Consider using regclient/actions to fetch image labels without downloading image

[tosfos]

Background

In PR #552, we optimized the MW version extraction workflow from ~4 minutes to ~30 seconds by using labels from the CanastaBase image. However, @vedmaka suggested in PR #552 review a further optimization.

Current Implementation

The workflow currently:

1. Builds a temporary Docker image
2. Runs it to extract MW_CORE_VERSION from environment variables
3. Takes ~30 seconds

Suggested Improvement

Use regclient/actions to fetch labels directly from the base image manifest without downloading the entire image. This would:

• Be faster (no image download)
• Use less bandwidth
• Be more efficient overall

Considerations

• regclient/actions is an external third-party action (not a standard GitHub feature)
• The action has low adoption (7 stars on GitHub)
• Current solution is already well-optimized at ~30 seconds
• Would add a dependency on an external action

Decision Needed

Should we:

1. Implement this optimization now?
2. Keep it as a future enhancement?
3. Reject it due to external dependency concerns?

Related

• Issue Improve MW version extraction in Docker workflow #545 (original optimization request - resolved by PR Fix mw version labels #552)
• PR Fix mw version labels #552 (the optimization that was implemented)

[vedmaka]

Be faster (no image download)

Not just that, but also to save on the HDD space required to download the image (~700MB)

The action has low adoption (7 stars on GitHub)

The library itself is well-maintained https://github.com/regclient/regclient and can be installed as a regular Go package (or run as a container) without using the action https://regclient.org/install/#downloading-binaries. There are also a few alternatives:

• https://github.com/containers/skopeo
• Use cURL to fetch the image labels from ghcr.io without any extra tools