start saving hdf5 produces error

[llorban]

There is an error when attempting to save hdf5 files.

Here are the steps:

Flydra launches with 8 cameras fine, except for the following warning:

/home/beelab/ros/flydra-kinetic/src/ros_flydra/nodes/main_brain:54: SyntaxWarning: The publisher should be created with an explicit keyword argument 'queue_size'. Please see http://wiki.ros.org/rospy/Overview/Publishers%20and%20Subscribers for more information.
  self.pub = rospy.Publisher("%s/tracking" % cam_id, sensor_msgs.msg.Image, subscriber_listener=self)

Cameras syncs okay:

beelab@beelab:~/ros/flydra-kinetic/src/ros_flydra$ roscd ros_flydra; python scripts/simple-console.py --sync
sync cameras
done

But when trying to start saving hdf5:
beelab@beelab:~/ros/flydra-kinetic/src/ros_flydra$ roscd ros_flydra; python scripts/simple-console.py --start-saving-hdf5

the following error is produced:

[ERROR] [1537378936.478427]: Error processing request: image cannot be None
['Traceback (most recent call last):\n', '  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py", line 625, in _handle_request\n    response = convert_return_to_response(self.handler(request), self.response_class)\n', '  File "/usr/lib/python2.7/dist-packages/flydra_core/MainBrain.py", line 676, in _ros_generic_service_dispatch\n    result = getattr(self, calledfunction)(**kwargs)\n', '  File "/usr/lib/python2.7/dist-packages/flydra_core/MainBrain.py", line 1226, in start_saving_data\n    raise ValueError(\'image cannot be None\')\n', 'ValueError: image cannot be None\n']

and in the other command line window:

beelab@beelab:~/ros/flydra-kinetic/src/ros_flydra$ roscd ros_flydra; python scripts/simple-console.py --start-saving-hdf5
start saving HDF5
Traceback (most recent call last):
  File "scripts/simple-console.py", line 100, in <module>
    start_saving_hdf5()
  File "scripts/simple-console.py", line 34, in start_saving_hdf5
    xx.call()
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py", line 515, in call
    responses = transport.receive_once()
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/impl/tcpros_base.py", line 727, in receive_once
    p.read_messages(b, msg_queue, sock) 
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py", line 353, in read_messages
    self._read_ok_byte(b, sock)
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py", line 336, in _read_ok_byte
    raise ServiceException("service [%s] responded with an error: %s"%(self.resolved_name, str))
rospy.service.ServiceException: service [/flydra_mainbrain/start_saving_data] responded with an error: error processing request: image cannot be None