ModuleNotFoundError: No module named 'ament_package'
Hello! I am using ROS2 dashing for building my program. I also have ROS Melodic in my system. For ROS2 instead of sourcing, the environment from source /opt/ros/dashing/setup.bash I am setting the CMAKE_PREFIX_PATH in CMakeLists.txt.
SET(CMAKE_PREFIX_PATH "${CMAKE_REFIX_PATH} home/pankhuri/ros2_ws/install;/opt/ros/dashing")
While building with colcon build --symlink-install My code works well but now since I have to avoid sourcing the path I am getting this error:
pankhuri@pankhuri-LENOVO-IDEAPAD-500-15ISK:~/week2$ colcon buildStarting >>> dummyexample
--- stderr: dummyexample
Traceback (most recent call last):
File "/opt/ros/dashing/share/ament_cmake_core/cmake/package_templates/templates_2_cmake.py", line 21, in <module>
from ament_package.templates import get_environment_hook_template_path
ModuleNotFoundError: No module named 'ament_package'
CMake Error at /opt/ros/dashing/share/ament_cmake_core/cmake/ament_cmake_package_templates-extras.cmake:41 (message):
execute_process(/usr/bin/python3
/opt/ros/dashing/share/ament_cmake_core/cmake/package_templates/templates_2_cmake.py
/home/pankhuri/week2/build/dummyexample/ament_cmake_package_templates/templates.cmake)
returned error code 1
Call Stack (most recent call first):
/opt/ros/dashing/share/ament_cmake_core/cmake/ament_cmake_coreConfig.cmake:38 (include)
/opt/ros/dashing/share/ament_cmake/cmake/ament_cmake_export_dependencies-extras.cmake:15 (find_package)
/opt/ros/dashing/share/ament_cmake/cmake/ament_cmakeConfig.cmake:38 (include)
CMakeLists.txt:13 (find_package)
---
Failed <<< dummyexample [ Exited with code 1 ]
Summary: 0 packages finished [0.36s]
1 package failed: dummyexample
1 package had stderr output: dummyexample
Some Snippets of my CMakeLists.txt are:
cmake_minimum_required(VERSION 3.5)
project(dummyexample)
#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 -Wunused-parameter)
endif()
SET(CMAKE_PREFIX_PATH "${CMAKE_REFIX_PATH} home/pankhuri/ros2_ws/install;/opt/ros/dashing")
find_package(ament_cmake REQUIRED)
find_package(rclcpp REQUIRED)
include_directories(
include
${rclcpp_INCLUDE_DIRS}
)
add_executable(main main.cpp)
target_link_libraries(main ${rclcppLIBRARIES} ${std_msgs_LIBRARIES} )
install(TARGETS main
DESTINATION bin)
Any suggestion in this matter would be helpful..
can you clarify why?
ament_packageis a Python module. Python uses thePYTHONPATHvariable. It doesn't retrieve theCMAKE_PREFIX_PATH, so setting is will not extend the Python search path.I am working on extending the support of some tools to ROS2 in such a way that they are compatible with both ROS1 and ROS2. So, I have to get both ROS1 and ROS2 libraries in CMakeLists.txt for compiling conditionally.
Setting CMAKE_PREFIX_PATH for ROS1 worked well without the need of sourcing the ROS Melodic. I wanted to do something similar for ROS2 too. I Understood why setting the CMAKE_PREFIX_PATH won't work for it. Can you suggest any alternative for this?
As long as none of your ROS nodes are
rospybased orroscppbased and need additional libraries, this could work. The environment will not be correctly setup though (missingROS_MASTER_URI,ROS_HOME,LD_LIBRARY_PATH,ROS_DISTRO,ROS_VERSION,ROS_PACKAGE_PATHand a nr of other variables).My ROS does have cpp file (rclcpp), which gives error here..
The error is in a Python script, which can't
importa certain Python module. The problem is inament_cmake_core, not in your node.I set the pythonpath first and then CMake_PREFIX_PATH with:
And this problem got solved.
Unless really necessary, I would recommend to not manually mutate these sort of environment variables.