Look in another location for grpc service methods (#8468)

if the service methods aren't found on the ImplBase, look for an AsyncService interface which *should* have the service methods.

Author: evanchooly

dd-java-agent/instrumentation/grpc-1.5/src/main/java/datadog/trace/instrumentation/grpc/server/MethodHandlersInstrumentation.java

@@ -43,7 +43,7 @@ public boolean isEnabled() {
   public void methodAdvice(MethodTransformer transformer) {
     transformer.applyAdvice(
         isConstructor().and(takesArguments(2)),
-        MethodHandlersInstrumentation.class.getName() + "$BuildAdvice");
+        "datadog.trace.instrumentation.grpc.server.MethodHandlersInstrumentation$BuildAdvice");
   }
 
   public static class BuildAdvice {
@@ -52,9 +52,21 @@ public static class BuildAdvice {
     public static void onEnter(@Advice.Argument(0) Object serviceImpl) {
       try {
         Class<?> serviceClass = serviceImpl.getClass();
-        Class<?> superclass = serviceClass.getSuperclass();
-        if (superclass != null) {
-          for (Method method : superclass.getDeclaredMethods()) {
+        Class<?> superClass = serviceClass.getSuperclass();
+        while (superClass != null && !superClass.getSimpleName().endsWith("ImplBase")) {
+          superClass = superClass.getSuperclass();
+        }
+        if (superClass != null) {
+          // bindService() would be the only method in this case and it's irrelevant
+          if (superClass.getDeclaredMethods().length == 1) {
+            for (Class<?> i : serviceClass.getInterfaces()) {
+              if (i.getSimpleName().equals("AsyncService")) {
+                superClass = i;
+                break;
+              }
+            }
+          }
+          for (Method method : superClass.getDeclaredMethods()) {
             try {
               entry(serviceClass.getDeclaredMethod(method.getName(), method.getParameterTypes()));
             } catch (Throwable e) {