Add kustomize build {repoUrl}

[Liujingfang1]

• Add githubLoader which checks out a repo, saves to a temp dir and creates a fileLoader with root at the temp dir
• Add NewLoader function to return either a fileLoader or githubLoader based on the input string
• Use NewLoader in both build and diff
• In fileLoader.New, if the input string is a repoUrl, return a githubLoader.

The accepted format of the repoUrl is
github.com/project/repo//subdir?ref=xxx

both subdir and ref are optional.

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[Liujingfang1]

Following examples all work
kustomize build github.com/kubernetes-sigs/kustomize//examples/multibases?ref=v1.0.6
kustomize build github.com/Liujingfang1/mysql
kustomize build github.com/Liujingfang1/kustomize//examples/helloWorld?ref=repoUrl2

kustomize build also works for those links as bases:

bases:
- github.com/kubernetes-sigs/kustomize//examples/multibases?ref=v1.0.6
- github.com/Liujingfang1/mysql
- github.com/Liujingfang1/kustomize//examples/helloWorld?ref=repoUrl2

In order to make go vet and metalinter happy, I manually removed some file in go-getter library. I don't think this hacky workaround is sustainable. What about we create a branch in go-getter repo with our desired change? @monopole Then we can use our branch safely with dep ensure.

[monopole]

couple of quick questions

[monopole]

NewLoader does this (it doesn't look right here).

[Liujingfang1]

There is slight difference between New and NewLoader. New creates a new fileLoader whose root is a relative path in current fileloader. NewLoader is more like creating a root loader, where we don't have an existing fileloader.

[monopole]

can this just mixin fileLoader (and use its fSys field)?

[Liujingfang1]

I think we can.

[monopole]

go vet and metalinter should ignore the vendored stuff (else everything would already be blowing up).

So all the deps come in because they have an s3 getter that comes along for the ride (no option to just get a subset of the getters).

I guess we can just vendor the world for now, rather than hack around it. Perhaps file an issue with hashicorp and move on.

[Liujingfang1]

So all the deps come in because they have an s3 getter that comes along for the ride (no option to just get a subset of the getters).

That's corret. The go-getter client contains several detectors for different kinds of repos(github, mecurial and so on), s3 is one of them. There is no option to get a subset of it.

I guess we can just vendor the world for now, rather than hack around it. Perhaps file an issue with hashicorp and move on.

I created a PR #262 on a different branch.

[monopole]

/lgtm

[monopole]

please add test coverage for this