Applied commands get reapplied after restart

[evanxg852000]

I have developed and key-value store with Bbolt. when testing, I noticed the previously applied commands get applied again after restart. I also tested this with the basic example in the repo. For an in-memory (volatile) key-value store this is fine. But for a persisted one this is creating duplicated values. I mean my raft commands are not idempotent so I want to make sure it only gets applied once.
Please, could you tell me how I do this?

Is there a way to tell to set the current node appliedIndex right after applying?
As I can see in the log, the apply index is always zero.

Note: I am just starting with a single node for now.

I have read this (#7), it's related but could not understand its relation to the snapshot

On a design note, how are you handling errors during apply?
My intuition was that the StateMache.Apply(data []byte) should return an error that informs the engine that we could not apply and therefore need to retry the same entry sequence. if no error appliedIndex gets updated forward.
I may be missing key understanding here, just trying to solidify my intuition around raft and this implementation. Thanks

[evanxg852000]

@kotyara85 Maybe your experience from this (#7) issue can help here

[evanxg852000]

Go it resolved here hashicorp/raft#523