Customized tracing with Zipkin is supported to allow users to add tracing spans at points of interest.

1. Include the following dependency

    <dependency>
      <groupId>org.apache.servicecomb</groupId>
      <artifactId>tracing-zipkin</artifactId>
    </dependency>

2. Enable tracing with annotation @EnableZipkinTracing on your application entry or configuration

Import tracing.zipkin.EnableZipkinTracing package

import org.apache.servicecomb.tracing.zipkin.EnableZipkinTracing;

Add annotation @EnableZipkinTracing

@SpringBootApplication
@EnableZipkinTracing
public class ZipkinSpanTestApplication {
  public static void main(String[] args) {
    SpringApplication.run(ZipkinSpanTestApplication.class);
  }
}

3. Add new span to the point of interest with annotation @Span

Import tracing.Span package

import org.apache.servicecomb.tracing.Span;

Add annotation @Span

@Component
public class SlowRepoImpl implements SlowRepo {
  private static final Logger logger = LoggerFactory.getLogger(SlowRepoImpl.class);

  private final Random random = new Random();

  @Span
  @Override
  public String crawl() throws InterruptedException {
    logger.info("in /crawl");
    Thread.sleep(random.nextInt(200));
    return "crawled";
  }
}

That's it!

Customized tracing span includes two pieces of data:

• span name - annotated method name
• call.path - annotated method signature

e.g. the example SlowRepoImpl in the previous section reports the following span

• Customized tracing with annotation only supports method calls in the request thread.
• Classes with @Span must be a spring managed bean. If you want to do load-time weaving for non spring beans, you have to do it manually according to this answer.