The TUI

better_launch comes with a sneaky, unobstrusive TUI (terminal user interface) based on prompt_toolkit, which will hover below the log output. You can start it by either passing ui=True to the launch_this wrapper, or by adding --bl_ui=enable on the command line. Use \ to switch between menu items.

See the single line of shortcuts at the bottom of each example? That's the TUI, and it will never take up more than 3 lines! Despite its simplicity, the TUI allows you a comfortable degree of control over all nodes managed by the better_launch process it is running in:

• listing a node's services and topics
• starting and stopping nodes
• triggering lifecycle transitions
• changing the log level
• etc.

Tip

It is also possible to change the key bindings. The settings page contains further details.

# Run this line to see it in action!
bl better_launch 02_ui.launch.py

The TUI is also able to manage nodes started from different shells and processes, even if they have been started by ROS2 or other means. To do so, pass the manage_foreign_nodes flag to the wrapper or command line. Be aware though that this will not capture their output - to get their output you will have to use the takeover action from the TUI, which will restart the node process with the original arguments.

Note

Foreign node processes are identified by having one of the following parameters in their arguments: __ns, __name, __node, --ros-args. This is always true for nodes started from launch files, but fails when they were started via ros2 run or other means. As far as I'm aware, there is no better way right now.