From 922775afaeff5cc2c1fc4b99b59e6c17f0582f5d Mon Sep 17 00:00:00 2001
From: "datadog-official[bot]"
 <214633350+datadog-official[bot]@users.noreply.github.com>
Date: Tue, 20 Jan 2026 16:40:50 +0000
Subject: [PATCH] Handle HTTP2 netty server status

Co-authored-by: dougqh <dougqh@gmail.com>
---
 .../HttpServerResponseTracingHandler.java     | 32 +++++++++++++++-
 .../Netty41Http2StatusPropagationTest.groovy  | 38 +++++++++++++++++++
 2 files changed, 69 insertions(+), 1 deletion(-)
 create mode 100644 dd-java-agent/instrumentation/netty/netty-4.1/src/test/groovy/Netty41Http2StatusPropagationTest.groovy

diff --git a/dd-java-agent/instrumentation/netty/netty-4.1/src/main/java/datadog/trace/instrumentation/netty41/server/HttpServerResponseTracingHandler.java b/dd-java-agent/instrumentation/netty/netty-4.1/src/main/java/datadog/trace/instrumentation/netty41/server/HttpServerResponseTracingHandler.java
index 1cf31f91eae..32afc422e19 100644
--- a/dd-java-agent/instrumentation/netty/netty-4.1/src/main/java/datadog/trace/instrumentation/netty41/server/HttpServerResponseTracingHandler.java
+++ b/dd-java-agent/instrumentation/netty/netty-4.1/src/main/java/datadog/trace/instrumentation/netty41/server/HttpServerResponseTracingHandler.java
@@ -16,6 +16,8 @@
 import io.netty.handler.codec.http.HttpHeaderNames;
 import io.netty.handler.codec.http.HttpResponse;
 import io.netty.handler.codec.http.HttpResponseStatus;
+import io.netty.handler.codec.http2.Http2Headers;
+import io.netty.handler.codec.http2.Http2HeadersFrame;
 
 @ChannelHandler.Sharable
 public class HttpServerResponseTracingHandler extends ChannelOutboundHandlerAdapter {
@@ -26,12 +28,40 @@ public void write(final ChannelHandlerContext ctx, final Object msg, final Chann
     final Context storedContext = ctx.channel().attr(CONTEXT_ATTRIBUTE_KEY).get();
     final AgentSpan span = spanFromContext(storedContext);
 
-    if (span == null || !(msg instanceof HttpResponse)) {
+    if (span == null
+        || !(msg instanceof HttpResponse || msg instanceof Http2HeadersFrame)) {
       ctx.write(msg, prm);
       return;
     }
 
     try (final ContextScope scope = storedContext.attach()) {
+      if (msg instanceof Http2HeadersFrame) {
+        final Http2HeadersFrame headersFrame = (Http2HeadersFrame) msg;
+        final Http2Headers headers = headersFrame.headers();
+        try {
+          ctx.write(msg, prm);
+        } catch (final Throwable throwable) {
+          DECORATE.onError(span, throwable);
+          span.setHttpStatusCode(500);
+          span.finish();
+          ctx.channel().attr(CONTEXT_ATTRIBUTE_KEY).remove();
+          throw throwable;
+        }
+
+        final CharSequence status = headers.status();
+        if (status != null) {
+          try {
+            DECORATE.onResponseStatus(span, HttpResponseStatus.parseLine(status).code());
+          } catch (IllegalArgumentException ignored) {
+            // ignore unparsable status and finish without setting http.status_code
+          }
+        }
+        DECORATE.beforeFinish(scope.context());
+        span.finish();
+        ctx.channel().attr(CONTEXT_ATTRIBUTE_KEY).remove();
+        return;
+      }
+
       final HttpResponse response = (HttpResponse) msg;
 
       try {
diff --git a/dd-java-agent/instrumentation/netty/netty-4.1/src/test/groovy/Netty41Http2StatusPropagationTest.groovy b/dd-java-agent/instrumentation/netty/netty-4.1/src/test/groovy/Netty41Http2StatusPropagationTest.groovy
new file mode 100644
index 00000000000..1b6e5bc490f
--- /dev/null
+++ b/dd-java-agent/instrumentation/netty/netty-4.1/src/test/groovy/Netty41Http2StatusPropagationTest.groovy
@@ -0,0 +1,38 @@
+import datadog.context.Context
+import datadog.trace.agent.test.InstrumentationSpecification
+import datadog.trace.instrumentation.netty41.AttributeKeys
+import datadog.trace.instrumentation.netty41.server.HttpServerResponseTracingHandler
+import datadog.trace.instrumentation.netty41.server.NettyHttpServerDecorator
+import io.netty.channel.embedded.EmbeddedChannel
+import io.netty.handler.codec.http.DefaultHttpRequest
+import io.netty.handler.codec.http.HttpMethod
+import io.netty.handler.codec.http.HttpVersion
+import io.netty.handler.codec.http2.DefaultHttp2Headers
+import io.netty.handler.codec.http2.DefaultHttp2HeadersFrame
+
+class Netty41Http2StatusPropagationTest extends InstrumentationSpecification {
+
+  def "http2 headers frame sets status on netty server span"() {
+    setup:
+    def channel = new EmbeddedChannel(HttpServerResponseTracingHandler.INSTANCE)
+    def request = new DefaultHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET, "/test")
+    def context = NettyHttpServerDecorator.DECORATE.startSpan(request, Context.root())
+    channel.attr(AttributeKeys.CONTEXT_ATTRIBUTE_KEY).set(context)
+
+    when:
+    def headers = new DefaultHttp2Headers().status("200")
+    channel.writeAndFlush(new DefaultHttp2HeadersFrame(headers, true))
+
+    then:
+    assertTraces(1) {
+      trace(1) {
+        span {
+          tags { "http.status_code" 200 }
+        }
+      }
+    }
+
+    cleanup:
+    channel.finishAndReleaseAll()
+  }
+}
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