README.md

opentracing-sparkjava

OpenTracing Instrumentation for SparkJava

This repo contains tracing filters and an exception handler for SparkJava. The filters extract tracing headers from incoming requests to create OpenTracing spans. These spans can be exported to a variety of backends including Jaeger, Hawkular, and others.

Dependencies

The Spark dependency is marked as compileOnly and must be supplied by the application.

compile group: 'com.sparkjava', name: 'spark-core', version: '2.7.+'

Usage

To enable tracing you need to add before, exception and afterAfter hooks:

OpenTracingSparkFilters sparkTracingFilters = new OpenTracingSparkFilters(tracer);
Spark.before(sparkTracingFilters.before());
Spark.afterAfter(sparkTracingFilters.afterAfter());
Spark.exception(sparkTracingFilters.exception());

// tracing is added for all routes
Spark.get("/hello", (req, res) -> "hello world");

To access the current span in a resource retrieve it from the request attributes using OpenTracingSparkFilters.SERVER_SPAN:

Spark.get("/path", (req, res) -> {
    Span span = req.attribute(OpenTracingSparkFilters.SERVER_SPAN);
    tracer.buildSpan("child").asChildOf(span).withTag("test", "value").start().finish();

    //do stuff
    return "hello world";
});