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._default_watch_loop_period = rospy.Duration(watch_loop_period) 
34          self._watch_loop_period = rospy.Duration(watch_loop_period) 
35          self._last_loop_timestamp = rospy.Time.now() 
36          self._internal_sleep_period = rospy.Duration(0, 200000000)  # 200ms 
37   
38 -    def set_watch_loop_period(self, period): 
39          ''' 
40            This is used via the gateway node service to configure the rate of the 
41            watcher thread. If not positive, it will reset to the default. 
42   
43            @param period : new setting in seconds 
44            @type float 
45          ''' 
46          self._watch_loop_period = self._default_watch_loop_period if period <= 0.0 else rospy.Duration(period) 
47   
48 -    def get_watch_loop_period(self): 
49          ''' 
50            Use Duration's to_sec() method to convert this to float. 
51   
52            @return the watcher loop period. 
53            @rtype rospy.Duration 
54          ''' 
55          return self._watch_loop_period 
56   
57 -    def start(self): 
58          ''' 
59            The watcher thread - monitors both the local master's system state (list of connections) 
60            and the various rules to make sure rules and existing connections or flips are in sync. 
61          ''' 
62          while not rospy.is_shutdown(): 
63              # don't waste time processing if we're not connected to at least one hub 
64              if self._gateway.is_connected(): 
65                  try: 
66                      connections = self._master.get_connection_state() 
67                  except httplib.ResponseNotReady: 
68                      rospy.logwarn("Gateway : received 'ResponseNotReady' from master api") 
69                      self._sleep() 
70                      continue 
71                  remote_gateway_hub_index = self._hub_manager.create_remote_gateway_hub_index() 
72                  self._gateway.update_flipped_interface(connections, remote_gateway_hub_index) 
73                  self._gateway.update_public_interface(connections) 
74                  self._gateway.update_pulled_interface(connections, remote_gateway_hub_index) 
75              self._sleep() 
76   
77 -    def _sleep(self): 
78          ''' 
79            Internal interruptible sleep loop to check for shutdown and update triggers. 
80            This lets us set a really long watch_loop update if we wish. 
81          ''' 
82          while not rospy.is_shutdown() and not self.trigger_update and (rospy.Time.now() - self._last_loop_timestamp < self._watch_loop_period): 
83              rospy.sleep(self._internal_sleep_period) 
84          self.trigger_update = False 
85          self._last_loop_timestamp = rospy.Time.now() 
86