grpc-gateway /kv/range hangs with auth enabled

[hexfusion]

etcdctl version: 3.1.0-rc.0
API version: 3.1

curl -H "Content-Type: application/json" -X POST -d '{"key": "Zm9v"}' https://127.0.0.1:2379/v3alpha/kv/range

If auth is disabled this works as expected but otherwise the request will hang. This response differs from a put.

curl -H "Content-Type: application/json" -X POST -d '{"key": "Zm9v", "value": "YmFy"}' https://127.0.0.1:2379/v3alpha/kv/put

which although does not work correctly because of #6643 does respond with {"Error":"auth: revision in header is old","Code":2}.

This appears to be regression from a distance.

[gyuho]

It works for me? Can you share the full commands to reproduce this?

[xiang90]

@gyuho I can reproduce it.

@mitake Can you take a look? This will bring etcd into busy loop. etcd starts to eat all CPUs.

[mitake]

@xiang90 @sbatschelet I also could reproduce the problem. Although the gateway does not support auth currently, it seems to be problematic. I'll work on it.

[xiang90]

@heyitsanthony I think this is due to the empty user thing you just fixed. Can you help to confirm? Thanks!

[heyitsanthony]

With patch:

$ curl -H "Content-Type: application/json" -X POST -d '{"key": "Zm9v"}' http://127.0.0.1:2379/v3alpha/kv/range
{"error":"etcdserver: user name is empty","code":3}

Without patch: hangs.

Looks like it's fixed. Closing.