Switch to using stream-metadata-go library

[cgwalters]

After we have a shared Go library for streams, we can use it
in e.g. coreos-assembler/mantle as well as openshift-install.

[cgwalters]

I moved most of the metadata definitions here to https://github.com/cgwalters/stream-metadata-go per discussion in coreos/fedora-coreos-tracker#98 (comment)

So if this PR and approach looks good I propose we move github.com/cgwalters/stream-metadata-go into coreos/ and then look to merge this!

[bgilbert]

I'm in favor. If we're moving these structs out to their own library, though, I think we should probably clean up the struct naming. It isn't very consistent with the terminology used elsewhere.

Also, maybe we should use a map of platforms rather than hardcoding the platform list into the struct? As is, we'll need to revendor the library every time we add a platform.

[cgwalters]

I think we should probably clean up the struct naming. It isn't very consistent with the terminology used elsewhere.

Do you have a specific example? Actually if you want feel free to just push code to master in https://github.com/cgwalters/stream-metadata-go - I just invited you as a collaborator. (Or do PRs as you prefer)

[cgwalters]

Also, maybe we should use a map of platforms rather than hardcoding the platform list into the struct? As is, we'll need to revendor the library every time we add a platform.

Some of them need special handling (mostly the public cloud ones like AWS/Azure/GCP) - but maybe the ones that are just "an image file" could be part of a string map I guess?

[bgilbert]

Okay, I've pushed a bunch of refactoring to that repo.

One open question: calling the package stream is a bit of a misnomer, since it also includes structs for release metadata. Should we move stream.go and release.go into their own subpackages, and/or rename the package and repo e.g. to coreos-metadata-go?

(eek, coreos-metadata.)

[cgwalters]

One open question: calling the package stream is a bit of a misnomer, since it also includes structs for release metadata.

Yeah, separate packages seems cleaner I guess.

[cgwalters]

Pushed https://github.com/cgwalters/stream-metadata-go/pull/1

[cgwalters]

OK this should be close to ready, just have the two dependency PRs outstanding.

[cgwalters]

OK lifting draft!