Support URLClassLoader addURL (#2772)

instrumentation/classloaders/javaagent-integration-tests/javaagent-integration-tests.gradle

@@ -0,0 +1,8 @@
+ext.skipPublish = true
+
+apply from: "$rootDir/gradle/instrumentation.gradle"
+
+dependencies {
+  testImplementation group: "org.apache.commons", name: "commons-lang3", version: "3.12.0"
+  testImplementation group: "commons-io", name: "commons-io", version: "2.8.0"
+}

instrumentation/classloaders/javaagent-integration-tests/src/main/java/instrumentation/TestInstrumentationModule.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package instrumentation;
+
+import static io.opentelemetry.javaagent.tooling.bytebuddy.matcher.ClassLoaderMatcher.hasClassesNamed;
+import static java.util.Collections.singletonList;
+import static net.bytebuddy.matcher.ElementMatchers.named;
+
+import com.google.auto.service.AutoService;
+import io.opentelemetry.javaagent.tooling.InstrumentationModule;
+import io.opentelemetry.javaagent.tooling.TypeInstrumentation;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import net.bytebuddy.asm.Advice;
+import net.bytebuddy.description.method.MethodDescription;
+import net.bytebuddy.description.type.TypeDescription;
+import net.bytebuddy.matcher.ElementMatcher;
+
+@AutoService(InstrumentationModule.class)
+public class TestInstrumentationModule extends InstrumentationModule {
+  public TestInstrumentationModule() {
+    super("test-instrumentation");
+  }
+
+  @Override
+  public List<TypeInstrumentation> typeInstrumentations() {
+    return singletonList(new TestTypeInstrumentation());
+  }
+
+  public static class TestTypeInstrumentation implements TypeInstrumentation {
+    @Override
+    public ElementMatcher<ClassLoader> classLoaderOptimization() {
+      return hasClassesNamed("org.apache.commons.lang3.SystemUtils");
+    }
+
+    @Override
+    public ElementMatcher<? super TypeDescription> typeMatcher() {
+      return named("org.apache.commons.lang3.SystemUtils");
+    }
+
+    @Override
+    public Map<? extends ElementMatcher<? super MethodDescription>, String> transformers() {
+      return Collections.singletonMap(named("getHostName"), MarkInstrumentedAdvice.class.getName());
+    }
+  }
+
+  public static class MarkInstrumentedAdvice {
+    @Advice.OnMethodExit
+    public static void methodExit(@Advice.Return(readOnly = false) String hostName) {
+      hostName = "not-the-host-name";
+    }
+  }
+}

instrumentation/classloaders/javaagent-integration-tests/src/test/groovy/AddUrlTest.groovy

@@ -0,0 +1,44 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import io.opentelemetry.instrumentation.test.AgentInstrumentationSpecification
+import org.apache.commons.io.IOUtils
+import org.apache.commons.lang3.SystemUtils
+
+class AddUrlTest extends AgentInstrumentationSpecification {
+
+  def "should instrument class after it is loaded via addURL"() {
+    given:
+    TestURLClassLoader loader = new TestURLClassLoader()
+
+    when:
+    // this is just to verify the assumption that TestURLClassLoader is not finding SystemUtils via
+    // the test class path (in which case the verification below would not be very meaningful)
+    loader.loadClass(SystemUtils.getName())
+
+    then:
+    thrown ClassNotFoundException
+
+    when:
+    // loading a class in the URLClassLoader in order to trigger
+    // a negative cache hit on org.apache.commons.lang3.SystemUtils
+    loader.addURL(IOUtils.getProtectionDomain().getCodeSource().getLocation())
+    loader.loadClass(IOUtils.getName())
+
+    loader.addURL(SystemUtils.getProtectionDomain().getCodeSource().getLocation())
+    def clazz = loader.loadClass(SystemUtils.getName())
+
+    then:
+    clazz.getClassLoader() == loader
+    clazz.getMethod("getHostName").invoke(null) == "not-the-host-name"
+  }
+
+  static class TestURLClassLoader extends URLClassLoader {
+
+    TestURLClassLoader() {
+      super(new URL[0], (ClassLoader) null)
+    }
+  }
+}

instrumentation/classloaders/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/javaclassloader/ClassLoaderInstrumentationModule.java

@@ -27,6 +27,7 @@ public class ClassLoaderInstrumentationModule extends InstrumentationModule {
   public List<TypeInstrumentation> typeInstrumentations() {
     return asList(
         new ClassLoaderInstrumentation(),
+        new UrlClassLoaderInstrumentation(),
         new ProxyInstrumentation(),
         new ResourceInjectionInstrumentation());
   }

instrumentation/classloaders/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/javaclassloader/UrlClassLoaderInstrumentation.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.instrumentation.javaclassloader;
+
+import static java.util.Collections.singletonMap;
+import static net.bytebuddy.matcher.ElementMatchers.isMethod;
+import static net.bytebuddy.matcher.ElementMatchers.isProtected;
+import static net.bytebuddy.matcher.ElementMatchers.isStatic;
+import static net.bytebuddy.matcher.ElementMatchers.named;
+import static net.bytebuddy.matcher.ElementMatchers.not;
+import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
+import static net.bytebuddy.matcher.ElementMatchers.takesArguments;
+
+import io.opentelemetry.javaagent.bootstrap.ClassLoaderMatcherCacheHolder;
+import io.opentelemetry.javaagent.tooling.TypeInstrumentation;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.Map;
+import net.bytebuddy.asm.Advice;
+import net.bytebuddy.description.method.MethodDescription;
+import net.bytebuddy.description.type.TypeDescription;
+import net.bytebuddy.matcher.ElementMatcher;
+
+public class UrlClassLoaderInstrumentation implements TypeInstrumentation {
+
+  @Override
+  public ElementMatcher<TypeDescription> typeMatcher() {
+    return named("java.net.URLClassLoader");
+  }
+
+  @Override
+  public Map<? extends ElementMatcher<? super MethodDescription>, String> transformers() {
+    return singletonMap(
+        isMethod()
+            .and(named("addURL"))
+            .and(takesArguments(1))
+            .and(takesArgument(0, URL.class))
+            .and(isProtected())
+            .and(not(isStatic())),
+        UrlClassLoaderInstrumentation.class.getName() + "$InvalidateClassLoaderMatcher");
+  }
+
+  public static class InvalidateClassLoaderMatcher {
+    @Advice.OnMethodExit(suppress = Throwable.class)
+    public static void onExit(@Advice.This URLClassLoader loader) {
+      ClassLoaderMatcherCacheHolder.invalidateAllCachesForClassLoader(loader);
+    }
+  }
+}

javaagent-bootstrap/src/main/java/io/opentelemetry/javaagent/bootstrap/ClassLoaderMatcherCacheHolder.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.bootstrap;
+
+import io.opentelemetry.instrumentation.api.caching.Cache;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.List;
+import org.checkerframework.checker.lock.qual.GuardedBy;
+
+/**
+ * A holder of all ClassLoaderMatcher caches. We store them in the bootstrap classloader so that
+ * instrumentation can invalidate the ClassLoaderMatcher for a particular ClassLoader, e.g. when
+ * {@link java.net.URLClassLoader#addURL(URL)} is called.
+ */
+public class ClassLoaderMatcherCacheHolder {
+
+  @GuardedBy("allCaches")
+  private static final List<Cache<ClassLoader, Boolean>> allCaches = new ArrayList<>();
+
+  private ClassLoaderMatcherCacheHolder() {}
+
+  public static void addCache(Cache<ClassLoader, Boolean> cache) {
+    synchronized (allCaches) {
+      allCaches.add(cache);
+    }
+  }
+
+  public static void invalidateAllCachesForClassLoader(ClassLoader loader) {
+    synchronized (allCaches) {
+      for (Cache<ClassLoader, Boolean> cache : allCaches) {
+        cache.remove(loader);
+      }
+    }
+  }
+}

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/bytebuddy/matcher/ClassLoaderMatcher.java

@@ -6,6 +6,7 @@
 package io.opentelemetry.javaagent.tooling.bytebuddy.matcher;
 
 import io.opentelemetry.instrumentation.api.caching.Cache;
+import io.opentelemetry.javaagent.bootstrap.ClassLoaderMatcherCacheHolder;
 import io.opentelemetry.javaagent.instrumentation.api.internal.InClassLoaderMatcher;
 import net.bytebuddy.matcher.ElementMatcher;
 
@@ -43,6 +44,7 @@ public final class ClassLoaderMatcher {
       for (int i = 0; i < resources.length; i++) {
         resources[i] = resources[i].replace(".", "/") + ".class";
       }
+      ClassLoaderMatcherCacheHolder.addCache(cache);
     }
 
     private boolean hasResources(ClassLoader cl) {

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/matcher/GlobalIgnoresMatcher.java

@@ -118,7 +118,9 @@ public class GlobalIgnoresMatcher<T extends TypeDescription>
     }
 
     if (name.startsWith("java.")) {
-      if (name.equals("java.net.URL") || name.equals("java.net.HttpURLConnection")) {
+      if (name.equals("java.net.URL")
+          || name.equals("java.net.HttpURLConnection")
+          || name.equals("java.net.URLClassLoader")) {
         return false;
       }
       if (name.startsWith("java.rmi.") || name.startsWith("java.util.concurrent.")) {

settings.gradle

@@ -86,6 +86,7 @@ include ':instrumentation:cassandra:cassandra-3.0:javaagent'
 include ':instrumentation:cassandra:cassandra-4.0:javaagent'
 include ':instrumentation:cdi-testing'
 include ':instrumentation:classloaders:javaagent'
+include ':instrumentation:classloaders:javaagent-integration-tests'
 include ':instrumentation:classloaders:javaagent-unittests'
 include ':instrumentation:couchbase:couchbase-2.0:javaagent'
 include ':instrumentation:couchbase:couchbase-2.0:javaagent-unittests'