Fix KafkaTemplate hiding exceptions when starting observation

[cfredri4]

This fixes that exceptions thrown from observation.start() are hidden by KafkaTemplate throwing a new exception due to registering observation error without successfully starting the observation.
Signed-off-by: Christian Fredriksson [email protected]

[cfredri4]

2025-03-03 22:04:37.235+0000 [foo] ERROR foo.Foo - [run] Exception occurred
java.lang.IllegalStateException: Span wasn't started - an observation must be started (not only created)
at io.micrometer.tracing.handler.TracingObservationHandler.getRequiredSpan(TracingObservationHandler.java:205)
at io.micrometer.tracing.handler.PropagatingSenderTracingObservationHandler.onError(PropagatingSenderTracingObservationHandler.java:94)
at io.micrometer.tracing.handler.PropagatingSenderTracingObservationHandler.onError(PropagatingSenderTracingObservationHandler.java:35)
at io.micrometer.observation.ObservationHandler$FirstMatchingCompositeObservationHandler.onError(ObservationHandler.java:157)
at io.micrometer.observation.SimpleObservation.notifyOnError(SimpleObservation.java:221)
at io.micrometer.observation.SimpleObservation.error(SimpleObservation.java:139)
at org.springframework.kafka.core.KafkaTemplate.observeSend(KafkaTemplate.java:811)
at org.springframework.kafka.core.KafkaTemplate.send(KafkaTemplate.java:608)
...

[artembilan]

Yeah... Agreed.
I see similar pattern in the ObservedAspect:

            observation.start();
            Observation.Scope scope = observation.openScope();
            try {
                Object result = pjp.proceed();

So, we indeed has to start an observation outside of the try..catch block.

More easier to understand how that supposed to be used is in the well-known Observation.observe() implementation:

    default void observe(Runnable runnable) {
        start();
        try (Scope scope = openScope()) {
            runnable.run();
        }
        catch (Throwable error) {
            error(error);
            throw error;
        }
        finally {
            stop();
        }
    }

[artembilan]

Signed-off-by: cfredri4 [email protected]

While email might be real, we would prefer to see a real, official contributor name in the commit.

Any chances that you can fix your GH account and local Git respectively?
This is an Open Source, so everything has to be as open as possible with respective appreciation credits to contributors.

Thank you for the fix!

[artembilan]

The DCO check has failed with:

Commit sha: [91376de](https://github.com/spring-projects/spring-kafka/pull/3779/commits/91376de75c9b340fe52bdf4714c492fe26247cf7), Author: cfredri4, Committer: cfredri4; Expected "cfredri4 [[email protected]](mailto:[email protected])", but got "Christian Fredriksson [[email protected]](mailto:[email protected])".

So, some else is off between your GH account and local Git.

Either way that looks good to me and I'm accepting your contribution and merging it.

Thank you again!