# ROS2 errors on VOXL2 Source: https://forum.modalai.com/topic/4057/ros2-errors-on-voxl2 Category: General Questions (https://forum.modalai.com/category/2/general-questions) Posted: 2025-01-02 18:22:38 UTC by Gary Holmgren Replies: 2 · Views: 728 ## Gary Holmgren · 2025-01-02 18:22:38 UTC I installed ROS2 Foxy on my Voxl2 using the instructions -sudo apt-get install voxl-ros2-foxy -sudo apt-get install voxl-microdds-agent -sudo apt-get install voxl-mpa-to-ros2 -voxl-configure-mpa-to-ros2 -source /opt/ros/foxy/setup.bash -export ROS_HOME=/opt/ros/foxy All seems to be okay but when I followed the ModalAI [tutorial](https://docs.modalai.com/building-ros2-nodes/?gad_source=2&gclid=Cj0KCQiA7NO7BhDsARIsADg_hIYZHBtM2VAYXTP7NQOOWTmHcV6iU5r7Envx1BhkSoEhcW9UnZ7_zusaAsIAEALw_wcB) I get the following errors. ``` voxl2:/$ cd voxl2:~$ mkdir -p colcon_ws/src voxl2:~$ cd colcon_ws voxl2:~/colcon_ws$ cd src voxl2:~/colcon_ws/src$ git clone https://github.com/PX4/px4_ros_com --recursive Cloning into 'px4_ros_com'... remote: Enumerating objects: 2288, done. remote: Counting objects: 100% (162/162), done. remote: Compressing objects: 100% (47/47), done. remote: Total 2288 (delta 128), reused 115 (delta 115), pack-reused 2126 (from 1) Receiving objects: 100% (2288/2288), 608.87 KiB | 3.60 MiB/s, done. Resolving deltas: 100% (1455/1455), done. voxl2:~/colcon_ws/src$ git clone https://github.com/PX4/px4_msgs --recursive Cloning into 'px4_msgs'... remote: Enumerating objects: 3283, done. remote: Counting objects: 100% (1092/1092), done. remote: Compressing objects: 100% (268/268), done. remote: Total 3283 (delta 961), reused 829 (delta 822), pack-reused 2191 (from 3) Receiving objects: 100% (3283/3283), 607.13 KiB | 3.92 MiB/s, done. Resolving deltas: 100% (2005/2005), done. voxl2:~/colcon_ws/src$ cd ../ voxl2:~/colcon_ws$ colcon build Starting >>> px4_msgs --- stderr: px4_msgs CMake Error at /opt/ros/foxy/share/rosidl_adapter/cmake/rosidl_adapt_interfaces.cmake:60 (message): execute_process(/usr/bin/python3 -m rosidl_adapter --package-name px4_msgs --arguments-file /home/root/colcon_ws/build/px4_msgs/rosidl_adapter__arguments__px4_msgs.json --output-dir /home/root/colcon_ws/build/px4_msgs/rosidl_adapter/px4_msgs --output-file /home/root/colcon_ws/build/px4_msgs/rosidl_adapter/px4_msgs.idls) returned error code 1: AttributeError processing template 'msg.idl.em' Traceback (most recent call last): File "/opt/ros/foxy/lib/python3.6/site-packages/rosidl_adapter/resource/__init__.py", line 48, in evaluate_template _interpreter = em.Interpreter( AttributeError: module 'em' has no attribute 'Interpreter' During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main "__main__", mod_spec) File "/usr/lib/python3.6/runpy.py", line 85, in _run_code exec(code, run_globals) File "/opt/ros/foxy/lib/python3.6/site-packages/rosidl_adapter/__main__.py", line 19, in sys.exit(main()) File "/opt/ros/foxy/lib/python3.6/site-packages/rosidl_adapter/main.py", line 55, in main pathlib.Path(relative_path), output_dir) File "/opt/ros/foxy/lib/python3.6/site-packages/rosidl_adapter/__init__.py", line 20, in convert_to_idl package_dir, package_name, interface_file, output_dir / 'msg') File "/opt/ros/foxy/lib/python3.6/site-packages/rosidl_adapter/msg/__init__.py", line 39, in convert_msg_to_idl expand_template('msg.idl.em', data, output_file, encoding='iso-8859-1') File "/opt/ros/foxy/lib/python3.6/site-packages/rosidl_adapter/resource/__init__.py", line 23, in expand_template content = evaluate_template(template_name, data) File "/opt/ros/foxy/lib/python3.6/site-packages/rosidl_adapter/resource/__init__.py", line 69, in evaluate_template _interpreter.shutdown() AttributeError: 'NoneType' object has no attribute 'shutdown' Call Stack (most recent call first): /opt/ros/foxy/share/rosidl_cmake/cmake/rosidl_generate_interfaces.cmake:130 (rosidl_adapt_interfaces) CMakeLists.txt:28 (rosidl_generate_interfaces) --- Failed <<< px4_msgs [4.33s, exited with code 1] Summary: 0 packages finished [4.71s] 1 package failed: px4_msgs 1 package had stderr output: px4_msgs 1 package not processed ``` Not sure what exactly here is causing the failure. Has anyone else had trouble building this tutorial? ## Reply by Zachary Lowell 0 · 2025-01-03 16:16:28 UTC @Gary-Holmgren said in [ROS2 errors on VOXL2](/post/20301): > -source /opt/ros/foxy/setup.bash > Hey @Gary-Holmgren! So this is an issue with a conflict in the emPY library - it should have been updated in the most recent SDK release - however the solution programmatically is the following: `python3 -m pip uninstall -y empy` `python3 -m pip install empy==3.3.4` https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-mpa-to-ros2/-/blob/dev/scripts/voxl-configure-mpa-to-ros2?ref_type=heads#L18 Cheers! Zach ## Reply by Gary Holmgren · 2025-01-05 03:10:57 UTC (in reply to Zachary Lowell 0) @Zachary-Lowell-0 Yes this did the trick, thankyou!