Can pull referrer with oras pull without knowing the digest

[SamirPS]

What is the version of your ORAS CLI

Version: 1.0.0-rc.1+unreleased Go version: go1.20 Git commit: 8bda262 Git tree state: clean

What would you like to be added?

For example, if I take this multi-arch image and copy it to azure

docker.io/library/ubuntu:lunar -> xxx.azurecr.io/test:lunar

I now have an artefact named one.json. I attach it to the amd64 platform with this command, for example:

oras attach xxx.azurecr.io/test:lunar --platform linux/amd64 one.json

Now if I do

oras discover xxx.azurecr.io/test:lunar

I will have 0 artefacts discovered, but if I do

oras discover xxx.azurecr.io/test:lunar  --platform linux/amd64

Oras will find the one.json artefact with this digest sha256:digestofsbom. These two outputs are excepted.

Now if I do:

oras pull xxx.azurecr.io/test:lunar  --platform linux/amd64

It will say downloaded empty artefacts. But if I do

oras pull xxx.azurecr.io/test:lunar@sha256:digestofsbom

It downloads the one.json artefact.

What @SteveLasker and I proposed is to add this command, for example, to pull the artefacts:

oras pull xxx.azurecr.io/test:lunar --platform linux/amd64 --artifactType application/spdx+json --top 1 --orderby desc

Why is this needed for ORAS?

Some people will use Oras without knowing anything about digest or manifest. It will permit to have for them a great user experience. Also, if I attached multiple files to the amd64 ( sbom, license,...), it's great to be able to download all files with a single command and not need to get the digest for each file.

Are you willing to submit PRs to contribute to this feature?

• Yes, I am willing to implement it.

[qweeah]

👍 Sounds like a counterpart of --include-subject to me.

[github-actions]

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[SamirPS]

Any news about this issue?

[qweeah]

Any news about this issue?

@shizhMSFT @FeynmanZhou @sajayantony for planning

[shizhMSFT]

The subject field is introduced for the OCI Index manifest in image-spec v1.0.0-rc4. We can continue the discussion from there.

[shizhMSFT]

@SamirPS You might be interested in opencontainers/image-spec#1020, especially the following diagram:

graph TD;

sboms-->lsbom;
sboms-.->index;
sboms-->wsbom;

lsbom[sbom]-.->linux;

index-->linux;
index-->windows;

wsbom[sbom]-.->windows;

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[shizhMSFT]

@sajayantony Currently, we don't have a standard to create the sboms in the above diagram. Will that be in the corresponding OCI spec? or it is purely up to the client implementation? If it is the latter, we probably can propose one solution for oras.