*: implement a retry logic for auth old revision in the client

[mitake]

fix #13300

@davissp14 could you try this one? I tried the change with https://github.com/mitake/etcd-things/tree/master/auth-failover and it worked

• add test, ideally for retry_intercepter.go

[mitake]

@r-ashish could you check this path? I think we should use errors.Is() instead of == here.

[mitake]

also line 155 would need change too. I'll add a unit test to the file for ensuring that the error handling logic is correct

[r-ashish]

yeah agree, looks okay.

[davissp14]

@mitake Seems to recover nicely! Thoughts on when this could get pushed out?

[davissp14]

Actually, one thing I did find is that tokens are not renewed at expire time:

{"level":"warn","ts":"2021-08-30T08:45:13.387-0500","logger":"etcd-client","caller":"v3/retry_interceptor.go:63","msg":"retrying of unary invoker failed","target":"etcd-endpoints://0xc00000c780/#initially=[http://127.0.0.1:2379]","attempt":0,"error":"rpc error: code = Unauthenticated desc = etcdserver: invalid auth token"}
Get failed: etcdserver: invalid auth token
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x160a32a]

goroutine 1 [running]:
main.main()
	/Users/davissp14/go/src/github.com/fly-examples/etcd/test.go:37 +0x48a
exit status 2

[mitake]

@davissp14 thanks for checking! I’ll fix the renew issue. Probably I can finalize this PR this weekend (or sometime next week), is this ok for you?

[mitake]

@davissp14 the issue should be fixed now, could you try again?

[mitake]

I think the change is ready to be reviewed, could you take a look @spzala @serathius ?

[spzala]

@mitake lgtm overall. Great job adding test :) Thanks!

[mitake]

@spzala thanks! I'm merging this PR then.

[mitake]

@davissp14 did this MR solve the issue on your env? I'll also make PRs for backporting this PR (and related ones) to stable releases.

[davissp14]

@mitake Was this change included in 3.5.1?

[hexfusion]

@davissp14 if you would like to raise the PR to backport to release-3.5 we can ensure it is part of 3.5.2.