Retrieve CABLE from GitHub repository instead of SVN

[ccarouge]

We need this to be released on time for the CABLE transition to GitHub. Should we have both options available at first if we need to compare with something that hasn't been moved to GitHub?

• [x] #204
• [x] #199
• [ ] #203

[SeanBryan51]

We will probably need to change the way we specify CABLE branches (realisations). We currently specify branches using the path and revision keys.

I propose we replace the path and revision keys with a repo key which can be used to specify an SVN repository or a Git repository:

realisations:
  - repo:
      svn:
        path: branches/Users/foo/my_branch
        revision: 123

realisations:
  - repo:
      git:
        branch: 136-some-feature-branch
        commit: bc08348

[SeanBryan51]

I want to create an interface that abstracts away the version control system being used, i.e. create a new utility module utils/repo.py that contains the following

class Repo(AbstractBaseClass):
    @abstractmethod
    def checkout(self, verbose=False):
        pass

    @abstractmethod
    def get_revision(self) -> str:
        pass

and have concrete implementations of this with a git and svn backend.

However the names repo.py and Repo might be confused with repository.py and CableRepository. I'm thinking I would like to rename repository.py to model.py and CableRepository to Model. This is mostly semantics but I think we should differentiate these two classes if possible.

[ccarouge]

Once we remove checkout and get_revision from the CableRepository class, don't we just end up with a ModelBuild class instead of a Model class?

[SeanBryan51]

@ccarouge I think I prefer Model over ModelBuild because the class is also a data structure for each "model" specified in realisations. E.g. it seems more natural to me that a Task is comprised of a Model rather than a ModelBuild.

[SeanBryan51]

We will need to address #199 because the CABLE GitHub repository has a different directory structure to the SVN repository. Any hard coded paths to files located in the CABLE repository will fail when working with the Git version.

[ccarouge]

I like the list of sub-issues. 👍