Are @Scheduled methods already disabled on @Shutdown?

[HerrDerb]

I have some @Scheduled methods for repeated flushing of data to an external system.
In a @Shutdown method, I flush the remaining data. Currently, I use a boolean flag running which I set to false in my @Shutdown method and which is queried within my @Scheduled method. This is, because I cannot find any information about the shutdown behaviour of @Scheduled methods -> https://quarkus.io/guides/scheduler-reference

simplified:

@Scheduled(every = "10s")
void schedule(){
  if(running){
    flush();
  }
}

@Shutdown
void schedule(){
 running=false;
 ....
}

Is this flag needed at all or are any @Scheduled methods already disabled at the time of the shutdown event?

[quarkus-bot[bot]]

/cc @mkouba (scheduler)

[mkouba]

So the ShutdownEvent is fired before the CDI container is shut down (otherwise we wouldn't be able to notify the observers) and the scheduler (in both cases, i.e. quarkus-scheduler and quarkus-quartz) is stopped when the CDI container is shut down. In other words, the @Scheduled methods are not "disabled" during the notification.

If you want to get rid of the running flag boiler plate then try to use the io.quarkus.scheduler.Scheduled.ApplicationNotRunning skip predicate, e.g. something like @Scheduled(every = "10s", skipExecutionIf = Scheduled.ApplicationNotRunning.class).

[HerrDerb]

Thank you. skipExecutionIf = Scheduled.ApplicationNotRunning.class is an absolut welcome replacement. Maybe this could be added to the Scheduler Refrence Guide?

[mkouba]

Sure, why not. Feel free to send a pull request! ;-)

https://quarkus.io/guides/doc-contribute-docs-howto

[HerrDerb]

👍 #38038

[HerrDerb]

One follow-up question. Regarding the ApplicationNotRunning predicate: https://github.com/quarkusio/quarkus/blob/main/extensions/scheduler/api/src/main/java/io/quarkus/scheduler/Scheduled.java#L268
Would it make sense to explicitly set the priority of the observers? For shutdown = 0 and startup = ~99999
If no priority defined, what is the default priority? I couldn't find this information, and unluckily it is ommited here: https://quarkus.io/guides/lifecycle#startup_annotation

[mkouba]

The default priority of a CDI observer method is jakarta.enterprise.inject.spi.ObserverMethod.DEFAULT_PRIORITY, i.e. 2500. And the same applies to @Startup.