I wrote a raft implementation that is used by quite a few well known systems (etcd, cockroachdb, docker swarmkit, tikv and quite a few closed source systems). Probably it qualifies the "production ready" standard :P.

With that experience, I can say that a real world raft implementation is not easy and VERY time consuming.

However, preparing the coding interview is definitely a order of magnitude more difficult for me. It requires me to waste all my time on something meaningless, and makes me feel sick.