ApplicationAvailability bean is auto-configured even if a custom one is already present

[acktsap]

Spring boot actuator autoconfigures ApplicationAvailability bean which is used in AvailabilityProbesAutoConfiguration and AvailabilityHealthContributorAutoConfiguration.

That is awesome since it automatically configures kubernetes probes in separate endpoints (liveness, readiness).

But if i want to replace ApplicationAvailability bean injected in LivenessStateHealthIndicator and ReadinessStateHealthIndicator i have to register ApplicationAvailability as @Primary since it's always registered by ApplicationAvailabilityAutoConfiguration.

This PR prevents auto-registeration of ApplicationAvailability bean when it's already present.

[acktsap]

Also i moved package from kubernetes to availability since it seems to make sense.

[wilkinsona]

Thanks, @acktsap.

Given that we have the ApplicationAvailability interface and a default implementation of it (ApplicationAvailabilityBean), it feels like a bug to me that you can't (without using @Primary) easily declare your own ApplicationAvailability implementation. That makes it tempting to schedule this for 2.7.x. It could, although I think it's very unlikely, be a breaking change if someone's relying on the current behavior where they end up with both their primary custom implementation and the default implementation co-existing. I can't think why someone would need that behavior though. Flagging for team attention in case I've overlooked something.

[snicoll]

@acktsap thank you for making your first contribution to Spring Boot.

[nickd147]

Hi All
i found in my case that after this changes
5e95ba8#diff-4520e41b59ccf0379a94bad29e96a802db342fc4a056a570db16ba0821f6b618

ApplicationAvailabilityBean is not being peaked up by DefaultListableBeanFactory
because of failing the checking

typeToMatch.isAssignableFrom(beanType)

where typeToMatch - ApplicationListener, beanType - ApplicationAvailability

in 2.7.10 it was
typeToMatch - ApplicationListener, beanType - ApplicationAvailabilityBean

and all worked well.

and as a result it's missed during publishing event in org.springframework.boot.context.event.EventPublishingRunListener#started

please check this.
to make it works in this version I need to create custom cnfiguration

[wilkinsona]

@dyakovni That has been fixed by #35161.