bake: x-bake extension field with compose

[crazy-max]

Ref. compose-spec/compose-spec#120 #183 (comment)

Might also need to update the compose-cli build options to handle x-bake in a follow-up.

cc @chris-crone

Signed-off-by: CrazyMax crazy-max@users.noreply.github.com

[tonistiigi]

Tags should be read from regular service tags. Cache-from also already exists.

[crazy-max]

@tonistiigi

Tags should be read from regular service tags.

Tags are only handled as a single value through image field in compose afaik, that's why it's available as an extension here.

Cache-from also already exists.

Ah yes cache_from is available in the compose v2 spec.

[dudicoco]

@tonistiigi

Tags should be read from regular service tags.

Tags are only handled as a single value through image field in compose afaik, that's why it's available as an extension here.

Cache-from also already exists.

Ah yes cache_from is available in the compose v2 spec.

Correct me if i'm wrong, but I believe the compose spec cache_from doesn't support all of the buildx cache features such as cache from local.