Source Code for Module rocon_gateway.watcher_thread

 1  #!/usr/bin/env python 
 2  # 
 3  # License: BSD 
 4  #   https://raw.github.com/robotics-in-concert/rocon_multimaster/hydro-devel/rocon_gateway/LICENSE 
 5  # 
 6  ############################################################################## 
 7  # Imports 
 8  ############################################################################## 
 9   
10  import rospy 
11  import httplib 
12   
13  ############################################################################## 
14  # Watcher 
15  ############################################################################## 
16   
17   
18 -class WatcherThread(object): 
19      ''' 
20        This used to be on a thread of its own, but now moved into 
21        the gateway's main thread for running. 
22      ''' 
23   
24 -    def __init__(self, gateway, watch_loop_period): 
25          self.trigger_update = False 
26          self._trigger_shutdown = False 
27          self._gateway = gateway 
28          self._master = gateway.master 
29          self._hub_manager = gateway.hub_manager 
30          self._hubs = self._hub_manager.hubs 
31          self._flipped_interface = gateway.flipped_interface 
32          self._pulled_interface = gateway.pulled_interface 
33          self._watch_loop_period = rospy.Duration(watch_loop_period) 
34          self._last_loop_timestamp = rospy.Time.now() 
35          self._internal_sleep_period = rospy.Duration(0, 200000000)  # 200ms 
36   
37 -    def start(self): 
38          ''' 
39            The watcher thread - monitors both the local master's system state (list of connections) 
40            and the various rules to make sure rules and existing connections or flips are in sync. 
41          ''' 
42          while not rospy.is_shutdown(): 
43              # don't waste time processing if we're not connnected to at least one hub 
44              if self._gateway.is_connected(): 
45                  try: 
46                      connections = self._master.get_connection_state() 
47                  except httplib.ResponseNotReady: 
48                      rospy.logwarn("Gateway : received 'ResponseNotReady' from master api") 
49                      self._sleep() 
50                      continue 
51                  remote_gateway_hub_index = self._hub_manager.create_remote_gateway_hub_index() 
52                  self._gateway.update_flipped_interface(connections, remote_gateway_hub_index) 
53                  self._gateway.update_public_interface(connections) 
54                  self._gateway.update_pulled_interface(connections, remote_gateway_hub_index) 
55              self._sleep() 
56   
57 -    def _sleep(self): 
58          ''' 
59            Internal interruptible sleep loop to check for shutdown and update triggers. 
60            This lets us set a really long watch_loop update if we wish. 
61          ''' 
62          while not rospy.is_shutdown() and not self.trigger_update and (rospy.Time.now() - self._last_loop_timestamp < self._watch_loop_period): 
63              rospy.sleep(self._internal_sleep_period) 
64          self.trigger_update = False 
65          self._last_loop_timestamp = rospy.Time.now() 
66