Resolve the issue of failing to retrieve attachments in dubbo 2.7.6 and 2.7.7

instrumentation/apache-dubbo-2.7/library-autoconfigure/src/main/java/io/opentelemetry/instrumentation/apachedubbo/v2_7/DubboHeadersGetter.java

@@ -6,14 +6,44 @@
 package io.opentelemetry.instrumentation.apachedubbo.v2_7;
 
 import io.opentelemetry.context.propagation.TextMapGetter;
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.invoke.MethodType;
+import java.util.Map;
+import org.apache.dubbo.rpc.RpcInvocation;
 
 enum DubboHeadersGetter implements TextMapGetter<DubboRequest> {
   INSTANCE;
 
+  private static final MethodHandle GET_OBJECT_ATTACHMENTS;
+
+  static {
+    MethodHandles.Lookup lookup = MethodHandles.lookup();
+    MethodHandle getObjectAttachments = null;
+    try {
+      getObjectAttachments =
+          lookup.findStatic(
+              RpcInvocation.class, "getObjectAttachments", MethodType.methodType(void.class));
+    } catch (Throwable t) {
+      // ignore
+    }
+    GET_OBJECT_ATTACHMENTS = getObjectAttachments;
+  }
+
   @Override
-  @SuppressWarnings("deprecation") // deprecation for dubbo 3.2.15
+  @SuppressWarnings("unchecked") // unchecked for 2.7.6, 2.7.7
   public Iterable<String> keys(DubboRequest request) {
-    return request.invocation().getAttachments().keySet();
+    RpcInvocation invocation = request.invocation();
+    try {
+      // In 2.7.6, 2.7.7, the StringToObjectMap implementation does not correctly retrieve the
+      // keySet. Therefore, it's advisable to always call getObjectAttachments when it is available.
+      if (GET_OBJECT_ATTACHMENTS != null) {
+        return ((Map<String, Object>) GET_OBJECT_ATTACHMENTS.invoke(invocation)).keySet();
+      }
+    } catch (Throwable t) {
+      // ignore
+    }
+    return invocation.getAttachments().keySet();
   }
 
   @Override

instrumentation/apache-dubbo-2.7/library-autoconfigure/src/test/java/io/opentelemetry/instrumentation/apachedubbo/v2_7/DubboHeadersGetterTest.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.apachedubbo.v2_7;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.when;
+
+import java.net.InetSocketAddress;
+import java.util.Iterator;
+import org.apache.dubbo.common.URL;
+import org.apache.dubbo.rpc.RpcContext;
+import org.apache.dubbo.rpc.RpcInvocation;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+class DubboHeadersGetterTest {
+
+  @Mock RpcContext context;
+
+  @Test
+  @SuppressWarnings("deprecation") // deprecation for RpcInvocation()
+  void testKeys() {
+    when(context.getUrl()).thenReturn(new URL("http", "localhost", 1));
+    when(context.getRemoteAddress()).thenReturn(new InetSocketAddress(1));
+    when(context.getLocalAddress()).thenReturn(new InetSocketAddress(1));
+
+    RpcInvocation invocation = new RpcInvocation();
+    invocation.setAttachment("key", "value");
+    DubboRequest request = DubboRequest.create(invocation, context);
+
+    Iterator<String> iterator = DubboHeadersGetter.INSTANCE.keys(request).iterator();
+    assertThat(iterator.hasNext()).isTrue();
+    assertThat(iterator.next()).isEqualTo("key");
+    assertThat(iterator.hasNext()).isFalse();
+  }
+}