Auto-configure ObservationRegistry in ScheduledTaskRegistrar for scheduled tasks observations

[bclozel]

As of Spring Framework 6.1.0-M2, a new instrumentation observes the execution of @Scheduled annotated methods. See spring-projects/spring-framework#29883.

To support this feature automatically, Spring Boot should configure the ObservationRegistry with a SchedulingConfigurer. As far as I understand, a SchedulingConfigurer bean is currently considered as a signal for auto-configuration backoff so we might need to tweak the approach here.

[mhalbritter]

I've got something working in https://github.com/mhalbritter/spring-boot/tree/mh/36119-auto-configure-observationregistry-in-scheduledtaskregistrar-for-scheduled-tasks-observations

This removes SchedulingConfigurer as a signal to back-off for the ThreadPoolTaskScheduler. And I had to update to Spring Framework 6.1.0-SNAPSHOT.

[Alos]

I've upgraded to Java 21 and Spring 3.2, turned on virtual threads and I still can't see spanIds in the logs, am I missing something else?

[bclozel]

@Alos does it work without virtual threads?

[Alos]

@bclozel after some tinkering, it looks like the issue might related to the Micrometer implementation with Spring Cloud GCP and/or the permissions needed to populate spanIds.

Thanks for the comment tho :)

[bclozel]

@Alos thanks for letting me know!

[Alos]

Ahhh I discovered something @bclozel, it looks like @Async annotated methods are not instrumented. For example:

 @Scheduled(
      fixedDelayString = "2",
      timeUnit = TimeUnit.SECONDS)
 @Async
  public void doSomething() throws InterruptedException {
    log.info(
        "->doSomething thread name: {} Id: {}",
        Thread.currentThread().getName(),
        Thread.currentThread().threadId());
    Thread.sleep(10000);
  }

Would not have any spanIds. Is the correct way to enable this to create a custom ThreadPoolTaskScheduler and add the instrumentation manually?

[bclozel]

I think this is similar to the event listener support for async: https://docs.spring.io/spring-framework/reference/integration/observability.html#observability.application-events