envoy redis_proxy can‘t support RESP3 HELLO CMD

[huntkalio]

Title: envoy redis_proxy can‘t support RESP3 HELLO CMD

Description:

I use a RESP3 redis client(lettuce) to connect envoy redis proxy,I found : 1) if envoy config downstream_auth_password, the use lettuce connect, envoy will return -NOAUTH Authentication required.

2) if envoy not config downstream_auth_password,then use lettuce connect, envoy will return -unsupported command 'HELLO'

If I use a RESP3 redis client(lettuce) to connect redis directly , there is no this problem.I think if envoy don't support HELLO，it should return -ERR unknown command 'HELLO' like redis server return , so redis client lettuce can siwtch to RESP2.

Repro steps: 1) use https://github.com/lettuce-io/lettuce-core redis client (java) to connect envoy 2) or use telnet like this [root@hadoop-master envoy]# telnet 127.0.0.1 63799 Trying 127.0.0.1... Connected to 127.0.0.1. Escape character is '^]'. *5 $5 HELLO $1 3 $4 AUTH $7 default $8 foobared

Config: envoy-redis-proxy-HELLO.yml.txt

[huntkalio]

like this issue： https://github.com/lettuce-io/lettuce-core/issues/1543 （this issue not use envoy，but use cloud redis server）

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[github-actions[bot]]

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[antonandreev123]

It seems that the issue is here is the fact that envoy redis filter returns incorrect response when HELLO command is issued:

localhost:6379> HELLO
(error) invalid request
localhost:6379>

It's not that HELLO is an invalid request here, but rather it is an unsupported command. We are using lettuce client and it issues HELLO to determine if it should use RESP2 or RESP3 protocols.

Interestingly envoy redis filter returns a different response if HELLO command has an argument:

localhost:6379> HELLO 3
(error) unsupported command 'HELLO'
localhost:6379>

[vrajannagari]

Any workarounds or updates on this, we see a similar issue "io.lettuce.core.RedisCommandExecutionException: unsupported command 'CLUSTER' at io.lettuce.core.ExceptionFactory.createExecutionException(" ?

[casperisfine]

I just had a quick look at what it would take since I just ran into the same issue. Unfortunately it's quite a lot of work:

• HELLO has to be forwarded to the backends, but that changes the response protocol. So if a proxy is used by different clients, some using RESP3, some RESP2, we'd need to keep two pools of connections.
• Then RESP3 contains many more types (e.g. float, boolean, etc). that would need to be added to the parser: https://github.com/antirez/RESP3/blob/master/spec.md
• Probably some other challenges I didn't forsee.

@mattklein123 since you re-opened and tagged this issue, do you know if it's on anyone's radar?

[mattklein123]

@mattklein123 since you re-opened and tagged this issue, do you know if it's on anyone's radar?

Not that I know of.

[darjisanket]

We are also facing same issue, any update on this issue.

[dorrogeray]

Just run into this issue when using relay for php. @casperisfine @mattklein123 I think that HELLO command will become more prevalent as various libraries start to support RESP3. For example, it was added to the main branch of predis/predis library at https://github.com/predis/predis/blob/main/src/Connection/Factory.php#L177.

I think this will make it unusable in combination with Envoy..

Any chance this will get adressed on the roadmap in the near future?

[caiberun]

Commands after 6.2 / 7.x are not supported so far. Please seriously consider supporting these as well as we are moving away from Redis 6.x. Please share your thoughts/roadmaps/timelines for this.

[zygisa]

👋 are there any updates on RESP 3 support for Envoy?