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authorTomás Touceda <chiiph@leap.se>2014-07-16 16:42:03 -0300
committerTomás Touceda <chiiph@leap.se>2014-07-16 16:42:03 -0300
commit34457adc72a4a4c0b4bff4791f4329bca66162c1 (patch)
tree279542ab3ce460d1f0bcd7943352c3e792c9f2c6 /src/leap/bitmask/backend/signaler.py
parent4f946ea2189e78da0488a28b3bb8a8aed997a1c5 (diff)
parent3d6629348aedf2a6863d242d96d64b3492e86f9a (diff)
Merge remote-tracking branch 'refs/remotes/ivan/feature/new-frontend-backend' into develop
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diff --git a/src/leap/bitmask/backend/signaler.py b/src/leap/bitmask/backend/signaler.py
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+# -*- coding: utf-8 -*-
+# signaler.py
+# Copyright (C) 2013, 2014 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/>.
+"""
+Signaler client.
+Receives signals from the backend and sends to the signaling server.
+"""
+import Queue
+import threading
+import time
+
+import zmq
+
+from leap.bitmask.backend.api import SIGNALS
+from leap.bitmask.backend.utils import get_frontend_certificates
+
+import logging
+logger = logging.getLogger(__name__)
+
+
+class Signaler(object):
+ """
+ Signaler client.
+ Receives signals from the backend and sends to the signaling server.
+ """
+ PORT = "5667"
+ SERVER = "tcp://localhost:%s" % PORT
+ POLL_TIMEOUT = 2000 # ms
+ POLL_TRIES = 500
+
+ def __init__(self):
+ """
+ Initialize the ZMQ socket to talk to the signaling server.
+ """
+ context = zmq.Context()
+ logger.debug("Connecting to signaling server...")
+ socket = context.socket(zmq.REQ)
+
+ # public, secret = zmq.curve_keypair()
+ client_keys = zmq.curve_keypair()
+ socket.curve_publickey = client_keys[0]
+ socket.curve_secretkey = client_keys[1]
+
+ # The client must know the server's public key to make a CURVE
+ # connection.
+ public, _ = get_frontend_certificates()
+ socket.curve_serverkey = public
+
+ socket.setsockopt(zmq.RCVTIMEO, 1000)
+ socket.connect(self.SERVER)
+ self._socket = socket
+
+ self._signal_queue = Queue.Queue()
+
+ self._do_work = threading.Event() # used to stop the worker thread.
+ self._worker_signaler = threading.Thread(target=self._worker)
+
+ def __getattribute__(self, name):
+ """
+ This allows the user to do:
+ S = Signaler()
+ S.SOME_SIGNAL
+
+ Just by having defined 'some_signal' in _SIGNALS
+
+ :param name: the attribute name that is requested.
+ :type name: str
+ """
+ if name in SIGNALS:
+ return name
+ else:
+ return object.__getattribute__(self, name)
+
+ def signal(self, signal, data=None):
+ """
+ Sends a signal to the signaling server.
+
+ :param signal: the signal to send.
+ :type signal: str
+ """
+ if signal not in SIGNALS:
+ raise Exception("Unknown signal: '{0}'".format(signal))
+
+ request = {
+ 'signal': signal,
+ 'data': data,
+ }
+
+ try:
+ request_json = zmq.utils.jsonapi.dumps(request)
+ except Exception as e:
+ msg = ("Error serializing request into JSON.\n"
+ "Exception: {0} Data: {1}")
+ msg = msg.format(e, request)
+ logger.critical(msg)
+ raise
+
+ # queue the call in order to handle the request in a thread safe way.
+ self._signal_queue.put(request_json)
+
+ def _worker(self):
+ """
+ Worker loop that processes the Queue of pending requests to do.
+ """
+ while self._do_work.is_set():
+ try:
+ request = self._signal_queue.get(block=False)
+ self._send_request(request)
+ except Queue.Empty:
+ pass
+ time.sleep(0.01)
+
+ logger.debug("Signaler thread stopped.")
+
+ def start(self):
+ """
+ Start the Signaler worker.
+ """
+ self._do_work.set()
+ self._worker_signaler.start()
+
+ def stop(self):
+ """
+ Stop the Signaler worker.
+ """
+ self._do_work.clear()
+
+ def _send_request(self, request):
+ """
+ Send the given request to the server.
+ This is used from a thread safe loop in order to avoid sending a
+ request without receiving a response from a previous one.
+
+ :param request: the request to send.
+ :type request: str
+ """
+ # logger.debug("Signaling '{0}'".format(request))
+ self._socket.send(request)
+
+ poll = zmq.Poller()
+ poll.register(self._socket, zmq.POLLIN)
+
+ reply = None
+ tries = 0
+
+ while True:
+ socks = dict(poll.poll(self.POLL_TIMEOUT))
+ if socks.get(self._socket) == zmq.POLLIN:
+ reply = self._socket.recv()
+ break
+
+ tries += 1
+ if tries < self.POLL_TRIES:
+ logger.warning('Retrying receive... {0}/{1}'.format(
+ tries, self.POLL_TRIES))
+ else:
+ break
+
+ if reply is None:
+ msg = "Timeout error contacting backend."
+ logger.critical(msg)
+ # else:
+ # msg = "Received reply for '{0}' -> '{1}'".format(request, reply)
+ # logger.debug(msg)