keyspace event subscription is no working for a cluster

[jigneshmpatel]

I am trying to subscribe to the keyspace events from dockerize bitnami Redis Cluster using lettuce 6.3.2 and lettuce 4.1.109.
This is my code

 public void subscribeToEncounterCheckoutTimeChannel(){
       logger.info("Inside subscribeToEncounterCheckoutTimeChannel()");
       StatefulRedisClusterPubSubConnection<String, String> pubsubConnection = connectToRedisCluster.getClusterPubSubConnection();
       pubsubConnection.setNodeMessagePropagation(true);
       //connection.addListener(new EncounterCheckoutTimeListener());
       pubsubConnection.addListener(new RedisClusterPubSubAdapter(){

           public void message(String pattern, String channel, String message) {
               String msg = message;
               logger.info("msg" + msg);

           }
       });

        //async setup
       RedisClusterPubSubAsyncCommands<String, String> asyncCommands = pubsubConnection.async();
       PubSubAsyncNodeSelection<String, String> masters =asyncCommands.upstream();
       NodeSelectionPubSubAsyncCommands<String, String> commands = masters.commands();

       logger.info("number of master nodes: "+masters.size());
       commands.psubscribe("__keyspace@0__:"+CacheConstants.EncounterCheckoutTime+"*");
         //OR
         //sync setup
       RedisClusterPubSubCommands<String, String> syncCommands = pubsubConnection.sync();

       syncCommands.upstream().commands().psubscribe("__keyspace@0__:"+CacheConstants.EncounterCheckoutTime+"*");


    }

But it is not able to fetch the message. I have tried very hard to make this work but this is not working. Is there a bug in the versions of lettuce I am using to make subscribing keyspace events?
I have posted the information on Stackoverflow also. It will be really helpful if there is appropriate guidance provided to debug an make this work.

[jigneshmpatel]

The explantation from lettuce documentation is not applicable i.e. the documentation requires an update with a working solution.
https://github.com/redis/lettuce/wiki/Pub-Sub
@mp911de is there anything I refer to figure out about fixing this issue?

[mp911de]

There's nothing to fix. If you're using RedisClusterPubSubAdapter, then you must override the methods that provide RedisClusterNode. Your variant public void message(String pattern, String channel, String message) doesn't override any existing listener nor adapter method.

[jigneshmpatel]

Thank you very much @mp911de et all. It fixed the issue.
However seems it is not consistently getting messages(Sometimes it works) if I set a message outside Redis cluster

redis-cli -c config set notify-keyspace-events  Kx 
redis-cli -c SETEX EncounterCheckoutTime:2 30 "Hello, Redis

It doesn't print anything I believe when the original node changes, despite setting
pubsubConnection.setNodeMessagePropagation(true);

On a different note, I am not getting the value for the message, my listener only prints
Got message expired on channel __keyspace@0__:EncounterCheckoutTime:3
But I am interested in getting key value both.

[jigneshmpatel]

To be more clear, the following works as somehow when deployed it nows about node with IP: 172.18.0.4

127.0.0.1:6379> SETEX EncounterCheckoutTime:1 120 "Hello, Redis"
-> Redirected to slot [11230] located at 172.18.0.4:6379
OK

but following key expiration which has been set on IP 172.18.0.5 is not received by the application.

172.18.0.4:6379> SETEX EncounterCheckoutTime:2 30  "Hello, Redis"
-> Redirected to slot [7101] located at  172.18.0.5:6379

These are cluster nodes

6abf93ea9d9448e7128c049e07fee65466b37c68 172.18.0.8:6379@16379 myself,master - 0 1715994847000 1 connected 0-5460
40202528f94e6929dccfffa8baafc546da4c52cb 172.18.0.2:6379@16379 slave b5a1c07679a393a13acaabebb3dac74510c906eb 0 1715994850174 7 connected
8720fcd760d54e9cb520af8ece17e0bf81b3630d 172.18.0.5:6379@16379 master - 0 1715994847079 2 connected 5461-10922
f14eee40833872d196c947cb14450b85f50374cf 172.18.0.6:6379@16379 slave 8720fcd760d54e9cb520af8ece17e0bf81b3630d 0 1715994848000 2 connected
645c7d56c16e0a73f113400c43619836c927a0c6 172.18.0.3:6379@16379 slave 6abf93ea9d9448e7128c049e07fee65466b37c68 0 1715994845013 1 connected
b5a1c07679a393a13acaabebb3dac74510c906eb 172.18.0.4:6379@16379 master - 0 1715994849126 7 connected 10923-16383

However, it worked when I set the following on each master node
config set notify-keyspace-events Kx or KExed
And after that even cluster level command started publishing too. e.g. following was not working previously
redis-cli -c SETEX EncounterCheckoutTime:2 30 "Hello, Redis

[jigneshmpatel]

So the missing part is what should I subscribe to instead of following:
psubscribe("__keyspace@0__:"+CacheConstants.EncounterCheckoutTime+"*");
so that I can receive key id and value both for expired keys.

[jigneshmpatel]

Also if the application has three servers how would it be possible to make that only one instance listen to key expiry events to avoid message duplication?

[jigneshmpatel]

Also wondering why expire message received twice
(lettuce-nioEventLoop-8-9) Got message expired on channel keyspace@0:EncounterCheckoutTime:3
(lettuce-nioEventLoop-8-9) Got message expired on channel keyspace@0:EncounterCheckoutTime:3

for the following command
config set notify-keyspace-events KExed