Get updated GUI ECM info when a user presses 'play'

[adlarkin]

Signed-off-by: Ashton Larkin ashton@openrobotics.org

🎉 New feature

Part of #1106

Requires:

• Add WorldControlState msg type gz-msgs#190
• Support emitting an event on play/pause/step gz-gui#306
• Add support for GUI entity creation #1122
• fix updating a component's data via SerializedState msg #1131

Summary

When simulation is paused, users might want to update the GUI's ECM directly. When simulation is resumed, the server's ECM needs to be updated to reflect any changes made in the GUI's ECM. This PR implements the server's ECM updating based on changes made in the GUI.

For a higher-level design discussion of how this functionality is implemented, see #1109 (comment).

Test it

Manual testing may need to be done in order to run a gui plugin that updates the GUI's ECM. Does anyone know how automated testing can be done for this, since it relies on GUI/Server interaction?

There are also some notes about testing the PRs new service from the command line in the PR description of gazebosim/gz-gui#306.

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• 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

[adlarkin]

Following the conversation in gazebosim/gz-gui#306 (comment), I have removed deprecation warnings/notes in e61eef9 since we will be supporting both the event and service options moving forward.

[adlarkin]

@nkoenig since the changes made in gazebosim/gz-gui#306 make the GUI listen to the world stats topic to get pause/play updates from the server, we might want to increase how frequently world stats messages are published to prevent slow response times when users press the play/pause GUI button. We could change the messages published per second to something like 10 or 15 (it's currently only 5): https://github.com/ignitionrobotics/ign-gazebo/blob/e61eef90a392896b85253ee971098f1eafe56162/src/SimulationRunner.cc#L672

Let me know what you think about this.

[nkoenig]

@nkoenig since the changes made in ignitionrobotics/ign-gui#306 make the GUI listen to the world stats topic to get pause/play updates from the server, we might want to increase how frequently world stats messages are published to prevent slow response times when users press the play/pause GUI button. We could change the messages published per second to something like 10 or 15 (it's currently only 5):

https://github.com/ignitionrobotics/ign-gazebo/blob/e61eef90a392896b85253ee971098f1eafe56162/src/SimulationRunner.cc#L672

Let me know what you think about this.

Can you open a separate PR with this change?

[adlarkin]

Can you open a separate PR with this change?

👍 see #1163

[nkoenig]

@scpeters , it looks like there are problems with homebrew that you're aware of. Is it okay to merge this, or should I wait for a homebrew fix?

[scpeters]

@scpeters , it looks like there are problems with homebrew that you're aware of. Is it okay to merge this, or should I wait for a homebrew fix?

I just merged the bottle for now; we can fix it later

I'll restart the homebrew job, which should have a better chance now

[nkoenig]

I just merged the bottle for now; we can fix it later

I'll restart the homebrew job, which should have a better chance now

Thanks.

[chapulina]

Sorry to join the party late, but is this thread-safe? It's dangerous to update the ECM in a transport callback. I think we should define a clear moment in the update loop when the ECM is updated with the new state; maybe before PreUpdate?

[adlarkin]

Thanks for pointing thread safety out - I totally missed this the first time around 🤦 @nkoenig is going to open another PR with a fix.