问使用远程父级的跟踪id和span id创建Opentelem遥测上下文

EN

  @GetMapping(value = "/second")
  public String sencondTest(@RequestHeader(value = "traceparent") String traceparent){
    try {
      Tracer tracer = openTelemetry.getTracer("cloud.events.second");

      TextMapGetter<ExtractModel> getter = new TextMapGetter<>() {
        @Override
        public String get(ExtractModel carrier, String key) {
          if (carrier.getHeaders().containsKey(key)) {
            return carrier.getHeaders().get(key);
          }
          return null;
        }

        @Override
        public Iterable<String> keys(ExtractModel carrier) {
          return carrier.getHeaders().keySet();
        }
      };

      ExtractModel model = new ExtractModel();
      model.addHeader("traceparent", traceparent);
      Context extractedContext = openTelemetry.getPropagators().getTextMapPropagator()
              .extract(Context.current(), model, getter);

      try (Scope scope = extractedContext.makeCurrent()) {
        // Automatically use the extracted SpanContext as parent.
        Span serverSpan = tracer.spanBuilder("CloudEvents Server")
                .setSpanKind(SpanKind.SERVER)
                .startSpan();
        try {

          Thread.sleep(150);
        } finally {
          serverSpan.end();
        }
      }

    } catch (InterruptedException e) {
      throw new RuntimeException(e);
    }

    return "Server Received!";
  }

// Use W3C Propagator(to extract span from HTTP headers) since we use the W3C specifications
TextMapPropagator textMapPropagator = W3CTraceContextPropagator.getInstance();

OpenTelemetrySdk openTelemetrySdk = OpenTelemetrySdk.builder()
        .setTracerProvider(tracerProvider)
        .setPropagators(ContextPropagators.create(textMapPropagator))
        .buildAndRegisterGlobal();

public class ExtractModel {

  private Map<String, String> headers;

  public void addHeader(String key, String value) {
    if (this.headers == null){
      headers = new HashMap<>();
    }
    headers.put(key, value);
  }

  public Map<String, String> getHeaders() {
    return headers;
  }

  public void setHeaders(Map<String, String> headers) {
    this.headers = headers;
  }
}