Rosbridge: Support reading and setting ROS params

[jtbandes]

Split from foxglove/studio#1662

Studio users connected to a data source via a Rosbridge connection (ROS 1 or 2) should be able to:

• Receive and read ROS params from their ROS stack
• Set ROS params by sending values back to the stack

[bertaveira]

This would be a very useful feature for when using studio to monitor live a remote device (since native ros2 connection normally has problems opposed to rosbridge). We currently ssh to the device which is not the cleanest or fastest way to change parameters

[Interpause]

Modifying node parameters are actually service calls in ROS2. So foxglove/studio#3552 should make it possible to adjust parameters for ROS2. Just waiting for an extension or official panel for service calls now...

[danclapp4]

@Interpause @bertaveira Great news, I have written a custom extension to do this exact thing for ros2! with a rosbridge connection, you can view, set, and load ros2 parameters. I am currently also trying to work on being able to save your parameters to a yml file for if you like your configuration, but want to keep messing with parameters.

Check it out! https://github.com/danclapp4/ros2-parameter-extension

[rgov]

Is there additional context on why the rosbridge data source does not support this yet? It is easy to set a param with roslibjs but perhaps context.watch("parameters") would require polling for parameter changes constantly?

[amacneil]

I can't speak to why rosbridge doesn't already support parameters, but FYI we have seen many performance issues with rosbridge so are currently working on a new Foxglove ROS Bridge node written in C++. This will eventually become the primary way to connect to ROS 1 & 2, and fully support parameters, services, and actions.