testing/legion/host_controller.py

   1 # Copyright 2015 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 """Defines the host controller base library.
   6
   7 This module is the basis on which host controllers are built and executed.
   8 """
   9
  10 import logging
  11 import sys
  12
  13 #pylint: disable=relative-import
  14 import client_lib
  15 import common_lib
  16 import discovery_server
  17
  18
  19 class HostController(object):
  20   """The base host controller class."""
  21
  22   def __init__(self):
  23     self._discovery_server = discovery_server.DiscoveryServer()
  24
  25   def SetUp(self):
  26     """Setup method used by the subclass."""
  27     pass
  28
  29   def Task(self):
  30     """Main task method used by the subclass."""
  31     pass
  32
  33   def TearDown(self):
  34     """Teardown method used by the subclass."""
  35     pass
  36
  37   def NewClient(self, *args, **kwargs):
  38     controller = client_lib.ClientController(*args, **kwargs)
  39     self._discovery_server.RegisterClientCallback(
  40         controller.otp, controller.OnConnect)
  41     return controller
  42
  43   def RunController(self):
  44     """Main entry point for the controller."""
  45     print ' '.join(sys.argv)
  46     common_lib.InitLogging()
  47     self._discovery_server.Start()
  48
  49     error = None
  50     tb = None
  51     try:
  52       self.SetUp()
  53       self.Task()
  54     except Exception as e:
  55       # Defer raising exceptions until after TearDown and _TearDown are called.
  56       error = e
  57       tb = sys.exc_info()[-1]
  58     try:
  59       self.TearDown()
  60     except Exception as e:
  61       # Defer raising exceptions until after _TearDown is called.
  62       # Note that an error raised here will obscure any errors raised
  63       # previously.
  64       error = e
  65       tb = sys.exc_info()[-1]
  66
  67     self._discovery_server.Shutdown()
  68     client_lib.ClientController.ReleaseAllControllers()
  69     if error:
  70       raise error, None, tb  #pylint: disable=raising-bad-type