MetricsBean.java

import io.prometheus.client.CollectorRegistry;
import io.prometheus.client.dropwizard.DropwizardExports;
import io.prometheus.client.hotspot.ClassLoadingExports;
import io.prometheus.client.hotspot.GarbageCollectorExports;
import io.prometheus.client.hotspot.MemoryPoolsExports;
import io.prometheus.client.hotspot.ThreadExports;
import io.prometheus.client.hotspot.VersionInfoExports;

import javax.enterprise.context.ApplicationScoped;
import javax.enterprise.context.Destroyed;
import javax.enterprise.context.Initialized;
import javax.enterprise.event.Observes;
import javax.inject.Inject;

import com.codahale.metrics.MetricRegistry;

/**
 * A bean, which is starting the metrics reporter during startup and its is shutting down the
 * reporter when application is destroyed.
 * 
 *
 */
@ApplicationScoped
public class MetricsBean {

  @Inject
  private MetricRegistry registry;

  public void init(@Observes @Initialized(ApplicationScoped.class) final Object init) {
    // DefaultExports.initialize();

    new MemoryPoolsExports().register();
    new GarbageCollectorExports().register();
    new ThreadExports().register();
    new ClassLoadingExports().register();
    new VersionInfoExports().register();

    CollectorRegistry.defaultRegistry.register(new DropwizardExports(registry));
  }

  public void destroy(@Observes @Destroyed(ApplicationScoped.class) final Object init) {
    CollectorRegistry.defaultRegistry.clear();
  }


}