[yocto] Building single package as image, respecting dependencies

[Norman Stetter]

Hi there,

I am currently working on a minimal CLI only system.
The image is based on 'core-image-base' using sysvinit and busybox.
To reduce image size and boot time, I removed as many packages as possible. For some application cases I will need python3 though.
My idea was to have python3 as some kind of add-on in a squashfs image, that can be mounted only when needed.

So I tried to build an image only containing the python3 package, but as little as possible otherwise, like this:

inherit image
IMAGE_FSTYPES = "squashfs-xz"
DEFAULT_TASK_PROVIDER = ""
DISTRO_EXTRA_RDEPENDS = ""
DISTRO_FEATURES = ""
POKY_DEFAULT_EXTRA_RDEPENDS = ""
IMAGE_FEATURES = ""
IMAGE_LINGUAS = ""
CORE_IMAGE_BASE_INSTALL = ""
RDEPENDS_${PN} = ""
PACKAGE_EXCLUDE = "busybox openssl run-postinsts update-rc.d"
VIRTUAL-RUNTIME_dev_manager = ""
VIRTUAL-RUNTIME_login_manager = ""
VIRTUAL-RUNTIME_init_manager = ""
VIRTUAL-RUNTIME_initscripts = ""
VIRTUAL-RUNTIME_keymaps = ""
VIRTUAL-RUNTIME_base-utils = ""
PREFERRED_PROVIDER_virtual/base-utils = ""

IMAGE_INSTALL = "python3"

But like this I can only manually exclude packages I already have in my main OS image. Some packages can't be excluded at all, as python3 depends on them and won't build if they are excluded.

Is there a way to have dependencies between images? So I could have the python-image build know which dependencies are already built into my OS image and therefore not include them itself?

Or would it be better to avoid building a second image and rather build 'python3' with my OS-image, adding it to PACKAGE_EXCLUDE and from within this build process pack all python3 files into an image? If I were to pursue this method, any suggestions on how to separate the python3 files from the rest of my rootfs, including the necessary dependencies?

Any advice and idea is much appreciated.

Mit freundlichen Grüßen / Best regards
Norman Stetter
SW ENWICKLUNG EMBEDDED SYSTEMS
Garz & Fricke GmbH

21079 Hamburg
Direct: +49 40 791899 - 477
Fax: +49 40 791899 - 39
Norman.Stetter at garz-fricke.com
www.garz-fricke.com<http://www.garz-fricke.com/>
WE MAKE IT YOURS!
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