Set up continuous integration

[dzhoshkun]

Closes #2

[joubs]

Hi both,

I have doubts about the docker images tags : during setup job we tag the new image with the current branch name, while we pull the "master" docker image during test job, is it an expected behavior?

I also read some warnings about using the dind service, I pursue my investigations and leave two interesting links :

https://jpetazzo.github.io/2015/09/03/do-not-use-docker-in-docker-for-ci/
https://blog.callr.tech/building-docker-images-with-gitlab-ci-best-practices/

[rmileskcl]

We should be specifying version numbers here to ensure that subsequent builds are the same - the only problem is that these versions aren't available indefinitely from the apt repositories, causing failed builds later on.
I'm not sure what the best solution is for this - I think for now it's okay, but in the future if we were to be more strict then we may have to come up with a more permanent (non trivial!) solution

[rmileskcl]

Hi Francois,

Good point regarding your concern with our tags - I think we could change registry.gitlab.com/gift-surg/puma/puma-ci-linux:master to be registry.gitlab.com/gift-surg/puma/puma-ci-linux:${CI_COMMIT_REF_SLUG} so that it always references the current branch.
9 times out of 10 this probably wont make any difference but will mean any changes to the Dockerfile will be picked up automatically.

Regarding DIND, it's certainly not an ideal solution, or one that I'd like to use if we were doing anything complicated but it's Gitlab's recommended method. It does have the drawback of not making use of the Docker cache which would speed up builds. Perhaps we could look at running them directly on Gift-Little instead? I think that would take some re-configuring of the CI runner but could be done.

[dzhoshkun]

The built and used Docker image paths are now identical.