Race condition in topo map visualisation when switching maps

[cdondrup]

When the map is switched using the new service, the visualisation breaks sometimes because it tries to look-up a node before it received the updated topo map.

Possible solution would be to remove the topomap callback and replace the member variable storing it with rospy.wait_for_message(...), that would make sure that you always have the up to date topo map but would also increase traffic. Maybe a cleaver exception handling where if the node is not found you try to update the map first and retry it, would be sufficient.

Here the error:

[ERROR] [WallTime: 1446638032.063907] bad callback: <bound method TopologicalVis.MapCallback of <topological_navigation.map_marker.TopologicalVis object at 0x7fb821b2a650>>
Traceback (most recent call last):
  File "/opt/ros/indigo/lib/python2.7/dist-packages/rospy/topics.py", line 711, in _invoke_callback
    cb(msg)
  File "/home/cdondrup/ros_ws/src/strands_navigation/topological_navigation/src/topological_navigation/map_marker.py", line 136, in MapCallback
    self._update_everything()
  File "/home/cdondrup/ros_ws/src/strands_navigation/topological_navigation/src/topological_navigation/map_marker.py", line 48, in _update_everything
    marker = self.get_edge_marker(i, j, idn)
  File "/home/cdondrup/ros_ws/src/strands_navigation/topological_navigation/src/topological_navigation/map_marker.py", line 67, in get_edge_marker
    V2= tmap_utils.get_node(self.lnodes, edge.node).pose.position
AttributeError: 'NoneType' object has no attribute 'pose'

This is a non-critical error as it only breaks the visualisation.

[Jailander]

Yes, I need it in a callback because I want the visualisation updated when an edge is deleted, however this piece of code should be completely rewritten to use the map manager services instead of that topological map class.