Overview

otel4s-oteljava modules provide implementation of the API interfaces. The implementation uses opentelemetry-java under the hood.

There are several advantages of using the otel4s-oteljava:

• Low memory overhead
• Extensive instrumentation ecosystem
• Easy integration with Java libraries
• Well-tested implementation

It's a recommended backend to use on JVM.

Getting Started

libraryDependencies ++= Seq(
  "org.typelevel" %% "otel4s-oteljava" % "0.11.2", // <1>
  "io.opentelemetry" % "opentelemetry-exporter-otlp" % "1.45.0" % Runtime, // <2>
  "io.opentelemetry" % "opentelemetry-sdk-extension-autoconfigure" % "1.45.0" % Runtime // <3>
)
javaOptions += "-Dotel.java.global-autoconfigure.enabled=true" // <4>

//> using lib "org.typelevel::otel4s-oteljava:0.11.2" // <1>
//> using lib "io.opentelemetry:opentelemetry-exporter-otlp:1.45.0" // <2>
//> using lib "io.opentelemetry:opentelemetry-sdk-extension-autoconfigure:1.45.0" // <3>
//> using `java-opt` "-Dotel.java.global-autoconfigure.enabled=true" // <4>

1. Add the otel4s-oteljava library
2. Add an OpenTelemetry exporter. Without the exporter, the application will crash
3. Add an OpenTelemetry autoconfigure extension
4. Enable OpenTelemetry SDK autoconfigure mode

Creating an autoconfigured instance

You can use OtelJava.autoConfigured to autoconfigure the SDK:

import cats.effect.{IO, IOApp}
import org.typelevel.otel4s.oteljava.OtelJava
import org.typelevel.otel4s.metrics.MeterProvider
import org.typelevel.otel4s.trace.TracerProvider

object TelemetryApp extends IOApp.Simple {

  def run: IO[Unit] =
    OtelJava.autoConfigured[IO]().use { otel4s =>
      program(otel4s.meterProvider, otel4s.tracerProvider)
    }

  def program(
      meterProvider: MeterProvider[IO], 
      tracerProvider: TracerProvider[IO]
  ): IO[Unit] =
    ???
}

The OtelJava.autoConfigured(...) relies on the environment variables and system properties to configure the SDK. For example, use export OTEL_SERVICE_NAME=auth-service to configure the name of the service.

See the full set of the supported options.

Accessing the global instance

There are several reasons to use the global instance:

• You are using the Java Agent
• You must reuse the global instance to interoperate with Java libraries
• You have no control over the entry point

In such a case, you can use the OtelJava.global to use the global OpenTelemetry instance:

import cats.effect.{IO, IOApp}
import org.typelevel.otel4s.oteljava.OtelJava
import org.typelevel.otel4s.metrics.MeterProvider
import org.typelevel.otel4s.trace.TracerProvider

object TelemetryApp extends IOApp.Simple {

  def run: IO[Unit] =
    OtelJava.global[IO].flatMap { otel4s =>
      program(otel4s.meterProvider, otel4s.tracerProvider)
    }

  def program(
      meterProvider: MeterProvider[IO], 
      tracerProvider: TracerProvider[IO]
  ): IO[Unit] =
    ???
}