Add classloader exclusions for drools generated classes (#11191)

# What Does This Do

Excludes in `ClassloaderMatchers` the most commonly used drools classloaders used to load dynamically generated classes from rules.

This is usually done by `PackageClassloader`. I added a list of commonly used classloaders (hoping that does not overload too much the matchers) and a test module inside instrumentations to test 6.x, 7.x, 8.x and 10.x

# Motivation

# Additional Notes

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Co-authored-by: andrea.marziali <andrea.marziali@datadoghq.com>

Author: amarziali

dd-java-agent/agent-tooling/src/main/java/datadog/trace/agent/tooling/bytebuddy/matcher/ClassLoaderMatchers.java

@@ -54,6 +54,10 @@ public static boolean canSkipClassLoaderByName(final ClassLoader loader) {
       case "com.alibaba.fastjson.util.ASMClassLoader":
       case "datadog.trace.bootstrap.DatadogClassLoader":
       case "datadog.trace.bootstrap.InstrumentationClassLoader":
+      // drools
+      case "org.drools.core.rule.PackageClassLoader":
+      case "org.drools.wiring.dynamic.PackageClassLoader":
+      case "org.drools.core.rule.JavaDialectRuntimeData$PackageClassLoader":
         return true;
     }
     if (CHECK_EXCLUDES) {

dd-java-agent/agent-tooling/src/test/groovy/datadog/trace/agent/test/ClassLoaderMatchersTest.groovy

@@ -5,6 +5,9 @@ import datadog.trace.bootstrap.instrumentation.log.LogContextScopeListener
 import datadog.trace.bootstrap.DatadogClassLoader
 import datadog.trace.test.util.DDSpecification
 import groovy.transform.CompileStatic
+import net.bytebuddy.ByteBuddy
+import net.bytebuddy.dynamic.loading.ClassLoadingStrategy
+import spock.lang.Unroll
 
 class ClassLoaderMatchersTest extends DDSpecification {
 
@@ -44,6 +47,29 @@ class ClassLoaderMatchersTest extends DDSpecification {
     LogContextScopeListener.name == "datadog.trace.bootstrap.instrumentation.log.LogContextScopeListener"
   }
 
+  @Unroll
+  def "skips drools classloader: #loaderName"() {
+    given:
+    ClassLoader loader = new ByteBuddy()
+      .subclass(ClassLoader)
+      .name(loaderName)
+      .make()
+      .load(ClassLoader.getSystemClassLoader(), ClassLoadingStrategy.Default.WRAPPER)
+      .getLoaded()
+      .getDeclaredConstructor(ClassLoader)
+      .newInstance(ClassLoader.getSystemClassLoader())
+
+    expect:
+    ClassLoaderMatchers.canSkipClassLoaderByName(loader)
+
+    where:
+    loaderName << [
+      "org.drools.core.rule.PackageClassLoader",
+      "org.drools.wiring.dynamic.PackageClassLoader",
+      "org.drools.core.rule.JavaDialectRuntimeData\$PackageClassLoader"
+    ]
+  }
+
   /*
    * A URLClassloader which only delegates java.* classes
    */

dd-java-agent/instrumentation/drools/drools-6.0/build.gradle

@@ -0,0 +1,80 @@
+apply from: "$rootDir/gradle/java.gradle"
+
+addTestSuiteForDir("latest7Test", "test")
+addTestSuiteForDir("latest8Test", "test")
+addTestSuiteForDir("latestDepTest", "test")
+
+testJvmConstraints {
+}
+repositories {
+  maven {
+    url = uri("https://repository.jboss.org/nexus/content/repositories/releases/")
+  }
+}
+dependencies {
+  testImplementation project(':dd-java-agent:testing')
+  testImplementation group: 'org.drools', name: 'drools-compiler', version: '6.0.0.Final'
+  testImplementation group: 'org.drools', name: 'drools-core', version: '6.0.0.Final'
+  testImplementation group: 'org.kie', name: 'kie-api', version: '6.0.0.Final'
+
+  latest7TestImplementation group: 'org.drools', name: 'drools-compiler', version: '7.+'
+  latest7TestImplementation group: 'org.drools', name: 'drools-core', version: '7.+'
+  latest7TestImplementation group: 'org.drools', name: 'drools-mvel', version: '7.+'
+  latest7TestImplementation group: 'org.kie', name: 'kie-api', version: '7.+'
+
+  latest8TestImplementation group: 'org.drools', name: 'drools-compiler', version: '8.+'
+  latest8TestImplementation group: 'org.drools', name: 'drools-core', version: '8.+'
+  latest8TestImplementation group: 'org.drools', name: 'drools-mvel', version: '8.+'
+  latest8TestImplementation group: 'org.kie', name: 'kie-api', version: '8.+'
+
+  // for now this is locked to 10.x not to add maintenance burden
+  latestDepTestImplementation group: 'org.drools', name: 'drools-compiler', version: '10.+'
+  latestDepTestImplementation group: 'org.drools', name: 'drools-core', version: '10.+'
+  latestDepTestImplementation group: 'org.drools', name: 'drools-mvel', version: '10.+'
+  latestDepTestImplementation group: 'org.kie', name: 'kie-api', version: '10.+'
+}
+
+configurations.matching { it.name.startsWith('latestDepTest') }.configureEach {
+  it.resolutionStrategy {
+    force group: 'org.slf4j', name: 'slf4j-api', version: libs.versions.slf4j.get()
+  }
+}
+
+tasks.named("test") {
+  testJvmConstraints {
+    maxJavaVersion = JavaVersion.VERSION_1_8
+  }
+}
+
+tasks.named("latest7Test") {
+  testJvmConstraints {
+    maxJavaVersion = JavaVersion.VERSION_11
+  }
+}
+
+tasks.named("latest8Test") {
+  testJvmConstraints {
+    minJavaVersion = JavaVersion.VERSION_11
+    maxJavaVersion = JavaVersion.VERSION_17
+  }
+}
+
+tasks.named("latestDepTest") {
+  testJvmConstraints {
+    minJavaVersion = JavaVersion.VERSION_17
+  }
+}
+
+project.afterEvaluate {
+  tasks.withType(Test).configureEach {
+    conditionalJvmArgs(
+      it,
+      JavaVersion.VERSION_16,
+      [
+        "--add-opens=java.base/java.lang.reflect=ALL-UNNAMED",
+        "--add-opens=java.base/java.text=ALL-UNNAMED",
+        "--add-opens=java.desktop/java.awt.font=ALL-UNNAMED",
+      ]
+      )
+  }
+}

dd-java-agent/instrumentation/drools/drools-6.0/src/test/groovy/datadog/trace/instrumentation/drools/DroolsClassLoaderExclusionTest.groovy

@@ -0,0 +1,62 @@
+package datadog.trace.instrumentation.drools
+
+import datadog.trace.agent.test.InstrumentationSpecification
+import datadog.trace.config.inversion.ConfigHelper
+import example.Person
+import org.kie.api.KieServices
+import org.kie.api.builder.KieFileSystem
+import org.kie.api.runtime.KieContainer
+import org.kie.api.runtime.KieSession
+
+class DroolsClassLoaderExclusionTest extends InstrumentationSpecification {
+  static ConfigHelper.StrictnessPolicy strictness
+
+  @Override
+  protected void configurePreAgent() {
+    // this is required otherwise checks will fail...
+    strictness = ConfigHelper.get().configInversionStrictFlag()
+    ConfigHelper.get().setConfigInversionStrict(ConfigHelper.StrictnessPolicy.TEST)
+    super.configurePreAgent()
+  }
+
+  def cleanup() {
+    ConfigHelper.get().setConfigInversionStrict(strictness)
+  }
+
+  def "should not instrument drools generated classes"() {
+    setup:
+    KieServices ks = KieServices.Factory.get()
+
+    KieFileSystem kfs = ks.newKieFileSystem()
+
+    kfs.write(
+      "src/main/resources/example/rules.drl",
+      ks.getResources().newClassPathResource("example/rules.drl")
+      )
+
+    ks.newKieBuilder(kfs).buildAll()
+    KieContainer kc = ks.newKieContainer(ks.getRepository().getDefaultReleaseId())
+    KieSession ksession = kc.newKieSession()
+
+    when:
+    Person john = new Person("John", 20)
+    Person bob = new Person("Bob", 15)
+
+    ksession.insert(john)
+    ksession.insert(bob)
+    int fired = ksession.fireAllRules()
+
+    then:
+    fired == 1
+    !bob.isAdult()
+    john.isAdult()
+
+    and:
+    // assert we do not transform the generated rule class (RuleInstrumentation would but the classloader should be ignored)
+    TRANSFORMED_CLASSES_TYPES.findAll { it.getName().startsWith("example.") }.isEmpty()
+
+    cleanup:
+    ksession?.dispose()
+  }
+}
+

dd-java-agent/instrumentation/drools/drools-6.0/src/test/java/example/Person.java

@@ -0,0 +1,44 @@
+package example;
+
+public class Person {
+  private String name;
+  private int age;
+  private boolean adult;
+
+  public Person() {}
+
+  public Person(String name, int age) {
+    this.name = name;
+    this.age = age;
+    this.adult = false;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public int getAge() {
+    return age;
+  }
+
+  public void setAge(int age) {
+    this.age = age;
+  }
+
+  public boolean isAdult() {
+    return adult;
+  }
+
+  public void setAdult(boolean adult) {
+    this.adult = adult;
+  }
+
+  @Override
+  public String toString() {
+    return "Person{name='" + name + "', age=" + age + ", adult=" + adult + "}";
+  }
+}

dd-java-agent/instrumentation/drools/drools-6.0/src/test/java/test/ConstructorAdvice.java

@@ -0,0 +1,8 @@
+package test;
+
+import net.bytebuddy.asm.Advice;
+
+public class ConstructorAdvice {
+  @Advice.OnMethodExit(suppress = Throwable.class)
+  public static void onExit() {}
+}

dd-java-agent/instrumentation/drools/drools-6.0/src/test/java/test/RuleInstrumentation.java

@@ -0,0 +1,34 @@
+package test;
+
+import static net.bytebuddy.matcher.ElementMatchers.isConstructor;
+
+import com.google.auto.service.AutoService;
+import datadog.trace.agent.tooling.Instrumenter;
+import datadog.trace.agent.tooling.InstrumenterModule;
+import datadog.trace.agent.tooling.bytebuddy.matcher.NameMatchers;
+import net.bytebuddy.description.type.TypeDescription;
+import net.bytebuddy.matcher.ElementMatcher;
+
+@AutoService(InstrumenterModule.class)
+public class RuleInstrumentation extends InstrumenterModule.Tracing
+    implements Instrumenter.ForTypeHierarchy, Instrumenter.HasMethodAdvice {
+
+  public RuleInstrumentation() {
+    super("drools-test");
+  }
+
+  @Override
+  public void methodAdvice(MethodTransformer transformer) {
+    transformer.applyAdvice(isConstructor(), "test.ConstructorAdvice");
+  }
+
+  @Override
+  public String hierarchyMarkerType() {
+    return null;
+  }
+
+  @Override
+  public ElementMatcher<TypeDescription> hierarchyMatcher() {
+    return NameMatchers.nameStartsWith("example.Rule");
+  }
+}

dd-java-agent/instrumentation/drools/drools-6.0/src/test/resources/example/rules.drl

@@ -0,0 +1,12 @@
+package example
+
+import example.Person
+
+rule "Mark person as adult"
+when
+    $p : Person(age >= 18, adult == false)
+then
+    $p.setAdult(true);
+    System.out.println("Rule fired for " + $p.getName());
+    update($p);
+end

settings.gradle.kts

@@ -335,6 +335,7 @@ include(
   ":dd-java-agent:instrumentation:datastax-cassandra:datastax-cassandra-4.0",
   ":dd-java-agent:instrumentation:dropwizard:dropwizard-views-0.7",
   ":dd-java-agent:instrumentation:dropwizard:dropwizard-0.8",
+  ":dd-java-agent:instrumentation:drools:drools-6.0",
   ":dd-java-agent:instrumentation:elasticsearch:elasticsearch-rest:elasticsearch-rest-5.0",
   ":dd-java-agent:instrumentation:elasticsearch:elasticsearch-rest:elasticsearch-rest-6.4",
   ":dd-java-agent:instrumentation:elasticsearch:elasticsearch-rest:elasticsearch-rest-7.0",