public delegate needed with indy

Author: SylvainJuge

instrumentation/spring/spring-webmvc/spring-webmvc-3.1/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/spring/webmvc/v3_1/DispatcherServletInstrumentation.java

@@ -17,6 +17,7 @@
 import io.opentelemetry.context.Scope;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
+import java.lang.reflect.Field;
 import java.util.List;
 import net.bytebuddy.asm.Advice;
 import net.bytebuddy.description.type.TypeDescription;
@@ -65,8 +66,20 @@ public static void afterRefresh(
       if (handlerMappings == null || !springCtx.containsBean("otelAutoDispatcherFilter")) {
         return;
       }
-      OpenTelemetryHandlerMappingFilter filter =
-          springCtx.getBean("otelAutoDispatcherFilter", OpenTelemetryHandlerMappingFilter.class);
+      Object bean = springCtx.getBean("otelAutoDispatcherFilter");
+      OpenTelemetryHandlerMappingFilter filter;
+      if (bean instanceof OpenTelemetryHandlerMappingFilter) {
+        // inline advice: no proxy class is used
+        filter = (OpenTelemetryHandlerMappingFilter) bean;
+      } else {
+        // non-inlined advice: proxy class is used
+        try {
+          Field delegate = bean.getClass().getField("delegate");
+          filter = (OpenTelemetryHandlerMappingFilter) delegate.get(bean);
+        } catch (NoSuchFieldException | IllegalAccessException e) {
+          throw new IllegalStateException(e);
+        }
+      }
       filter.setHandlerMappings(handlerMappings);
     }
   }

instrumentation/spring/spring-webmvc/spring-webmvc-6.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/spring/webmvc/v6_0/DispatcherServletInstrumentation.java

@@ -17,6 +17,7 @@
 import io.opentelemetry.context.Scope;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
+import java.lang.reflect.Field;
 import java.util.List;
 import net.bytebuddy.asm.Advice;
 import net.bytebuddy.description.type.TypeDescription;
@@ -66,8 +67,20 @@ public static void afterRefresh(
         return;
       }
 
-      OpenTelemetryHandlerMappingFilter filter =
-          springCtx.getBean("otelAutoDispatcherFilter", OpenTelemetryHandlerMappingFilter.class);
+      Object bean = springCtx.getBean("otelAutoDispatcherFilter");
+      OpenTelemetryHandlerMappingFilter filter;
+      if (bean instanceof OpenTelemetryHandlerMappingFilter) {
+        // inline advice: no proxy class is used
+        filter = (OpenTelemetryHandlerMappingFilter) bean;
+      } else {
+        // non-inlined advice: proxy class is used
+        try {
+          Field delegate = bean.getClass().getField("delegate");
+          filter = (OpenTelemetryHandlerMappingFilter) delegate.get(bean);
+        } catch (NoSuchFieldException | IllegalAccessException e) {
+          throw new IllegalStateException(e);
+        }
+      }
       filter.setHandlerMappings(handlerMappings);
     }
   }

javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/instrumentation/indy/IndyProxyFactory.java

@@ -93,7 +93,8 @@ public DynamicType.Unloaded<?> generateProxy(
             .implement(classToProxy.getInterfaces())
             .name(proxyClassName)
             .annotateType(classToProxy.getDeclaredAnnotations())
-            .defineField(DELEGATE_FIELD_NAME, Object.class, Modifier.PRIVATE | Modifier.FINAL);
+            // field must be public to enable resolving the proxy target using introspection
+            .defineField(DELEGATE_FIELD_NAME, Object.class, Modifier.PUBLIC | Modifier.FINAL);
 
     for (MethodDescription.InDefinedShape method : classToProxy.getDeclaredMethods()) {
       if (method.isPublic()) {