concourse / concourse/docker-image-resource

fetchDigest is not backwards compatible according to Image Manifest v2, Schema 2

Open
#257 5 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

enhancement help wanted
Dominant language
Go
Stars
162
Forks
250
PR merge metrics
No merged PRs in 30d

Description

According to Image Manifest V 2, Schema 2 (bottom of the page for Backwards Compatibility) the fetchDigest function does not accept the "fat manifest" header application/vnd.docker.distribution.manifest.list.v2+json. This is causing a "no version found" error when trying to fetch a docker image with a manifest built in this format.

I believe you could just add the extra header and it should work. I did a little local testing and it managed to find something and start the job (ran into a non-concourse related problem where I didn't test further).

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start in cmd/check/main.go at fetchDigest around line 116, then review the Image Manifest V2, Schema 2 backwards-compatibility guidance linked in the issue. Verify that images using the manifest list media type no longer produce a "no version found" error, and add or update a focused test if the existing check tests cover this path.

Written by the indexing model from the issue text.

Assessment

Tech stack
docker, go
Domain
devops
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
48/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.