How to Grab Auto-Generated KafkaTemplate in Spring Cloud Stream?

Question

A few examples for implementing HealthIndicator needs a KafkaTemplate. I don't actually manually create a KafkaTemplate but the HealthIndicator requires one. Is there a way to automatically grab the created KafkaTemplate (that uses the application.yml configurations)? This is versus manually creating duplicated configurations that already exist in the application.yml in a newly created consumerFactory.

Answer 1

See this answer.

(S)he wanted to get access to the template's ProducerFactory but you can use the same technique to just get a reference to the template.

That said, the binder comes with its own health indicator.

https://github.com/spring-cloud/spring-cloud-stream-binder-kafka/blob/a7299df63f495af3a798637551c2179c947af9cf/spring-cloud-stream-binder-kafka/src/main/java/org/springframework/cloud/stream/binder/kafka/KafkaBinderHealthIndicator.java#L52

Answer 2

We also had the same requirement of creating a custom health checker Spring Cloud stream. We leveraged the inbuild health checker(KafkaBinderHealthIndicator). But while injecting the KafkaBinderHealthIndicator bean facing lot of issue. So instead of that we inject the health checker holder HealthContributorRegistry, and got the KafkaBinderHealthIndicator bean from it.

Example:

@Component
@Slf4j
@RequiredArgsConstructor
public class KafkaHealthChecker implements ComponentHealthChecker {

  private final HealthContributorRegistry registry;


  public String checkHealth() {
    String status;
    try {
      BindersHealthContributor bindersHealthContributor = (BindersHealthContributor)
          registry.getContributor("binders");
      KafkaBinderHealthIndicator kafkaBinderHealthIndicator = (KafkaBinderHealthIndicator)
          bindersHealthContributor.getContributor("kafka");

      Health health = kafkaBinderHealthIndicator.health();
      status = UP.equals(health.getStatus()) ? "OK" : "FAIL";
    } catch (Exception e) {
      log.error("Error occurred while checking the kafka health ", e);
      status = "DEGRADED";
    }
    return status;
  }

}