how to use\connect to sonatype nexus docker registry v2 api in a web application?

Question

I have a private sonatype nexus repository manager OSS 3.25.1-04 container running on a vm (with nginx routing from docker.io to repo manager url) that contains a few repositories, one of them is a docker registry.

I want to use the docker registry v2 api from a react app to get a listing for the docker images in the repository and maybe some more metrics about the repo and its contents.

I tried calling the api directly: https://nexus3:8083/v2/_catalog but got 401 UnAuthorized in the response when checking the devtools network tab

Then to login to the api I tried using https://auth.docker.io/token?service=registry.docker.io&scope=repository:samalba/my-app:pull,push when substituting samalba/my-app with my own registry and example docker image. I know this link is to get token for only this image couldn't find one for the entire api (it didn't work anyway)

Could use some help on how to connect to the api\get jwt token and using it or how to use the api with http instead

Answer 1

A few things may be going on. First, try just using basic authentication and seeing if that works. Additionally, you may need to set some additional headers to connect to nexus / sonatype. Here is an example with curl:

curl -H "Accept: application/vnd.docker.distribution.manifest.v2+json" -H "Content-Type: application/json" -H "User-Agent: docker/20.10.14" -u username:password -i https://nexus3:8083/v2/_catalog

Note the user agent field -- i've run into issues where the authentication layer is filtering out for the docker user agent.

If that still doesn't work, then the next thing you can look for is to see if the registry response with the header www-authenticate. This means you will need to first authenticate with that service to retrieve a Bearer token, and then you can pass that back to the registry using the Authorization header instead of basic auth.

Hope that helps.