Push support for types.OCI

[Avi Deitcher]

When calling PushManifestList, it always sets the image.Type to types.Docker, which resolves to "application/vnd.docker.distribution.manifest.list.v2+json". It never uses types.OCI, which resolves to the OCI "application/vnd.oci.image.index.v1+json".

Besides the desire to push out a proper OCI index, Docker Hub appears to have an issue where it will accept creation of a new index (POST) with the "application/vnd.docker.distribution.manifest.list.v2+json" media type, but gets quite unhappy when you update an existing one (PUT).

We shouldn't have to work around Hub's bugs, of course, but it would be good for us to be able to specify the OCI index vs Docker multi-arch manifest.

Unless there is some way to set it that it I am missing?

[Avi Deitcher]

And if it isn't, and you want a PR, I am happy to open one. I guess another parameter for PushManifestList()?

[Phil Estes]

I almost didn't believe you, but then I found it was you who removed that feature 😇 😓 😂

When you moved the code around to be more "library consumable" in #104 we lost the client context that was being used to differentiate OCI vs. Docker v2 pushes. Of course totally my bad to miss this when I reviewed the PR!

25aa9ae#diff-90831dc0f77a32f7a21aba91c0a5e34a15910c0709e2f20fb951d3b0c02afedaL140-L143

So, that OCI flag needs to get into the PushManifestList function so we can return to that behavior.

[Avi Deitcher]

I did that? 🤣

I will open a PR for it.

[Phil Estes]

Thanks!

[Avi Deitcher]

Have a look at #181