Spring Boot Actuator: How to get metrics uptime inside a custom HealthIndicator?

Question

I want to do a custom HealthIndicator that depends on the application uptime.

@Component
public class HealthActuator implements HealthIndicator {

    private final MetricsEndpoint metricsEndpoint;

    @Autowired
    public HealthActuator(MetricsEndpoint metricsEndpoint) {
        this.metricsEndpoint = metricsEndpoint;
    }

    @Override
    public Health health() {
        long uptime = (Long) metricsEndpoint.invoke().get("uptime");
        // logic with uptime
        return Health.up().build();
    }

}

But there is an error: a circular dependency between 2 beans in the application context.

I can get uptime metric with a rest call to my endpoint /actuator/health.

But maybe is it possible to do it programmatically?

P.S. Log stacktrace:

11-01 14:34:09 WARN org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'healthActuator' defined in file [/Users/serge/projects/bb/bb-imapl/target/classes/bb/imapl/config/HealthActuator.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.actuate.autoconfigure.EndpointAutoConfiguration': Bean instantiation via constructor failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.boot.actuate.autoconfigure.EndpointAutoConfiguration$$EnhancerBySpringCGLIB$$2bb06d4a]: Constructor threw exception; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'healthActuator': Requested bean is currently in creation: Is there an unresolvable circular reference?
11-01 14:34:09 WARN org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'healthActuator' defined in file [/Users/serge/projects/bb/bb-imapl/target/classes/bb/imapl/config/HealthActuator.class]: Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.actuate.autoconfigure.EndpointAutoConfiguration': Bean instantiation via constructor failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.boot.actuate.autoconfigure.EndpointAutoConfiguration$$EnhancerBySpringCGLIB$$2bb06d4a]: Constructor threw exception; nested exception is org.springframework.beans.factory.BeanCurrentlyInCreationException: Error creating bean with name 'healthActuator': Requested bean is currently in creation: Is there an unresolvable circular reference?
11-01 14:34:09 ERROR org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter - 

***************************
APPLICATION FAILED TO START
***************************

Description:

There is a circular dependency between 2 beans in the application context:
    - healthActuator defined in file [/Users/serge/projects/bb/bb-imapl/target/classes/bb/imapl/config/HealthActuator.class]
    - org.springframework.boot.actuate.autoconfigure.EndpointAutoConfiguration
    - healthActuator


11-01 14:34:09 ERROR org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter - 

Answer 1

If you do not like setter injection, it should also be possible to work around this with @Lazy...

@Autowired
public HealthActuator(@Lazy MetricsEndpoint metricsEndpoint) {
    this.metricsEndpoint = metricsEndpoint;
}

Answer 2

EndpointAutoConfiguration has a dependency on HealthIndicator (which you implemented with HealthActuator).

So you end up with a circular dependency. This happens when 2 beans needs each other to instantiate themselves (through constructor injection). You can break the cycle by using a setter injection:

@Component
public class HealthActuator implements HealthIndicator {
    private MetricsEndpoint metricsEndpoint;

    @Autowired
    private void setMetricsEndpoint(MetricsEndpoint metricsEndpoint) {
        this.metricsEndpoint = metricsEndpoint;
    }

    public HealthActuator() {
    }

    @Override
    public Health health() {
        long uptime = (Long) metricsEndpoint.invoke().get("uptime");
        // logic with uptime
        return Health.up().build();
    }
}