oci.md

Constructing OCI artifacts compatible with gom

To build an OCI artifact to be compatible with the gom play feature that can load a gokrazy image from an OCI artifacts, users will need to build an OCI artifact like so:

	// The OCI artifact blueprint:
	//   +---------------------------------------------------+
	//   |                                                   |
	//   |                                +----------------+ |
	//   |                             +-->      ....      | |
	//   |            +-------------+  |  +---+ Config +---+ |
	//   | (reference)+-->   ...     +--+                  | |
	//   |            ++ Manifest  ++  |  +----------------+ |
	//   |                             +-->      ...       | |
	//   |                                +---+ Layer  +---+ |
	//   |                                                   |
	//   +------------------+ registry +---------------------+

The OCI artifact should consist of A Manifest, a Config, and several Layers. For it to be compatible with gom, it must:

• Manifest:

  • The Manifest must be of MediaType: application/vnd.oci.image.manifest.v1+json
  • Schema version 2
  • Have an annotation with key org.opencontainers.image.created and value a string representing the creation time in RFC3339 format.

• Config:

  • The Config must be of MediaType: application/vnd.unknown.config.v1+json (nested in the Manifest under, 'config')
  • Have an empty content

• Layers:

  • Have exactly 3 layers (nested in the Manifest under 'layers')
  • The 3 Layers must be of MediaType: application/vnd.oci.image.layer.v1.tar
  • Each of these Layers must have an annotation key org.opencontainers.image.title set to the filename of the specific thing they contain: "mbr.img","boot.img","root.img" (don't change them)
  • The Layer should be pushed as is and not archived nor compressed

The reference implementation on how to archive this in Go can be found here at damdo/oci-artifacts.