Proxy returns MOVED responses

[JanBerktold]

I have noticed that the proxy appears to return MOVED responses, therefore not hiding slot movements properly. Looking at the code, this appears to be confined to transactions currently (https://github.com/artix75/redis-cluster-proxy/blob/unstable/src/proxy.c#L4225) but I may be missing other parts of it.

In our case, this lead to our 'smart' client switching to cluster mode and trying to bypass the proxy. Solutions I can see:

1. Retry transactions(?)
2. Rewrite error messages to not follow standard MOVED format. i.e. replace with cancelled due to cluster topology change

[artix75]

The proxy should handle MOVED replies if the client is not under a transaction. So this is the behavior:

• If a MOVED reply is detected and the client is not under MULTI transaction, the proxy enqueues the query and updates its internal map of the cluster.
• After it has completed the update of the cluster map, it routes the query again to the correct node, replying then to the client that shouldn't receive the MOVED reply, but the correct reply.

If the client is under MULTI transaction:

• The proxy waits for the transaction to be completed (EXEC or DISCARD), replies the transaction (with the MOVED reply error inside) and then updates its cluster map.

[JanBerktold]

So I just reproduced the C# StackExchange.Redis client acting up and trying to switch into cluster mode after reading the MOVED error inside of the transaction. For starters, what do you think about changing that specific error message?

I'm not fully convinced, that that's the original error that I saw though - Going to be digging deeper for a 2nd repro case there.

[artix75]

@JanBerktold Were you under a MULTI transaction?

[JanBerktold]

@artix75 Yes!