[Feature Request] support Docker HUB with registry manager

[olljanat]

Is your feature request related to a problem? Please describe.
Registry manager extension does not work with Docker HUB.

Describe the solution you'd like
Currently registry manager extension works only with private registries but it would be nice if we can use it also with Docker HUB.

Some technical details
https://registry-1.docker.io/v2/_catalog endpoint (doc) which is used list repositories from is blocked on Docker HUB because it is non-authenticated endpoint which would list all repositories on there.

However because their own needs on web and Docker Desktop they have another https://hub.docker.com/v2/repositories/<org name> endpoint which can be used to fetch list of those repositories and after that all other Docker Registry HTTP API V2 endpoints can be used.

Here is example script created by one of Docker support engineers that how to call that API: https://gist.github.com/kizbitz/e59f95f7557b4bbb8bf2

[olljanat]

@ncresswell FYI. Related our discussion on today.

cc @deviantony

[deviantony]

Since the first work on this via #2987 only allows us to browse (read only features) can we investigate the usage of the DockerHub API if it is publicly available?

[olljanat]

Yes those features are available but it looks that they actually API gateway/etc on address cloud.docker.com as front of those features.

However those can be easily found using debug proxy tools like Fiddler.
Example tag you can remove by calling address like https://cloud.docker.com/v2/repositories/portainer/portainer/tags/latest/ with method DELETE and authentication cookie.

[xAt0mZ]

Actually cloud.docker.com is not only an API, it is also a UI for dockerhub registry browsing (similar to hub.docker.com).
I will try to find a documentation, or will build one based on actions allowed on cloud.docker.com UI.