OmniGraph fails to connect certain nodes with the Python API

Omniverse Isaac Sim
1

I get the following error:

omni.graph.core._impl.errors.OmniGraphError: OmniGraphError: Failed to connect /ROSRobotDescription/ros2_subscriber.outputs:data -> /ROSRobotDescription/insert_attribute.inputs:attrToInsert

When i try create add this graph:

og.Controller.edit(
    {"graph_path": "/ROSRobotDescription", "evaluator_name": "execution"},
    {
        og.Controller.Keys.CREATE_NODES: [
            ("OnPlaybackTick", "omni.graph.action.OnPlaybackTick"),
            ("send_custom_event", "omni.graph.action.SendCustomEvent"),
            ("ros2_subscriber", "omni.isaac.ros2_bridge.ROS2Subscriber"),
            ("bundle_constructor", "omni.graph.nodes.BundleConstructor"),
            ("insert_attribute", "omni.graph.nodes.InsertAttribute"),
            ("ros2_context", "omni.isaac.ros2_bridge.ROS2Context"),
        ],
        og.Controller.Keys.CONNECT: [
            ("OnPlaybackTick.outputs:tick", "ros2_subscriber.inputs:execIn"),
            ("OnPlaybackTick.outputs:tick", "send_custom_event.inputs:execIn"),
            ("ros2_context.outputs:context", "ros2_subscriber.inputs:context"),
            ("ros2_subscriber.outputs:data", "insert_attribute.inputs:attrToInsert"),
            ("bundle_constructor.outputs_bundle", "insert_attribute.inputs:data"),
            ("insert_attribute.outputs_data", "send_custom_event.inputs:bundle"),
        ],
        og.Controller.Keys.SET_VALUES: [
            ("send_custom_event.inputs:eventName", "MY_CUSTOM_EVENT"),
            ("ros2_subscriber.inputs:messageName", "String"),
            ("ros2_subscriber.inputs:messagePackage", "std_msgs"),
            ("ros2_subscriber.inputs:messageSubfolder", "msg"),
            ("ros2_subscriber.inputs:topicName", "/robot_description"),
            ("insert_attribute.inputs:outputAttrName", "data"),
        ],
    },
)

It works well if i remove ("ros2_subscriber.outputs:data", "insert_attribute.inputs:attrToInsert") and connect them in the IsaacSim graph editor.

I assume that it’s related to the ROS2 Subscriber determines its outputs dynamically, but i couldn’t figure it out how to connect the nodes later from code.

Isaac Sim 4.1.0

2

The Subscriber’s message is not fixed in the edit function.
So ros2_subscriber.outputs:data is not exist.

You can connect those after edit().
like this:

og.Controller.edit(
    {"graph_path": "/ROSRobotDescription", "evaluator_name": "execution"},
    {
        og.Controller.Keys.CREATE_NODES: [
            ("OnPlaybackTick", "omni.graph.action.OnPlaybackTick"),
            ("send_custom_event", "omni.graph.action.SendCustomEvent"),
            ("ros2_subscriber", "omni.isaac.ros2_bridge.ROS2Subscriber"),
            ("bundle_constructor", "omni.graph.nodes.BundleConstructor"),
            ("insert_attribute", "omni.graph.nodes.InsertAttribute"),
            ("ros2_context", "omni.isaac.ros2_bridge.ROS2Context"),
        ],
        og.Controller.Keys.CONNECT: [
            ("OnPlaybackTick.outputs:tick", "ros2_subscriber.inputs:execIn"),
            ("OnPlaybackTick.outputs:tick", "send_custom_event.inputs:execIn"),
            ("ros2_context.outputs:context", "ros2_subscriber.inputs:context"),
            ("bundle_constructor.outputs_bundle", "insert_attribute.inputs:data"),
            ("insert_attribute.outputs_data", "send_custom_event.inputs:bundle"),
        ],
        og.Controller.Keys.SET_VALUES: [
            ("send_custom_event.inputs:eventName", "MY_CUSTOM_EVENT"),
            ("ros2_subscriber.inputs:messageName", "String"),
            ("ros2_subscriber.inputs:messagePackage", "std_msgs"),
            ("ros2_subscriber.inputs:messageSubfolder", "msg"),
            ("ros2_subscriber.inputs:topicName", "/robot_description"),
            ("insert_attribute.inputs:outputAttrName", "data"),
        ],
    },
)

og.Controller.connect("/ROSRobotDescription/ros2_subscriber.outputs:data", "/ROSRobotDescription/insert_attribute.inputs:attrToInsert")
3

It works! Thank you! :)

4

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