Add Scala concurrent plugin

.java-version

@@ -0,0 +1 @@
+9

apm-agent-plugins/apm-java-concurrent-plugin/pom.xml

@@ -36,4 +36,21 @@
         </dependency>
     </dependencies>
 
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.2.0</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>test-jar</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
 </project>

apm-agent-plugins/apm-scala-concurrent-plugin/pom.xml

@@ -0,0 +1,92 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <artifactId>apm-agent-plugins</artifactId>
+        <groupId>co.elastic.apm</groupId>
+        <version>1.15.1-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>apm-scala-concurrent-plugin</artifactId>
+    <name>${project.groupId}:${project.artifactId}</name>
+
+    <properties>
+        <apm-agent-parent.base.dir>${project.basedir}/../..</apm-agent-parent.base.dir>
+        <maven.compiler.target>9</maven.compiler.target>
+        <maven.compiler.testTarget>9</maven.compiler.testTarget>
+    </properties>
+
+    <dependencies>
+<!--        <dependency>-->
+<!--            <groupId>${project.groupId}</groupId>-->
+<!--            <artifactId>apm-java-concurrent-plugin</artifactId>-->
+<!--            <version>${project.version}</version>-->
+<!--            <scope>test</scope>-->
+<!--        </dependency>-->
+<!--        <dependency>-->
+<!--            <groupId>${project.groupId}</groupId>-->
+<!--            <artifactId>apm-java-concurrent-plugin</artifactId>-->
+<!--            <version>${project.version}</version>-->
+<!--            <type>test-jar</type>-->
+<!--            <scope>test</scope>-->
+<!--        </dependency>-->
+        <dependency>
+            <groupId>org.scalatest</groupId>
+            <artifactId>scalatest_2.13</artifactId>
+            <version>3.1.1</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <testSourceDirectory>src/test/scala</testSourceDirectory>
+        <plugins>
+            <plugin>
+                <groupId>net.alchim31.maven</groupId>
+                <artifactId>scala-maven-plugin</artifactId>
+                <version>4.3.1</version>
+                <configuration>
+                    <scalaVersion>2.13.1</scalaVersion>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>scala-test-compile</id>
+                        <phase>process-test-resources</phase>
+                        <goals>
+                            <goal>testCompile</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <!-- disable surefire -->
+            <plugin>
+              <groupId>org.apache.maven.plugins</groupId>
+              <artifactId>maven-surefire-plugin</artifactId>
+              <version>2.22.2</version>
+              <configuration>
+                <skipTests>true</skipTests>
+              </configuration>
+            </plugin>
+            <!-- enable scalatest -->
+            <plugin>
+                <groupId>org.scalatest</groupId>
+                <artifactId>scalatest-maven-plugin</artifactId>
+                <version>2.0.0</version>
+                <configuration>
+                    <reportsDirectory>${project.build.directory}/surefire-reports</reportsDirectory>
+                    <stdout>W</stdout>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>scala-test</id>
+                        <goals>
+                            <goal>test</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

apm-agent-plugins/apm-scala-concurrent-plugin/src/main/java/co/elastic/apm/agent/scala/concurrent/FutureInstrumentation.java

@@ -0,0 +1,66 @@
+/*-
+ * #%L
+ * Elastic APM Java agent
+ * %%
+ * Copyright (C) 2018 - 2020 Elastic and contributors
+ * %%
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you 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.
+ * #L%
+ */
+package co.elastic.apm.agent.scala.concurrent;
+
+import co.elastic.apm.agent.bci.ElasticApmInstrumentation;
+import co.elastic.apm.agent.bci.VisibleForAdvice;
+import net.bytebuddy.asm.Advice;
+import net.bytebuddy.description.method.MethodDescription;
+import net.bytebuddy.description.type.TypeDescription;
+import net.bytebuddy.matcher.ElementMatcher;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static net.bytebuddy.matcher.ElementMatchers.*;
+
+public class FutureInstrumentation extends ElasticApmInstrumentation {
+
+    @Override
+    public ElementMatcher<? super TypeDescription> getTypeMatcher() {
+        return hasSuperType(named("scala.concurrent.Future"))
+            .or(hasSuperType(named("scala.concurrent.impl.Promise")))
+            .or(hasSuperType(named("scala.concurrent.impl.Promise$Transformation")))
+            .or(hasSuperType(named("scala.concurrent.Future$")));
+    }
+
+    @Override
+    public ElementMatcher<? super MethodDescription> getMethodMatcher() {
+        return named("onComplete").and(returns(void.class))
+            .or(named("transform").and(returns(named("scala.concurrent.Future"))))
+            .or(named("transformWith").and(returns(named("scala.concurrent.Future"))))
+            .or(named("result"));
+    }
+
+    @Override
+    public Collection<String> getInstrumentationGroupNames() {
+        return Arrays.asList("concurrent", "future");
+    }
+
+    @VisibleForAdvice
+    @Advice.OnMethodEnter(suppress = Throwable.class)
+    public static void test() {}
+
+}

apm-agent-plugins/apm-scala-concurrent-plugin/src/main/resources/META-INF/services/co.elastic.apm.agent.bci.ElasticApmInstrumentation

@@ -0,0 +1 @@
+co.elastic.apm.agent.scala.concurrent.FutureInstrumentation

apm-agent-plugins/apm-scala-concurrent-plugin/src/test/scala/co/elastic/apm/agent/scala/concurrent/FutureInstrumentationSpec.scala

@@ -0,0 +1,91 @@
+package co.elastic.apm.agent.scala.concurrent
+
+import java.util.concurrent.Executors
+
+import co.elastic.apm.agent.MockReporter
+import co.elastic.apm.agent.bci.ElasticApmAgent
+import co.elastic.apm.agent.configuration.{CoreConfiguration, SpyConfiguration}
+import co.elastic.apm.agent.impl.transaction.Transaction
+import co.elastic.apm.agent.impl.{ElasticApmTracer, ElasticApmTracerBuilder}
+import net.bytebuddy.agent.ByteBuddyAgent
+import org.scalatest.BeforeAndAfterEach
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+import org.stagemonitor.configuration.ConfigurationRegistry
+
+import scala.concurrent.duration._
+import scala.concurrent.{Await, ExecutionContext, ExecutionContextExecutor, Future}
+
+class FutureInstrumentationSpec extends AnyFlatSpec with Matchers with BeforeAndAfterEach {
+
+  implicit def executionContext: ExecutionContextExecutor =
+    ExecutionContext.fromExecutor(Executors.newFixedThreadPool(1))
+
+  private var reporter: MockReporter = _
+  private var tracer: ElasticApmTracer = _
+  private var coreConfiguration: CoreConfiguration = _
+  private var transaction: Transaction = _
+
+  override def beforeEach: Unit = {
+    reporter = new MockReporter
+    val config: ConfigurationRegistry = SpyConfiguration.createSpyConfig
+    coreConfiguration = config.getConfig(classOf[CoreConfiguration])
+    tracer = new ElasticApmTracerBuilder().configurationRegistry(config).reporter(reporter).build
+    ElasticApmAgent.initInstrumentation(tracer, ByteBuddyAgent.install)
+    transaction = tracer.startRootTransaction(null).withName("Transaction").activate()
+  }
+
+  override def afterEach: Unit = {
+    transaction.deactivate().end()
+    ElasticApmAgent.reset()
+  }
+
+  "test" should "test" in {
+    new TestFutureTraceMethods().invokeAsync()
+    reporter.getTransactions should have size 1
+  }
+
+  private class TestFutureTraceMethods {
+
+    /**
+     * Calling this method results in this method call tree:
+     *
+     *                      main thread                         |           worker thread
+     * -------------------------------------------------------------------------------------------
+     * invokeAsync                                              |
+     *      |                                                   |
+     *      --- blockingMethodOnMainThread                      |
+     *                     |                                    |
+     *                     --- nonBlockingMethodOnMainThread    |
+     *                                      |                   |
+     *                                      --------------------------> methodOnWorkerThread
+     *                                                          |                |
+     *                                                          |                --- longMethod
+     *                                                          |
+     */
+    def invokeAsync(): Unit = blockingMethodOnMainThread()
+
+    private def blockingMethodOnMainThread(): Unit = {
+      try {
+        Await.result(nonBlockingMethodOnMainThread(), 10.seconds)
+      } catch {
+        case e: Exception => e.printStackTrace()
+      }
+    }
+
+    private def nonBlockingMethodOnMainThread(): Future[Unit] =
+      Future(methodOnWorkerThread())
+
+    private def methodOnWorkerThread(): Unit = longMethod()
+
+    private def longMethod(): Unit = {
+      try {
+        Thread.sleep(100)
+      } catch {
+        case e: InterruptedException => e.printStackTrace()
+      }
+    }
+
+  }
+
+}

apm-agent-plugins/pom.xml

@@ -40,6 +40,7 @@
         <module>apm-jms-plugin</module>
         <module>apm-hibernate-search-plugin</module>
         <module>apm-redis-plugin</module>
+        <module>apm-scala-concurrent-plugin</module>
         <module>apm-error-logging-plugin</module>
         <module>apm-jmx-plugin</module>
         <module>apm-mule4-plugin</module>