Chapter 20. Eclipse MicroProfile

As defined by the Eclipse MicroProfile OpenTracing specification, CDI beans are traced if the org.eclipse.microprofile.opentracing.Traced annotation is present, either at the class or at the method level. Tracing can be disabled by setting the annotation value to false. Similarly, a custom operation name can be set by specifying the parameter operationName for that annotation. The semantics are defined by the MicroProfile OpenTracing specification.

The following example demonstrates how to configure tracing for a CDI bean. Note that tracing can be specified at the method level.

import org.eclipse.microprofile.opentracing.Traced;

@Traced
public class TracedBean {
    public void doSomething() {
    }

    @Traced(true)
    public void doSomethingTraced() {
    }

    @Traced(false)
    public void doSomethingNotTraced() {
    }
}

The following example demonstrates how to specify an operation name for the OpenTracing Span for this trace point.

import org.eclipse.microprofile.opentracing.Traced;

@Traced(operationName = "my-custom-class-operation-name")
public class CustomOperationNameBean {

    @Traced(operationName = "my-custom-method-operation-name")
    public void doSomething() {
    }

    @Traced
    public void doSomethingElse() {
    }
}

JAX-RS endpoints are traced by default if the microprofile-opentracing-smallrye subsystem is present in the server configuration.

To disable tracing for JAX-RS endpoints, add the @Traced(false) annotation to the JAX-RS endpoint at the class or method level as described in Enable or Disable Tracing for CDI Beans above.

If you need something more complex than what is provided by the default Jaeger Java Client, you can provide your own tracer by implementing a TracerResolver that returns the Tracer with the desired state. In this case, the default tracer will not be used.

The following example demonstrates how to create a new implementation of TracerResolver that returns a custom implementation of the Tracer class.

import io.opentracing.Tracer;
import io.opentracing.contrib.tracerresolver.TracerResolver;
import org.myproject.opentracing.CustomTracer;

public static class MyTracerResolver extends TracerResolver {
    @Override
    protected Tracer resolve() {
        return new CustomTracer();
    }
}

The default implementation provided by the microprofile-health-smallrye subsystem performs a basic health check. For more detailed information, on either the server or application status, custom health checks may be included. Any CDI beans that include the org.eclipse.microprofile.health.Health annotation at the class level are automatically discovered and invoked at runtime.

The following example demonstrates how to create a new implementation of a health check that returns an UP state.

import org.eclipse.microprofile.health.Health;
import org.eclipse.microprofile.health.HealthCheck;
import org.eclipse.microprofile.health.HealthCheckResponse;

@Health
public class HealthTest implements HealthCheck {

    @Override
    public HealthCheckResponse call() {
        return HealthCheckResponse.named("health-test").up().build();
    }
}

Once deployed, any subsequent health check queries will include the custom checks, as seen below.

/subsystem=microprofile-health-smallrye:check
{
    "outcome" => "success",
    "result" => {
        "outcome" => "UP",
        "checks" => [{
            "name" => "health-test",
            "state" => "UP"
        }]
    }
}