Merge remote branch 'cros/upstream' into master

scheduler/drones.py

 import cPickle, os, tempfile, logging
 import common
 from autotest_lib.scheduler import drone_utility, email_manager
 from autotest_lib.client.common_lib import error, global_config
 
 
 AUTOTEST_INSTALL_DIR = global_config.global_config.get_config_value('SCHEDULER',
                                                  'drone_installation_directory')
 
+class DroneUnreachable(Exception):
+    """The drone is non-sshable."""
+    pass
+
+
 class _AbstractDrone(object):
     """
     Attributes:
     * allowed_users: set of usernames allowed to use this drone.  if None,
             any user can use this drone.
     """
     def __init__(self):
         self._calls = []
         self.hostname = None
         self.enabled = True
@@ skipping 84 matching lines @@
         else:
             self.queue_call('send_file_to', drone.hostname, source_path,
                             destination_path, can_fail)
 
 
 class _RemoteDrone(_AbstractDrone):
     def __init__(self, hostname):
         super(_RemoteDrone, self).__init__()
         self.hostname = hostname
         self._host = drone_utility.create_host(hostname)
+        if not self._host.is_up():
+            logging.error('Drone %s is unpingable, kicking out', hostname)
+            raise DroneUnreachable
         self._autotest_install_dir = AUTOTEST_INSTALL_DIR
 
 
     def set_autotest_install_dir(self, path):
         self._autotest_install_dir = path
 
 
     def shutdown(self):
         super(_RemoteDrone, self).shutdown()
         self._host.close()
@@ skipping 25 matching lines @@
             self.queue_call('send_file_to', drone.hostname, source_path,
                             destination_path, can_fail)
 
 
 def get_drone(hostname):
     """
     Use this factory method to get drone objects.
     """
     if hostname == 'localhost':
         return _LocalDrone()
-    return _RemoteDrone(hostname)
+    try:
+        return _RemoteDrone(hostname)
+    except DroneUnreachable:
+        return None