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Missing rosidl type support for custom message in Python [Eloquent]

asked 2019-11-28 12:54:27 -0500

TCantelobre gravatar image

What I am trying to achieve: within my workspace, create a ament_cmake package with custom messages called navigation_msgs and publish them in an ament_python package.

What works: ros2 interface show navigation_msgs/EulerAttitude correctly displays my message. I am also able to import the message in Python from navigation_msgs.msg import EulerAttitude. Furthermore, within the same package I can publish built-in messages like geometry_msgs (Vector3)

What does not work: when trying to ros2 run pub_node not_working I get a typesupport error (the trace is below). It is raised when I call create_publisher in the NotWorkingNode constructor.

Setup: Ubuntu 18.04 with ROS3 Eloquent from APT. ros2 doctor works. (in fact the problem if the same with Dashing, also from APT.)

How to reproduce: attached code is a minimal workspace with ros2 run pub_node working and ros2 run pub_node working. working should work and notworking should give the error.

TCantelobre@1044617:~/bug$ ros2 run pub_node  notworking 
 Traceback (most recent call last):
     File "/opt/ros/eloquent/lib/python3.6/site-packages/rosidl_generator_py/", line 40, in import_type_support
        return importlib.import_module(module_name, package=pkg_name)
     File "/usr/lib/python3.6/importlib/", line 126, in import_module
        return _bootstrap._gcd_import(name[level:], package, level)
     File "<frozen importlib._bootstrap>", line 994, in _gcd_import
     File "<frozen importlib._bootstrap>", line 971, in _find_and_load
     File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
     File "<frozen importlib._bootstrap>", line 658, in _load_unlocked
     File "<frozen importlib._bootstrap>", line 571, in module_from_spec
     File "<frozen importlib._bootstrap_external>", line 922, in create_module
     File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  ImportError: /home/TCantelobre/bug/install/navigation_msgs/lib/ undefined symbol: rosidl_typesupport_fastrtps_c__get_message_type_support_handle__std_msgs__msg__Header

  During handling of the above exception, another exception occurred:

  Traceback (most recent call last):
     File "/home/TCantelobre/bug/install/pub_node/lib/pub_node/notworking", line 11, in <module>
load_entry_point('pub-node==0.0.0', 'console_scripts', 'notworking')()
     File "/home/TCantelobre/bug/install/pub_node/lib/python3.6/site-packages/pub_node/", line 28, in main
not_working_node = NotWorkingNode()
     File "/home/TCantelobre/bug/install/pub_node/lib/python3.6/site-packages/pub_node/", line 16, in __init__
self.publisher = self.create_publisher(EulerAttitude, "attitude", 100)
     File "/opt/ros/eloquent/lib/python3.6/site-packages/rclpy/", line 1094, in create_publisher
     File "/opt/ros/eloquent/lib/python3.6/site-packages/rclpy/", line 29, in check_for_type_support
     File "/home/TCantelobre/bug/install/navigation_msgs/lib/python3.6/site-packages/navigation_msgs/msg/", line 27, in __import_type_support__
          module = import_type_support('navigation_msgs')
     File "/opt/ros/eloquent/lib/python3.6/site-packages/rosidl_generator_py/", line 42, in import_type_support
          raise UnsupportedTypeSupport(pkg_name)
 rosidl_generator_py.import_type_support_impl.UnsupportedTypeSupport: Could not import 'rosidl_typesupport_c' for package 'navigation_msgs'
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Quick comment, I can't upload the files because I don't have enough reputation... would be happy to put them in a Google Drive or something if necessary. Looking forward to hearing from you!

TCantelobre gravatar image TCantelobre  ( 2019-11-29 10:05:13 -0500 )edit

Any solution to this problem, as I am also facing the same while building custom msg in dashing , using cyclonedds rmw ?

charvi gravatar image charvi  ( 2020-02-02 13:24:07 -0500 )edit

I also do have the same issue, however I am creating a custom service using eloquent, not a message using dashing. Has there been any progress concerning this question?

doekaschi gravatar image doekaschi  ( 2020-07-16 04:22:42 -0500 )edit

1 Answer

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answered 2020-07-17 01:32:13 -0500

doekaschi gravatar image

I had the same issue and did some research to fix it. For me, the problem was, that I had not declared the dependencies of the message(s) correctly when defining it in the CMakeLists.txt. For furhter info, please check out this question that solved my issue:

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Thank you @doekaschi , I also did the same to solve this issue.

charvi gravatar image charvi  ( 2020-09-21 00:52:23 -0500 )edit

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Asked: 2019-11-28 12:54:27 -0500

Seen: 361 times

Last updated: Jul 17 '20