Re: [RFC PATCH 14/15] gitlab-ci: Allow forks to use different set of jobs

["Alex Bennée" <alex.bennee@linaro.org>]

Philippe Mathieu-Daudé <f4bug@amsat.org> writes:

> +Stefan/Peter
>
> On 4/19/21 12:59 PM, Thomas Huth wrote:
>> On 19/04/2021 12.51, Daniel P. Berrangé wrote:
>>> On Mon, Apr 19, 2021 at 12:48:25PM +0200, Thomas Huth wrote:
>>>> On 19/04/2021 12.36, Daniel P. Berrangé wrote:
>>>>> On Mon, Apr 19, 2021 at 12:20:55PM +0200, Thomas Huth wrote:
>>>>>> On 19/04/2021 12.10, Erik Skultety wrote:
>>>>>>> On Mon, Apr 19, 2021 at 10:40:53AM +0100, Daniel P. Berrangé wrote:
>>>>>>>> On Mon, Apr 19, 2021 at 01:34:47AM +0200, Philippe Mathieu-Daudé
>>>>>>>> wrote:
>>>>>>>>> Forks run the same jobs than mainstream, which might be overkill.
>>>>>>>>> Allow them to easily rebase their custom set, while keeping using
>>>>>>>>> the mainstream templates, and ability to pick specific jobs from
>>>>>>>>> the mainstream set.
>>>>>>>>>
>>>>>>>>> To switch to your set, simply add your .gitlab-ci.yml as
>>>>>>>>> .gitlab-ci.d/${CI_PROJECT_NAMESPACE}.yml (where
>>>>>>>>> CI_PROJECT_NAMESPACE
>>>>>>>>> is your gitlab 'namespace', usually username). This file will be
>>>>>>>>> used instead of the default mainstream set.
>>>>>>>>
>>>>>>>> I find this approach undesirable, because AFAICT, it means you have
>>>>>>>> to commit this extra file to any of your downstream branches that
>>>>>>>> you want this to be used for.  Then you have to be either delete it
>>>>>>>> again before sending patches upstream, or tell git-publish to
>>>>>>>> exclude the commit that adds this.
>>>>>>>>
>>>>>>>> IMHO any per-contributor overhead needs to not involve committing
>>>>>>>> stuff to their git branches, that isn't intended to go upstream.
>>>>>>>
>>>>>>> Not just that, ideally, they should also run all the upstream
>>>>>>> workloads before
>>>>>>> submitting a PR or posting patches because they'd have to respin
>>>>>>> because of a
>>>>>>> potential failure in upstream pipelines anyway.
>>>>>>
>>>>>> It's pretty clear that you want to run the full QEMU CI before
>>>>>> submitting
>>>>>> patches to the QEMU project, but I think we are rather talking
>>>>>> about forks
>>>>>> here that are meant not meant for immediately contributing to upstream
>>>>>> again, like RHEL where we only build the KVM-related targets and
>>>>>> certainly
>>>>>> do not want to test other things like CPUs that are not capable of
>>>>>> KVM, or a
>>>>>> branch where Philippe only wants to check his MIPS-related work during
>>>>>> development.
>>>>>> For contributing patches to upstream, you certainly have to run the
>>>>>> full CI,
>>>>>> but for other things, it's sometimes really useful to cut down the CI
>>>>>> machinery (I'm also doing this in my development branches manually
>>>>>> some
>>>>>> times to speed up the CI), so I think this series make sense, indeed.
>>>>>
>>>>> For a downstream like RHEL, I'd just expect them to replace the main
>>>>> .gitlab-ci.yml entirely to suit their downstream needs.
>>>>
>>>> But that still means that we should clean up the main .gitlab-ci.yml
>>>> file
>>>> anyway, like it is done in this series, to avoid that you always get
>>>> conflicts in this big file with your downstream-only modifications.
>>>> So at
>>>> least up to patch 11 or 12, I think this is a very valuable work that
>>>> Philippe is doing here.
>>>
>>> I don't see a real issue with downstream conflicts. They'll just
>>> periodically pick a release to base themselves off and change once
>>> every 6 months or more.
>> 
>> It's not only downstream distros that rebase every 6 month. Like
>> Philippe, I'm sometimes hacking my .gitlab-ci.yml of my development
>> branch to speed up the CI during my development cycles (i.e. I'm
>> removing the jobs that I do not need). And I'm regularly rebasing my
>> development branchs. Conflicts in .gitlab-ci.yml are then always
>> painful, so a leaner main .gitlab-ci.yml file would be helpful for me,
>> too, indeed.
>
> Not sure if following up this thread or start a new one, but I got
> blocked again from Gitlab, tagged as a crypto miner for running QEMU
> CI...
> [1]
> https://about.gitlab.com/handbook/support/workflows/investigate_blocked_pipeline.html#trends--high-priority-cases
>
> I pushed 5 different branches to my repository in less than 1h,
> kicking 580 jobs [*].
>
> I didn't try to stress Gitlab, it was a simple "one time in the month
> rebase unmerged branches, push them before respining on the mailing
> list".
>
> I'm considering changing my workflow:
> - not push more than 2 branches per hour (I know 3/h works, so choose
>   a lower number, as we want to add more tests).
> - merge multiple branches locally and push the merged result and
>   bisect / re-push on failure

I stack my branches - so usually I have a:

 testing/next
 gdb/next
 whatever my current hack is

Every week I re-base the branches and re-build my current hacking tree.
If an actual problem shows up in CI I'll bisect on one of my beefy boxes
to fix it and then fix and re-push testing/next and whatever my tip is.

> - run less testing
> - do not run testing

I run a lot of testing locally (or rather on a beefy server) so I'm
really only using GitLab for final validation of trees rather than day 2
day.

>
> This sounds counter productive and doesn't scale to a community of
> contributors asked to use Gitlab.
>
> So far I don't have better idea than this series.
>
> Who is interested in sending patches to improve our workflow?
>
> Thanks,
>
> Phil.
>
> [*] NB I have 3 extra runners added to my namespace, but it didn't
> help, as per [1] I got blocked by reaching an API rate limit.


-- 
Alex Bennée