build: s/glide/dep

[gbbr]

dep init automatically converted the glide files. Double-checked commits for each dependency.

[AlexJF]

Shouldn't this package along with datadog-agent and golang.org/x/sys appear in Gopkg.toml in addition to the lock file?

[gbbr]

Based on my understanding of what the Gopkg.toml file represents, I think that it only holds a set of "hand-written" rules, in this case constraints to certain tags that dep init has found in the glide configuration. I think the repos you've mentioned didn't have these constraints, they've only had commits set.

I would assume that if we ever want to update (using something like dep ensure -update) the toml file will block us from going past the tag in the constraint.

More info here

[AlexJF]

Ok the actual explanation for this I guess comes from https://github.com/golang/dep/blob/master/docs/glossary.md#direct-dependency (emphasis mine):

A project's direct dependencies are those that it imports from one or more of its packages, or includes in its required list in Gopkg.toml.

I guess dep automatically adds implicit required entries in Gopkg.toml for detected external imports.

Seems a bit strange to allow hidden implicit dependencies like this though, at least coming from almost any other language.

[gbbr]

Thanks for reviewing Alex. Not sure what to say about your strange finding though :)