✨ speed up container image builds

[mateusoliveira43]

Why the changes were made

When building a container image for different arch than you are on, if --platform=${BUILDPLATFORM} is not in FROM statement in Dockerfile, build will take longer.

On a project I work, we build container images for testing in clusters that can either be amd64 or arm64. So, sometimes the developer is on the same arch they need to build, sometimes not.

docker-buildx could fix the problem, but would build an unnecessary extra arch (for delivering the product, it does make sense to create all archs possible, but for developing, just building teh arch you need make developemt cycle faster).

How to test the changes made

Run docker-build docker-push and docker-buildx commands and check if they still work (and are not slower).

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @mateusoliveira43. Thanks for your PR.

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[camilamacedo86]

This code was added to ensure it functions as expected, specifically enabling Docker to generate images with support for all the platforms listed above. Could you confirm that everything will continue to work as intended after your changes?

To move forward, could we please add CI tests? We could create a new GitHub workflow (like build) that builds a sample, triggers this target, and verifies that the generated image supports all required platforms. What do you think? Does this make sense?

[mateusoliveira43]

sure, CI approach is good, will see how to create a test for it

[camilamacedo86]

I just want to share with you that it is implemented as it is because, as far as I remember, the suggestion you are making here did not work well. So, for any changes here, we really need to properly ensure and with a CI so that we can ensure that we have no regressions.