Re: [PATCH] gitlab-ci: Only push Docker 'latest' image when building default branch

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 2/16/21 10:52 AM, Daniel P. Berrangé wrote:
> On Tue, Feb 16, 2021 at 08:05:09AM +0100, Philippe Mathieu-Daudé wrote:
>> On 2/16/21 7:55 AM, Thomas Huth wrote:
>>> On 15/02/2021 20.28, Philippe Mathieu-Daudé wrote:
>>>> While we are interested in building docker images in different
>>>> branches, it only makes sense to push 'latest' to the registry
>>>> when this is the project default branch (usually 'master').
>>>>
>>>> Else when pushing different branches concurrently we might have
>>>> inconsistent image state between branches.
>>>>
>>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>>> ---
>>>>   .gitlab-ci.d/containers.yml | 2 +-
>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/.gitlab-ci.d/containers.yml b/.gitlab-ci.d/containers.yml
>>>> index 90fac85ce46..52a915f4141 100644
>>>> --- a/.gitlab-ci.d/containers.yml
>>>> +++ b/.gitlab-ci.d/containers.yml
>>>> @@ -17,7 +17,7 @@
>>>>             -t "qemu/$NAME" -f "tests/docker/dockerfiles/$NAME.docker"
>>>>             -r $CI_REGISTRY_IMAGE
>>>>       - docker tag "qemu/$NAME" "$TAG"
>>>> -    - docker push "$TAG"
>>>> +    - test "$CI_COMMIT_BRANCH" = "$CI_DEFAULT_BRANCH" && docker push
>>>> "$TAG"
>>>
>>> So does that mean that the following stages in the CI (i.e. build, test)
>>> are only always (i.e. also for the non-master branches) going to use
>>> containers that have been build on the master branch?
>>
>> Hmm good point. Should we use "$CI_COMMIT_BRANCH" instead of "latest"?
> 
> This doesn't work because git branch names are not guaranteed to be
> valid docker tag names. Please see my thread here:
> 
>   https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg03535.html

Indeed this thread describes the problem I am having. I'll see if there
are follow up on your thread.

Another way of fixing this is to find a way to only allow 1 pipeline at
a time. I haven't tried it yet because I don't like the idea of making
CI slower, but this is still better than debugging inconsistent
pipelines when Docker images are rebuilt.

Regards,

Phil.