jaeger-dropwizard

Dropwizard

Maven Dependency

If you are using dropwizard then you can add the following:

<dependency>
    <groupId>com.uber.jaeger</groupId>
    <artifactId>jaeger-dropwizard</artifactId>
    <version>$jaegerVersion</version>
</dependency>

Instrumentation

As dropwizard is a JAX-RS implementation, we build upon jaeger-jaxrs2 and add some convenience configuration files and support for dropwizard metrics.

Simply add a JaegerFeature to the dropwizard server and client. If you use other clients, like an Apache Http Client, make sure to instrument them as well.

Jaeger’s dropwizard jar exposes a configuration object com.uber.jaeger.dropwizard.Configuration. If your service reads in its configuration through a pojo object then you can use this Configuration class to read the yaml format specified above.

The following is an example of adding the Jaeger Feature to a JAX-RS based framework that creates a dropwizard/jersey client.

Client

import com.uber.jaeger.context.TracingUtils;

// JaegerConfig gets initialized by whichever dropwizard configuration reader you are using.
com.uber.jaeger.dropwizard.Configuration jaegerConfig;

// For context propagation across threads
ExecutorService tracedExecutor = TracingUtils.tracedExecutor(Executors.newCachedThreadPool());

// Enable tracing for inbound requests
JaegerFeature jaegerFeature = new JaegerFeature(configuration.getJaegerConfig());


RxClient<RxListenableFutureInvoker> reactiveClient = 
    Rx.from(
        ClientBuilder.newClient().register(jaegerFeature),
        RxListenableFutureInvoker.class,
        tracedExecutor);

Client inertClient = ClientBuilder.newClient()
    /* Arbitrary configuration code … */
    .register(jaegerFeature);

Server

@Override
public void run(T configuration, Environment environment) throws Exception {
    JaegerFeature jaegerFeature = new JaegerFeature(configuration.getJaegerConfig());
    environment.jersey().register(jaegerFeature);
}

Configuration

The minimal configuration in base.yaml should look like this:

jaeger:
  serviceName: my-service-name 

In a yaml configuration file you must specify a serviceName. It is also possible to specify a ‘disable’ flag set to true, or false. Jaeger should ALWAYS be ENABLED except in case of emergencies where you are sure there is a problem with Jaeger. If the disable field is left out then Jaeger will be enabled by default.

Metrics

In order for Jaeger to report metrics properly it needs to be configured with a metric registry.

import com.uber.jaeger.dropwizard.TracingUtils;

// Dropwizard's metrics registry class
MetricsRegistry registry = new MetricsRegistry();

// JaegerConfig gets initialized by whichever dropwizard configuration reader you are using.
com.uber.jaeger.dropwizard.Configuration jaegerConfig;

jaegerConfig.setMetricRegistry(registry);

final Client client = new JerseyClientBuilder(env)
    /* Arbitrary configuration code … */
    .register(TracingUtils.clientFilter(jaegerConfig);