Fix raftexample possible idempotent-problem

[chenyang8094]

issue ref: #16425

I know that the current kvstore does not have idempotence problems (even if the wal log is replayed multiple times), because it uses a map structure (key value). But I think raftexample should fully consider this scenario. Just like the etcd server, by maintaining a consistentIndex in the db to avoid the idempotence problem of replaying wal.

[ahrtr]

Thanks for the PR.

• raftexample is just an example, it doesn't have to be perfect.
• We are planning to remove raftexample from etcd repo, and implement a self-contained example in raft repo. Pls see Implement a self-contained raft example raft#2

So please do not spend too much effort to improve raftexample. Instead, if you have bandwidth and be interested, please help to resolve etcd-io/raft#2

[chenyang8094]

Thanks for the PR.

• raftexample is just an example, it doesn't have to be perfect.
• We are planning to remove raftexample from etcd repo, and implement a self-contained example in raft repo. Pls see Implement a self-contained raft example raft#2

So please do not spend too much effort to improve raftexample. Instead, if you have bandwidth and be interested, please help to resolve etcd-io/raft#2

I see. Although the raftexample is just one example, it may actually be more important than we think. In my work, I have seen many projects using raft based on raftexample. There are also countless articles on the Internet analyzing raftexample. The reason is that raftexample is indeed a simple and effective way to learn how to use etcd/raft. Therefore, I think that raftexample should show the precautions when using etcd-raft library as much as possible, and provide more help to everyone who is looking at this project. I just took a little time to work out the little imperfection I got.

As for the issue etcd-io/raft#2 , I will continue to pay attention, thank you.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed after 21 days if no further activity occurs. Thank you for your contributions.

[jmhbnz]

Discussed during sig-etcd triage meeting. Given we are moving raftexample suggest we close this pr. @ahrtr do you agree?