otel4s-sdk

SDK backend is an alternative to the otel4s-oteljava. The backend is implemented in Scala from scratch. Available for JVM, Scala.js, and Scala Native. While the implementation is compliant with the OpenTelemetry specification, it remains experimental and some functionality may be lacking and the memory overhead may be noticeable.

Getting started

libraryDependencies ++= Seq(
  "org.typelevel" %%% "otel4s-sdk" % "0.19.3", // <1>
  "org.typelevel" %%% "otel4s-sdk-exporter" % "0.19.3" // <2>
)

//> using dep "org.typelevel::otel4s-sdk::0.19.3" // <1>
//> using dep "org.typelevel::otel4s-sdk-exporter::0.19.3" // <2>

1. Add the otel4s-sdk library
2. Add the otel4s-sdk-exporter library. Without the exporter, the application will crash

Then use OpenTelemetrySdk.autoConfigured to autoconfigure the SDK:

import cats.effect.{IO, IOApp}
import org.typelevel.otel4s.sdk.OpenTelemetrySdk
import org.typelevel.otel4s.sdk.exporter.otlp.autoconfigure.OtlpExportersAutoConfigure
import org.typelevel.otel4s.metrics.MeterProvider
import org.typelevel.otel4s.trace.TracerProvider

object TelemetryApp extends IOApp.Simple {

  def run: IO[Unit] =
    OpenTelemetrySdk
      .autoConfigured[IO]( // register OTLP exporters configurer
        _.addExportersConfigurer(OtlpExportersAutoConfigure[IO]) 
      )
      .use { autoConfigured =>
        val sdk = autoConfigured.sdk
        program(sdk.meterProvider, sdk.tracerProvider)
      }

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

Configuration

The .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.

Limitations

No autoload of third-party components

Since Scala Native and Scala.js lack SPI support, third-party components cannot be loaded dynamically as OpenTelemetry Java does.

Hence, the configurers must be registered manually:

OpenTelemetrySdk.autoConfigured[IO](
  _.addExportersConfigurer(OtlpExportersAutoConfigure[IO])
)