Distributed Tracing

Module helidon-tracing defines tracing API and SPI that is used throughout Helidon. As we need to support both OpenTracing and OpenTelemetry tracing, this abstraction is required to keep tracing an integral part of Helidon.

Module helidon-tracing-providers-opentracing adds support for opentracing based tracers (such as Zipkin). Module helidon-tracing-providers-opentelemetry adds support for opentelemetry based tracers (such as Jaeger).

Usage

To use tracing in SE, add a dependency on helidon-tracing and a tracer implementation and register tracer with server configuration.

pom.xml:

<dependency>
    <!-- to add tracer builder -->
    <groupId>io.helidon.tracing</groupId>
    <artifactId>helidon-tracing</artifactId>
</dependency>
<dependency>
    <!-- to add zipkin support -->
    <groupId>io.helidon.tracing</groupId>
    <artifactId>helidon-tracing-providers-zipkin</artifactId>
</dependency>

code using config:

return WebServer.builder()
                .config(config.get("webserver"))
                .tracer(TracerBuilder.create(config.get("tracing"))
                                        .buildAndRegister())
                .build();

To customize configuration of zipkin, see ZipkinTracerBuilder javadoc. Basics:

tracing:
  # required
  service: "service-name"
  # default is "localhost"
  host: "zipkin"

Modules

Module helidon-tracing

Contains an abstracted Builder for tracers and an SPI to connect various tracer implementations.

Example:

// create a tracer for service "myService"
Tracer tracer = TracerBuilder.create("myService")
    // running on host "zipkin" - probably in docker or k8s
    .collectorHost("zipkin")
    // build the tracer and register as global tracer
    .buildAndRegister();

Example using Config:

// create a tracer from configuration
Tracer tracer = TracerBuilder.create(config.get("tracing"))    
    // build the tracer and register as global tracer
    .buildAndRegister();

and associated configuration:

tracing:
  service: "myService"
  host: "zipkin"

Module helidon-tracing-providers-zipkin

Integration with Zipkin (https://zipkin.io/). Easiest approach is to use a docker image zipkin that, by default, runs on the expected hostname and port.

When you add this module to classpath, the SPI is automatically picked up and Zipkin tracer would be used.

See class ZipkinTracerBuilder for documentation of supported configuration options. The classes in this module should not be used directly, use helidon-tracing module API instead (unless you want to create a hard source code dependency on Zipkin tracer).