Description
In what version(s) of Spring for Apache Kafka are you seeing this issue?
3.3.6
Describe the bug
Batch @KafkaListener is not observable, non-batch is observable - it causes Prometheus metric conflict.
When observability is enabled and there is one non-batch @KafkaListener, metric
http://localhost:8080/actuator/prometheus?includedNames=spring_kafka_listener_seconds is ok:
spring_kafka_listener_seconds_sum{error="none",messaging_kafka_consumer_group="aaa",messaging_operation="receive",messaging_source_kind="topic",messaging_source_name="bbb",messaging_system="kafka",spring_kafka_listener_id="org.springframework.kafka.KafkaListenerEndpointContainer#0-0"} 0.0016962
When second, batch @KafkaListener is added, it breaks non-batch metrics
spring_kafka_listener_seconds_sum{exception="none",name="org.springframework.kafka.KafkaListenerEndpointContainer#0-0",result="success"} 0.0
Logs contains warning with explanation:
The meter (MeterId{name='spring.kafka.listener', tags=[tag(error=none),tag(messaging.kafka.consumer.group=aaa),tag(messaging.operation=receive),tag(messaging.source.kind=topic),tag(messaging.source.name=bbb),tag(messaging.system=kafka),tag(spring.kafka.listener.id=org.springframework.kafka.KafkaListenerEndpointContainer#1-0)]}) registration has failed
To Reproduce
- Build application with
- org.springframework.kafka:spring-kafka
- org.springframework.boot:spring-boot-starter-actuator
- io.micrometer:micrometer-registry-prometheus
- org.springframework.boot:spring-boot-starter-web (for easy metric inspection)
Make sure: spring.kafka.listener.observation-enabled=true
Experiment with different combination of batch and non-batch @KafkaListener
Expected behavior
It cannot be accepted that adding batch listener breaks already working obsevations
When observability is enabled, metric for each listener should be registered with same set of tags, regardless listener is batch or non-batch). When some tag has no value, use placeholder "none"
Similar issue for MongoDB: spring-projects/spring-data-mongodb#4994