在Spring Boot healtcheck状态更改时收到通知

Question

Is there a way to get notified when the status of the registered health check indicators changes? For example, when the healthcheck indicator of database becomes down, I would like to take some actions.

Actually, my final goal is to export healthcheck status to Prometheus' metrics. So, when there is status change, I want to update health metrics.

Answer 1

I assume your question refers to Micrometer issue 416 and Micrometer-Docs issue 39 .

As per documentation, you can register the custom HealthMetricsConfiguration . The value of the gauge is determined by the status the ComposeHealthIndicator returns and is actually changing depending on the state of the single HealthIndicator s.

I am using afformentioned HealthMetricsConfiguration (just with different status value mappings as discussed in issue 416).

Wen't ahead and implemented a custom alternating health indicator:

@Component
public class AlternatingHealthIndicator extends AbstractHealthIndicator {

    @Override
    protected void doHealthCheck(Builder builder) throws Exception {
        int minute = LocalDateTime.now().getMinute();
        boolean minuteIsEven = minute % 2 == 0;
        builder.status(minuteIsEven ? Status.UP : Status.DOWN);
        builder.withDetail("description", "UP when current minute is even; DOWN when current minute is odd");
        builder.withDetail("currentMinute", minute);
        builder.withDetail("minuteIsEven", minuteIsEven);
    }

}

The health gauge exported on the Prometheus endpoint is minutely changing from 1=UP to -2=DOWN . Here's a visualization:

Regarding alerting, you can use Grafana alerting or look into Prometheus' Alertmanager.