Migrating ServerInstrumentation from restlet 2

Author: LikeTheSalad

instrumentation/restlet/restlet-2.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/restlet/v2_0/ServerInstrumentation.java

@@ -19,6 +19,7 @@
 import io.opentelemetry.javaagent.bootstrap.http.HttpServerResponseCustomizerHolder;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
+import javax.annotation.Nullable;
 import net.bytebuddy.asm.Advice;
 import net.bytebuddy.description.type.TypeDescription;
 import net.bytebuddy.matcher.ElementMatcher;
@@ -44,54 +45,66 @@ public void transform(TypeTransformer transformer) {
 
   @SuppressWarnings("unused")
   public static class ServerHandleAdvice {
+    public static class AdviceScope {
+      private final Context context;
+      private final Scope scope;
 
-    @Advice.OnMethodEnter(suppress = Throwable.class)
-    public static void beginRequest(
-        @Advice.Argument(0) Request request,
-        @Advice.Argument(1) Response response,
-        @Advice.Local("otelContext") Context context,
-        @Advice.Local("otelScope") Scope scope) {
-
-      Context parentContext = currentContext();
-
-      if (!instrumenter().shouldStart(parentContext, request)) {
-        return;
+      private AdviceScope(Context context, Scope scope) {
+        this.context = context;
+        this.scope = scope;
       }
 
-      context = instrumenter().start(parentContext, request);
-      scope = context.makeCurrent();
-    }
+      @Nullable
+      public static AdviceScope start(Request request) {
+        Context parentContext = currentContext();
 
-    @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
-    public static void finishRequest(
-        @Advice.Argument(0) Request request,
-        @Advice.Argument(1) Response response,
-        @Advice.Thrown Throwable exception,
-        @Advice.Local("otelContext") Context context,
-        @Advice.Local("otelScope") Scope scope) {
+        if (!instrumenter().shouldStart(parentContext, request)) {
+          return null;
+        }
 
-      if (scope == null) {
-        return;
+        Context context = instrumenter().start(parentContext, request);
+        return new AdviceScope(context, context.makeCurrent());
       }
 
-      scope.close();
+      public void end(Throwable exception, Request request, Response response) {
+        scope.close();
 
-      if (Status.CLIENT_ERROR_NOT_FOUND.equals(response.getStatus())) {
-        HttpServerRoute.update(context, CONTROLLER, serverSpanName(), "/*");
-      }
+        if (Status.CLIENT_ERROR_NOT_FOUND.equals(response.getStatus())) {
+          HttpServerRoute.update(context, CONTROLLER, serverSpanName(), "/*");
+        }
 
-      HttpServerResponseCustomizerHolder.getCustomizer()
-          .customize(context, response, RestletResponseMutator.INSTANCE);
+        HttpServerResponseCustomizerHolder.getCustomizer()
+            .customize(context, response, RestletResponseMutator.INSTANCE);
 
-      if (exception != null) {
-        instrumenter().end(context, request, response, exception);
-        return;
+        if (exception != null) {
+          instrumenter().end(context, request, response, exception);
+          return;
+        }
+
+        // Restlet suppresses exceptions and sets the throwable in status
+        Throwable statusThrowable = response.getStatus().getThrowable();
+
+        instrumenter().end(context, request, response, statusThrowable);
       }
+    }
 
-      // Restlet suppresses exceptions and sets the throwable in status
-      Throwable statusThrowable = response.getStatus().getThrowable();
+    @Nullable
+    @Advice.OnMethodEnter(suppress = Throwable.class)
+    public static AdviceScope beginRequest(
+        @Advice.Argument(0) Request request, @Advice.Argument(1) Response response) {
+      return AdviceScope.start(request);
+    }
 
-      instrumenter().end(context, request, response, statusThrowable);
+    @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
+    public static void finishRequest(
+        @Advice.Argument(0) Request request,
+        @Advice.Argument(1) Response response,
+        @Advice.Thrown @Nullable Throwable exception,
+        @Advice.Enter @Nullable AdviceScope adviceScope) {
+
+      if (adviceScope != null) {
+        adviceScope.end(exception, request, response);
+      }
     }
   }
 }