Base server complete including modules, STOMP protocol over Websockets

and ZMQ Router/Dealer implementations.

gns3server/modules/base.py

@@ -0,0 +1,149 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2013 GNS3 Technologies Inc.
+#
+# 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/>.
+
+import multiprocessing
+import zmq
+
+import logging
+log = logging.getLogger(__name__)
+
+
+class IModule(multiprocessing.Process):
+    """
+    Module interface
+    """
+
+    destination = {}
+
+    def __init__(self, name=None, args=(), kwargs={}):
+
+        multiprocessing.Process.__init__(self,
+                                         name=name,
+                                         args=args,
+                                         kwargs=kwargs)
+
+        self._context = None
+        self._ioloop = None
+        self._stream = None
+        self._host = args[0]
+        self._port = args[1]
+        self._current_session = None
+        self._current_destination = None
+
+    def setup(self):
+        """
+        Sets up PyZMQ and creates the stream to handle requests
+        """
+
+        self._context = zmq.Context()
+        self._ioloop = zmq.eventloop.ioloop.IOLoop.instance()
+        self._stream = self.create_stream(self._host, self._port, self.decode_request)
+
+    def create_stream(self, host=None, port=0, callback=None):
+        """
+        Creates a new ZMQ stream
+        """
+
+        socket = self._context.socket(zmq.DEALER)
+        socket.setsockopt(zmq.IDENTITY, self.name.encode("utf-8"))
+        if host and port:
+            log.info("ZeroMQ client ({}) connecting to {}:{}".format(self.name, host, port))
+            try:
+                socket.connect("tcp://{}:{}".format(host, port))
+            except zmq.error.ZMQError as e:
+                log.critical("Could not connect to ZeroMQ server on {}:{}, reason: {}".format(host, port, e))
+                raise SystemExit
+        else:
+            log.info("ZeroMQ client ({}) connecting to ipc:///tmp/gns3.ipc".format(self.name))
+            try:
+                socket.connect("ipc:///tmp/gns3.ipc")
+            except zmq.error.ZMQError as e:
+                log.critical("Could not connect to ZeroMQ server on ipc:///tmp/gns3.ipc, reason: {}".format(e))
+                raise SystemExit
+
+        stream = zmq.eventloop.zmqstream.ZMQStream(socket, self._ioloop)
+        if callback:
+            stream.on_recv(callback)
+        return stream
+
+    def run(self):
+        """
+        Sets up everything and starts the event loop
+        """
+
+        self.setup()
+        try:
+            self._ioloop.start()
+        except KeyboardInterrupt:
+            return
+
+    def stop(self):
+        """
+        Stops the event loop
+        """
+
+        #zmq.eventloop.ioloop.IOLoop.instance().stop()
+        self._ioloop.stop()
+
+    def send_response(self, response):
+        """
+        Sends a response back to the requester
+        """
+
+        # add session and destination to the response
+        response = [self._current_session, self._current_destination, response]
+        log.debug("ZeroMQ client ({}) sending: {}".format(self.name, response))
+        self._stream.send_json(response)
+
+    def decode_request(self, request):
+        """
+        Decodes the request to JSON
+        """
+
+        try:
+            request = zmq.utils.jsonapi.loads(request[0])
+        except ValueError:
+            self.send_response("ValueError")  # FIXME: explicit json error
+            return
+
+        log.debug("ZeroMQ client ({}) received: {}".format(self.name, request))
+        self._current_session = request[0]
+        self._current_destination = request[1]
+
+        if self._current_destination not in self.destination:
+            # FIXME: return error if destination not found!
+            return
+        log.debug("Routing request to {}: {}".format(self._current_destination, request[2]))
+        self.destination[self._current_destination](self, request[2])
+
+    def destinations(self):
+        """
+        Channels handled by this modules.
+        """
+
+        return self.destination.keys()
+
+    @classmethod
+    def route(cls, destination):
+        """
+        Decorator to register a destination routed to a method
+        """
+
+        def wrapper(method):
+            cls.destination[destination] = method
+            return method
+        return wrapper