Spring Cloud Kubernetes - Use Informers instead of Watchers

[a-maggioni]

Is your feature request related to a problem? Please describe. On Spring Boot 3.2.2 with Spring Cloud 2023.0.0 the following warning appears in the logs when Kubernetes leader election is in use: io.fabric8.kubernetes.client.WatcherException: too old resource version: 18679401 (18803484) at io.fabric8.kubernetes.client.dsl.internal.AbstractWatchManager.onStatus(AbstractWatchManager.java:273) ~[kubernetes-client-5.10.2.jar!/:na] at io.fabric8.kubernetes.client.dsl.internal.AbstractWatchManager.onMessage(AbstractWatchManager.java:257) ~[kubernetes-client-5.10.2.jar!/:na] at io.fabric8.kubernetes.client.dsl.internal.WatcherWebSocketListener.onMessage(WatcherWebSocketListener.java:93) ~[kubernetes-client-5.10.2.jar!/:na] at okhttp3.internal.ws.RealWebSocket.onReadMessage(RealWebSocket.kt:333) ~[okhttp-4.9.3.jar!/:na] at okhttp3.internal.ws.WebSocketReader.readMessageFrame(WebSocketReader.kt:245) ~[okhttp-4.9.3.jar!/:na] at okhttp3.internal.ws.WebSocketReader.processNextFrame(WebSocketReader.kt:106) ~[okhttp-4.9.3.jar!/:na] at okhttp3.internal.ws.RealWebSocket.loopReader(RealWebSocket.kt:293) ~[okhttp-4.9.3.jar!/:na] at okhttp3.internal.ws.RealWebSocket$connect$1.onResponse(RealWebSocket.kt:195) ~[okhttp-4.9.3.jar!/:na] at okhttp3.internal.connection.RealCall$AsyncCall.run(RealCall.kt:519) ~[okhttp-4.9.3.jar!/:na] at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[na:na] at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[na:na] at java.base/java.lang.Thread.run(Thread.java:840) ~[na:na] Caused by: io.fabric8.kubernetes.client.KubernetesClientException: too old resource version: 18679401 (18803484) ... 12 common frames omitted

Describe the solution you'd like According to this, Spring Cloud should migrate from using raw Watchers to Informers.

Additional context See this for further details.

[wind57]

when this one is ready : https://github.com/spring-cloud/spring-cloud-kubernetes/pull/1658 this issue is going to be closed, because in that implementation, we do not use watchers or informers at all

[viktorpergjoka]

If you need to use Informers with spring you can check out this:

https://github.com/viktorpergjoka/spring-k8swatcher

[wind57]

this is very neat! I took a fast pass over it and I really liked it! I hope to have time to look more into it and see if I can "steal" some of your ideas. :)