Propagate grizzly http span in filters if nothing is active (#9016)

Author: amarziali

dd-java-agent/instrumentation/grizzly-http-2.3.20/src/main/java/datadog/trace/instrumentation/grizzlyhttp232/DefaultFilterChainInstrumentation.java

@@ -1,6 +1,9 @@
 package datadog.trace.instrumentation.grizzlyhttp232;
 
 import static datadog.trace.agent.tooling.bytebuddy.matcher.NameMatchers.named;
+import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.activateSpan;
+import static datadog.trace.bootstrap.instrumentation.api.AgentTracer.activeSpan;
+import static datadog.trace.bootstrap.instrumentation.decorator.HttpServerDecorator.DD_SPAN_ATTRIBUTE;
 import static net.bytebuddy.matcher.ElementMatchers.isMethod;
 import static net.bytebuddy.matcher.ElementMatchers.isPrivate;
 import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
@@ -9,7 +12,11 @@
 import datadog.trace.agent.tooling.Instrumenter;
 import datadog.trace.agent.tooling.InstrumenterModule;
 import datadog.trace.api.InstrumenterConfig;
+import datadog.trace.bootstrap.instrumentation.api.AgentScope;
+import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
 import java.util.Collections;
+import net.bytebuddy.asm.Advice;
+import org.glassfish.grizzly.filterchain.FilterChainContext;
 
 @AutoService(InstrumenterModule.class)
 public class DefaultFilterChainInstrumentation extends InstrumenterModule.Tracing
@@ -51,5 +58,34 @@ public void methodAdvice(MethodTransformer transformer) {
             .and(takesArgument(0, named("org.glassfish.grizzly.filterchain.FilterChainContext")))
             .and(takesArgument(1, named("java.lang.Throwable"))),
         packageName + ".DefaultFilterChainAdvice");
+    transformer.applyAdvice(
+        isMethod()
+            .and(named("executeFilter"))
+            .and(takesArgument(2, named("org.glassfish.grizzly.filterchain.FilterChainContext"))),
+        getClass().getName() + "$PropagateServerSpanAdvice");
+  }
+
+  public static class PropagateServerSpanAdvice {
+    @Advice.OnMethodEnter(suppress = Throwable.class)
+    public static AgentScope onEnter(@Advice.Argument(2) final FilterChainContext ctx) {
+      final AgentSpan active = activeSpan();
+      // don't activate a span if already one is active
+      if (active != null) {
+        return null;
+      }
+      final Object span = ctx.getAttributes().getAttribute(DD_SPAN_ATTRIBUTE);
+      if (span instanceof AgentSpan) {
+        // activate the http server span when nothing is already active
+        return activateSpan((AgentSpan) span);
+      }
+      return null;
+    }
+
+    @Advice.OnMethodExit(suppress = Throwable.class, onThrowable = Throwable.class)
+    public static void onExit(@Advice.Enter final AgentScope scope) {
+      if (scope != null) {
+        scope.close();
+      }
+    }
   }
 }