Useful Debugging Tips

Logging trick

The following saves stdout to a log file while still having the log display in terminal:

• ros2 launch <package> <launch file> | tee <log file>
  • e.g. ros2 launch nav2_bringup tb3_simulation_launch.py | tee tb3_bringup_debug.log
• This can be useful for closely inspecting the logs, or to copy content from the logs

For debugging transforms:

• Print transformations
  • ros2 run tf2_ros tf2_echo laser_link map
• Visualize transformations in real time
  • ros2 run rqt_tf_tree rqt_tf_tree (need to install it first)
• Visualize transformations once
  • ros2 run tf2_tools view_frames

For testing launch files

• List parameters
  • ros2 launch <package> <launch file> -s
• More detailed outputs for debugging
  • ros2 launch <package> <launch file> -d -a

For testing new nodes

• It can be helpful to run a new node by itself outside of any launch file first. Parameters and topic mapping can be set from the commandline:

  • ros2 run <package> <executable> --ros-args -p some_param:=some_value -p other_param:=other_value -r old_topic:=new_topic -r other_old_topic:=other_new_topic

• Interact with parameters from commandline

  • ros2 param list
  • ros2 param get <node> <parameter>
  • ros2 param set <node> <parameter> <value>
    • Use parameter callback to allow parameter setting while node is running.