Add support for ros-simulation/simulation_interfaces 1.0.0 in Ionic

[scpeters]

Desired behavior

Standard ROS interfaces have been defined for interacting with simulation in the ros-simulation/simulation_interfaces package, which has just had its 1.0.0 release by @adamdbrw. We should consider how to support these interfaces in Gazebo. Since the upcoming ROS 2 Kilted release will use Gazebo Ionic, we should add support for Ionic if possible.

Alternatives considered

Implementation suggestion

Options:

• Use ros_gz_bridge, mapping to existing protos used in Gazebo and adding/duplicating missing protos as needed.
• Write code to start ROS services using simulation_interfaces and interface with Gazebo's current interfaces.

Additional context

[scpeters]

We discussed this during todays Gazebo PMC meeting.

• There is support for implementing these interfaces in Gazebo to allow users to more easily switch between simulators and to allow simulators to focus on what they are best at.
• There was a concern raised about not wanting to negatively impact existing code that doesn't use these interfaces and a suggestion to implement the interfaces in a separate repository (either here in ros_gz or another one) rather than pushing changes up to the native gazebo packages.
• The next question is which interfaces to implement first. We shouldn't feel obligated to implement them all but will make a good faith effort.

Please feel free to continue discussion here.

[adamdbrw]

@scpeters @azeey
Is there a plan to implement these interfaces anytime soon? O3DE and Isaac Sim did so already. There will be a talk covering the interfaces on ROSCon and I would love to showcase Gazebo as well.

[azeey]

Yes @adamdbrw , it might not be complete, but we hope to have an implementation with good coverage by ROSCon.

[Cavalletta98]

Hi @azeey are going to support also Gazebo Harmonic? If not, how we can leverage these standard interfaces into Gazebo Harmonic?

[azeey]

#790 has been merged and released into Rolling which is currently paired with Gazebo Jetty. The plan is to backport it to Kilted and Jazzy. Humble and Iron will not be supported for now as they would require additional work to backport the gzserver node.

The following upstream (Gazebo) PRs will first need to be backported all the way to Harmonic, which is the Gazebo version paired with Jazzy:

• Fix deadlock in service requests when running local callbacks gz-transport#671
• Refactor Transport service handlers UserCommands gz-sim#2996 followed by Fix UserCommands services so that they return the actual status the executed command gz-sim#2999
• Expose APIs for clearing the ECMs internal state tracking addition and removal gz-sim#3002
• Add EntitySemantics system that enables setting categories and tags gz-sim#3005

[Cavalletta98]

Thank you @azeey . When will be official release the new version of Gazebo Harmonic with the simulation interfaces?