Configurable repository path

[stevenpall]

Having the repository being built checked out to a specific directory would be useful in various cases.

[bradrydzewski]

@stevenpall there is partial support for this feature:

git:
  path: path/to/clone

This clones the repository into /var/cache/drone/src/{ git.path }. This could be adjusted to work with absolute paths (that start with /). If is probably just a one or two line change here:
https://github.com/drone/drone/blob/0a6227930dce3e356667506bc950530a9d847c61/server/worker/docker/docker.go#L119

[bradrydzewski]

@stevenpall I think the path forward here is to alter the following configuration to respect absolute paths in the .drone.yml file:

git:
  path: path/to/clone

It could look something like this:

path := r.Repo.Host + "/" + r.Repo.Owner + "/" + r.Repo.Name
    repo := &repo.Repo{
        Name:   path,
        Path:   r.Repo.CloneURL,
        Branch: r.Commit.Branch,
        Commit: r.Commit.Sha,
        PR:     r.Commit.PullRequest,
-       Dir:    filepath.Join("/var/cache/drone/src", git.GitPath(script.Git, path)),
        Depth:  git.GitDepth(script.Git),
    }

+ if len(script.Git) != 0 && filepath.IsAbs(script.Git) {
+   repo.Dir = git.GitPath(script.Git, path)
+ } else {
+   repo.Dir = filepath.Join("/var/cache/drone/src", git.GitPath(script.Git, path))
+ }

I do agree the current default directory (/var/cache/drone) is not ideal. This is one of the reasons we'll switch to use the default WORKDIR as defined in the Dockerfile (detailed in #749). This is important for compatibility with the official Docker language stacks (see #483).

[stevenpall]

@bradrydzewski That makes sense, and I like the idea of using WORKDIR to define the clone path. What do you foresee the timeline being on PR 3 of #749 getting merged in?

As an aside, I was having a pretty hard time testing the changes made in my fork since a lot of the Makefile has github.com/drone/drone hardcoded. What is the preferred method of building and running Drone from a fork like this for testing?