ci: use caching from docker to run test in CI

[domire8]

Description

• Revamp build structure #159

Let's start small, first would be to run the tests with the caching action from docker and github.

Review guidelines

Estimated Time of Review: 5 minutes

Checklist before merging:

• Confirm that the relevant changelog(s) are up-to-date in case of any user-facing changes

[domire8]

As we can see here this works rather okay out of the box, but I have tried it several times now and somehow it always executes the build stage even if the source code didn't change. I'm not sure what is invalidating the cache for that stage

[domire8]

This seems to work now, thanks @LouisBrunner

[LouisBrunner]

.dockerignore is better for ignoring specific folder

[domire8]

When I put stuff into dockerignore, I can't copy them anymore. I just want to be selective with copying to not invalidate caches unintentionally. If you copy . then docker will continue at this line, even though you maybe only changed something in python, so the cpp build is not necessary

[domire8]

Okay I'm now finally kind of happy with this PR. Instead of having 3 different test actions (source, proto, python) where you'ds see immediately which tests have failed, everything is now tested in the same step and will just fail somewhere during the build action. However, this allows for best caching. To see that, I invite you to check the last 3 successful workflow runs:

• the first one needed to build the image from scratch and took 13mins
• the second one had a change in the cpp tests, so just needed to rebuild the cpp sources and tests and took 6mins
• the third one only needed to rerun the python tests, so took less than a minute.

Leaving those two last commits here for you to see the workflows, then I'll have to remove it again

[eeberhard]

Thank you for the additional example commits to see the caching. The actions and workflow are definitely much simpler now.

N.B. after this we will have to update the branch protection rules which currently expect and require the existing actions to run

[domire8]

N.B. after this we will have to update the branch protection rules which currently expect and require the existing actions to run

I'm not sure, I can't see them under the branch settings. I had the same thoughts as you though