rocon interactions fails in pairing yaml objects

asked 2019-10-09 13:15:13 -0500

teddybouch gravatar image

I'm trying to get an exploration behavior working on a Turtlebot with a Kobuki base running ROS Kinetic on Ubuntu 16.04.5, which I'm accessing from a desktop computer with basically the same setup. Right now I'm working with turtlebot_exploration_3d (, which appears to be intended for ROS Indigo, though I don't think that's the cause of my issue. The Turtlebot itself seems to run fine, and I got started with the platform by going through the CoffeeBot tutorial (, so I at least have that baseline.

According to the turtlebot_exploration_3d documentation, the first step to running this is to run the 'minimal_explo.launch' file un the turtlebot_exploration_3d package. Initially I had some issues with kinetic and xenial not being valid entries in the rocon rules.yaml, but after adding those entries for application_framework and operating_system it seemed to get past that just fine. Now I'm seeing an error that I can't seem to track down:

setting /run_id to c67329f4-eabd-11e9-bd4c-7c7a9105e52e
process[rosout-1]: started with pid [9021]
started core service [/rosout]
process[robot_state_publisher-2]: started with pid [9039]
process[diagnostic_aggregator-3]: started with pid [9040]
process[mobile_base_nodelet_manager-4]: started with pid [9041]
process[cmd_vel_mux_nodelet_manager-5]: started with pid [9045]
process[bumper2pointcloud_nodelet_manager-6]: started with pid [9054]
process[mobile_base-7]: started with pid [9057]
process[bumper2pointcloud-8]: started with pid [9063]
process[cmd_vel_mux-9]: started with pid [9069]
process[turtlebot_laptop_battery-10]: started with pid [9084]
process[rocon/app_manager-11]: started with pid [9096]
process[rocon/master-12]: started with pid [9104]
process[rocon/zeroconf/zeroconf-13]: started with pid [9107]
process[capability_server-14]: started with pid [9119]
process[rocon/interactions-15]: started with pid [9129]
[ INFO] [1570643643.697325449]: Zeroconf: service successfully established [turtlebot][_ros-master._tcp][11311]
Traceback (most recent call last):
  File "/opt/ros/kinetic/lib/rocon_interactions/", line 20, in <module>
    interactions_manager = rocon_interactions.InteractionsManager()
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rocon_interactions/", line 90, in __init__
    (pairings, interactions) = utils.load_msgs_from_yaml_resource(resource_name)
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rocon_interactions/", line 173, in load_msgs_from_yaml_resource
    (pairings, interactions) = load_msgs_from_yaml_file(yaml_filename)
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/rocon_interactions/", line 121, in load_msgs_from_yaml_file
    pairing_yaml_objects = yaml_objects['pairings']
TypeError: list indices must be integers, not str
[rocon/interactions-15] process has died [pid 9129, exit code 1, cmd /opt/ros/kinetic/lib/rocon_interactions/ interactions/rapp_list:=app_manager/rapp_list interactions/status:=app_manager/status interactions/start_rapp:=app_manager/start_rapp interactions/stop_rapp:=app_manager/stop_rapp __name:=interactions __log:=/home/turtlebot/.ros/log/c67329f4-eabd-11e9-bd4c-7c7a9105e52e/rocon-interactions-15.log].
log file: /home/turtlebot/.ros/log/c67329f4-eabd-11e9-bd4c-7c7a9105e52e/rocon-interactions-15*.log

The best that I can tell, there's a yaml file somewhere that describes interactions within the system to rocon and it's being parsed incorrectly into a list rather than into a dictionary, so when the Python script tries to access yaml_objects['pairings'] it can't parse the key correctly. But I can't find where the file is specified that is being accessed to try to debug it. I've search ROS Answers and Google, but ... (more)

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As an update, I've been able to figure out that the offending file is /turtlebot_bringup/interactions/admin.interactions and that there is a call to yaml.load that is loading the file into a list. Looking at the script, it's pretty clear that this is out of sync with the interactions file - it's looking for dictionary entries for 'interactions', 'pairings', and 'parameters', and none of those words are even in the file. I think that my next step is to roll back and see what (if any) interactions are being defined with rocon in the baseline turtlebot instance that I have working and use that as a baseline. But I'm having difficulty figuring out why rocon is necessary here in the first place. The ROS wiki ( indicates that it's intended to enable multimaster ROS, and I should only ...(more)

teddybouch gravatar image teddybouch  ( 2019-10-10 07:26:59 -0500 )edit