API to get when a Docker tag was pushed/created

[parkr]

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I'm looking for a timestamp for each Docker tag from ghcr.io

The Docker Hub API gives me back rich metadata for each tag including last_updated:

$ curl https://hub.docker.com/v2/repositories/library/monica/tags/ | jq .
{
  "count": 161,
  "next": "https://hub.docker.com/v2/repositories/library/monica/tags/?page=2&page_size=10",
  "previous": null,
  "results": [
    {
      "creator": 1156886,
      "id": 114871391,
      "images": [
        {
          "architecture": "amd64",
          "features": "",
          "variant": null,
          "digest": "sha256:d8372b75ebdf58e11e2d0740ebea519a1ab05713f1f3969b302afb855614e48c",
          "os": "linux",
          "os_features": "",
          "os_version": null,
          "size": 212496192,
          "status": "active",
          "last_pulled": "2024-05-17T19:00:04.301911Z",
          "last_pushed": "2024-05-14T19:40:32.043167Z"
        },
        # ... snip
     ]
 --> "last_updated": "2024-05-14T19:42:08.294229Z", <--
    "last_updater": 1156886,
    "last_updater_username": "doijanky",
    "name": "latest",
    "repository": 9711628,
    "full_size": 212496192,
    "v2": true,
    "tag_status": "active",
    "tag_last_pulled": "2024-05-17T20:00:08.897881Z",
    "tag_last_pushed": "2024-05-14T19:42:08.294229Z",
    "media_type": "application/vnd.docker.distribution.manifest.list.v2+json",
    "content_type": "image",
    "digest": "sha256:166ecd36f5600a2abbcccc0dce94670fb1827e6f7096b79d30a3f7ab3557989d"
},
# ... snip

This API response can be used to say the latest tag was last updated on 2024-05-14T19:42:08.294229Z.

However, it doesn't work for GHCR.io:

$ curl -v https://ghcr.io/v2/repositories/gethomepage/homepage/tags/
< HTTP/2 404 
< content-type: text/plain; charset=utf-8
< x-content-type-options: nosniff
< date: Fri, 17 May 2024 20:06:08 GMT
< content-length: 19
< 
404 page not found

What I've Tried

I can fetch all tags by paginating /v2/${repo}/tags/list.

$ export GITHUB_TOKEN=...
$ export repo=gethomepage/homepage
$ export token=$(curl -H "Authorization: Bearer $GITHUB_TOKEN" -s "https://ghcr.io/token?service=ghcr.io&scope=repository:${repo}:pull" | jq -r .token)
$ curl -i -H "Authorization: Bearer $token" https://ghcr.io/v2/${repo}/tags/list?n=100
HTTP/2 200 
content-type: application/json
docker-distribution-api-version: registry/2.0
link: </v2/gethomepage/homepage/tags/list?last=nightly&n=5>; rel="next"
content-length: 85

{"name":"gethomepage/homepage","tags":["main","v0.7.2","latest","v0.7.3","nightly"]}

This seems to be a rough implementation of the OCI image manifest API, specifically /v2/OWNER/REPO/tags/list.

I know GitHub has this info since it shows up in the UI:

[parkr]

It looks like you can paginate the versions with more metadata here: https://docs.github.com/en/rest/packages/packages?apiVersion=2022-11-28#list-package-versions-for-a-package-owned-by-an-organization

$ curl -L   -H "Accept: application/vnd.github+json"   \
  -H "Authorization: Bearer $GITHUB_TOKEN"   \
  -H "X-GitHub-Api-Version: 2022-11-28"   \
  -v \
  'https://api.github.com/orgs/gethomepage/packages/container/homepage/versions?state=active&per_page=100' | jq .
< HTTP/2 200 
< server: GitHub.com
< date: Fri, 17 May 2024 20:18:55 GMT
< content-type: application/json; charset=utf-8
< x-github-media-type: github.v3; format=json
< link: <https://api.github.com/organizations/122929872/packages/container/homepage/versions?state=active&per_page=100&page=2>; rel="next", <https://api.github.com/organizations/122929872/packages/container/homepage/versions?state=active&per_page=100&page=46>; rel="last"
< x-github-api-version-selected: 2022-11-28

[
  # ... snip
  {
    "id": 212381245,
    "name": "sha256:43a3ee88abe3b37c64bc52ea93da01c3dcb4a332a953bcd7f438c8d7328d3947",
    "url": "https://api.github.com/orgs/gethomepage/packages/container/homepage/versions/212381245",
    "package_html_url": "https://github.com/orgs/gethomepage/packages/container/package/homepage",
    "created_at": "2024-05-06T05:20:30Z",
    "updated_at": "2024-05-06T05:20:30Z",
    "html_url": "https://github.com/orgs/gethomepage/packages/container/homepage/212381245",
    "metadata": {
      "package_type": "container",
      "container": {
        "tags": [
          "v0.8.13",
          "latest"
        ]
      }
    }
  }
]