On 2018-08-27 09:44, Claudius Heine wrote:
> On 2018-08-27 09:25, [ext] Claudius Heine wrote:
>> Hi Jan,
>>
>> On 2018-08-27 08:41, [ext] Jan Kiszka wrote:
>>> Hi all,
>>>
>>> I was wondering if / how we could model the increasingly common case
>>> of building very similar target images more efficiently.
>>>
>>> A devel image, e.g., likely consists of almost the same base package
>>> set as the release image. It may only add further packages and maybe
>>> replace very few (like customization packages). When building both,
>>> we could save time - specifically when doing cross - by bootstrapping
>>> the baseline only once. We already do that for the debootstrap step,
>>> but not yet for further packages.
>>>
>>> What do you think? And how could that be modeled from user perspective?
>>
>> That is not very easy.
>>
>> A complex way this could be done by having a `common image` recipe
>> that depends on other image recipes to deploy their required package
>> list,
>
> What I meant by that is each image recipe writes its package list into
> its own text file in the 'deploy' directory.
>
>> then figure out the common dependencies of all of them and build the
>> custom image.
>
> s/custom/common/
>
> Problem scenario here is:
>
>   Image A: depends on A which depends on D
>   Image B: depends on B which depends on D
>
> Since D is not named in any recipes, but should be installed in the
> `common image` as automatically selected package (not as manual). This
> scripting is a bit tricky.
>
>> Then those other image recipes depend of the `common image` recipe in
>> turn to create it, copy it and base their own customizations on top.
>>
>>  From a user perspective they would have to add their image recipes
>> into a global variable or bbappend, so that is available in the
>> `common image` recipe. The rest could be done in the image classes.
>>
>> Cheers,
>> Claudius
>

Hmm, I'm not seeing yet where the complication could come from. I would
have expected the following:

- write a new image recipe include that takes a preexisting image in
   form of a rootfs as input (rather than using setup_root_file_system)

- create specialized images on top of that which depend on some base
   image recipe as well as additional IMAGE_INSTALL recipes and may come
   with own IMAGE_PREINSTALLs (always on top of base images)

- push all common IMAGE_PREINSTALLs into base image recipes, same for
   all IMAGE_INSTALLs

And done. What am I missing?

Jan