For most users, the out-of-the-box instrumentation is completely sufficient and nothing more has to be done. Sometimes, however, users wish to create spans for their own custom code without needing to make many code changes.

If you add the WithSpan annotation to a method, the method is wrapped in a span. The SpanAttribute annotation allows you to capture the method arguments as attributes.

package otel;

import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.SpanKind;
import io.opentelemetry.instrumentation.annotations.SpanAttribute;
import io.opentelemetry.instrumentation.annotations.WithSpan;
import org.springframework.stereotype.Component;

/** Test WithSpan */
@Component
public class TracedClass {

  @WithSpan
  public void tracedMethod() {}

  @WithSpan(value = "span name")
  public void tracedMethodWithName() {
    Span currentSpan = Span.current();
    currentSpan.addEvent("ADD EVENT TO tracedMethodWithName SPAN");
    currentSpan.setAttribute("isTestAttribute", true);
  }

  @WithSpan(kind = SpanKind.CLIENT)
  public void tracedClientSpan() {}

  @WithSpan
  public void tracedMethodWithAttribute(@SpanAttribute("attributeName") String parameter) {}
}

@RestController
public class MyControllerManagedBySpring {

    @GetMapping("/ping")
    public void aMethod() {
        anotherMethod();
    }

    @WithSpan
    public void anotherMethod() {
    }
}

{{< comment >}} Note that we have to use the alert shortcode because it contains tab panes.

{{< /comment >}}

{{% alert title="Note" %}}

To be able to use the OpenTelemetry annotations, you have to add the Spring Boot Starter AOP dependency to your project:

{{< tabpane text=true >}} {{% tab header="Maven (pom.xml)" lang=Maven %}}

<dependencies>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
  </dependency>
</dependencies>

{{% /tab %}} {{% tab header="Gradle (build.gradle)" lang=Gradle %}}

dependencies {
  implementation("org.springframework.boot:spring-boot-starter-aop")
}

{{% /tab %}} {{< /tabpane >}}

{{% /alert %}}

You can disable the OpenTelemetry annotations by setting the otel.instrumentation.annotations.enabled property to false.

In declarative configuration, use the centralized instrumentation lists instead:

otel:
  distribution:
    spring_starter:
      instrumentation:
        disabled:
          - annotations

You can customize the span by using the elements of the WithSpan annotation:

You can set the attribute name from the value element of the SpanAttribute annotation:

Beyond the use of annotations, the OpenTelemetry API allows you to obtain a tracer that can be used custom instrumentation.