godep save fails on empty grpc_lb_v1 package for grpc 1.6+

[jpbetz]

When upgrading kubernetes from grpc 1.3.0 to 1.7.4, godep save reported this error:

godep: no buildable Go source files in /usr/local/google/home/jpbetz/Projects/k8s/src/k8s.io/kubernetes/_output/local/go/src/google.golang.org/grpc/grpclb/grpc_lb_v1                                                                                                                              
 !!! Error in hack/godep-save.sh:69
...

After locally adding a doc.go placeholder file to the grpc/grpclb/grpc_lb_v1 dir in grpc source, the godep save command ran successfully.

I'll attempt to create a minimal example that reproduces the issue.

go version go1.9.1 linux/amd64
godep v79 (linux/amd64/go1.8.1.typealias)
kubernetes master (@ b97e17603b)

[jpbetz]

Was able to resolve this. Once the grpc/grpclb/grpc_lb_v1 package was excluded (godep get google.golang.org/grpc/... will exclude it) as will removing it from Godeps.json, godeps correctly ignored the directory.

[jpbetz]

godep issue: tools/godep#554

[dfawley]

Thanks! I had a feeling that was the problem -- we have no .go files in that path, so the error is accurate; it's just not clear why it would be an error.

[jpbetz]

@dfawley If you're willing to merge it, #1743 would be a huge help to kubernetes for getting grpc upgraded. We're currently stuck on 1.3.0. We'd need a new 1.7.x cut with it though..

I was hoping that maybe we could get this fixed in godep, but the project has had no activity since February this year, so I'm doubtful that even if we authored the PR that it would get merged. The only other paths forward are #1743 or to wait till a large number of kubernetes' transitive dependencies are on grpc 1.7.x.