Re: [OE-core] [PATCH 1/6] package_rpm.bbclass: Handle posttrans scriptlets

["Zoltan Boszormenyi" <zboszor@pr.hu>]

2021. 08. 23. 15:23 keltezéssel, Richard Purdie írta:
> On Mon, 2021-08-23 at 15:14 +0200, Zoltan Boszormenyi via lists.openembedded.org
> wrote:
>> It's documented at www.rpm.org, Red Hat and SuSE.
>>
>> https://docs.fedoraproject.org/en-US/packaging-guidelines/Scriptlets/
>> https://en.opensuse.org/openSUSE:Packaging_scriptlet_snippets
>> https://rpm-packaging-guide.github.io/
>>
>> It's available since RPM 4.4. RPM 4.16.1.3 is in Hardknott.
>>
>> A short Google search showed that *maybe* dpkg also supports it,
>> or at least there are(were?) plans to implement it:
>> https://wiki.debian.org/i18n/TranslationDebsProposals
>>
>> With postinst, the time when the scriptlet runs may depend
>> on the order of the packages in the upgrade transaction and
>> may run with the older binaries in place.
>>
>> The posttrans scriptlet runs at the very end of the
>> install/upgrade transaction, just like the OPKG "intercept"
>> scripts.
>>
>> I successfully tested it long ago with a kernel upgrade
>> that was running dracut on the new version, plus a dracut
>> upgrade in the same session. Dissecting the initramfs proved
>> that with postinst, the old dracut version generated it,
>> while with posttrans, the new one did.
>>
>> Who would want to use it? Anyone who needs some finalizer
>> script to be run at the end of an RPM/DNF transaction.
>>
>> I started on Angstrom and I know opkg doesn't implement this
>> and Yocto inherited it. This patch is basically a heads up
>> that there's another way to do the same thing. Maybe opkg
>> implements this some day, maybe not. Anyway, Yocto in general
>> will need more changes before the main package.bbclass can
>> start to use it for all package formats.
>>
> 
> There is a bigger issue here which is how can anyone use this without making
> their recipe rpm specific? I'm very reluctant to add functionality like this
> unless we have a way to emulate it or fall back on the other package formats.

Indeed. This patch can be dropped.

Full disclosure: I don't use this anymore, since I implemented
another two bbclass recipes to generate the kernel's initramfs
either during the kernel build (and ship it in a subpackage) or
during do_rootfs and move it out of the way in the image postprocess
script so e.g. a squashfs image will have it separately.
They work well for my use limited cases:
* full OS installed on disk
* squashfs for PXE-based remote booted machines

FYI: the dracutsysrootdir feature in recent dracut versions is my work.

I just carried this patch for a couple of years now and I thought maybe
someone sees some value in it.

> 
> The intercept pieces are used by both rpm and opkg and actually do something
> slightly different, they stack common calls until the end of the transaction.
> This means for example we can call "ldconfig" once rather than in every
> postinst.
> 
> Cheers,
> 
> Richard
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