+# mac_auth.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/>.
+
+"""
+Authentication system for events.
+
+This is not implemented yet.
+"""
+
+
+class MacMethod(object):
+    """
+    Representation of possible MAC authentication methods.
+    """
+
+    MAC_NONE = 'none'
+    MAC_HMAC = 'hmac'
diff --git a/src/leap/common/events/server.py b/src/leap/common/events/server.py
new file mode 100644
index 0000000..5cc1add
--- /dev/null
+++ b/src/leap/common/events/server.py
@@ -0,0 +1,150 @@
+# -*- coding: utf-8 -*-
+# server.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 server for the events mechanism.
+
+A server can receive different kinds of requests from components:
+
+  1. Registration request: store component port number to be notified when
+     a specific signal arrives.
+
+  2. Signal request: redistribute the signal to registered components.
+"""
+
+
+import logging
+import sets
+
+
+from protobuf.socketrpc import RpcService
+from leap.common.events import (
+    events_pb2 as proto,
+    daemon,
+)
+
+
+logger = logging.getLogger(__name__)
+
+
+SERVER_PORT = 8090
+
+# the `registered_components` dictionary below should have the following
+# format:
+#
+#     { event_signal: [ port, ... ], ... }
+#
+registered_components = {}
+
+
+def ensure_server(port=SERVER_PORT):
+    """
+    Make sure the server is running on the given port.
+
+    Attempt to connect to given local port. Upon success, assume that the
+    events server has already been started. Upon failure, start events server.
+
+    @param port: the port in which server should be listening
+    @type port: int
+
+    @return: the daemon instance or nothing
+    @rtype: EventsServerDaemon or None
+    """
+    try:
+        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        s.connect(('localhost', port))
+        s.close()
+        logger.info('Server is already running on port %d.', port)
+        return None
+    except socket.error:
+        logger.info('Launching server on port %d.', port)
+        return EventsServerDaemon.ensure(port)
+
+
+class EventsServerService(proto.EventsServerService):
+    """
+    Service for receiving events in components.
+    """
+
+    def register(self, controller, request, done):
+        """
+        Register a component port to be signaled when specific events come in.
+
+        @param controller: used to mediate a single method call
+        @type controller: protobuf.socketrpc.controller.SocketRpcController
+        @param request: the request received from the component
+        @type request: leap.common.events.events_pb2.RegisterRequest
+        @param done: callback to be called when done
+        @type done: protobuf.socketrpc.server.Callback
+        """
+        logger.info("Received registration request: %s" % str(request))
+        # add component port to signal list
+        if request.event not in registered_components:
+            registered_components[request.event] = sets.Set()
+        registered_components[request.event].add(request.port)
+        # send response back to component
+        response = proto.EventResponse()
+        response.status = proto.EventResponse.OK
+        done.run(response)
+
+    def signal(self, controller, request, done):
+        """
+        Perform an RPC call to signal all components registered to receive a
+        specific signal.
+
+        @param controller: used to mediate a single method call
+        @type controller: protobuf.socketrpc.controller.SocketRpcController
+        @param request: the request received from the component
+        @type request: leap.common.events.events_pb2.SignalRequest
+        @param done: callback to be called when done
+        @type done: protobuf.socketrpc.server.Callback
+        """
+        logger.info('Received signal from component: %s', str(request))
+        # send signal to all registered components
+        # TODO: verify signal auth
+        if request.event in registered_components:
+            for port in registered_components[request.event]:
+
+                def callback(req, resp):
+                    logger.info("Signal received by " + str(port))
+
+                service = RpcService(proto.EventsComponentService_Stub,
+                                     port, 'localhost')
+                service.signal(request, callback=callback)
+        # send response back to component
+        response = proto.EventResponse()
+        response.status = proto.EventResponse.OK
+        done.run(response)
+
+
+class EventsServerDaemon(daemon.EventsSingletonDaemon):
+    """
+    Singleton class for starting an events server daemon.
+    """
+
+    @classmethod
+    def ensure(cls, port):
+        """
+        Make sure the daemon is running on the given port.
+
+        @param port: the port in which the daemon should listen
+        @type port: int
+
+        @return: a daemon instance
+        @rtype: EventsServerDaemon
+        """
+        return cls.ensure_service(port, EventsServerService())