[BUG] FailoverClusterClient ignore DB option

[khasanovbi]

FailoverClusterClient ignore DB from config

Expected Behavior

FailoverClusterClient use DB from FailoverOptions

Current Behavior

FailoverClusterClient use default DB: 0 option

[ndyakov]

@khasanovbi thank you for reporting, as you can see from

go-redis/universal.go

Line 20 in d863956

// Database to be selected after connecting to the server.

, the DB option is available only for single-node clients (and single node failover client). It is not available for Cluster Clients.

[khasanovbi]

Yes, but this is a valid Redis configuration.
I'm using Redis Sentinel.
Previously I was using FailoverClient with DB: 1, but wanted to go not only to master but also to replicas with RouteByLatency.
To do this I switched to using FailoverClusterClient, I realize it is a pseudo cluster client but it should be able to go to DB:1.

[ndyakov]

@khasanovbi I understand your use case, but under the hood the FailoverClusterClient is using the ClusterClient. The SELECT command for selecting a database is not enabled in cluster mode. Although I am against adding the DB option for the cluster client, I think there is a good workaround you can utilize. You should be able to use

go-redis/options.go

Line 46 in 9762559

OnConnect func(ctx context.Context, cn *Conn) error

and execute cn.Select yourself:

....
    OnConnect: func(ctx context.Context, cn *redis.Conn) error {
        _, err := cn.Select(ctx, 1)
        return err
    },
....

Feel free to close this if you are satisfied with the workaround.

[khasanovbi]

Ok, thank you for workaround, perhaps this should then be specified in the documentation?

[khasanovbi]

I tried such workaround, but it try to send select command to sentinel, instead of redis instance.

sentinel: GetMasterAddrByName master=\"test\" failed: ERR unknown command 'select', with args beginning with: '1' "

Maybe we could add SentinelDialer, OnSentinelConnect fields to FailoverOptions to distinguish such connections

[ndyakov]

Hm, correct, the sentinel client will inherit the same callback. I assume you can simply check if the err is the unknown command err and ignore it. Any other error should make sense for your application.

[ndyakov]

@khasanovbi I will close this issue for now, feel free to reopen if the solution doesn't work for you and you would like to discuss a different approach.

[khasanovbi]

Hi @ndyakov
I don't really like this solution as we are making an extra call, and we also have to catch an error by message.
I would suggest moving the db select to the client constructor and prepare some small PR #3342, PTAL.

PS. I'm don't have permissions to reopen issue)