Add an example how to use otel instrumentation

build.sbt

@@ -36,7 +36,10 @@ Global / testFrameworks       := Seq(new TestFramework("zio.test.sbt.ZTestFramew
 
 addCommandAlias("fmt", "all scalafmtSbt scalafmt test:scalafmt")
 addCommandAlias("check", "all scalafmtSbtCheck scalafmtCheck test:scalafmtCheck")
-addCommandAlias("compileExamples", "opentracingExample/compile;opentelemetryExample/compile")
+addCommandAlias(
+  "compileExamples",
+  "opentracingExample/compile;opentelemetryExample/compile;opentelemetryInstrumentationExample/compile"
+)
 
 lazy val root =
   project
@@ -79,6 +82,19 @@ lazy val opentelemetryExample =
     .settings(libraryDependencies := Dependencies.opentelemetryExample)
     .dependsOn(opentelemetry)
 
+lazy val opentelemetryInstrumentationExample =
+  project
+    .in(file("opentelemetry-instrumentation-example"))
+    .settings(stdSettings("opentelemetry-instrumentation-example"))
+    .settings(publish / skip := true)
+    .settings(onlyWithScala2)
+    .settings(libraryDependencies := Dependencies.opentelemetryInstrumentationExample)
+    .dependsOn(opentelemetry)
+    .enablePlugins(JavaAgent)
+    .settings(
+      javaAgents += "io.opentelemetry.javaagent" % "opentelemetry-javaagent" % Dependencies.Versions.opentelemetry % "compile;runtime"
+    )
+
 lazy val docs =
   project
     .in(file("zio-telemetry-docs"))

docs/opentelemetry-instrumentation-example.md

@@ -0,0 +1,36 @@
+---
+id: opentelemetry-instrumentation-example
+title: "OpenTelemetry Automatic Instrumentation Example"
+---
+
+Firstly, start Jaeger by running the following command:
+```bash
+docker run --rm -it \
+  -p 16686:16686 \
+  -p 14250:14250 \
+  jaegertracing/all-in-one:1.36
+```
+
+Then start the server application
+```bash
+sbt -J-Dotel.service.name=example-server \
+    -J-Dotel.traces.exporter=jaeger \
+    -J-Dotel.exporter.jaeger.endpoint=http://localhost:14250 \
+    -J-Dotel.propagators=jaeger \
+    -J-Dotel.traces.sampler=always_on \ 
+    "opentelemetryInstrumentationExample/runMain zio.telemetry.opentelemetry.instrumentation.example.ServerApp"
+
+
+```
+
+and the client application which will send one request to the server application
+```bash
+sbt -J-Dotel.service.name=example-client \
+    -J-Dotel.traces.exporter=jaeger \
+    -J-Dotel.exporter.jaeger.endpoint=http://localhost:14250 \
+    -J-Dotel.propagators=jaeger \
+    -J-Dotel.traces.sampler=always_on \  
+    "opentelemetryInstrumentationExample/runMain zio.telemetry.opentelemetry.instrumentation.example.ClientApp"
+```
+
+Head over to [http://localhost:16686/](http://localhost:16686/) to see the result.

opentelemetry-instrumentation-example/src/main/resources/application.conf

@@ -0,0 +1,4 @@
+server {
+  host = "0.0.0.0"
+  port = 9000
+}

opentelemetry-instrumentation-example/src/main/scala/zio/telemetry/opentelemetry/instrumentation/example/ClientApp.scala

@@ -0,0 +1,27 @@
+package zio.telemetry.opentelemetry.instrumentation.example
+
+import sttp.client3.asynchttpclient.zio.AsyncHttpClientZioBackend
+import zio.config.magnolia.descriptor
+import zio.config.typesafe.TypesafeConfig
+import zio.telemetry.opentelemetry.instrumentation.example.config.AppConfig
+import zio._
+import zio.telemetry.opentelemetry.instrumentation.example.http.HttpClient
+
+object ClientApp extends ZIOAppDefault {
+
+  private val configLayer = TypesafeConfig.fromResourcePath(descriptor[AppConfig])
+
+  private val httpBackendLayer: TaskLayer[Backend] =
+    ZLayer.scoped {
+      ZIO.acquireRelease(AsyncHttpClientZioBackend())(_.close().ignore)
+    }
+
+  override def run: Task[ExitCode] =
+    ZIO
+      .serviceWithZIO[HttpClient](_.health.flatMap(r => Console.printLine(s"Health: $r")).exitCode)
+      .provide(
+        configLayer,
+        httpBackendLayer,
+        HttpClient.live
+      )
+}

opentelemetry-instrumentation-example/src/main/scala/zio/telemetry/opentelemetry/instrumentation/example/ServerApp.scala

@@ -0,0 +1,23 @@
+package zio.telemetry.opentelemetry.instrumentation.example
+
+import zio._
+import zio.config.typesafe.TypesafeConfig
+import zio.config.magnolia._
+import zio.telemetry.opentelemetry.instrumentation.example.config.AppConfig
+import zio.telemetry.opentelemetry.instrumentation.example.http.HttpServer
+import zio.telemetry.opentelemetry.context.ContextStorage
+
+object ServerApp extends ZIOAppDefault {
+
+  private val configLayer = TypesafeConfig.fromResourcePath(descriptor[AppConfig])
+
+  override def run: Task[ExitCode] =
+    ZIO
+      .serviceWithZIO[HttpServer](_.start.exitCode)
+      .provide(
+        configLayer,
+        HttpServer.live,
+        ContextStorage.fiberRef
+      )
+
+}

opentelemetry-instrumentation-example/src/main/scala/zio/telemetry/opentelemetry/instrumentation/example/config/AppConfig.scala

@@ -0,0 +1,3 @@
+package zio.telemetry.opentelemetry.instrumentation.example.config
+
+case class AppConfig(server: ServerConfig)

opentelemetry-instrumentation-example/src/main/scala/zio/telemetry/opentelemetry/instrumentation/example/config/ServerConfig.scala

@@ -0,0 +1,3 @@
+package zio.telemetry.opentelemetry.instrumentation.example.config
+
+case class ServerConfig(host: String, port: Int)

opentelemetry-instrumentation-example/src/main/scala/zio/telemetry/opentelemetry/instrumentation/example/http/HttpClient.scala

@@ -0,0 +1,32 @@
+package zio.telemetry.opentelemetry.instrumentation.example.http
+
+import sttp.client3._
+import sttp.model.Uri
+import zio._
+import zio.telemetry.opentelemetry.instrumentation.example.Backend
+import zio.telemetry.opentelemetry.instrumentation.example.config.AppConfig
+
+case class HttpClient(backend: Backend, config: AppConfig) {
+
+  private val backendUrl =
+    Uri
+      .safeApply(config.server.host, config.server.port)
+      .map(_.withPath("status"))
+      .left
+      .map(new IllegalArgumentException(_))
+
+  def health: Task[String] =
+    for {
+      url      <- ZIO.fromEither(backendUrl)
+      response <- backend.send(basicRequest.get(url.withPath("health")).response(asStringAlways))
+      result    = response.body
+    } yield result
+
+}
+
+object HttpClient {
+
+  val live: RLayer[AppConfig with Backend, HttpClient] =
+    ZLayer.fromFunction(HttpClient.apply _)
+
+}

opentelemetry-instrumentation-example/src/main/scala/zio/telemetry/opentelemetry/instrumentation/example/http/HttpServer.scala

@@ -0,0 +1,24 @@
+package zio.telemetry.opentelemetry.instrumentation.example.http
+
+import zio._
+import zhttp.service.Server
+import zio.Console.printLine
+import zio.telemetry.opentelemetry.instrumentation.example.config.AppConfig
+
+case class HttpServer(config: AppConfig) {
+
+  def start: ZIO[Any, Throwable, Nothing] =
+    for {
+      _     <- Server.start(config.server.port, HttpServerApp.routes)
+      _     <- printLine(s"HttpServer started on port ${config.server.port}")
+      never <- ZIO.never
+    } yield never
+
+}
+
+object HttpServer {
+
+  val live: URLayer[AppConfig, HttpServer] =
+    ZLayer.fromFunction(HttpServer.apply _)
+
+}

opentelemetry-instrumentation-example/src/main/scala/zio/telemetry/opentelemetry/instrumentation/example/http/HttpServerApp.scala

@@ -0,0 +1,13 @@
+package zio.telemetry.opentelemetry.instrumentation.example.http
+
+import zhttp.http._
+import zio.ZIO
+
+object HttpServerApp {
+
+  val routes: HttpApp[Any, Throwable] =
+    Http.collectZIO { case _ @Method.GET -> _ / "health" =>
+      ZIO.succeed(Response.ok)
+    }
+
+}

opentelemetry-instrumentation-example/src/main/scala/zio/telemetry/opentelemetry/instrumentation/example/package.scala

@@ -0,0 +1,12 @@
+package zio.telemetry.opentelemetry.instrumentation
+
+import sttp.capabilities.WebSockets
+import sttp.capabilities.zio.ZioStreams
+import sttp.client3.SttpBackend
+import zio.Task
+
+package object example {
+
+  type Backend = SttpBackend[Task, ZioStreams with WebSockets]
+
+}

project/Dependencies.scala

@@ -89,4 +89,10 @@ object Dependencies {
     Orgs.grpc          % "grpc-netty-shaded"             % ExampleVersions.grpcNetty
   )
 
+  lazy val opentelemetryInstrumentationExample = example ++ Seq(
+    Orgs.opentelemetry % "opentelemetry-exporter-jaeger" % Versions.opentelemetry,
+    Orgs.opentelemetry % "opentelemetry-sdk"             % Versions.opentelemetry,
+    Orgs.grpc          % "grpc-netty-shaded"             % ExampleVersions.grpcNetty
+  )
+
 }

project/plugins.sbt

@@ -7,6 +7,7 @@ addSbtPlugin("org.scalameta"                     % "sbt-scalafmt"     % "2.4.6")
 addSbtPlugin("org.scalameta"                     % "sbt-mdoc"         % "2.3.7")
 addSbtPlugin("org.scoverage"                     % "sbt-scoverage"    % "2.0.7")
 addSbtPlugin("dev.zio"                           % "zio-sbt-website"  % "0.3.10")
+addSbtPlugin("com.lightbend.sbt"                 % "sbt-javaagent"    % "0.1.6")
 
 libraryDependencies += "org.snakeyaml" % "snakeyaml-engine" % "2.6"