ratpack-zipkin

Zipkin support for Ratpack.

Uses Brave for the underlying Zipkin support.

Binaries

Using Gradle:

compile 'com.github.hyleung:ratpack-zipkin:1.0.1'

Using Maven:

<dependency>
  <groupId>com.github.hyleung</groupId>
  <artifactId>ratpack-zipkin</artifactId>
  <version>1.0.1</version>
</dependency>

Getting Started

Zipkin

First you'll need to (obviously) get Zipkin up and running. The quickest way to do this is using Docker and docker-compose.

Clone docker-zipkin

Start the Zipkin stack by running;

docker-compose up

Ratpack

SR/SS Spans

The mimimal configuration:

RatpackServer.start(server -> server
    .serverConfig(config -> config.port(serverPort))
    .registry(Guice.registry(binding -> binding
        .module(ServerTracingModule.class, config -> config.serviceName("some-service-name")
        .bind(HelloWorldHandler.class)
    ))(
    .handlers(chain -> chain
        ...)
);

This should add a HandlerDecorator that adds server send (SS) and server receive (SS) tracing using the default settings.

There's a small demo app in ratpack-zipkin-example.

CS/CR Spans

ZipkinHttpClient provides some HTTP client functionality - similar to Ratpack's own HttpClient. There are separate methods for each of the supported HTTP methods (GET, POST, PUT, PATCH, OPTIONS, HEAD). Tracing of streamed responses is not supported.

@Inject ZipkinHttpClient client
...
client.get(new URI("http://example.com", requestSpec -> ...))
    ... 

The underlying implementation is just a wrapper that delegates most of the work to a standard Ratpack HttpClient - just adds a little bit of instrumentation around the client request/response. Eventually, the hope is that this custom Http client will go away, but that requires some extra hooks the normal Ratpack HTTP client.

Local Spans

For local spans, use the normal Brave LocalTracer:

@Inject LocalTracer tracer

...
tracer.startNewSpan("My component", "an operation");
...
tracer.finishSpan();

Currently nested local spans don't work - but hopefully soon!