Hi Marek,

On 7/22/22 08:53, Marek S?omiany wrote:
> Hello everyone,
>
> I am working on creating a custom class (basically own image signing) that
> will be using a client's python module, but to simplify I'll use as an
> example a python3 module Magic as it behaves in exactly the same way. I'm
> working on dunfell.
>
> So basically in recipe I am using depends to add the module and it works in
> example like that:
>
> inherit python3native
> DEPENDS += "python3-magic-native"
> do_sometask(){
>          python3 ${S}/testapp.py
> }
>
> and in testapp.py importing magic works fine, but when I'm trying to import
> magic in python function, bitbake-style python functions or in anonymous
> python functions it fails to find the module.
> as an example that do NOT work:
> def foo(d):
>      import magic
>      mime = magic.Magic(mime=True)
>      return "foo"
>
> python do_bar () {
>      bb.warn(foo(d))
> }
>
> Neither it works in do_bar nor in foo as shown above. Always ends up with:
> Exception: ModuleNotFoundError: No module named 'magic'
>
> I have also tried to set variable:
> PYTHON_SITEPACKAGES_DIR =
> "${WORKDIR}/recipe-sysroot/usr/lib/python3.8/site-packages"
> but it does nothing in my case.
>
> Can you help me with this?
>

Anonymous functions are run during parsing before anything is built.
Therefore, I don't think it'll be possible to use a python module from a
recipe in an anonymous function.

In order to use native binaries from recipes in another recipe, the
binaries need to be in the recipe sysroot-native directory. This is what
DEPENDS does behind the scenes, it adds a dependency for one task of
your recipe on the population of sysroot-native from all dependencies
(DEPENDS). Therefore, your DEPENDS will be enough if it happens in any
task running after the do_prepare_recipe_sysroot task of your recipe.

Don't forget that a task is run only if it's in the path of a task
requested by the user or another recipe as a dependency. Usually it
needs to be in the path of the do_build task. e.g. addtask my_task after
do_prepare_recipe_sysroot is not enough if you want my_task to always
run during a normal build because nothing has a dependency ON my_task.
addtask my_task after do_prepare_recipe_sysroot before do_configure for
example, will work, because when do_configure will need to be run, it'll
ask my_task to be run too by bitbake.

Cheers,
Quentin