Experimental Scala extensions for the Open Zipkin Brave library. This is not considered fit for production use and APIs are still influx and will change without notice. If you are looking for mature and stable instrumentation for Scala Futures, Akka, Akka Http or Monix we suggest looking at Kamon.
First we would like to give recognition to several existing libraries that helped with the initial implementations here.
https://github.com/levkhomich/akka-tracing
https://github.com/kamon-io/kamon-akka
https://github.com/FindHotel/akka-stream-trace
Why a new set of libraries when there are already a few choices?
At SmartThings we use the Brave trace instrumentation library extensively across all of our Java based micro services. While some of the mentioned libraries would have given sufficient and or better trace instrumentation for Akka Http, we wanted to provide our developers access to the already familiar Brave API. Additionally we wanted to build on a consistent span reporter implementation which meets our needs now and allows for greater flexibility in the future.
Long term we hope that this grows into a mature project worthy of becoming part of the OpenZipkin Brave instrumentation libraries.
The Core module contains Scala specific Tracing helpers.
Right now this just includes a TracedFuture which manages
span scope and naming.
The Config module provides patterns for building a tracer using Typesafe Config. Since Typesafe Config is widely used in the Scala ecosystem, this should give a quick way for any Scala project to add basic tracing support.
The Akka module provides Akka instrumentation. This is currently limited to a custom Akka Dispatcher that is used to wrap the ExecutorService with the Brave CurrentSpanContext to handle context propagation across threads.
The Akka Http module provides Brave Http instrumentation adapters, a custom BidiFlow
and some additional syntax for akka.http.scaladsl.HttpExt which adds two methods
bindAndHandleWithTracing and singleReqeustWithTracing. In addition there are several
Akka Http directives that provide convenient access to the SpanCustomizer and Tracing
instances.
For an example of both server and client tracing please refer to
smartthings.brave.scala.examples.http.AkkaHttpExample in the examples module.