Using Custom ROS Messages in Script Editor

Hello,

I am trying to use my own custom ros messages in a publisher that I run on the Script Editor in Omniverse Isaac Sim, but I keep getting the following error:

2022-03-24 14:29:11 [18,583ms] [Error] [asyncio] [/home/user/.local/share/ov/pkg/isaac_sim-2021.2.1/kit/python/lib/python3.7/asyncio/base_events.py:1619] Task exception was never retrieved
future: <Task finished coro=<my_task() done, defined at executing: Python 0...:32> exception=UnsupportedTypeSupport("Could not import 'rosidl_typesupport_c' for package 'my_test_msgs'")>
Traceback (most recent call last):
  File "/home/user/.local/share/ov/pkg/isaac_sim-2021.2.1/exts/omni.isaac.ros2_bridge/omni/isaac/rclpy/rosidl_generator_py/import_type_support_impl.py", line 46, in import_type_support
    return importlib.import_module(module_name, package=pkg_name)
  File "/home/user/.local/share/ov/pkg/isaac_sim-2021.2.1/kit/python/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 965, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'my_test_msgs.my_test_msgs_s__rosidl_typesupport_c'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "executing: Python 0...", line 34, in my_task
  File "/home/user/.local/share/ov/pkg/isaac_sim-2021.2.1/exts/omni.isaac.ros2_bridge/omni/isaac/rclpy/rclpy/node.py", line 1140, in create_publisher
    check_for_type_support(msg_type)
  File "/home/user/.local/share/ov/pkg/isaac_sim-2021.2.1/exts/omni.isaac.ros2_bridge/omni/isaac/rclpy/rclpy/type_support.py", line 29, in check_for_type_support
    msg_type.__class__.__import_type_support__()
  File "/home/user/.local/share/ov/pkg/isaac_sim-2021.2.1/exts/omni.isaac.ros2_bridge/omni/isaac/rclpy/my_test_msgs/msg/_num.py", line 27, in __import_type_support__
    module = import_type_support('my_test_msgs')
  File "/home/user/.local/share/ov/pkg/isaac_sim-2021.2.1/exts/omni.isaac.ros2_bridge/omni/isaac/rclpy/rosidl_generator_py/import_type_support_impl.py", line 48, in import_type_support
    raise UnsupportedTypeSupport(pkg_name)
rosidl_generator_py.import_type_support_impl.UnsupportedTypeSupport: Could not import 'rosidl_typesupport_c' for package 'my_test_msgs'

These are the steps that I followed:

I created a package with a custom message following the tutorial here.

Here’s my CMakeLists.txt:

cmake_minimum_required(VERSION 3.5)
project(dsd_test_msgs)

# Default to C99
if(NOT CMAKE_C_STANDARD)
  set(CMAKE_C_STANDARD 99)
endif()

# Default to C++14
if(NOT CMAKE_CXX_STANDARD)
  set(CMAKE_CXX_STANDARD 14)
endif()

if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
  add_compile_options(-Wall -Wextra -Wpedantic)
endif()

# find dependencies
find_package(ament_cmake REQUIRED)
find_package(rclcpp REQUIRED)
find_package(rosidl_default_generators REQUIRED)

if(BUILD_TESTING)
  find_package(ament_lint_auto REQUIRED)
  ament_lint_auto_find_test_dependencies()
endif()

rosidl_generate_interfaces(${PROJECT_NAME}
    "msg/Num.msg"
)

ament_package()

And my package.xml:

<?xml version="1.0"?>
<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
<package format="3">
  <name>dsd_test_msgs</name>
  <version>0.0.0</version>
  <description>TODO: Package description</description>
  <maintainer email="***">user</maintainer>
  <license>TODO: License declaration</license>

  <buildtool_depend>ament_cmake</buildtool_depend>

  <test_depend>ament_lint_auto</test_depend>
  <test_depend>ament_lint_common</test_depend>
  
  <build_depend>rosidl_default_generators</build_depend>

  <exec_depend>rosidl_default_runtime</exec_depend>

  <member_of_group>rosidl_interface_packages</member_of_group>

  <export>
    <build_type>ament_cmake</build_type>
  </export>
</package>

and I created a test message in /msg/Num.msg that looks like this:

int64 num

I then build the package from my workspace with:

colcon build --packages-select my_test_msgs

I then copy the contents from

$ROS_WORKSPACE/install/my_test_msgs/lib/python3.8/site-packages/my_test_msgs

to

/home/user/.local/share/ov/pkg/isaac_sim-2021.2.1/exts/omni.isaac.ros2_bridge/omni/isaac/rclpy/my_test_msgs

After that I go to the Script Editor in Isaac Sim and I try to run this async ros publisher:

import asyncio
import rclpy
import omni
import numpy as np

from my_test_msgs.msg import Num

try:
    rclpy.init()
except:
    print("rclpy has already been initialized, do nothing.")



async def my_task():
    node = rclpy.create_node('my_publisher')
    pub = node.create_publisher(Num, 'chatter', 10)
   
    msg = Num()
    while rclpy.ok():   
        msg.num = (1).astype(np.int64)
        pub.publish(msg)
        
        await asyncio.sleep(1.0)
    pub.unregister()
    pub = None

asyncio.ensure_future(my_task())

And I keep getting the UnsupportedTypeSupport error message form above.
What am I missing?

Hi @jominga

I got it to work by including the necessary libraries in the extension.toml file of an extension. Regarding trying to load the library from the script editor, I never tested with it. One very important thing is that the ROS message package is compiled using the same version of Isaac Sim’s python (python 3.7).

Ask directly in the Isaac Sim forum (Omniverse Isaac Sim - NVIDIA Developer Forums) for better support