Fix Bolt server span: store protocol in SofaRequest props instead of ThreadLocal

Author: ValentinZakharov

dd-java-agent/instrumentation/sofarpc/sofarpc-5.0/src/main/java/datadog/trace/instrumentation/sofarpc/BoltServerProcessorInstrumentation.java

@@ -5,6 +5,7 @@
 import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
 import static net.bytebuddy.matcher.ElementMatchers.takesArguments;
 
+import com.alipay.sofa.rpc.core.request.SofaRequest;
 import datadog.trace.agent.tooling.Instrumenter;
 import net.bytebuddy.asm.Advice;
 
@@ -28,13 +29,16 @@ public void methodAdvice(MethodTransformer transformer) {
 
   public static class HandleRequestAdvice {
     @Advice.OnMethodEnter(suppress = Throwable.class)
-    public static void enter() {
-      SofaRpcProtocolContext.set("bolt");
+    public static void enter(@Advice.Argument(2) SofaRequest request) {
+      // Bolt dispatches business logic to a thread pool, so a ThreadLocal would not survive the
+      // handoff. Store the protocol on the SofaRequest itself — the same object is passed to
+      // ProviderProxyInvoker.invoke() on the worker thread.
+      if (request != null) {
+        request.addRequestProp(SofaRpcProtocolContext.REQUEST_PROP_PROTOCOL, "bolt");
+      }
     }
 
     @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
-    public static void exit() {
-      SofaRpcProtocolContext.clear();
-    }
+    public static void exit() {}
   }
 }

dd-java-agent/instrumentation/sofarpc/sofarpc-5.0/src/main/java/datadog/trace/instrumentation/sofarpc/ProviderProxyInvokerInstrumentation.java

@@ -17,6 +17,7 @@
 import datadog.trace.bootstrap.instrumentation.api.AgentScope;
 import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
 import datadog.trace.bootstrap.instrumentation.api.AgentSpanContext;
+import java.util.Map;
 import net.bytebuddy.asm.Advice;
 
 public class ProviderProxyInvokerInstrumentation
@@ -40,9 +41,20 @@ public void methodAdvice(MethodTransformer transformer) {
   public static class InvokeAdvice {
     @Advice.OnMethodEnter(suppress = Throwable.class)
     public static AgentScope enter(@Advice.Argument(0) SofaRequest request) {
-      // Protocol is set in thread-local by transport-specific instrumentation before this call.
-      // If null, the transport is not instrumented — skip.
+      // For H2C / REST / Triple the protocol is set in a thread-local by transport-specific
+      // instrumentation that runs on the same thread as this method.
+      // For Bolt the business logic is dispatched to a thread pool, so the protocol is stored
+      // directly on the SofaRequest instead (see BoltServerProcessorInstrumentation).
       String protocol = SofaRpcProtocolContext.get();
+      if (protocol == null && request != null) {
+        Map<String, Object> props = request.getRequestProps();
+        if (props != null) {
+          Object p = props.get(SofaRpcProtocolContext.REQUEST_PROP_PROTOCOL);
+          if (p instanceof String) {
+            protocol = (String) p;
+          }
+        }
+      }
       if (protocol == null) {
         return null;
       }

dd-java-agent/instrumentation/sofarpc/sofarpc-5.0/src/main/java/datadog/trace/instrumentation/sofarpc/SofaRpcProtocolContext.java

@@ -3,6 +3,13 @@
 /** Thread-local carrier for the SOFA RPC transport protocol name. */
 public final class SofaRpcProtocolContext {
 
+  /**
+   * Key used to store the transport protocol in {@code SofaRequest.requestProps} for transports
+   * that dispatch business logic to a thread pool (e.g. Bolt). Using a request prop instead of a
+   * ThreadLocal ensures the value survives the handoff to the worker thread.
+   */
+  public static final String REQUEST_PROP_PROTOCOL = "_dd.sofarpc.protocol";
+
   private static final ThreadLocal<String> PROTOCOL = new ThreadLocal<>();
 
   private SofaRpcProtocolContext() {}