Loadbalancer with SERVICE mode cannot discover newly created services

[limo520]

If the application is started before the Kubernetes service is created, it will fail to discover the service. It seems to be because CachingServiceInstanceListSupplier with KubernetesClientServicesListSupplier#get only query k8s services once on the first call.

I'm not sure if this is intentional or a bug, and the module involved is spring-cloud-kubernetes-client-loadbalancer

[wind57]

you are correct that we will not re-discover again.

But wouldn't the catalog watcher tell you that there is a change in endpoints / endpointslices and thus a potential change in services, so that you can call it again? I think this is the intention here, but @ryanjbaxter can confirm / infirm

[ryanjbaxter]

You can configure the cache behavior so it will refresh the cache after a given ttl
https://docs.spring.io/spring-cloud-commons/reference/4.2/spring-cloud-commons/loadbalancer.html#loadbalancer-caching

[limo520]

it will refresh the cache after a given ttl

I expected this behavior, but in reality, it doesn't actually refresh now.

[ryanjbaxter]

So you have a ttl set but after that period you are saying the cache is not updated?

[limo520]

Yes.

[ryanjbaxter]

Then we will need to investigate further.

[wind57]

is there a way you can provide a sample for us to re-produce against?

[limo520]

Here's a simple example, run DemoApplicationTests to reproduce.

[wind57]

@ryanjbaxter I might have miss-understood the point here, but that ttl seems to only expire entries, not re-populate the cache in the background. I also dug a little bit in the code of loadbalancer and don't see such an option. Granted, my experience is very limited in this field

[wind57]

on the other hand, the CacheFlux is indeed configured with onCacheMissResume / andWriteWith. still digging in the code