As a oc-mirror user, I want the tar generated by mirror to disk process to be as small as possible so that its transfer to the enclaves is as quick as possible.

Background:

After the first demo done by the team, the initial solution that consisted of archiving the whole cache and sending it through the one-way diode to the enclaves was refused by the stakeholders.

CFE-966 studied a solution to include in the tar:

• only new images
• only new blobs and manifests

This story is about implementing the studied solution.

Acceptance criteria:

• Scenario 1:  mirroring additional images - No previous history
  • Create a first mirroring with additionalImage: 
    quay.io/okd/scos-release:4.14.0-0.okd-scos-2023-10-19-123226
  • MirrorToDisk should be successful
  • The tar.gz should be available under working-dir
  • the DiskToMirror based on the above generated tar.gz should be successful
  • The destination registry should have this image, and I should be able to inspect it using skopeo inspect
• Scenario 2: mirroring additional images - with previous history
  • Create a second mirroring with additionalImage: 
    quay.io/okd/scos-release:4.14.0-0.okd-scos-2023-10-19-111256
    • This can be with the same imageSetConfig of scenario1, to which we append this image
  • MirrorToDisk should be successful
  • The tar.gz should be available under working-dir
    • The tar.gz should not contain blobs  97da74cc6d8fa5d1634eb1760fd1da5c6048619c264c23e62d75f3bf6b8ef5c4 nor d8190195889efb5333eeec18af9b6c82313edd4db62989bd3a357caca4f13f0e (previously mirrored)
  • The size of the tar.gz should be smaller than the first tar.gz
  • the DiskToMirror based on the above generated tar.gz should be successful
  • The destination registry should have this new image, and I should be able to inspect it using skopeo inspect it by tag