add support for kubernetes.io/dockerconfigjson

[Sayrus]

Hello,

I am currently using an operator which requires a .docker/config.json instead of .dockercfg.
Would that be possible to implement the secret type kubernetes.io/dockerconfigjson. It seems that it is the recommended way now and I can't find many recent mentions of kubernetes.io/dockercfg but I can't find any deprecation or reason for that either.

The main difference is the field name named .dockerconfigjson instead of .dockercfg and it contains a Docker auth token instead of username/password/email.

It would be awesome if the operator could transform username/password into a Docker Auth Token but that seems a bit harder than just pulling the token directly from Vault.

Also it might be interesting to add on the documentation that DOCKERCFG only works with KV1 or will fail with KV2 (or maybe it is not intended, if so I can try to provide more information on a separate issue).

It seems duplicating the current DOCKERCFG implementation can create a DOCKERCONFIGJSON that pulls the auth token easily. I can provide a PR for this if you want me to. However, it makes sense to support both username/password and auth token (as kubectl does, I have not checked how it is implemented there).

Best Regards,

[felipem1210]

This would be a great implementation. Did you make it?

[Sayrus]

This would be a great implementation. Did you make it?

Unfortunately, we stopped using the project so we haven't made an implementation for this feature.