My set-up:

1. Spring boot app based on version 3.1.3
2. Added dependency spring-boot-starter-actuator
3. Added custom metric MyHealthMetricsExportConfiguration according to the documentation (shown below)
4. Under /actuator/metrics I can see health metric
5. I’ve downloaded the latest otel java agent from github
6. I’ve added the config in intellij “vm options”:

-javaagent:./opentelemetry-javaagent.jar
-Dotel.metrics.exporter=otlp

1. I’ve run otel collector with receiver set to otlp

The question

I don’t know how to make otel agent ‘to see’ and export spring metrics like f.e. ‘MyHealthMetricsExportConfiguration’. On that blog it should be as simple as:

  // Unregister the OpenTelemetryMeterRegistry from Metrics.globalRegistry and make it available
  // as a Spring bean instead.
  @Bean
  @ConditionalOnClass(name = "io.opentelemetry.javaagent.OpenTelemetryAgent")
  public MeterRegistry otelRegistry() {
    Optional<MeterRegistry> otelRegistry = Metrics.globalRegistry.getRegistries().stream()
        .filter(r -> r.getClass().getName().contains("OpenTelemetryMeterRegistry"))
        .findAny();
    otelRegistry.ifPresent(Metrics.globalRegistry::remove);
    return otelRegistry.orElse(null);
  }

But that doesn’t work for me. First of all durig bean creation Metrics.globalRegistry.getRegistries() is empty. Second of all, no health metric is available in otel collector. What can I do to make this agent send my custom metric to collector ?

@Configuration(proxyBeanMethods = false)
public class MyHealthMetricsExportConfiguration {

    public MyHealthMetricsExportConfiguration(MeterRegistry registry, HealthEndpoint healthEndpoint) {
        // This example presumes common tags (such as the app) are applied elsewhere
        Gauge.builder("health", healthEndpoint, this::getStatusCode).strongReference(true).register(registry);
    }

    private int getStatusCode(HealthEndpoint health) {
        Status status = health.health().getStatus();
        if (Status.UP.equals(status)) {
            return 3;
        }
        if (Status.OUT_OF_SERVICE.equals(status)) {
            return 2;
        }
        if (Status.DOWN.equals(status)) {
            return 1;
        }
        return 0;
    }

}