examples: Could not import 'rosidl_typesupport_c' for package

Bug report

Required Info:

Operating System:
- Ubuntu 20.04
Installation type:
- Binaries
Version or commit hash:
- foxy
Client library (if applicable):
- rclpy

I have a set of packages built using ament_python in a workspace and have been trying to create a separate package, built using ament-cmake to contain custom message and service types. I was getting an error and posted it here, but have not found an answer. Then, I attempted to use the custom interface tutorial, which has steps for editing past rclpy examples to use custom interfaces. I ran into the same problem with the same output.

Steps to reproduce issue

Follow the rclpy publisher / subscriber or service / client tutorials and then the custom interfaces tutorial, editing those previous tutorial scripts to test the new interfaces.

colcon build should run without error. Then try running your new, edited script using ros2 run py_pubsub talkeretc.

Expected behavior

Should see the output at the end of the custom interfaces tutorial

Actual behavior

Here are some outputs from using ros2 run for different edited scripts.

talker

Traceback (most recent call last):
  File "/opt/ros/foxy/lib/python3.8/site-packages/rosidl_generator_py/import_type_support_impl.py", line 46, in import_type_support
    return importlib.import_module(module_name, package=pkg_name)
  File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 973, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'tutorial_interfaces.tutorial_interfaces_s__rosidl_typesupport_c'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/joaquin/mlabs/dev_ws/install/py_pubsub/lib/py_pubsub/talkercustom", line 11, in <module>
    load_entry_point('py-pubsub==0.0.0', 'console_scripts', 'talkercustom')()
  File "/home/joaquin/mlabs/dev_ws/install/py_pubsub/lib/python3.8/site-packages/py_pubsub/publisher_member_function_custom.py", line 27, in main
    minimal_publisher = MinimalPublisher()
  File "/home/joaquin/mlabs/dev_ws/install/py_pubsub/lib/python3.8/site-packages/py_pubsub/publisher_member_function_custom.py", line 11, in __init__
    self.publisher_ = self.create_publisher(Num, 'topic', 10)     # CHANGE
  File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/node.py", line 1140, in create_publisher
    check_for_type_support(msg_type)
  File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/type_support.py", line 29, in check_for_type_support
    msg_type.__class__.__import_type_support__()
  File "/home/joaquin/mlabs/dev_ws/install/tutorial_interfaces/lib/python3.7/site-packages/tutorial_interfaces/msg/_num.py", line 27, in __import_type_support__
    module = import_type_support('tutorial_interfaces')
  File "/opt/ros/foxy/lib/python3.8/site-packages/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 'tutorial_interfaces'

listener

Traceback (most recent call last):
  File "/opt/ros/foxy/lib/python3.8/site-packages/rosidl_generator_py/import_type_support_impl.py", line 46, in import_type_support
    return importlib.import_module(module_name, package=pkg_name)
  File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 973, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'tutorial_interfaces.tutorial_interfaces_s__rosidl_typesupport_c'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/joaquin/mlabs/dev_ws/install/py_pubsub/lib/py_pubsub/listenercustom", line 11, in <module>
    load_entry_point('py-pubsub==0.0.0', 'console_scripts', 'listenercustom')()
  File "/home/joaquin/mlabs/dev_ws/install/py_pubsub/lib/python3.8/site-packages/py_pubsub/subscriber_member_function_custom.py", line 25, in main
    minimal_subscriber = MinimalSubscriber()
  File "/home/joaquin/mlabs/dev_ws/install/py_pubsub/lib/python3.8/site-packages/py_pubsub/subscriber_member_function_custom.py", line 11, in __init__
    self.subscription = self.create_subscription(
  File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/node.py", line 1201, in create_subscription
    check_for_type_support(msg_type)
  File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/type_support.py", line 29, in check_for_type_support
    msg_type.__class__.__import_type_support__()
  File "/home/joaquin/mlabs/dev_ws/install/tutorial_interfaces/lib/python3.7/site-packages/tutorial_interfaces/msg/_num.py", line 27, in __import_type_support__
    module = import_type_support('tutorial_interfaces')
  File "/opt/ros/foxy/lib/python3.8/site-packages/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 'tutorial_interfaces'

service

Traceback (most recent call last):
  File "/opt/ros/foxy/lib/python3.8/site-packages/rosidl_generator_py/import_type_support_impl.py", line 46, in import_type_support
    return importlib.import_module(module_name, package=pkg_name)
  File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 973, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'tutorial_interfaces.tutorial_interfaces_s__rosidl_typesupport_c'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/joaquin/mlabs/dev_ws/install/py_srvcli/lib/py_srvcli/service custom", line 11, in <module>
    load_entry_point('py-srvcli==0.0.0', 'console_scripts', 'service custom')()
  File "/home/joaquin/mlabs/dev_ws/install/py_srvcli/lib/python3.8/site-packages/py_srvcli/service_member_function_custom.py", line 22, in main
    minimal_service = MinimalService()
  File "/home/joaquin/mlabs/dev_ws/install/py_srvcli/lib/python3.8/site-packages/py_srvcli/service_member_function_custom.py", line 11, in __init__
    self.srv = self.create_service(AddThreeInts, 'add_three_ints', self.add_three_ints_callback)        # CHANGE
  File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/node.py", line 1295, in create_service
    check_for_type_support(srv_type)
  File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/type_support.py", line 29, in check_for_type_support
    msg_type.__class__.__import_type_support__()
  File "/home/joaquin/mlabs/dev_ws/install/tutorial_interfaces/lib/python3.7/site-packages/tutorial_interfaces/srv/_add_three_ints.py", line 300, in __import_type_support__
    module = import_type_support('tutorial_interfaces')
  File "/opt/ros/foxy/lib/python3.8/site-packages/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 'tutorial_interfaces'

client

Traceback (most recent call last):
  File "/opt/ros/foxy/lib/python3.8/site-packages/rosidl_generator_py/import_type_support_impl.py", line 46, in import_type_support
    return importlib.import_module(module_name, package=pkg_name)
  File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 973, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'tutorial_interfaces.tutorial_interfaces_s__rosidl_typesupport_c'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/joaquin/mlabs/dev_ws/install/py_srvcli/lib/py_srvcli/clientcustom", line 11, in <module>
    load_entry_point('py-srvcli==0.0.0', 'console_scripts', 'clientcustom')()
  File "/home/joaquin/mlabs/dev_ws/install/py_srvcli/lib/python3.8/site-packages/py_srvcli/client_member_function_custom.py", line 26, in main
    minimal_client = MinimalClientAsync()
  File "/home/joaquin/mlabs/dev_ws/install/py_srvcli/lib/python3.8/site-packages/py_srvcli/client_member_function_custom.py", line 11, in __init__
    self.cli = self.create_client(AddThreeInts, 'add_three_ints')       # CHANGE
  File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/node.py", line 1248, in create_client
    check_for_type_support(srv_type)
  File "/opt/ros/foxy/lib/python3.8/site-packages/rclpy/type_support.py", line 29, in check_for_type_support
    msg_type.__class__.__import_type_support__()
  File "/home/joaquin/mlabs/dev_ws/install/tutorial_interfaces/lib/python3.7/site-packages/tutorial_interfaces/srv/_add_three_ints.py", line 300, in __import_type_support__
    module = import_type_support('tutorial_interfaces')
  File "/opt/ros/foxy/lib/python3.8/site-packages/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 'tutorial_interfaces'

As you can see, there is a pattern.

Additional information

I’m not the first person to have this problem, and I haven’t been able to find a solution or a workaround thus far. Should I stick to using pre-built messages? Build all my packages with ament_cmake?

About this issue

Original URL
State: closed
Created 3 years ago
Reactions: 3
Comments: 28 (2 by maintainers)

Most upvoted comments

I had the same issue: My solution: One of may message dependencies(e.g. nav_msgs) was not included in my CMakeList.txt. Once it was added, the problem got resolved. If you have custom messages in your package, that could be the reason.

Bmoradi93 on Jul 29, 2021

I had this issue also, but in my case it was due to having a Conda environment enabled. Disabling the conda environment with conda deactivate before cleaning the workspace with rm -rf build install and building the workspace again with colcon build fixed the issue for me. For people more fluent with Python virtual environments there may be a way to get these working together, but I have no advice to give on that

ciaran-helgen on Oct 12, 2023

I know this issue was just closed, but it’s happening to me too.

I have a hunch it has to do with mixing python versions. As it mentions here: 🌐 Using Python Packages with ROS 2

Note

A cautionary note, if you intended to use pre-packaged binaries (either deb files, or the “fat” binary distributions), the Python interpreter must match what was used to build the original binaries. If you intend to use something like virtualenv or pipenv, make sure to use the system interpreter. If you use something like conda, it is very likely that the interpreter will not match the system interpreter and will be incompatible with ROS2 binaries.

I have noticed I can use the std_msgs just fine, but my custom interfaces give the Could not import 'rosidl_typesupport_c' for package error. If I look at what Python sees in sys.path, I see that my interfaces use Python 3.8 while the std_msgs (and the rest of my ROS binary) were compiled with 3.7.

I haven’t been able to roll my build back to 3.7 or get an updated binary using 3.8 yet, but that’s my current theory.

mozilla2012 on Feb 25, 2022

I had the same issue. I follow this answer add DEPENDENCIES in rosidl_generate_interfaces to solve this problem.

ChangcongWang on Jan 11, 2022

Hey everyone, I had the same issue with ‘rosidl_typesupport_c’ and I’ve solved it after reading the comment of @mozilla2012. In Ubuntu 20.04 LTS, I use virtualenv to run python 3.7 and 3.8 (which is used by the system interpreter). After settings up a new python3.8 venv + running rosdep install und colcon build with this particular python version, I was able to launch ROS2 without the mentioned problem.

Conclusion: Your python interpreter must match what was used to build the original binaries.

lhmwtum on Feb 28, 2022

Hello, I met the same problem as you. I found that this is because I currently use the anaconda environment instead of the system environment of python3.6. When I use ‘’$ conda deactivate‘’ command, the error disappeared.I hope it can help you.

little-bookworm on Jan 29, 2022

I solved the issue by using a different version of python, the one that is also used in the ros2 code. The exact version is in the build folder of your ros2 workspace. Just run grep python . -r and you’ll find the version somewhere in there.

I also used virtualenv instead of changing my python version globally.

You also might need to install some of the modules along the way, like empy 3.3.4, lark, catkin_pkg, since some older python versions might not include those packages, that newer versions have builtin.

kamronkhakimov on Apr 9, 2024

Hi, I had the same issue, building in docker and running in another environment. The issue was a version mismatch of ros-galactic-rosidl-typessuport-c between the building environment and the running environment. Hope this helps as I’ve lost some hours on it 🙄

PymZoR on May 24, 2022