Vertx OpenTracing

Vert.x integrates with OpenTracing thanks to the Jaeger client.

You can configure Vert.x to use the Jaeger client configured via Environment

Vertx vertx = Vertx.vertx(new VertxOptions()
  .setTracingOptions(
    new OpenTracingOptions()
  )
);

You can also pass a custom Tracer allowing for greater control over the configuration.

Vertx vertx = Vertx.vertx(new VertxOptions()
  .setTracingOptions(
    new OpenTracingOptions(tracer)
  )
);

Tracing policy

The tracing policy defines the behavior of a component when tracing is enabled:

PROPAGATE: the component reports a span in the active trace
ALWAYS: the component reports a span in the active trace or creates a new active trace
IGNORE: the component will not be involved in any trace.

The tracing policy is usually configured in the component options.

HTTP tracing

The Vert.x HTTP server and client reports span around HTTP requests:

operationName: the HTTP method
tags
http.method: the HTTP method
http.url: the request URL
http.status_code: the HTTP status code

The default HTTP server tracing policy is ALWAYS, you can configure the policy with setTracingPolicy

HttpServer server = vertx.createHttpServer(new HttpServerOptions()
  .setTracingPolicy(TracingPolicy.IGNORE)
);

The default HTTP client tracing policy is PROPAGATE, you can configure the policy with setTracingPolicy

HttpClient client = vertx.createHttpClient(new HttpClientOptions()
  .setTracingPolicy(TracingPolicy.IGNORE)
);

To initiate a trace for a client call, you need to create it first and make Vert.x aware of it by using OpenTracingUtil.setSpan:

Span span = tracer.buildSpan("my-operation")
  .withTag("some-key", "some-value")
  .start();
OpenTracingUtil.setSpan(span);
// Do something, e.g. client request
span.finish();

In an HTTP scenario between two Vert.x services, a span will be created client-side, then the trace context will be propagated server-side and another span will be added to the trace.

EventBus tracing

The Vert.x EventBus reports spans around message exchanges.

The default sending policy is PROPAGATE, you can configure the policy with setTracingPolicy.

DeliveryOptions options = new DeliveryOptions().setTracingPolicy(TracingPolicy.ALWAYS);
vertx.eventBus().send("the-address", "foo", options);