Kamon Monix

Kamon Monix module provides bytecode instrumentation to gather metrics and perform automatic Context propagation on your behalf.

Adding the Module

The module currently works with monix 3.0.0-RC2. To get started add the following to your build.sbt.

resolvers           += Resolver.bintrayRepo("bogdanromanx", "maven")
libraryDependencies += "com.github.bogdanromanx" %% "kamon-monix" % "1.0.0-M2"

Run

The kamon-monix module requires you to start your application using the AspectJ Weaver Agent. You can achieve that quickly with Kamon's sbt-aspectj-runner plugin or take a look at the Kamon documentation for other options.

Just by adding this module in the project dependencies, the Kamon context is propagated across the different threads where the Monix Tasks are executed.

You can also define custom spans around Monix tasks to trace various parts of the codebase:

import kamon.monix.Monix._
import monix.eval.Task
import monix.execution.Scheduler
import scala.concurrent.duration._
import scala.language.postfixOps

// required when attempting to run a task
implicit val s: Scheduler = Scheduler.global

val task = withSpan("my-span", Map("span.kind" -> "application")) {
  Task.gatherUnordered(1 to 5 map { idx => Task.sleep((idx * 10) millis) })
}

task.runAsync

The module also provides additional withSpan methods that can wrap cats transformers for Monix's Task: withSpanEitherT, withSpanOptionT, withSpanIorT, withSpanIdT and withSpanStateT.

The kamon-monix-app module in this repository shows a simple example of an application using this module with kamon-akka-http instrumentation and kamon-jaeger as a reporter.