feat: add pekko-grpc instrumentation

build.sbt

@@ -139,6 +139,7 @@ val instrumentationProjects = Seq[ProjectReference](
   `kamon-akka-grpc`,
   `kamon-pekko`,
   `kamon-pekko-http`,
+  `kamon-pekko-grpc`,
   `kamon-play`,
   `kamon-okhttp`,
   `kamon-tapir`,
@@ -526,6 +527,31 @@ lazy val `kamon-pekko-http` = (project in file("instrumentation/kamon-pekko-http
     ),
   )).dependsOn(`kamon-pekko`, `kamon-testkit` % "test")
 
+lazy val `kamon-pekko-grpc` = (project in file("instrumentation/kamon-pekko-grpc"))
+  .enablePlugins(JavaAgent, PekkoGrpcPlugin)
+  .disablePlugins(AssemblyPlugin)
+  .settings(instrumentationSettings)
+  .settings(Seq(
+    PB.additionalDependencies := Seq.empty,
+    crossScalaVersions := Seq(`scala_2.12_version`, `scala_2.13_version`),
+    libraryDependencies ++= Seq(
+      kanelaAgent % "provided",
+
+      "org.apache.pekko" %% "pekko-http" % pekkoHttpVersion % "provided",
+      "org.apache.pekko" %% "pekko-stream" % "1.0.1" % "provided",
+      "org.apache.pekko" %% "pekko-discovery"% "1.0.0" % "provided",
+
+      "com.thesamet.scalapb"    %% "scalapb-runtime"   % "0.11.8" % "provided",
+      "org.apache.pekko"        %% "pekko-grpc-runtime" % "1.0.0" % "provided",
+      "io.grpc"                 %  "grpc-stub"         % "1.43.2" % "provided",
+
+
+      scalatest % "test",
+      slf4jApi % "test",
+      logbackClassic % "test",
+    )
+  )).dependsOn(`kamon-pekko-http`, `kamon-testkit` % "test")
+
 lazy val `kamon-akka-grpc` = (project in file("instrumentation/kamon-akka-grpc"))
   .enablePlugins(JavaAgent, AkkaGrpcPlugin)
   .disablePlugins(AssemblyPlugin)
@@ -998,6 +1024,7 @@ lazy val `kamon-bundle-dependencies-2-12-and-up` = (project in file("bundle/kamo
     `kamon-finagle`,
     `kamon-pekko`,
     `kamon-pekko-http`,
+    `kamon-pekko-grpc`,
     `kamon-tapir`,
     `kamon-alpakka-kafka`
   )

instrumentation/kamon-pekko-grpc/src/main/java/kamon/instrumentation/pekko/grpc/PekkoGRPCUnmarshallingContextPropagation.java

@@ -0,0 +1,49 @@
+package kamon.instrumentation.pekko.grpc;
+
+import org.apache.pekko.http.javadsl.model.HttpEntity;
+import kamon.Kamon;
+import kamon.context.Context;
+import kanela.agent.libs.net.bytebuddy.asm.Advice;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+import java.util.function.Function;
+
+public class PekkoGRPCUnmarshallingContextPropagation {
+
+  @Advice.OnMethodExit()
+  public static void onExit(
+      @Advice.Return(readOnly = false) CompletionStage<?> returnValue,
+      @Advice.Argument(0) Object firstArgument) {
+
+    if(firstArgument instanceof HttpEntity && returnValue instanceof CompletableFuture) {
+      final Context currentContext = Kamon.currentContext();
+
+      // NOTES: The wrapper is only overriding thenCompose because it is the only function that gets called
+      //        after GrpcMarshalling.unmarshall in the auto-generated HandlerFactory for gRPC services. In
+      //        the future this might be removed if we instrument CompletionStage directly.
+      returnValue = new ContextPropagatingCompletionStage<>((CompletableFuture) returnValue, currentContext);
+    }
+  }
+
+
+  public static class ContextPropagatingCompletionStage<T> extends CompletableFuture<T> {
+    private final CompletableFuture<T> wrapped;
+    private final Context context;
+
+    public ContextPropagatingCompletionStage(CompletableFuture<T> wrapped, Context context) {
+      this.wrapped = wrapped;
+      this.context = context;
+    }
+
+    @Override
+    public <U> CompletableFuture<U> thenCompose(Function<? super T, ? extends CompletionStage<U>> fn) {
+      Function<? super T, ? extends CompletionStage<U>> wrapperFunction = (t) -> {
+        return Kamon.runWithContext(context, () -> fn.apply(t));
+      };
+
+      return wrapped.thenCompose(wrapperFunction);
+    }
+  }
+
+}

instrumentation/kamon-pekko-grpc/src/main/resources/reference.conf

@@ -0,0 +1,20 @@
+# ======================================= #
+# Kamon-Pekko-gRPC Reference Configuration #
+# ======================================= #
+
+kanela.modules {
+  pekko-grpc {
+    name = "Pekko gRPC Instrumentation"
+    description = "Context propagation and tracing for Pekko gRPC"
+    enabled = yes
+
+    instrumentations = [
+      "kamon.instrumentation.pekko.grpc.PekkoGrpcServerInstrumentation"
+    ]
+
+    within = [
+      "^org.apache.pekko.grpc.internal..*",
+      "^org.apache.pekko.grpc.scaladsl.GrpcMarshalling$"
+    ]
+  }
+}

instrumentation/kamon-pekko-grpc/src/main/scala/kamon/instrumentation/pekko/grpc/PekkoGrpcServerInstrumentation.scala

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2013-2021 The Kamon Project <https://kamon.io>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kamon.instrumentation.pekko.grpc
+
+import kamon.Kamon
+import kanela.agent.api.instrumentation.InstrumentationBuilder
+import kanela.agent.libs.net.bytebuddy.asm.Advice
+
+class PekkoGrpcServerInstrumentation extends InstrumentationBuilder {
+
+  /**
+    * Support for Pekko gRPC servers.
+    *
+    * gRPC requests get their spans started by the ServerFlowWrapper in the Pekko HTTP instrumentation like any other
+    * requests, but they never go through any instrumentation that gives a good operation name to the Span and forces
+    * taking a sampling decision.
+    *
+    * This instrumentation gives a proper name and tags to the span when it matches one of the exposed services,
+    * otherwise the span remains unchanged. Assumes no actual implementation of `pekko.grpc.internal.TelemetrySpi` is
+    * configured.
+    */
+  onType("org.apache.pekko.grpc.internal.NoOpTelemetry$")
+    .advise(method("onRequest"), PekkoGRPCServerRequestHandler)
+
+
+  onType("org.apache.pekko.grpc.scaladsl.GrpcMarshalling")
+    .advise(method("unmarshal"), classOf[PekkoGRPCUnmarshallingContextPropagation])
+}
+
+object PekkoGRPCServerRequestHandler {
+
+  @Advice.OnMethodEnter()
+  def enter(@Advice.Argument(0) serviceName: String, @Advice.Argument(1) method: String): Unit = {
+    val fullSpanName = serviceName + "/" + method
+    Kamon.currentSpan()
+      .name(fullSpanName)
+      .tagMetrics("component", "pekko.grpc.server")
+      .tagMetrics("rpc.system", "grpc")
+      .tagMetrics("rpc.service", serviceName)
+      .tagMetrics("rpc.method", method)
+      .takeSamplingDecision()
+  }
+}

instrumentation/kamon-pekko-grpc/src/test/protobuf/helloworld.proto

@@ -0,0 +1,41 @@
+syntax = "proto3";
+
+option java_multiple_files = true;
+option java_package = "kamon.instrumentation.pekko.grpc";
+option java_outer_classname = "HelloWorldProto";
+
+package helloworld;
+
+////////////////////////////////////// The greeting service definition.
+service GreeterService {
+  //////////////////////
+  // Sends a greeting //
+  ////////*****/////////
+  //      HELLO       //
+  ////////*****/////////
+  rpc SayHello (HelloRequest) returns (HelloReply) {}
+
+  // Comment spanning
+  // on several lines
+  rpc ItKeepsTalking (stream HelloRequest) returns (HelloReply) {}
+
+  /*
+   * C style comments
+   */
+  rpc ItKeepsReplying (HelloRequest) returns (stream HelloReply) {}
+
+  /* C style comments
+   * on several lines
+   * with non-empty heading/trailing line */
+  rpc StreamHellos (stream HelloRequest) returns (stream HelloReply) {}
+}
+
+// The request message containing the user's name.
+message HelloRequest {
+  string name = 1;
+}
+
+// The response message containing the greetings
+message HelloReply {
+  string message = 1;
+}

instrumentation/kamon-pekko-grpc/src/test/resources/application.conf

@@ -0,0 +1 @@
+pekko.http.server.preview.enable-http2 = on

instrumentation/kamon-pekko-grpc/src/test/resources/logback.xml

@@ -0,0 +1,12 @@
+<configuration>
+    <statusListener class="ch.qos.logback.core.status.NopStatusListener"/>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT"/>
+    </root>
+</configuration>

instrumentation/kamon-pekko-grpc/src/test/scala/kamon/instrumentation/pekko/grpc/GreeterServiceImpl.scala

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2013-2021 The Kamon Project <https://kamon.io>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kamon.instrumentation.pekko.grpc
+
+import scala.concurrent.Future
+import org.apache.pekko.NotUsed
+import org.apache.pekko.stream.Materializer
+import org.apache.pekko.stream.scaladsl.Sink
+import org.apache.pekko.stream.scaladsl.Source
+
+
+class GreeterServiceImpl(implicit mat: Materializer) extends GreeterService {
+  import mat.executionContext
+
+  override def sayHello(in: HelloRequest): Future[HelloReply] = {
+    Future.successful(HelloReply(s"Hello, ${in.name}"))
+  }
+
+  override def itKeepsTalking(in: Source[HelloRequest, NotUsed]): Future[HelloReply] = {
+    in.runWith(Sink.seq).map(elements => HelloReply(s"Hello, ${elements.map(_.name).mkString(", ")}"))
+  }
+
+  override def itKeepsReplying(in: HelloRequest): Source[HelloReply, NotUsed] = {
+    Source(s"Hello, ${in.name}".toList).map(character => HelloReply(character.toString))
+  }
+
+  override def streamHellos(in: Source[HelloRequest, NotUsed]): Source[HelloReply, NotUsed] = {
+    in.map(request => HelloReply(s"Hello, ${request.name}"))
+  }
+}

instrumentation/kamon-pekko-grpc/src/test/scala/kamon/instrumentation/pekko/grpc/PekkoGrpcTracingSpec.scala

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2013-2021 The Kamon Project <https://kamon.io>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kamon.instrumentation.pekko.grpc
+
+import org.apache.pekko.actor.ActorSystem
+import org.apache.pekko.grpc.GrpcClientSettings
+import org.apache.pekko.http.scaladsl.Http
+import kamon.tag.Lookups.plain
+import kamon.testkit.{InitAndStopKamonAfterAll, TestSpanReporter}
+import org.scalatest.OptionValues
+import org.scalatest.concurrent.Eventually
+import org.scalatest.matchers.should.Matchers
+import org.scalatest.wordspec.AnyWordSpec
+
+import scala.concurrent.duration._
+
+class PekkoGrpcTracingSpec extends AnyWordSpec with InitAndStopKamonAfterAll with Matchers with Eventually
+    with TestSpanReporter with OptionValues {
+
+  implicit val system = ActorSystem("pekko-grpc-instrumentation")
+  implicit val ec = system.dispatcher
+
+  val greeterService = GreeterServiceHandler(new GreeterServiceImpl())
+  val serverBinding = Http()
+    .newServerAt("127.0.0.1", 8598)
+    .bind(greeterService)
+
+
+  val client = GreeterServiceClient(GrpcClientSettings.connectToServiceAt("127.0.0.1", 8598).withTls(false))
+
+  "the Pekko gRPC instrumentation" should {
+    "create spans for the server-side" in {
+      client.sayHello(HelloRequest("kamon"))
+
+      eventually(timeout(5 seconds)) {
+        val span = testSpanReporter().nextSpan().value
+        span.operationName shouldBe "helloworld.GreeterService/SayHello"
+        span.metricTags.get(plain("component")) shouldBe "pekko.grpc.server"
+        span.metricTags.get(plain("rpc.system")) shouldBe "grpc"
+        span.metricTags.get(plain("rpc.service")) shouldBe "helloworld.GreeterService"
+        span.metricTags.get(plain("rpc.method")) shouldBe "SayHello"
+      }
+    }
+  }
+
+  override protected def beforeAll(): Unit = {
+    super.beforeAll()
+    enableFastSpanFlushing()
+  }
+}

project/plugins.sbt

@@ -14,3 +14,4 @@ addSbtPlugin("com.jsuereth" % "sbt-pgp" % "2.0.1")
 addSbtPlugin("de.heikoseeberger" % "sbt-header" % "5.5.0")
 
 addSbtPlugin("com.lightbend.akka.grpc" % "sbt-akka-grpc" % "2.1.3")
+addSbtPlugin("org.apache.pekko" % "pekko-grpc-sbt-plugin" % "1.0.0")