So, basically there is no standalone tool that takes a tarball and prepares a file system image contained in it to be pushed to Docker Hub. And no “docker import” is not standalone, because it requires the whole of Docker. Dear #lazyweb, I want something like “img” that takes a tarball as input.
For reference: https://github.com/genuinetools/img
If nobody has done it before, maybe O should fork “img” and call the newfangled creature “omg”. Now that would be a cool name.
Also, I don't want huge monster tools like Packer or “docker-compose”, they reek of bloat. Of I need something complex to make my images, I would use Vagga for that anyway, which will happily output tarballs.