Isaac-Sim 5.1 Omnigraph: How to connect an output in the parent graph to the input of a subgraph via Python scripting

[JohnYanxinLiu]

I'm trying to create a cascaded set of functions that will automate the creation of a robot and organize a set of sensors into their own subgraphs. It would be particularly helpful to be able to feed the ROS2 context that I have into these subgraphs.

The way I have it at the moment is as such:

def create_robot():
        graph_handle, _, _, _ = og.Controller.edit(
                {
                    "graph_path": graph_path,
                },
                {
                    og.Controller.Keys.CREATE_NODES: [
                        (ros2Context_node_name, "isaacsim.ros2.bridge.ROS2Context")
                    ]
                    # ... (creating other parent-level nodes and connections)
                }
        return graph_handle

Then, later for a a function to, I would have the following:

def add_sensor(parent_graph_handle):
        controller.edit(
                graph_id=parent_graph_path,
                edit_commands={
                    og.Controller.Keys.CREATE_NODES: [
                        (
                            sensor_subgraph_name,
                            {
                            og.Controller.Keys.PROMOTE_ATTRIBUTES: [
                                (f"{sensor_helper}.inputs:context", f"inputs:context"),
                            ],
                            # ... (creating other parent-level nodes and connections)
                       )
                 }
        )       

Is there any guidance detailing how I would feed the parent graph's ros2 context output into the newly created promoted attribute of this subgraph? Ideally, I would like to know how I could perform some operations along the lines of
og.Controller.connect("/Graph/my_subgraph.inputs:input_name", "/some_node.outputs:output")
however, every guess I've tried to take resutls in the following error:

2026-02-10T01:50:39Z [10,132ms] [Error] [omni.kit.app._impl] [py stderr]:     raise og.OmniGraphError(f"Failed to connect {src_path} -> {dst_path}") from error
2026-02-10T01:50:39Z [10,132ms] [Error] [omni.kit.app._impl] [py stderr]: omni.graph.core._impl.errors.OmniGraphError: OmniGraphError: Failed to connect /Path/To/ParentGraph.outputs:context -> /Path/To/Child/SensorGraph.inputs:context

Thanks!

[zwdoescode]

@JohnYanxinLiu Please check out this tutorial CompoundNodes

[zwdoescode]

I will close this ticket since it has been inactive. Please feel free to re-open it if you have more updates.