Don't call Thread#setContextClassLoader() (#7391)

Related to #7220

Unfortunately it doesn't fix the aforementioned issue; while the CL used
is no longer the agent classloader, gauge collection still throws that
error.
Still, I think this is a good change that removes one source of agent's
CL leaking into application runtime.

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/AgentInstaller.java

@@ -19,7 +19,6 @@ import io.opentelemetry.context.Scope;
 import io.opentelemetry.instrumentation.api.internal.ConfigPropertiesUtil;
 import io.opentelemetry.instrumentation.api.internal.EmbeddedInstrumentationProperties;
 import io.opentelemetry.javaagent.bootstrap.AgentClassLoader;
-import io.opentelemetry.javaagent.bootstrap.AgentInitializer;
 import io.opentelemetry.javaagent.bootstrap.BootstrapPackagePrefixesHolder;
 import io.opentelemetry.javaagent.bootstrap.ClassFileTransformerHolder;
 import io.opentelemetry.javaagent.bootstrap.DefineClassHelper;
@@ -78,7 +77,7 @@ public class AgentInstaller {
 
   private static final Map<String, List<Runnable>> CLASS_LOAD_CALLBACKS = new HashMap<>();
 
-  public static void installBytebuddyAgent(Instrumentation inst) {
+  public static void installBytebuddyAgent(Instrumentation inst, ClassLoader extensionClassLoader) {
     addByteBuddyRawSetting();
 
     Integer strictContextStressorMillis = Integer.getInteger(STRICT_CONTEXT_STRESSOR_MILLIS);
@@ -90,34 +89,37 @@ public class AgentInstaller {
     logVersionInfo();
     if (ConfigPropertiesUtil.getBoolean(JAVAAGENT_ENABLED_CONFIG, true)) {
       setupUnsafe(inst);
-      List<AgentListener> agentListeners = loadOrdered(AgentListener.class);
+      List<AgentListener> agentListeners = loadOrdered(AgentListener.class, extensionClassLoader);
-      installBytebuddyAgent(inst, agentListeners);
+      installBytebuddyAgent(inst, extensionClassLoader, agentListeners);
     } else {
       logger.fine("Tracing is disabled, not installing instrumentations.");
     }
   }
 
   private static void installBytebuddyAgent(
-      Instrumentation inst, Iterable<AgentListener> agentListeners) {
+      Instrumentation inst,
+      ClassLoader extensionClassLoader,
+      Iterable<AgentListener> agentListeners) {
 
     WeakRefAsyncOperationEndStrategies.initialize();
 
-    EmbeddedInstrumentationProperties.setPropertiesLoader(
+    EmbeddedInstrumentationProperties.setPropertiesLoader(extensionClassLoader);
-        AgentInitializer.getExtensionsClassLoader());
 
     setDefineClassHandler();
 
     // If noop OpenTelemetry is enabled, autoConfiguredSdk will be null and AgentListeners are not
     // called
-    AutoConfiguredOpenTelemetrySdk autoConfiguredSdk = installOpenTelemetrySdk();
+    AutoConfiguredOpenTelemetrySdk autoConfiguredSdk =
+        installOpenTelemetrySdk(extensionClassLoader);
 
     ConfigProperties sdkConfig = autoConfiguredSdk.getConfig();
     InstrumentationConfig.internalInitializeConfig(new ConfigPropertiesBridge(sdkConfig));
     copyNecessaryConfigToSystemProperties(sdkConfig);
 
-    setBootstrapPackages(sdkConfig);
+    setBootstrapPackages(sdkConfig, extensionClassLoader);
 
-    for (BeforeAgentListener agentListener : loadOrdered(BeforeAgentListener.class)) {
+    for (BeforeAgentListener agentListener :
+        loadOrdered(BeforeAgentListener.class, extensionClassLoader)) {
       agentListener.beforeAgent(autoConfiguredSdk);
     }
 
@@ -140,7 +142,7 @@ public class AgentInstaller {
       agentBuilder = agentBuilder.with(new ExposeAgentBootstrapListener(inst));
     }
 
-    agentBuilder = configureIgnoredTypes(sdkConfig, agentBuilder);
+    agentBuilder = configureIgnoredTypes(sdkConfig, extensionClassLoader, agentBuilder);
 
     if (AgentConfig.isDebugModeEnabled(sdkConfig)) {
       agentBuilder =
@@ -152,7 +154,7 @@ public class AgentInstaller {
     }
 
     int numberOfLoadedExtensions = 0;
-    for (AgentExtension agentExtension : loadOrdered(AgentExtension.class)) {
+    for (AgentExtension agentExtension : loadOrdered(AgentExtension.class, extensionClassLoader)) {
       if (logger.isLoggable(FINE)) {
         logger.log(
             FINE,
@@ -196,9 +198,11 @@ public class AgentInstaller {
     }
   }
 
-  private static void setBootstrapPackages(ConfigProperties config) {
+  private static void setBootstrapPackages(
+      ConfigProperties config, ClassLoader extensionClassLoader) {
     BootstrapPackagesBuilderImpl builder = new BootstrapPackagesBuilderImpl();
-    for (BootstrapPackagesConfigurer configurer : load(BootstrapPackagesConfigurer.class)) {
+    for (BootstrapPackagesConfigurer configurer :
+        load(BootstrapPackagesConfigurer.class, extensionClassLoader)) {
       configurer.configure(builder, config);
     }
     BootstrapPackagePrefixesHolder.setBoostrapPackagePrefixes(builder.build());
@@ -209,9 +213,10 @@ public class AgentInstaller {
   }
 
   private static AgentBuilder configureIgnoredTypes(
-      ConfigProperties config, AgentBuilder agentBuilder) {
+      ConfigProperties config, ClassLoader extensionClassLoader, AgentBuilder agentBuilder) {
     IgnoredTypesBuilderImpl builder = new IgnoredTypesBuilderImpl();
-    for (IgnoredTypesConfigurer configurer : loadOrdered(IgnoredTypesConfigurer.class)) {
+    for (IgnoredTypesConfigurer configurer :
+        loadOrdered(IgnoredTypesConfigurer.class, extensionClassLoader)) {
       configurer.configure(builder, config);
     }
 

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/AgentStarterImpl.java

@@ -62,18 +62,9 @@ public class AgentStarterImpl implements AgentStarter {
   @Override
   public void start() {
     extensionClassLoader = createExtensionClassLoader(getClass().getClassLoader(), javaagentFile);
-    ClassLoader savedContextClassLoader = Thread.currentThread().getContextClassLoader();
-    try {
-      Thread.currentThread().setContextClassLoader(extensionClassLoader);
-      internalStart();
-    } finally {
-      Thread.currentThread().setContextClassLoader(savedContextClassLoader);
-    }
-  }
 
-  private void internalStart() {
     Iterator<LoggingCustomizer> loggingCustomizers =
-        ServiceLoader.load(LoggingCustomizer.class).iterator();
+        ServiceLoader.load(LoggingCustomizer.class, extensionClassLoader).iterator();
     LoggingCustomizer loggingCustomizer;
     if (loggingCustomizers.hasNext()) {
       loggingCustomizer = loggingCustomizers.next();
@@ -84,7 +75,7 @@ public class AgentStarterImpl implements AgentStarter {
     Throwable startupError = null;
     try {
       loggingCustomizer.init();
-      AgentInstaller.installBytebuddyAgent(instrumentation);
+      AgentInstaller.installBytebuddyAgent(instrumentation, extensionClassLoader);
       WeakConcurrentMapCleaner.start();
     } catch (Throwable t) {
       // this is logged below and not rethrown to avoid logging it twice

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/OpenTelemetryInstaller.java

@@ -5,11 +5,9 @@
 
 package io.opentelemetry.javaagent.tooling;
 
-import io.opentelemetry.javaagent.bootstrap.AgentInitializer;
 import io.opentelemetry.javaagent.bootstrap.OpenTelemetrySdkAccess;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.autoconfigure.AutoConfiguredOpenTelemetrySdk;
-import io.opentelemetry.sdk.autoconfigure.AutoConfiguredOpenTelemetrySdkBuilder;
 import io.opentelemetry.sdk.common.CompletableResultCode;
 import java.util.Arrays;
 
@@ -21,17 +19,14 @@ public final class OpenTelemetryInstaller {
    *
    * @return the {@link AutoConfiguredOpenTelemetrySdk}
    */
-  public static AutoConfiguredOpenTelemetrySdk installOpenTelemetrySdk() {
+  public static AutoConfiguredOpenTelemetrySdk installOpenTelemetrySdk(
-    AutoConfiguredOpenTelemetrySdkBuilder builder =
+      ClassLoader extensionClassLoader) {
-        AutoConfiguredOpenTelemetrySdk.builder().setResultAsGlobal(true);
 
-    ClassLoader classLoader = AgentInitializer.getExtensionsClassLoader();
+    AutoConfiguredOpenTelemetrySdk autoConfiguredSdk =
-    if (classLoader != null) {
+        AutoConfiguredOpenTelemetrySdk.builder()
-      // May be null in unit tests.
+            .setResultAsGlobal(true)
-      builder.setServiceClassLoader(classLoader);
+            .setServiceClassLoader(extensionClassLoader)
-    }
+            .build();
-
-    AutoConfiguredOpenTelemetrySdk autoConfiguredSdk = builder.build();
     OpenTelemetrySdk sdk = autoConfiguredSdk.getOpenTelemetrySdk();
 
     OpenTelemetrySdkAccess.internalSetForceFlush(

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/SafeServiceLoader.java

@@ -30,9 +30,9 @@ public final class SafeServiceLoader {
    */
   // Because we want to catch exception per iteration
   @SuppressWarnings("ForEachIterable")
-  public static <T> List<T> load(Class<T> serviceClass) {
+  public static <T> List<T> load(Class<T> serviceClass, ClassLoader classLoader) {
     List<T> result = new ArrayList<>();
-    ServiceLoader<T> services = ServiceLoader.load(serviceClass);
+    ServiceLoader<T> services = ServiceLoader.load(serviceClass, classLoader);
     for (Iterator<T> iterator = new SafeIterator<>(services.iterator()); iterator.hasNext(); ) {
       T service = iterator.next();
       if (service != null) {
@@ -43,11 +43,12 @@ public final class SafeServiceLoader {
   }
 
   /**
-   * Same as {@link #load(Class)}, but also orders the returned implementations by comparing their
+   * Same as {@link #load(Class, ClassLoader)}, but also orders the returned implementations by
-   * {@link Ordered#order()}.
+   * comparing their {@link Ordered#order()}.
    */
-  public static <T extends Ordered> List<T> loadOrdered(Class<T> serviceClass) {
+  public static <T extends Ordered> List<T> loadOrdered(
-    List<T> result = load(serviceClass);
+      Class<T> serviceClass, ClassLoader classLoader) {
+    List<T> result = load(serviceClass, classLoader);
     result.sort(Comparator.comparing(Ordered::order));
     return result;
   }

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/instrumentation/InstrumentationLoader.java

@@ -13,6 +13,7 @@ import com.google.auto.service.AutoService;
 import io.opentelemetry.javaagent.bootstrap.InstrumentationHolder;
 import io.opentelemetry.javaagent.extension.instrumentation.InstrumentationModule;
 import io.opentelemetry.javaagent.tooling.AgentExtension;
+import io.opentelemetry.javaagent.tooling.Utils;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
 import java.util.logging.Logger;
 import net.bytebuddy.agent.builder.AgentBuilder;
@@ -27,7 +28,8 @@ public class InstrumentationLoader implements AgentExtension {
   @Override
   public AgentBuilder extend(AgentBuilder agentBuilder, ConfigProperties config) {
     int numberOfLoadedModules = 0;
-    for (InstrumentationModule instrumentationModule : loadOrdered(InstrumentationModule.class)) {
+    for (InstrumentationModule instrumentationModule :
+        loadOrdered(InstrumentationModule.class, Utils.getExtensionsClassLoader())) {
       if (logger.isLoggable(FINE)) {
         logger.log(
             FINE,

javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/test/HelperInjectionTest.groovy

@@ -61,7 +61,7 @@ class HelperInjectionTest extends Specification {
   def "helpers injected on bootstrap classloader"() {
     setup:
     ByteBuddyAgent.install()
-    AgentInstaller.installBytebuddyAgent(ByteBuddyAgent.getInstrumentation())
+    AgentInstaller.installBytebuddyAgent(ByteBuddyAgent.getInstrumentation(), this.class.classLoader)
     String helperClassName = HelperInjectionTest.getPackage().getName() + '.HelperClass'
     HelperInjector injector = new HelperInjector("test", [helperClassName], [], this.class.classLoader, ByteBuddyAgent.getInstrumentation())
     URLClassLoader bootstrapChild = new URLClassLoader(new URL[0], (ClassLoader) null)

javaagent-tooling/src/test/groovy/io/opentelemetry/javaagent/tooling/OpenTelemetryInstallerTest.groovy

@@ -24,7 +24,7 @@ class OpenTelemetryInstallerTest extends Specification {
 
   def "should initialize GlobalOpenTelemetry"() {
     when:
-    def otelInstaller = OpenTelemetryInstaller.installOpenTelemetrySdk()
+    def otelInstaller = OpenTelemetryInstaller.installOpenTelemetrySdk(OpenTelemetryInstaller.classLoader)
 
     then:
     otelInstaller != null

javaagent-tooling/src/test/java/io/opentelemetry/javaagent/tooling/config/ConfigurationFileLoaderTest.java

@@ -46,7 +46,7 @@ class ConfigurationFileLoaderTest {
 
     // when
     AutoConfiguredOpenTelemetrySdk autoConfiguredSdk =
-        OpenTelemetryInstaller.installOpenTelemetrySdk();
+        OpenTelemetryInstaller.installOpenTelemetrySdk(this.getClass().getClassLoader());
 
     // then
     assertThat(autoConfiguredSdk.getConfig().getString("custom.key")).isEqualTo("42");

muzzle/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/AgentTooling.java

@@ -32,7 +32,8 @@ public final class AgentTooling {
 
   private static ClassLoader getBootstrapProxy() {
     Iterator<BootstrapProxyProvider> iterator =
-        ServiceLoader.load(BootstrapProxyProvider.class).iterator();
+        ServiceLoader.load(BootstrapProxyProvider.class, AgentTooling.class.getClassLoader())
+            .iterator();
     if (iterator.hasNext()) {
       BootstrapProxyProvider bootstrapProxyProvider = iterator.next();
       return bootstrapProxyProvider.getBootstrapProxy();

muzzle/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/ClassLoaderMatcher.java

@@ -33,7 +33,7 @@ public class ClassLoaderMatcher {
   public static Map<String, List<Mismatch>> matchesAll(
       ClassLoader classLoader, boolean injectHelpers, Set<String> excludedInstrumentationNames) {
     Map<String, List<Mismatch>> result = new HashMap<>();
-    ServiceLoader.load(InstrumentationModule.class)
+    ServiceLoader.load(InstrumentationModule.class, ClassLoaderMatcher.class.getClassLoader())
         .forEach(
             module -> {
               if (module.instrumentationNames().stream()

muzzle/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/ReferencesPrinter.java

@@ -26,7 +26,7 @@ public final class ReferencesPrinter {
    */
   public static void printMuzzleReferences() {
     for (InstrumentationModule instrumentationModule :
-        ServiceLoader.load(InstrumentationModule.class)) {
+        ServiceLoader.load(InstrumentationModule.class, ReferencesPrinter.class.getClassLoader())) {
       try {
         System.out.println(instrumentationModule.getClass().getName());
         for (ClassRef ref :

testing/agent-exporter/src/main/java/io/opentelemetry/javaagent/testing/bytebuddy/TestAgentListener.java

@@ -10,6 +10,7 @@ import static java.util.logging.Level.SEVERE;
 import io.opentelemetry.javaagent.extension.ignore.IgnoredTypesConfigurer;
 import io.opentelemetry.javaagent.tooling.EmptyConfigProperties;
 import io.opentelemetry.javaagent.tooling.SafeServiceLoader;
+import io.opentelemetry.javaagent.tooling.Utils;
 import io.opentelemetry.javaagent.tooling.ignore.AdditionalLibraryIgnoredTypesConfigurer;
 import io.opentelemetry.javaagent.tooling.ignore.GlobalIgnoredTypesConfigurer;
 import io.opentelemetry.javaagent.tooling.ignore.IgnoreAllow;
@@ -51,7 +52,8 @@ public class TestAgentListener implements AgentBuilder.Listener {
   private static Trie<IgnoreAllow> buildOtherConfiguredIgnores() {
     IgnoredTypesBuilderImpl builder = new IgnoredTypesBuilderImpl();
     for (IgnoredTypesConfigurer configurer :
-        SafeServiceLoader.loadOrdered(IgnoredTypesConfigurer.class)) {
+        SafeServiceLoader.loadOrdered(
+            IgnoredTypesConfigurer.class, Utils.getExtensionsClassLoader())) {
       // skip built-in agent ignores
       if (configurer instanceof AdditionalLibraryIgnoredTypesConfigurer
           || configurer instanceof GlobalIgnoredTypesConfigurer) {