Docker - check private registry image version

Question

What CLI commands do I need to use in order to check if the image in my private docker registry is a newer version than the one currently running on my server?

E.g.

Answer 1

AFAIK, this is not possible right now.

The only thing I see would be to pull the registry to check if there is a new version of your image (would then have a different ID than your locally stored image):

docker pull your/image:tag

But yes, that would mean fetching the new images (if any).

If you have a look at the registry API documentation, you'll see that if you don't mind scripting a bit, you could get this information without actually downloading the image, by fetching the image tags and check if the returned ID for the tag matches the ID of the local image you have with the same tag.

That being said, having something to "check for updates" integrated into the docker CLI would be a nice addition.