Refactor air pressure demo

[caguero]

Refactors the air_pressure demo leveraging the latest improvements in ros_gz. If we're happy with it, I'll propagate the refactor to all the demos.

• I replaced the previous launch file from Python to XML because I think it's the recommendation (and looks easier) but I'll still keep some of the demos in Python to offer some variety.
• I added the QoS support as well. I noticed that because of the QoS, rqt_topic isn't able to show any data. This was probably happening before. Does anybody know if we can pass QoS settings to rqt_topic?

Summary

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[ahcorde]

I can see these errors:

[gz-3] Warning [Utils.cc:132] [/sdf/model[@name="force_torque_demo"]/link[@name="base_plate"]/static:<data-string>:L3]: XML Element[static], child of element[link], not defined in SDF. Copying[static] as children of [link].
[gz-3] Warning [Utils.cc:132] [/sdf/model[@name="force_torque_demo"]/link[@name="base_plate"]/static:<data-string>:L3]: XML Element[static], child of element[link], not defined in SDF. Copying[static] as children of [link].

rqt_topic is not able to show the value, maybe a bad topic configuration ? the readme shows how to read the value with cmd commands, maybe remove rqt_topic from the launch file ?

[caguero]

I can see these errors:

[gz-3] Warning [Utils.cc:132] [/sdf/model[@name="force_torque_demo"]/link[@name="base_plate"]/static:<data-string>:L3]: XML Element[static], child of element[link], not defined in SDF. Copying[static] as children of [link].
[gz-3] Warning [Utils.cc:132] [/sdf/model[@name="force_torque_demo"]/link[@name="base_plate"]/static:<data-string>:L3]: XML Element[static], child of element[link], not defined in SDF. Copying[static] as children of [link].

rqt_topic is not able to show the value, maybe a bad topic configuration ? the readme shows how to read the value with cmd commands, maybe remove rqt_topic from the launch file ?

I think this is the issue that I mentioned in the description. Because of the QoS seetings of the publisher, rqt cannot show it. Is it possible to pass QoS settings to the rqt subscriber?

[caguero]

I can see these errors:

[gz-3] Warning [Utils.cc:132] [/sdf/model[@name="force_torque_demo"]/link[@name="base_plate"]/static:<data-string>:L3]: XML Element[static], child of element[link], not defined in SDF. Copying[static] as children of [link].
[gz-3] Warning [Utils.cc:132] [/sdf/model[@name="force_torque_demo"]/link[@name="base_plate"]/static:<data-string>:L3]: XML Element[static], child of element[link], not defined in SDF. Copying[static] as children of [link].

These errors look unrelated to ros_gz. I do see them if I launch gz sim -v 4 sensors.sdf.

[ahcorde]

I created this draft PR ros-visualization/rqt_topic#51 to try to override the QoS in rqt_topic, but for now it's not working.

[ahcorde]

Do you mind to try these last 3 suggestions ?

[caguero]

Do you mind to try these last 3 suggestions ?

I tried ros-visualization/rqt_topic#51 in combination with your three suggestions:

1. Bridge the clock topic.
2. Pass QoS settings and use_sim_time to rqt_topic.
3. Pass use_sim_time to the ros_gz bridge.

I'm getting the following issue:

[component_container-1] [ERROR] [1733502964.485608076] [ros_gz_container]: Component constructor threw an exception: parameter 'use_sim_time' has invalid type: Wrong parameter type, parameter {use_sim_time} is of type {bool}, setting it to {string} is not allowed.

It looks like there's an issue passing 'use_sim_time': True to the bridge. I tried using 'True' as well as a string but getting the same error.

I also tried just passing the QoS settings to rqt_topic and the bridge without setting use_sime_time. In fact, I removed the /clock bridge from the yaml file as well and things seem to work.

Independently of the bridge problem, why do we need to pass use_sim_time?

[ahcorde]

I had to use upper case for 'true' otherwise the code was not working, is this happening to you ?

the clock bridge is required by rqt_topic

[ahcorde]

It's working without the clock bridge, I don't know what I was doing wrong.

You just need to use the new changes from @azeey. Otherwise LGTM

[caguero]

It's working without the clock bridge, I don't know what I was doing wrong.

You just need to use the new changes from @azeey. Otherwise LGTM

Thanks, good to go again!

[caguero]

@ahcorde , are you OK with the changes now?