fix: Build.Repo and Build.CacheRepo now uses buildRepo()

[hcsaustrup]

Fixed assignment of Build.Repo and Build.CacheRepo so it not only contains the specified repo, but also registry by using buildRepo().
This required for pushing images to private repositories.

[myers]

I got stung by this as well.

A work around is to set the repo in your .drone.yml to have the registry / repo.

[hcsaustrup]

Turns out CacheRepo also needed buildRepo()

[ymage]

Hi,

It seems I can't push anymore on docker hub public repo since this change.
Before, it generated some --destination=<myrepo>/<myimage>:latest => Push OK
Now, it generates --destination=https://index.docker.io/v1/<myrepo>/<myimage>:latest => Push KO

I tried with vanilla kaniko and it seems the issue comes from this added registry url prefix.

[shubham149]

Thanks a lot @ymage for bringing it up.

The aim for this change was to prefix the registry url in the repo name but looks like a lot of cases are missing here.

1. If registry URL is public dockerhub, the full repo name: index.docker.io//: but this change generates repo name as https://index.docker.io/v1/<myrepo>/<myimage>:latest. Also, it needs to handle repo's without dockerhubUsr e.g. alpine image.
2. https:// is usually present in the registry url but should not be mentioned in the repo name.

There can be other cases which might have missed here. I am inclined towards making a backward incompatible change where user has to mention PLUGIN_EXPAND_REPO to prepend registry url to the repo.

[shubham149]

@hcsaustrup @myers I am going ahead with the backward incompatible change here: #48