Adding a cross-task eventing server.

testing/legion/lib/task_registration_server.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """The registration server used to register tasks.
 
 The registration server is started by the test controller and allows the tasks
 to register themselves when they start. Authentication of the tasks controllers
 is based on an OTP passed to the run_task binary on startup.
 """
 
 import logging
 import threading
 
 from legion.lib import common_lib
 from legion.lib.rpc import SimpleJSONRPCServer
 
 
 class TaskRegistrationServer(object):
   """Discovery server run on the host."""
 
   def __init__(self):
     self._expected_tasks = {}
     self._rpc_server = None
     self._thread = None
     self._port = common_lib.GetUnusedPort()
-    # Register for the shutdown event
-    common_lib.OnShutdown += self.Shutdown
 
   @property
   def port(self):
     return self._port
 
   def _RegisterTaskRPC(self, otp, ip, port):
     """The RPC used by a task to register with the registration server."""
     assert otp in self._expected_tasks
     cb = self._expected_tasks.pop(otp)
     cb(ip, port)
@@ skipping 11 matching lines @@
     self._rpc_server.register_function(
         self._RegisterTaskRPC, 'RegisterTask')
     self._thread = threading.Thread(target=self._rpc_server.serve_forever)
     self._thread.start()
 
   def Shutdown(self):
     """Shuts the discovery server down."""
     if self._thread and self._thread.is_alive():
       logging.info('Shutting down task registration server')
       self._rpc_server.shutdown()