Action graph functions can be exposed as free functions in the _rclpy_pybind11 C extension module.

[fujitatomoya]

Description

Service/Topic graph functions (like get_service_names_and_types_by_node) are implemented as free functions in C++ rclpy/src/rclpy/graph.cpp and exposed to Python as free functions in the _rclpy_pybind11 C extension module. but action graph functions (like get_action_client_names_and_types_by_node) are implemented as methods of the rclpy::Node C++ class rclpy/src/rclpy/node.cpp and exposed on the Node's handle.

I do not think this is bug, but it would be probably nice to keep the consistent interfaces with action as well.

Motivation

better user-friendly and consistent interfaces.

Design / Implementation Considerations

https://github.com/ros2/rclpy/blob/rolling/rclpy/rclpy/action/__init__.py, those are the target APIs to be moved to graph C implementation, and to be exposed to Python as free functions in the _rclpy_pybind11 C extension module.

Additional Information

Probably we need to give them deprecation warning to this API replacement.

[asymingt]

In triage today we decided to add this one to the L-turtle feature roadmap. I updated the project to reflect this.