Trying to extract codegen plugin (#3521)

* Muzzle code generation moved to a separate plugin
* Restored old MuzzleCodeGenerationPlugin to use until the new one is published
* The simplest dependency management possible

Co-authored-by: Anuraag Agrawal <aanuraag@amazon.co.jp>

buildSrc/build.gradle.kts

@@ -27,6 +27,9 @@ dependencies {
   implementation(gradleApi())
   implementation(localGroovy())
 
+  //TODO start using this when separate codegen plugin is published
+//  implementation("io.opentelemetry.instrumentation.gradle:opentelemetry-codegen:1.4.0-alpha-SNAPSHOT")
+
   implementation("org.eclipse.aether:aether-connector-basic:1.1.0")
   implementation("org.eclipse.aether:aether-transport-http:1.1.0")
   implementation("org.apache.maven:maven-aether-provider:3.3.9")

buildSrc/src/main/kotlin/io.opentelemetry.instrumentation.javaagent-codegen.gradle.kts

@@ -7,6 +7,7 @@ plugins {
   `java-library`
 }
 
+//TODO remove this when separate codegen plugin is published
 /**
  * Starting from version 1.10.15, ByteBuddy gradle plugin transformation task autoconfiguration is
  * hardcoded to be applied to javaCompile task. This causes the dependencies to be resolved during

buildSrc/src/main/kotlin/io.opentelemetry.instrumentation.javaagent-instrumentation.gradle.kts

@@ -1,6 +1,7 @@
 plugins {
   id("io.opentelemetry.instrumentation.javaagent-testing")
   id("io.opentelemetry.instrumentation.muzzle-check")
+  id("io.opentelemetry.instrumentation.javaagent-codegen")
 }
 
 dependencies {

buildSrc/src/main/kotlin/io.opentelemetry.instrumentation.javaagent-testing.gradle.kts

@@ -30,9 +30,7 @@ dependencies {
 
   testImplementation("io.opentelemetry.javaagent:opentelemetry-testing-common")
 
-  add("codegen", "io.opentelemetry.javaagent:opentelemetry-javaagent-bootstrap")
   add("codegen", "io.opentelemetry.javaagent:opentelemetry-javaagent-tooling")
-  add("codegen", "io.opentelemetry.javaagent:opentelemetry-javaagent-extension-api")
 }
 
 val testInstrumentation by configurations.creating {

buildSrc/src/main/kotlin/io/opentelemetry/instrumentation/gradle/codegen/ClasspathByteBuddyPlugin.kt

@@ -20,6 +20,7 @@ import java.net.URLClassLoader
  * by taking a delegate class name and class path as arguments and loading the plugin class from the
  * provided classloader when the plugin is instantiated.
  */
+//TODO remove together with io.opentelemetry.instrumentation.javaagent-codegen.gradle
 class ClasspathByteBuddyPlugin(
   classPath: Iterable<File>, sourceDirectory: File, className: String
 ) : Plugin {

buildSrc/src/main/kotlin/io/opentelemetry/instrumentation/gradle/codegen/ClasspathTransformation.kt

@@ -15,6 +15,7 @@ import java.io.File
  * exposed to Gradle via [Classpath] annotation, which cannot be done if it is returned by
  * [Transformation.getArguments].
  */
+//TODO remove together with io.opentelemetry.instrumentation.javaagent-codegen.gradle
 class ClasspathTransformation(
   @get:Classpath val classpath: Iterable<File>,
   @get:Input val pluginClassName: String

buildSrc/src/main/kotlin/otel.java-conventions.gradle.kts

@@ -285,6 +285,7 @@ configurations.configureEach {
       substitute(module("io.opentelemetry.javaagent:opentelemetry-javaagent-tooling")).using(project(":javaagent-tooling"))
       substitute(module("io.opentelemetry.javaagent:opentelemetry-agent-for-testing")).using(project(":testing:agent-for-testing"))
       substitute(module("io.opentelemetry.javaagent:opentelemetry-testing-common")).using(project(":testing-common"))
+      substitute(module("io.opentelemetry.javaagent:opentelemetry-muzzle")).using(project(":muzzle"))
     }
 
     // The above substitutions ensure dependencies managed by this BOM for external projects refer to this repo's projects here.

buildSrc/src/main/kotlin/otel.spotless-conventions.gradle.kts

@@ -20,6 +20,9 @@ spotless {
     // ktfmt() // only supports 4 space indentation
     ktlint().userData(mapOf("indent_size" to "2", "continuation_indent_size" to "2"))
     licenseHeaderFile(rootProject.file("gradle/enforcement/spotless.license.java"), "(package|import|public)")
+    targetExclude(
+      "src/main/kotlin/io.opentelemetry.instrumentation.javaagent-codegen.gradle.kts",
+      "build/**")
   }
   format("misc") {
     // not using "**/..." to help keep spotless fast

dependencyManagement/build.gradle.kts

@@ -58,7 +58,7 @@ val DEPENDENCY_SETS = listOf(
     "net.bytebuddy",
     // When updating, also update buildSrc/build.gradle.kts
     "1.11.2",
-    listOf("byte-buddy", "byte-buddy-agent")
+    listOf("byte-buddy", "byte-buddy-agent", "byte-buddy-gradle-plugin")
   ),
   DependencySet(
     "org.mockito",

docs/contributing/muzzle.md

@@ -44,7 +44,7 @@ and is shared between all type instrumentations. The bytecode of this method (ba
 ByteBuddy plugin using an ASM code visitor.
 
 The source code of the compile-time plugin is located in the `javaagent-tooling` module,
-package `io.opentelemetry.javaagent.tooling.muzzle.collector`.
+package `io.opentelemetry.javaagent.muzzle.generation.collector`.
 
 ### Runtime reference matching
 

examples/extension/build.gradle

@@ -11,6 +11,8 @@ plugins {
   See https://imperceptiblethoughts.com/shadow/ for more details about Shadow plugin.
    */
   id "com.github.johnrengelman.shadow" version "6.1.0"
+
+  id "io.opentelemetry.instrumentation.javaagent-codegen" version "0.1.0"
 }
 
 group 'io.opentelemetry.example'

examples/extension/gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

examples/extension/settings.gradle

@@ -1 +1,8 @@
+pluginManagement {
+  repositories {
+    gradlePluginPortal()
+    mavenLocal()
+  }
+}
+
 rootProject.name = 'opentelemetry-java-instrumentation-extension-demo'

gradle-plugins/build.gradle.kts

@@ -0,0 +1,27 @@
+plugins {
+  `kotlin-dsl`
+  `maven-publish`
+
+  id("com.gradle.plugin-publish")
+}
+
+group = "io.opentelemetry.instrumentation.gradle"
+version = "0.1.0"
+
+repositories {
+  mavenCentral()
+  mavenLocal()
+}
+
+dependencies {
+  implementation("com.google.guava:guava:30.1.1-jre")
+  implementation("net.bytebuddy:byte-buddy-gradle-plugin:1.11.2")
+  implementation("io.opentelemetry.javaagent:opentelemetry-muzzle:1.4.0-alpha-SNAPSHOT")
+  implementation("io.opentelemetry.javaagent:opentelemetry-javaagent-extension-api:1.4.0-alpha-SNAPSHOT")
+}
+
+pluginBundle {
+  website = "https://opentelemetry.io"
+  vcsUrl = "https://github.com/open-telemetry/opentelemetry-java-instrumentation"
+  tags = listOf("opentelemetry", "instrumentation")
+}

gradle-plugins/settings.gradle.kts

@@ -0,0 +1,6 @@
+pluginManagement {
+  plugins {
+    id("com.gradle.plugin-publish") version "0.15.0"
+    id("org.jetbrains.kotlin.jvm") version "1.5.10"
+  }
+}

gradle-plugins/src/main/java/io/opentelemetry/javaagent/muzzle/generation/AdviceClassNameCollector.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.muzzle.generation;
+
+import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
+import java.util.HashSet;
+import java.util.Set;
+import net.bytebuddy.agent.builder.AgentBuilder;
+import net.bytebuddy.description.method.MethodDescription;
+import net.bytebuddy.matcher.ElementMatcher;
+
+final class AdviceClassNameCollector implements TypeTransformer {
+  private final Set<String> adviceClassNames = new HashSet<>();
+
+  @Override
+  public void applyAdviceToMethod(
+      ElementMatcher<? super MethodDescription> methodMatcher, String adviceClassName) {
+    adviceClassNames.add(adviceClassName);
+  }
+
+  @Override
+  public void applyTransformer(AgentBuilder.Transformer transformer) {}
+
+  Set<String> getAdviceClassNames() {
+    return adviceClassNames;
+  }
+}

gradle-plugins/src/main/java/io/opentelemetry/javaagent/muzzle/generation/MuzzleCodeGenerationPlugin.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.muzzle.generation;
+
+import io.opentelemetry.javaagent.extension.instrumentation.InstrumentationModule;
+import java.net.URLClassLoader;
+import net.bytebuddy.build.Plugin;
+import net.bytebuddy.description.type.TypeDefinition;
+import net.bytebuddy.description.type.TypeDescription;
+import net.bytebuddy.dynamic.ClassFileLocator;
+import net.bytebuddy.dynamic.DynamicType;
+
+/**
+ * This class is a ByteBuddy build plugin that is responsible for generating actual implementation
+ * of some {@link InstrumentationModule} methods. Auto-generated methods have the word "muzzle" in
+ * their names.
+ *
+ * <p>This class is used in the gradle build scripts, referenced by each instrumentation module.
+ */
+public final class MuzzleCodeGenerationPlugin implements Plugin {
+
+  private static final TypeDescription instrumentationModuleType =
+      new TypeDescription.ForLoadedType(InstrumentationModule.class);
+
+  private final URLClassLoader classLoader;
+
+  public MuzzleCodeGenerationPlugin(URLClassLoader classLoader) {
+    this.classLoader = classLoader;
+  }
+
+  @Override
+  public boolean matches(TypeDescription target) {
+    if (target.isAbstract()) {
+      return false;
+    }
+    boolean isInstrumentationModule = false;
+    TypeDefinition instrumentation = target.getSuperClass();
+    while (instrumentation != null) {
+      if (instrumentation.equals(instrumentationModuleType)) {
+        isInstrumentationModule = true;
+        break;
+      }
+      instrumentation = instrumentation.getSuperClass();
+    }
+    return isInstrumentationModule;
+  }
+
+  @Override
+  public DynamicType.Builder<?> apply(
+      DynamicType.Builder<?> builder,
+      TypeDescription typeDescription,
+      ClassFileLocator classFileLocator) {
+    return builder.visit(new MuzzleCodeGenerator(classLoader));
+  }
+
+  @Override
+  public void close() {}
+}