Is there a way to get tags of a docker image on github container registry (ghcr.io) via curl or gh command?

Question

Is there a way to get tags of a docker image on github container registry via curl or gh command?

curl \
  -H "Accept: application/vnd.github+json" \
  -H "Authorization: Bearer ${GH_TOKEN}"\
  -H "X-GitHub-Api-Version: 2022-11-28" \
  https://api.github.com/orgs/${ORG}/packages/container/${CONTAINER_IMG}

I have tried above but it does not give me docker tags for the iamge.

I am expecting to get the docker tags of ghcr.io containers.

Answer 1

If your environment allows installing software, it is easier to use skopeo. It is available by default on GitHub Action's Linux environment, and in most distros package repos.

skopeo list-tags --registry-token ${GH_TOKEN} docker://ghcr.io/${ORG}/${CONTAINER_IMG}

Answer 2

With curl, the commands look like:

#!/bin/sh

repo="${1:-regclient/regctl}"
token=$(curl -s "https://ghcr.io/token?service=ghcr.io&scope=repository:${repo}:pull" \
             -u "${username}:$(cat $HOME/.docker/ghcr_token)" \
        | jq -r '.token')
curl -H "Authorization: Bearer $token" \
     -s "https://ghcr.io/v2/${repo}/tags/list" | jq .

Note that you need to provide a login to the token command (in the -u option). The tags/list API is a standard registry API, not specific to GHCR, but auth will have different hosts for their token server, or just use basic auth without a token.

Tools that simplify registry APIs like this include Google's crane, RedHat's skopeo, or my own regclient.