socket.io-redis-adapter createShardedAdapter usage question

[giovanni-bertoncelli]

Hi,
I was wondering if the createShardedAdapter of socket.io-redis-adapter is meant to be used only with Redis.Cluster clients or if it does actually works with single Redis clients too. I'm asking this since I have some issues using the sharded adapter with a single Redis client

Thank you!

[darrachequesne]

It should work with single Redis clients. Could you please share the issues you are experiencing?

[giovanni-bertoncelli]

Sure!
While using a serverless sharded Redis server on Amazon Elastic Cache, I get two kinds of anomalies:

1. Using createShardedAdapter with any kind of ioredis client I always get some anomalies when using async fetchSockets(): some remote sockets seem to be invisible on different replicas.
2. Using createShardedAdapter specifically with a ioredis Redis.Cluster client I get almost always a Too Many Clusters Redirects - MOVED error. Already tried increasing maxRedirects option in ioredis client, the only way to resolve this error is by increasing retryDelayOnMoved (I've not verified seriously right now though). Either ways, the issue 1 still remains.

[giovanni-bertoncelli]

Any hints on this?

[giovanni-bertoncelli]

Hi, @darrachequesne , I think maybe redis/ioredis#1759 this can answer my questions? Do you have any updates on this matter?

[darrachequesne]

Yes, unfortunately redis/ioredis#1759 indeed prevents the usage of the ioredis package with the sharded adapter...

[giovanni-bertoncelli]

Thank you @darrachequesne ! Do you suggest to migrate to the redis stream adapter for this use case?

[darrachequesne]

You could indeed migrate to the redis stream adapter. Please make sure to benchmark it against your specific use case, since the guarantees of both adapters are a bit different.