How to build a freestanding Zephyr application with cmake and venv?

[sebistark]

How to build a freestanding Zephyr application with cmake and venv?

And how does it work when python modules were installed within python venv?

I always get an error ModuleNotFoundError: No module named 'pykwalify'.

the global pip list does not contain this module, but the pip list in venv contains it, as expected.

Here is the whole log:

**** CMake Configure of configuration build for project demoapp ****
/usr/bin/cmake -S . -B build -GUnix Makefiles 
CMake Warning:
  Ignoring empty string ("") provided on the command line.


Loading Zephyr default modules (Freestanding).
-- Application: /home/xxx/workspace_STM/demoapp
-- CMake version: 3.29.6
-- Found Python3: /usr/bin/python3 (found suitable version "3.10.12", minimum required is "3.8") found components: Interpreter
-- Cache files will be written to: /home/xxx/.cache/zephyr
-- Zephyr version: 3.6.99 (/home/xxx/RTOS-exploration/zephyrproject/zephyr)
CMake Error at /home/xxx/RTOS-exploration/zephyrproject/zephyr/cmake/modules/boards.cmake:193 (message):
  Error finding board: nucleo_h563zi

  Error message: Traceback (most recent call last):

    File "/home/xxx/RTOS-exploration/zephyrproject/zephyr/scripts/list_boards.py", line 11, in <module>
      import pykwalify.core

  ModuleNotFoundError: No module named 'pykwalify'

Call Stack (most recent call first):
  /home/xxx/RTOS-exploration/zephyrproject/zephyr/cmake/modules/zephyr_default.cmake:132 (include)
  /home/xxx/RTOS-exploration/zephyrproject/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
  /home/xxx/RTOS-exploration/zephyrproject/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:159 (include_boilerplate)
  CMakeLists.txt:6 (find_package)


-- Configuring incomplete, errors occurred!

[sebistark]

I found a workaround.
put the following two commands in CMakeLists before "findpackage()"

set(Python3_EXECUTABLE "/home/xxx/RTOS-exploration/zephyrproject/.venv/bin/activate")
set(PYTHON_EXECUTABLE ${Python3_EXECUTABLE})

This path is were python venv is located.

[yashi]

Setting some variable in CMakeLists.txt might work. But but the standard way to use venv is

$ source <venv>/bin/activate

See https://docs.python.org/3/library/venv.html#how-venvs-work

Or you can use one of virtual environment tools, such as conda, pipenv, poetry.
Assuming you have already installed all python dependencies:

❯ cd zephyr-project
❯ pipenv shell  # or `source .venv/bin/activate`
❯ export ZEPHYR_BASE=`pwd`/zephyr
❯ export BOARD=native_sim
❯ cmake -B builddir -S zephyr/samples/hello_world
❯ ninja -C builddir

[sebistark]

Thank you for your reply.

I think you are right. This is the proper way, if you do everything in the shell.
However, I wanted to find a solution, where one can import CMakeLists.txt in an IDE (e.g. Eclipse or STMCubeIDE) and compile it from there.

[yashi]

OK. I can understand that.

However, all I did was set a few environment variables.

What source .venv/bin/activate does is set environment variables. It basically sets:

• PATH
• VIRTUAL_ENV
• VIRTUAL_ENV_PROMPT

These are called environment variable because they might differ in other situations. If the CMakeLists.txt is used only by you, your solution should be fine. But if you are planning to work with your team, it's gonna be a problem.

ps.
VS code seems to have venv support: https://code.visualstudio.com/docs/python/environments

I'm not an IDE guy but Eclipse and STMCubeIDE should have some support for Python as well.

Anyway, happy hacking 😄

[sebistark]

Thanks a lot 😄