Add reset to Timer in ConnectionBasedTransport

[wkentaro]

Why?

On Kinetic we have below error, and this PR fixes it by resetting the timer.

[ERROR] [1535796247.786932, 1535792085.063646]: [/get_heightmap] [sleep] ROS time moved backwards: 1.407559397s
Exception in thread Thread-4:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 801, in __bootstrap_inner
    self.run()
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/timer.py", line 226, in run
    r.sleep()
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/timer.py", line 103, in sleep
    sleep(self._remaining(curr_time))
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/timer.py", line 164, in sleep
    raise rospy.exceptions.ROSTimeMovedBackwardsException(time_jump)
ROSTimeMovedBackwardsException: ROS time moved backwards

Exception in thread Thread-4:
Traceback (most recent call last):
  File "/usr/lib/python2.7/threading.py", line 801, in __bootstrap_inner
    self.run()
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/timer.py", line 226, in run
    r.sleep()
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/timer.py", line 103, in sleep
    sleep(self._remaining(curr_time))
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/timer.py", line 164, in sleep
    raise rospy.exceptions.ROSTimeMovedBackwardsException(time_jump)
ROSTimeMovedBackwardsException: ROS time moved backwards

^C[image_view-9] killing on exit
[tile_image-8] killing on exit
[get_heightmap/output/depth_view-7] killing on exit
[get_heightmap-6] killing on exit
[heightmap_frame_publisher-5] killing on exit
[bbox_to_tf-4] killing on exit
[bbox_array_to_bbox-3] killing on exit
[rosbag_play-2] killing on exit
[rosout-1] killing on exit
[master] killing on exit
shutting down processing monitor...
... shutting down processing monitor complete
done

[k-okada]

do you think it is possible to just show warning message when the time moved backwards?
catch except rospy.exceptions.ROSTimeMovedBackwardsException within our code and execute self.last_time = rospy.rostime.get_rostime()

[wkentaro]

Actually, I have no idea to achieve it, except for deriving the rospy.Timer and change its behavior.
Do you mean reset=True is too complicated? Or should I show the warning of the time backward?

[k-okada]

Or should I show the warning of the time backward?

yes, may be you can send PR to upstream