How to support patching files from SRC_URI before adding to cpio archive

[Klinke, Tobias Alexander]

Internal

Hi,

I'm generating a .swu archive by inheriting from swupdate-image.bbclass and I add some additional files to the archive by listing them in SRC_URI.
For one of those files (my sw-versions file) I want to modify it before adding it to the cpio archive by replacing some placeholders in do_unpack:append() with information from my CI build.
Here is the relevant code (using kirkstone, but should be applicable to newer branches as well):

SRC_URI += " \
file://sw-versions \
file://some-other-script.sh \
"

# Replace @VERSION@ in sw-versions
python do_unpack:append() {
from pathlib import Path
sw_versions_path = Path(f"{d.getVar('WORKDIR')}/sw-versions")
sw_versions_template = sw_versions_path.read_text()
version = d.getVar('SOME_CI_STUFF', True)
sw_versions_content = sw_versions_template.replace("@VERSION@", version)
sw_versions_path.write_text(sw_versions_content)
}
inherit swupdate-image


However, the resulting .swu keeps containing the original unmodified file from the source directory.
I suspect the reason is that in swupdate-common.bbclass the swupdate_create_cpio() function copies the files from S directory.
Is there any reason why they are not taken from WORKDIR to allow patching in do_unpack() as above?
Or is there another mechanism to add additional generated files to the .swu archive?

Best regards,
Tobias Klinke
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[Stefano Babic]

Hallo Tobias,

On 4/4/25 17:02, 'Klinke, Tobias Alexander' via swupdate wrote:
> Internal
>

???

> Hi,
>
> I'm generating a .swu archive by inheriting from swupdate-image.bbclass and I add some additional files to the archive by listing them in SRC_URI.
> For one of those files (my sw-versions file) I want to modify it before adding it to the cpio archive by replacing some placeholders in do_unpack:append() with information from my CI build.
> Here is the relevant code (using kirkstone, but should be applicable to newer branches as well):
>
> SRC_URI += " \
> file://sw-versions \
> file://some-other-script.sh \
> "
>
> # Replace @VERSION@ in sw-versions

Variable substitution is supported out-of-the-box in sw-description only.

> python do_unpack:append() {
> from pathlib import Path
> sw_versions_path = Path(f"{d.getVar('WORKDIR')}/sw-versions")
> sw_versions_template = sw_versions_path.read_text()
> version = d.getVar('SOME_CI_STUFF', True)
> sw_versions_content = sw_versions_template.replace("@VERSION@", version)
> sw_versions_path.write_text(sw_versions_content)
> }
> inherit swupdate-image
>
>
> However, the resulting .swu keeps containing the original unmodified file from the source directory.
> I suspect the reason is that in swupdate-common.bbclass the swupdate_create_cpio() function copies the files from S directory.

Or even that you append() does not run at all, because this is an image
and not a package , and do_unpack() runs just for packages....

The layer fetches the files in SRC_URI and there is no support for vars
substitution. Files are then copied into ${S}.

> Is there any reason why they are not taken from WORKDIR to allow patching in do_unpack() as above?
> Or is there another mechanism to add additional generated files to the .swu archive?

You should generate them in a package and put the generated files into
${DEPLOY_DIR_IMAGE}.

Best regards,
Stefano Babic

[Klinke, Tobias Alexander]

Hi Stefano,

thanks for the quick reply.
Indeed ${DEPLOY_DIR_IMAGE} is what I've been looking for.
I now have a recipe that deploys my generated sw-versions file to ${DEPLOY_DIR_IMAGE} and in my image recipe I added it to ${SWUPDATE_IMAGES}:

SWUPDATE_IMAGES += "sw-versions"

For me, the documentation in https://sbabic.github.io/swupdate/building-with-yocto.html#the-swupdate-class was not clear that you can add literally anything to ${SWUPDATE_IMAGES} - not just images - as long as it is in ${DEPLOY_DIR_IMAGE}.

I'd be happy to contribute a patch to documentation - if you think that it makes sense.

Best regards,
Tobias
________________________________________
Von: Stefano Babic <stefan...@swupdate.org>
Gesendet: Freitag, 4. April 2025 17:38
An: Klinke, Tobias Alexander <tobiasalexa...@draeger.com>; swup...@googlegroups.com <swup...@googlegroups.com>
Betreff: [External] Re: [swupdate] How to support patching files from SRC_URI before adding to cpio archive

[Stefano Babic]

Hi Tobias,

On 08.04.25 17:07, 'Klinke, Tobias Alexander' via swupdate wrote:
> Hi Stefano,
>
> thanks for the quick reply.
> Indeed ${DEPLOY_DIR_IMAGE} is what I've been looking for.
> I now have a recipe that deploys my generated sw-versions file to ${DEPLOY_DIR_IMAGE} and in my image recipe I added it to ${SWUPDATE_IMAGES}:
>
> SWUPDATE_IMAGES += "sw-versions"
>
> For me, the documentation in https://sbabic.github.io/swupdate/building-with-yocto.html#the-swupdate-class was not clear that you can add literally anything to ${SWUPDATE_IMAGES} - not just images - as long as it is in ${DEPLOY_DIR_IMAGE}.
>
> I'd be happy to contribute a patch to documentation - if you think that it makes sense.

Please sned your patch to make the topic more clear - because I
developed it, it is to me often clear out-of-the-box, and my doc can
have some "implicit" things. I am happy to receive patches to make
documentation better.

Best regards,
Stefano