Merge pull request #1733 from chengyouling/develop-spi

Changed classloader to fixed the problem that classes cannot be loaded in the tomcat scenario

Author: Sherlockhan

sermant-agentcore/sermant-agentcore-core/src/main/java/io/sermant/core/classloader/ClassLoaderManager.java

@@ -45,6 +45,8 @@ public class ClassLoaderManager {
 
     private static FrameworkClassLoader frameworkClassLoader;
 
+    private static ClassLoader userClassLoader;
+
     private ClassLoaderManager() {
     }
 
@@ -88,6 +90,26 @@ public PluginClassLoader run() {
         });
     }
 
+    public static void setUserClassLoader(ClassLoader userClassLoader) {
+        ClassLoaderManager.userClassLoader = userClassLoader;
+    }
+
+    /**
+     * get ContextClassLoader or UserClassLoader
+     *
+     * @return ClassLoader
+     */
+    public static ClassLoader getContextClassLoaderOrUserClassLoader() {
+        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+        if (classLoader != null) {
+            return classLoader;
+        }
+
+        // In some Tomcat scenarios, sermant cannot obtain the class loader of the current thread.
+        // In this case, the host class loader is used to load classes.
+        return userClassLoader;
+    }
+
     public static SermantClassLoader getSermantClassLoader() {
         return sermantClassLoader;
     }

sermant-agentcore/sermant-agentcore-core/src/main/java/io/sermant/core/plugin/agent/enhance/ClassLoaderLoadClassInterceptor.java

@@ -47,6 +47,7 @@ public ClassLoaderLoadClassInterceptor() {
 
     @Override
     public ExecuteContext before(ExecuteContext context) throws Exception {
+        ClassLoaderManager.setUserClassLoader((ClassLoader) context.getObject());
         return context;
     }
 

sermant-agentcore/sermant-agentcore-core/src/main/java/io/sermant/core/plugin/classloader/PluginClassLoader.java

@@ -16,6 +16,7 @@
 
 package io.sermant.core.plugin.classloader;
 
+import io.sermant.core.classloader.ClassLoaderManager;
 import io.sermant.core.common.LoggerFactory;
 import io.sermant.core.config.ConfigManager;
 import io.sermant.core.plugin.agent.config.AgentConfig;
@@ -133,9 +134,16 @@ public Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundExce
 
     private Class<?> getClassFromLocalClassLoader(String name) {
         ClassLoader loader = localLoader.get(Thread.currentThread().getId());
-
+        if (loader == null) {
+            LOGGER.log(Level.FINE, "localLoader is null, thread name is {0}, classs name is {1}.",
+                    new Object[]{Thread.currentThread().getName(), name});
+        }
         if (loader == null && useContextLoader) {
-            loader = Thread.currentThread().getContextClassLoader();
+            loader = ClassLoaderManager.getContextClassLoaderOrUserClassLoader();
+            if (loader == null) {
+                LOGGER.log(Level.WARNING, "contextClassLoader is null, thread name is {0}, classs name is {1}.",
+                        new Object[]{Thread.currentThread().getName(), name});
+            }
         }
         Class<?> clazz = null;
 

sermant-agentcore/sermant-agentcore-core/src/main/java/io/sermant/core/plugin/subscribe/processor/IntegratedEventListenerAdapter.java

@@ -17,6 +17,7 @@
 
 package io.sermant.core.plugin.subscribe.processor;
 
+import io.sermant.core.classloader.ClassLoaderManager;
 import io.sermant.core.service.dynamicconfig.common.DynamicConfigEvent;
 import io.sermant.core.service.dynamicconfig.common.DynamicConfigListener;
 
@@ -43,7 +44,7 @@ public class IntegratedEventListenerAdapter implements DynamicConfigListener {
     public IntegratedEventListenerAdapter(ConfigProcessor processor, String rawGroup) {
         this.processor = processor;
         this.rawGroup = rawGroup;
-        this.classLoader = Thread.currentThread().getContextClassLoader();
+        this.classLoader = ClassLoaderManager.getContextClassLoaderOrUserClassLoader();
     }
 
     @Override
@@ -54,7 +55,7 @@ public void process(DynamicConfigEvent event) {
 
         // The classloader at subscription time may not be the same as the classloader at listener configuration
         // time, so need to restore it
-        ClassLoader currentClassLoader = Thread.currentThread().getContextClassLoader();
+        ClassLoader currentClassLoader = ClassLoaderManager.getContextClassLoaderOrUserClassLoader();
         try {
             Thread.currentThread().setContextClassLoader(classLoader);
             processor.process(rawGroup, event);

sermant-agentcore/sermant-agentcore-core/src/main/java/io/sermant/core/utils/ClassUtils.java

@@ -17,6 +17,7 @@
 
 package io.sermant.core.utils;
 
+import io.sermant.core.classloader.ClassLoaderManager;
 import io.sermant.core.common.LoggerFactory;
 
 import java.io.IOException;
@@ -111,7 +112,7 @@ public static Optional<Class<?>> loadClass(String className, ClassLoader classLo
     public static Optional<Object> createInstance(String className, ClassLoader classLoader, Class<?>[] paramTypes) {
         ClassLoader curClassLoader = classLoader;
         if (curClassLoader == null) {
-            curClassLoader = Thread.currentThread().getContextClassLoader();
+            curClassLoader = ClassLoaderManager.getContextClassLoaderOrUserClassLoader();
         }
         try {
             final Class<?> clazz = curClassLoader.loadClass(className);

sermant-agentcore/sermant-agentcore-core/src/main/java/io/sermant/core/utils/ReflectUtils.java

@@ -17,6 +17,7 @@
 
 package io.sermant.core.utils;
 
+import io.sermant.core.classloader.ClassLoaderManager;
 import io.sermant.core.common.LoggerFactory;
 
 import java.lang.reflect.AccessibleObject;
@@ -166,7 +167,7 @@ private static Optional<Class<?>> loadClass(String className) {
             return Optional.empty();
         }
         return CLASS_CACHE.computeIfAbsent(className, value -> {
-            final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
+            final ClassLoader contextClassLoader = ClassLoaderManager.getContextClassLoaderOrUserClassLoader();
             try {
                 return Optional.ofNullable(contextClassLoader.loadClass(className));
             } catch (ClassNotFoundException ignored) {

sermant-agentcore/sermant-agentcore-implement/src/main/java/io/sermant/implement/config/SermantYamlConstructor.java

@@ -16,6 +16,7 @@
 
 package io.sermant.implement.config;
 
+import io.sermant.core.classloader.ClassLoaderManager;
 import io.sermant.core.exception.SermantRuntimeException;
 
 import org.yaml.snakeyaml.LoaderOptions;
@@ -35,7 +36,7 @@ public class SermantYamlConstructor extends Constructor {
      */
     public SermantYamlConstructor() {
         super(Object.class, new LoaderOptions());
-        loader = Thread.currentThread().getContextClassLoader();
+        loader = ClassLoaderManager.getContextClassLoaderOrUserClassLoader();
     }
 
     /**

sermant-agentcore/sermant-agentcore-implement/src/main/java/io/sermant/implement/service/dynamicconfig/nacos/NacosBufferedClient.java

@@ -22,6 +22,7 @@
 import com.alibaba.nacos.api.exception.NacosException;
 import com.alibaba.nacos.client.auth.impl.NacosAuthLoginConstant;
 
+import io.sermant.core.classloader.ClassLoaderManager;
 import io.sermant.core.common.LoggerFactory;
 import io.sermant.core.config.ConfigManager;
 import io.sermant.core.service.dynamicconfig.config.DynamicConfig;
@@ -229,7 +230,7 @@ private Properties createProperties(String connectString, int sessionTimeout, St
      * @throws NacosInitException Connect to Nacos failed
      */
     private void createNacosClient(String connectString, Properties properties) {
-        ClassLoader tempClassLoader = Thread.currentThread().getContextClassLoader();
+        ClassLoader tempClassLoader = ClassLoaderManager.getContextClassLoaderOrUserClassLoader();
         Thread.currentThread().setContextClassLoader(this.getClass().getClassLoader());
         try {
             nacosClient = new NacosClient(properties);

sermant-plugins/sermant-dynamic-config/dynamic-config-plugin/src/main/java/io/sermant/dynamic/config/inject/DynamicClassInjectDefine.java

@@ -17,6 +17,7 @@
 
 package io.sermant.dynamic.config.inject;
 
+import io.sermant.core.classloader.ClassLoaderManager;
 import io.sermant.core.plugin.config.PluginConfigManager;
 import io.sermant.core.service.inject.ClassInjectDefine;
 import io.sermant.core.utils.ClassUtils;
@@ -42,6 +43,7 @@ public Plugin plugin() {
     @Override
     public boolean canInject() {
         return PluginConfigManager.getPluginConfig(DynamicConfiguration.class).isEnableDynamicConfig()
-                && ClassUtils.loadClass(REFRESH_CLASS, Thread.currentThread().getContextClassLoader()).isPresent();
+                && ClassUtils.loadClass(REFRESH_CLASS, ClassLoaderManager.getContextClassLoaderOrUserClassLoader())
+                .isPresent();
     }
 }

sermant-plugins/sermant-dynamic-config/dynamic-config-plugin/src/main/java/io/sermant/dynamic/config/interceptors/SpringFactoriesInterceptor.java

@@ -17,6 +17,7 @@
 
 package io.sermant.dynamic.config.interceptors;
 
+import io.sermant.core.classloader.ClassLoaderManager;
 import io.sermant.core.common.LoggerFactory;
 import io.sermant.core.plugin.agent.entity.ExecuteContext;
 import io.sermant.core.service.ServiceManager;
@@ -94,7 +95,7 @@ private boolean isHasMethodLoadSpringFactories() {
 
     private void injectConfigurationsWithLowVersion(Object result, String factoryName) {
         final ClassInjectService service = ServiceManager.getService(ClassInjectService.class);
-        final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
+        final ClassLoader contextClassLoader = ClassLoaderManager.getContextClassLoaderOrUserClassLoader();
         if (result instanceof List) {
             final List<String> convertedResult = (List<String>) result;
             CLASS_DEFINES.forEach(classInjectDefine -> {
@@ -108,7 +109,7 @@ private void injectConfigurationsWithLowVersion(Object result, String factoryNam
 
     private void injectConfigurations(Object result) {
         final ClassInjectService service = ServiceManager.getService(ClassInjectService.class);
-        final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
+        final ClassLoader contextClassLoader = ClassLoaderManager.getContextClassLoaderOrUserClassLoader();
         final boolean isMultiValueMap = result instanceof MultiValueMap;
         if (result instanceof Map) {
             // spring 高版本处理, 针对List其为不可变list，需做一层处理