[CRaC] DefaultLifecycleProcessor and stopping beans on first refresh

[rvansa]

Hi,

I started hacking a solution that would close Cassandra connections on checkpoint, following [1] and registering a Lifecycle that would let the Cassandra session 'suspend'. The checkpoint and restore works in my prototype when I issue the checkpoint via jcmd <pid> JDK.checkpoint, but if I try automatic checkpoint through -Dspring.context.checkpoint=onRefresh the Lifecycle.stop() is not called: at this point DefaultLifecycleProcessor.running is false and stopForRestart() is not invoked.

I would like to ask what's the reason and if there's any better pattern; [2] explains that the connections are established too early (before first refresh). Is that a show-stopper? We can close those connections and keep going.

An alternative solution would be to not use the Lifecycle and register as a org.crac.Resource; however I understand that it's preferred to integrate the handling into Spring using that rather than directly.

CC @sdeleuze

[1] https://github.com/spring-projects/spring-boot/blob/main/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/jdbc/DataSourceCheckpointRestoreConfiguration.java
[2] #1486

[rvansa]

Closing in favor of spring-projects/spring-framework#34510