MicrometerMetricsService

MicrometerMetricsService.java

@Slf4j
public class MicrometerMetricsService {
	private DualMetric metricValidTemplate;

	// Not possible to convert to a local variable, it is not working!
	private final RepositoryMetricProvider repositoryMetricProvider = new RepositoryMetricProvider();

	private final List<HealthIndicator> healthIndicators;


	public MicrometerMetricsService(MeterRegistry registry, HealthContributorRegistry healthContributorRegistry) {
		final String METRIC_HEALTH = Constants.SUBSYSTEM_NAME.toLowerCase() + ".health";
		final String RESOURCE_COUNT_METRIC = Constants.SUBSYSTEM_NAME.toLowerCase() + ".resourcecount";
		final String TEMPLATE_COUNT_METRIC = Constants.SUBSYSTEM_NAME.toLowerCase() + ".templatecount";

		this.metricValidTemplate = new DualMetric(registry, Constants.SUBSYSTEM_NAME.toLowerCase(), "validtemplate");

		// Health indicators
		this.healthIndicators = healthContributorRegistry.stream() //
				.map(c -> this.getIndicatorFromContributor(c)) //
				.collect(Collectors.toList());
		Gauge.builder(METRIC_HEALTH, healthIndicators, MicrometerMetricsService::healthToCode) //
				.description("The current value of the composite health endpoint").register(registry);

		// Count of resources
		Gauge.builder(RESOURCE_COUNT_METRIC, this.repositoryMetricProvider, RepositoryMetricProvider::getResourceCountMetric)
				.description("The current count of resources").baseUnit("pcs").register(registry);

		// Count of templates
		Gauge.builder(TEMPLATE_COUNT_METRIC, this.repositoryMetricProvider, RepositoryMetricProvider::getResourceCountMetric)
				.description("The current count of templates").baseUnit("pcs").register(registry);
	}

	private HealthIndicator getIndicatorFromContributor(NamedContributor<HealthContributor> namedContributor) {
		log.debug(String.format("Using health contributor: '%s'", namedContributor.getName()));

		HealthContributor contributor = namedContributor.getContributor();
		if (contributor instanceof HealthIndicator) {
			return (HealthIndicator) contributor;
		}

		if (contributor instanceof CompositeHealthContributor) {
			CompositeHealthContributor compositeHealthContributor = (CompositeHealthContributor) contributor;
			for (NamedContributor<HealthContributor> elementOfComposite : compositeHealthContributor) {
				return getIndicatorFromContributor(elementOfComposite);
			}
		}

		throw new UnexpectedConditionException();
	}

	private static int healthToCode(List<HealthIndicator> indicators) {
		for (HealthIndicator indicator : indicators) {
			Status status = indicator.health().getStatus();
			if (Status.DOWN.equals(status)) {
				return 0;
			}
		}

		return 1;
	}
}