Split out :instrumentation:netty:netty-4.1 library (#6820)

Resolves #6734. Builds on #6811.

instrumentation/netty/netty-4-common/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4/common/AbstractNettyChannelPipelineInstrumentation.java

@@ -153,6 +153,11 @@ public abstract class AbstractNettyChannelPipelineInstrumentation implements Typ
           .getName()
           .startsWith("io.opentelemetry.javaagent.instrumentation.netty.")) {
         pipeline.removeLast();
+      } else if (handler
+          .getClass()
+          .getName()
+          .startsWith("io.opentelemetry.instrumentation.netty.")) {
+        pipeline.removeLast();
       }
     }
   }

instrumentation/netty/netty-4-common/library/src/main/java/io/opentelemetry/instrumentation/netty/v4/common/HttpRequestAndChannel.java

@@ -3,7 +3,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.instrumentation.netty.v4.common.internal;
+package io.opentelemetry.instrumentation.netty.v4.common;
 
 import com.google.auto.value.AutoValue;
 import io.netty.channel.Channel;
@@ -11,23 +11,29 @@ import io.netty.handler.codec.http.HttpRequest;
 import java.net.SocketAddress;
 import javax.annotation.Nullable;
 
-/**
+/** A tuple of an {@link HttpRequest} and a {@link Channel}. */
- * This class is internal and is hence not for public use. Its APIs are unstable and can change at
- * any time.
- */
 @AutoValue
 public abstract class HttpRequestAndChannel {
 
+  /** Create a new {@link HttpRequestAndChannel}. */
   public static HttpRequestAndChannel create(HttpRequest request, Channel channel) {
     return new AutoValue_HttpRequestAndChannel(request, channel, channel.remoteAddress());
   }
 
+  /** Returns the {@link HttpRequest}. */
   public abstract HttpRequest request();
 
+  /** Returns the {@link Channel}. */
   public abstract Channel channel();
 
-  // we're capturing the remote address early because in case of timeouts or other connection issues
+  /**
-  // netty may return null when calling Channel.remoteAddress() at the end of processing
+   * Return the {@link Channel#remoteAddress()} present when this {@link HttpRequestAndChannel} was
+   * created.
+   *
+   * <p>We capture the remote address early because netty may return null when calling {@link
+   * Channel#remoteAddress()} at the end of processing in cases of timeouts or other connection
+   * issues.
+   */
   @Nullable
   public abstract SocketAddress remoteAddress();
 }

instrumentation/netty/netty-4-common/library/src/main/java/io/opentelemetry/instrumentation/netty/v4/common/internal/HttpSchemeUtil.java

@@ -6,6 +6,7 @@
 package io.opentelemetry.instrumentation.netty.v4.common.internal;
 
 import io.netty.channel.ChannelHandler;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 
 /**
  * This class is internal and is hence not for public use. Its APIs are unstable and can change at

instrumentation/netty/netty-4-common/library/src/main/java/io/opentelemetry/instrumentation/netty/v4/common/internal/client/HttpRequestHeadersSetter.java

@@ -6,7 +6,7 @@
 package io.opentelemetry.instrumentation.netty.v4.common.internal.client;
 
 import io.opentelemetry.context.propagation.TextMapSetter;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 
 enum HttpRequestHeadersSetter implements TextMapSetter<HttpRequestAndChannel> {
   INSTANCE;

instrumentation/netty/netty-4-common/library/src/main/java/io/opentelemetry/instrumentation/netty/v4/common/internal/client/NettyClientInstrumenterFactory.java

@@ -7,7 +7,8 @@ package io.opentelemetry.instrumentation.netty.v4.common.internal.client;
 
 import io.netty.channel.Channel;
 import io.netty.handler.codec.http.HttpResponse;
-import io.opentelemetry.api.GlobalOpenTelemetry;
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.instrumentation.api.instrumenter.AttributesExtractor;
 import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
 import io.opentelemetry.instrumentation.api.instrumenter.InstrumenterBuilder;
 import io.opentelemetry.instrumentation.api.instrumenter.SpanKindExtractor;
@@ -19,7 +20,7 @@ import io.opentelemetry.instrumentation.api.instrumenter.net.NetClientAttributes
 import io.opentelemetry.instrumentation.api.instrumenter.net.PeerServiceAttributesExtractor;
 import io.opentelemetry.instrumentation.netty.common.internal.HttpClientSpanKeyAttributesExtractor;
 import io.opentelemetry.instrumentation.netty.common.internal.NettyConnectionRequest;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import java.util.List;
 import java.util.Map;
 
@@ -29,35 +30,36 @@ import java.util.Map;
  */
 public final class NettyClientInstrumenterFactory {
 
+  private final OpenTelemetry openTelemetry;
   private final String instrumentationName;
   private final boolean connectionTelemetryEnabled;
   private final boolean sslTelemetryEnabled;
-  private final List<String> capturedRequestHeaders;
-  private final List<String> capturedResponseHeaders;
   private final Map<String, String> peerServiceMapping;
 
   public NettyClientInstrumenterFactory(
+      OpenTelemetry openTelemetry,
       String instrumentationName,
       boolean connectionTelemetryEnabled,
       boolean sslTelemetryEnabled,
-      List<String> capturedRequestHeaders,
-      List<String> capturedResponseHeaders,
       Map<String, String> peerServiceMapping) {
+    this.openTelemetry = openTelemetry;
     this.instrumentationName = instrumentationName;
     this.connectionTelemetryEnabled = connectionTelemetryEnabled;
     this.sslTelemetryEnabled = sslTelemetryEnabled;
-    this.capturedRequestHeaders = capturedRequestHeaders;
-    this.capturedResponseHeaders = capturedResponseHeaders;
     this.peerServiceMapping = peerServiceMapping;
   }
 
-  public Instrumenter<HttpRequestAndChannel, HttpResponse> createHttpInstrumenter() {
+  public Instrumenter<HttpRequestAndChannel, HttpResponse> createHttpInstrumenter(
+      List<String> capturedRequestHeaders,
+      List<String> capturedResponseHeaders,
+      List<AttributesExtractor<HttpRequestAndChannel, HttpResponse>>
+          additionalHttpAttributeExtractors) {
     NettyHttpClientAttributesGetter httpClientAttributesGetter =
         new NettyHttpClientAttributesGetter();
     NettyNetClientAttributesGetter netAttributesGetter = new NettyNetClientAttributesGetter();
 
     return Instrumenter.<HttpRequestAndChannel, HttpResponse>builder(
-            GlobalOpenTelemetry.get(),
+            openTelemetry,
             instrumentationName,
             HttpSpanNameExtractor.create(httpClientAttributesGetter))
         .setSpanStatusExtractor(HttpSpanStatusExtractor.create(httpClientAttributesGetter))
@@ -69,6 +71,7 @@ public final class NettyClientInstrumenterFactory {
         .addAttributesExtractor(NetClientAttributesExtractor.create(netAttributesGetter))
         .addAttributesExtractor(
             PeerServiceAttributesExtractor.create(netAttributesGetter, peerServiceMapping))
+        .addAttributesExtractors(additionalHttpAttributeExtractors)
         .addOperationMetrics(HttpClientMetrics.get())
         .buildClientInstrumenter(HttpRequestHeadersSetter.INSTANCE);
   }
@@ -78,7 +81,7 @@ public final class NettyClientInstrumenterFactory {
 
     InstrumenterBuilder<NettyConnectionRequest, Channel> instrumenterBuilder =
         Instrumenter.<NettyConnectionRequest, Channel>builder(
-                GlobalOpenTelemetry.get(), instrumentationName, NettyConnectionRequest::spanName)
+                openTelemetry, instrumentationName, NettyConnectionRequest::spanName)
             .addAttributesExtractor(NetClientAttributesExtractor.create(netAttributesGetter))
             .addAttributesExtractor(
                 PeerServiceAttributesExtractor.create(netAttributesGetter, peerServiceMapping));
@@ -108,7 +111,7 @@ public final class NettyClientInstrumenterFactory {
     NettySslNetAttributesGetter netAttributesGetter = new NettySslNetAttributesGetter();
     Instrumenter<NettySslRequest, Void> instrumenter =
         Instrumenter.<NettySslRequest, Void>builder(
-                GlobalOpenTelemetry.get(), instrumentationName, NettySslRequest::spanName)
+                openTelemetry, instrumentationName, NettySslRequest::spanName)
             .addAttributesExtractor(NetClientAttributesExtractor.create(netAttributesGetter))
             .addAttributesExtractor(
                 PeerServiceAttributesExtractor.create(netAttributesGetter, peerServiceMapping))

instrumentation/netty/netty-4-common/library/src/main/java/io/opentelemetry/instrumentation/netty/v4/common/internal/client/NettyHttpClientAttributesGetter.java

@@ -9,7 +9,7 @@ import static io.opentelemetry.instrumentation.netty.v4.common.internal.HttpSche
 
 import io.netty.handler.codec.http.HttpResponse;
 import io.opentelemetry.instrumentation.api.instrumenter.http.HttpClientAttributesGetter;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.List;

instrumentation/netty/netty-4-common/library/src/main/java/io/opentelemetry/instrumentation/netty/v4/common/internal/client/NettyNetClientAttributesGetter.java

@@ -11,7 +11,7 @@ import static io.opentelemetry.semconv.trace.attributes.SemanticAttributes.NetTr
 import io.netty.channel.socket.DatagramChannel;
 import io.netty.handler.codec.http.HttpResponse;
 import io.opentelemetry.instrumentation.api.instrumenter.net.InetSocketAddressNetClientAttributesGetter;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import javax.annotation.Nullable;

instrumentation/netty/netty-4-common/library/src/main/java/io/opentelemetry/instrumentation/netty/v4/common/internal/server/HttpRequestHeadersGetter.java

@@ -6,7 +6,7 @@
 package io.opentelemetry.instrumentation.netty.v4.common.internal.server;
 
 import io.opentelemetry.context.propagation.TextMapGetter;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import javax.annotation.Nullable;
 
 enum HttpRequestHeadersGetter implements TextMapGetter<HttpRequestAndChannel> {

instrumentation/netty/netty-4-common/library/src/main/java/io/opentelemetry/instrumentation/netty/v4/common/internal/server/NettyHttpServerAttributesGetter.java

@@ -9,7 +9,7 @@ import static io.opentelemetry.instrumentation.netty.v4.common.internal.HttpSche
 
 import io.netty.handler.codec.http.HttpResponse;
 import io.opentelemetry.instrumentation.api.instrumenter.http.HttpServerAttributesGetter;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import java.util.List;
 import javax.annotation.Nullable;
 

instrumentation/netty/netty-4-common/library/src/main/java/io/opentelemetry/instrumentation/netty/v4/common/internal/server/NettyNetServerAttributesGetter.java

@@ -10,7 +10,7 @@ import static io.opentelemetry.semconv.trace.attributes.SemanticAttributes.NetTr
 
 import io.netty.channel.socket.DatagramChannel;
 import io.opentelemetry.instrumentation.api.instrumenter.net.InetSocketAddressNetServerAttributesGetter;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
 import javax.annotation.Nullable;

instrumentation/netty/netty-4-common/library/src/main/java/io/opentelemetry/instrumentation/netty/v4/common/internal/server/NettyServerInstrumenterFactory.java

@@ -6,7 +6,7 @@
 package io.opentelemetry.instrumentation.netty.v4.common.internal.server;
 
 import io.netty.handler.codec.http.HttpResponse;
-import io.opentelemetry.api.GlobalOpenTelemetry;
+import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
 import io.opentelemetry.instrumentation.api.instrumenter.http.HttpRouteHolder;
 import io.opentelemetry.instrumentation.api.instrumenter.http.HttpServerAttributesExtractor;
@@ -15,7 +15,7 @@ import io.opentelemetry.instrumentation.api.instrumenter.http.HttpSpanNameExtrac
 import io.opentelemetry.instrumentation.api.instrumenter.http.HttpSpanStatusExtractor;
 import io.opentelemetry.instrumentation.api.instrumenter.net.NetServerAttributesExtractor;
 import io.opentelemetry.instrumentation.netty.common.internal.NettyErrorHolder;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import java.util.List;
 
 /**
@@ -25,6 +25,7 @@ import java.util.List;
 public final class NettyServerInstrumenterFactory {
 
   public static Instrumenter<HttpRequestAndChannel, HttpResponse> create(
+      OpenTelemetry openTelemetry,
       String instrumentationName,
       List<String> capturedRequestHeaders,
       List<String> capturedResponseHeaders) {
@@ -32,9 +33,7 @@ public final class NettyServerInstrumenterFactory {
     NettyHttpServerAttributesGetter httpAttributesGetter = new NettyHttpServerAttributesGetter();
 
     return Instrumenter.<HttpRequestAndChannel, HttpResponse>builder(
-            GlobalOpenTelemetry.get(),
+            openTelemetry, instrumentationName, HttpSpanNameExtractor.create(httpAttributesGetter))
-            instrumentationName,
-            HttpSpanNameExtractor.create(httpAttributesGetter))
         .setSpanStatusExtractor(HttpSpanStatusExtractor.create(httpAttributesGetter))
         .addAttributesExtractor(
             HttpServerAttributesExtractor.builder(httpAttributesGetter)

instrumentation/netty/netty-4.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_0/AbstractChannelHandlerContextInstrumentation.java

@@ -15,7 +15,7 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.util.Attribute;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.instrumentation.netty.common.internal.NettyErrorHolder;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
 import net.bytebuddy.asm.Advice;

instrumentation/netty/netty-4.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_0/AttributeKeys.java

@@ -8,7 +8,7 @@ package io.opentelemetry.javaagent.instrumentation.netty.v4_0;
 import io.netty.handler.codec.http.HttpResponse;
 import io.netty.util.AttributeKey;
 import io.opentelemetry.context.Context;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 

instrumentation/netty/netty-4.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_0/client/HttpClientRequestTracingHandler.java

@@ -14,7 +14,7 @@ import io.netty.handler.codec.http.HttpRequest;
 import io.netty.util.Attribute;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import io.opentelemetry.javaagent.instrumentation.netty.v4_0.AttributeKeys;
 
 public class HttpClientRequestTracingHandler extends ChannelOutboundHandlerAdapter {

instrumentation/netty/netty-4.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_0/client/HttpClientResponseTracingHandler.java

@@ -15,7 +15,7 @@ import io.netty.handler.codec.http.LastHttpContent;
 import io.netty.util.Attribute;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import io.opentelemetry.javaagent.instrumentation.netty.v4_0.AttributeKeys;
 
 public class HttpClientResponseTracingHandler extends ChannelInboundHandlerAdapter {

instrumentation/netty/netty-4.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_0/client/NettyClientSingletons.java

@@ -6,14 +6,16 @@
 package io.opentelemetry.javaagent.instrumentation.netty.v4_0.client;
 
 import io.netty.handler.codec.http.HttpResponse;
+import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import io.opentelemetry.instrumentation.netty.v4.common.internal.client.NettyClientInstrumenterFactory;
 import io.opentelemetry.instrumentation.netty.v4.common.internal.client.NettyConnectionInstrumenter;
 import io.opentelemetry.instrumentation.netty.v4.common.internal.client.NettySslInstrumenter;
 import io.opentelemetry.javaagent.bootstrap.internal.CommonConfig;
 import io.opentelemetry.javaagent.bootstrap.internal.DeprecatedConfigPropertyWarning;
 import io.opentelemetry.javaagent.bootstrap.internal.InstrumentationConfig;
+import java.util.Collections;
 
 public final class NettyClientSingletons {
 
@@ -42,13 +44,16 @@ public final class NettyClientSingletons {
   static {
     NettyClientInstrumenterFactory factory =
         new NettyClientInstrumenterFactory(
+            GlobalOpenTelemetry.get(),
             "io.opentelemetry.netty-4.0",
             connectionTelemetryEnabled,
             sslTelemetryEnabled,
+            CommonConfig.get().getPeerServiceMapping());
+    INSTRUMENTER =
+        factory.createHttpInstrumenter(
             CommonConfig.get().getClientRequestHeaders(),
             CommonConfig.get().getClientResponseHeaders(),
-            CommonConfig.get().getPeerServiceMapping());
+            Collections.emptyList());
-    INSTRUMENTER = factory.createHttpInstrumenter();
     CONNECTION_INSTRUMENTER = factory.createConnectionInstrumenter();
     SSL_INSTRUMENTER = factory.createSslInstrumenter();
   }

instrumentation/netty/netty-4.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_0/server/HttpServerRequestTracingHandler.java

@@ -14,7 +14,7 @@ import io.netty.handler.codec.http.HttpRequest;
 import io.netty.util.Attribute;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import io.opentelemetry.javaagent.instrumentation.netty.v4_0.AttributeKeys;
 
 public class HttpServerRequestTracingHandler extends ChannelInboundHandlerAdapter {

instrumentation/netty/netty-4.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_0/server/HttpServerResponseTracingHandler.java

@@ -15,7 +15,7 @@ import io.netty.handler.codec.http.HttpResponse;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
 import io.opentelemetry.instrumentation.netty.common.internal.NettyErrorHolder;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import io.opentelemetry.javaagent.instrumentation.netty.v4_0.AttributeKeys;
 import javax.annotation.Nullable;
 

instrumentation/netty/netty-4.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_0/server/NettyServerSingletons.java

@@ -6,8 +6,9 @@
 package io.opentelemetry.javaagent.instrumentation.netty.v4_0.server;
 
 import io.netty.handler.codec.http.HttpResponse;
+import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import io.opentelemetry.instrumentation.netty.v4.common.internal.server.NettyServerInstrumenterFactory;
 import io.opentelemetry.javaagent.bootstrap.internal.CommonConfig;
 
@@ -15,6 +16,7 @@ public final class NettyServerSingletons {
 
   private static final Instrumenter<HttpRequestAndChannel, HttpResponse> INSTRUMENTER =
       NettyServerInstrumenterFactory.create(
+          GlobalOpenTelemetry.get(),
           "io.opentelemetry.netty-4.0",
           CommonConfig.get().getServerRequestHeaders(),
           CommonConfig.get().getServerResponseHeaders());

instrumentation/netty/netty-4.1/javaagent/build.gradle.kts

@@ -25,6 +25,7 @@ muzzle {
 
 dependencies {
   library("io.netty:netty-codec-http:4.1.0.Final")
+  implementation(project(":instrumentation:netty:netty-4.1:library"))
   implementation(project(":instrumentation:netty:netty-4-common:javaagent"))
   implementation(project(":instrumentation:netty:netty-4-common:library"))
   implementation(project(":instrumentation:netty:netty-common:library"))

instrumentation/netty/netty-4.1/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_1/AbstractChannelHandlerContextInstrumentation.java

@@ -5,7 +5,8 @@
 
 package io.opentelemetry.javaagent.instrumentation.netty.v4_1;
 
-import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.NettyClientSingletons.instrumenter;
+import static io.opentelemetry.instrumentation.netty.v4_1.internal.client.HttpClientRequestTracingHandler.HTTP_REQUEST;
+import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.NettyClientSingletons.instrumenter;
 import static net.bytebuddy.matcher.ElementMatchers.isMethod;
 import static net.bytebuddy.matcher.ElementMatchers.named;
 import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
@@ -14,10 +15,10 @@ import io.netty.channel.ChannelHandlerContext;
 import io.netty.util.Attribute;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.instrumentation.netty.common.internal.NettyErrorHolder;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.AttributeKeys;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.NettyClientSingletons;
 import net.bytebuddy.asm.Advice;
 import net.bytebuddy.description.type.TypeDescription;
 import net.bytebuddy.matcher.ElementMatcher;
@@ -51,8 +52,7 @@ public class AbstractChannelHandlerContextInstrumentation implements TypeInstrum
       if (clientContext != null) {
         ctx.channel().attr(AttributeKeys.CLIENT_PARENT_CONTEXT).remove();
         contextAttr.remove();
-        HttpRequestAndChannel request =
+        HttpRequestAndChannel request = ctx.channel().attr(HTTP_REQUEST).getAndRemove();
-            ctx.channel().attr(NettyClientSingletons.HTTP_REQUEST).getAndRemove();
         instrumenter().end(clientContext, request, null, throwable);
         return;
       }

instrumentation/netty/netty-4.1/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_1/BootstrapInstrumentation.java

@@ -5,7 +5,7 @@
 
 package io.opentelemetry.javaagent.instrumentation.netty.v4_1;
 
-import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.NettyClientSingletons.connectionInstrumenter;
+import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.NettyClientSingletons.connectionInstrumenter;
 import static net.bytebuddy.matcher.ElementMatchers.isConstructor;
 import static net.bytebuddy.matcher.ElementMatchers.named;
 import static net.bytebuddy.matcher.ElementMatchers.takesArgument;

instrumentation/netty/netty-4.1/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_1/ChannelInstrumentation.java

@@ -12,6 +12,7 @@ import static net.bytebuddy.matcher.ElementMatchers.named;
 import static net.bytebuddy.matcher.ElementMatchers.namedOneOf;
 
 import io.netty.channel.Channel;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.AttributeKeys;
 import io.opentelemetry.javaagent.bootstrap.Java8BytecodeBridge;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;

instrumentation/netty/netty-4.1/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_1/NettyChannelPipelineInstrumentation.java

@@ -5,7 +5,7 @@
 
 package io.opentelemetry.javaagent.instrumentation.netty.v4_1;
 
-import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.NettyClientSingletons.sslInstrumenter;
+import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.NettyClientSingletons.sslInstrumenter;
 import static net.bytebuddy.matcher.ElementMatchers.isMethod;
 import static net.bytebuddy.matcher.ElementMatchers.nameStartsWith;
 import static net.bytebuddy.matcher.ElementMatchers.named;
@@ -22,15 +22,15 @@ import io.netty.handler.codec.http.HttpResponseEncoder;
 import io.netty.handler.codec.http.HttpServerCodec;
 import io.opentelemetry.instrumentation.api.util.VirtualField;
 import io.opentelemetry.instrumentation.netty.v4.common.internal.client.NettySslInstrumentationHandler;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.client.HttpClientRequestTracingHandler;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.client.HttpClientResponseTracingHandler;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.client.HttpClientTracingHandler;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.server.HttpServerRequestTracingHandler;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.server.HttpServerResponseTracingHandler;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.server.HttpServerTracingHandler;
 import io.opentelemetry.javaagent.bootstrap.CallDepth;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
 import io.opentelemetry.javaagent.instrumentation.netty.v4.common.AbstractNettyChannelPipelineInstrumentation;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.HttpClientRequestTracingHandler;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.HttpClientResponseTracingHandler;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.HttpClientTracingHandler;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.server.HttpServerRequestTracingHandler;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.server.HttpServerResponseTracingHandler;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.server.HttpServerTracingHandler;
 import net.bytebuddy.asm.Advice;
 
 public class NettyChannelPipelineInstrumentation
@@ -105,18 +105,18 @@ public class NettyChannelPipelineInstrumentation
       ChannelHandler ourHandler = null;
       // Server pipeline handlers
       if (handler instanceof HttpServerCodec) {
-        ourHandler = new HttpServerTracingHandler();
+        ourHandler = new HttpServerTracingHandler(NettyServerSingletons.instrumenter());
       } else if (handler instanceof HttpRequestDecoder) {
-        ourHandler = new HttpServerRequestTracingHandler();
+        ourHandler = new HttpServerRequestTracingHandler(NettyServerSingletons.instrumenter());
       } else if (handler instanceof HttpResponseEncoder) {
-        ourHandler = new HttpServerResponseTracingHandler();
+        ourHandler = new HttpServerResponseTracingHandler(NettyServerSingletons.instrumenter());
         // Client pipeline handlers
       } else if (handler instanceof HttpClientCodec) {
-        ourHandler = new HttpClientTracingHandler();
+        ourHandler = new HttpClientTracingHandler(NettyClientSingletons.instrumenter());
       } else if (handler instanceof HttpRequestEncoder) {
-        ourHandler = new HttpClientRequestTracingHandler();
+        ourHandler = new HttpClientRequestTracingHandler(NettyClientSingletons.instrumenter());
       } else if (handler instanceof HttpResponseDecoder) {
-        ourHandler = new HttpClientResponseTracingHandler();
+        ourHandler = new HttpClientResponseTracingHandler(NettyClientSingletons.instrumenter());
         // the SslHandler lives in the netty-handler module, using class name comparison to avoid
         // adding a dependency
       } else if (handler.getClass().getName().equals("io.netty.handler.ssl.SslHandler")) {

instrumentation/netty/netty-4.1/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_1/NettyClientSingletons.java

@@ -3,26 +3,22 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.javaagent.instrumentation.netty.v4_1.client;
+package io.opentelemetry.javaagent.instrumentation.netty.v4_1;
 
 import io.netty.handler.codec.http.HttpResponse;
-import io.netty.util.AttributeKey;
+import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import io.opentelemetry.instrumentation.netty.v4.common.internal.client.NettyClientInstrumenterFactory;
 import io.opentelemetry.instrumentation.netty.v4.common.internal.client.NettyConnectionInstrumenter;
 import io.opentelemetry.instrumentation.netty.v4.common.internal.client.NettySslInstrumenter;
 import io.opentelemetry.javaagent.bootstrap.internal.CommonConfig;
 import io.opentelemetry.javaagent.bootstrap.internal.DeprecatedConfigPropertyWarning;
 import io.opentelemetry.javaagent.bootstrap.internal.InstrumentationConfig;
+import java.util.Collections;
 
 public final class NettyClientSingletons {
 
-  public static final AttributeKey<HttpRequestAndChannel> HTTP_REQUEST =
-      AttributeKey.valueOf(NettyClientSingletons.class, "http-client-request");
-  static final AttributeKey<HttpResponse> HTTP_RESPONSE =
-      AttributeKey.valueOf(NettyClientSingletons.class, "http-client-response");
-
   private static final boolean connectionTelemetryEnabled;
   private static final boolean sslTelemetryEnabled;
 
@@ -48,13 +44,16 @@ public final class NettyClientSingletons {
   static {
     NettyClientInstrumenterFactory factory =
         new NettyClientInstrumenterFactory(
+            GlobalOpenTelemetry.get(),
             "io.opentelemetry.netty-4.1",
             connectionTelemetryEnabled,
             sslTelemetryEnabled,
+            CommonConfig.get().getPeerServiceMapping());
+    INSTRUMENTER =
+        factory.createHttpInstrumenter(
             CommonConfig.get().getClientRequestHeaders(),
             CommonConfig.get().getClientResponseHeaders(),
-            CommonConfig.get().getPeerServiceMapping());
+            Collections.emptyList());
-    INSTRUMENTER = factory.createHttpInstrumenter();
     CONNECTION_INSTRUMENTER = factory.createConnectionInstrumenter();
     SSL_INSTRUMENTER = factory.createSslInstrumenter();
   }

instrumentation/netty/netty-4.1/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_1/NettyServerSingletons.java

@@ -3,24 +3,20 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.javaagent.instrumentation.netty.v4_1.server;
+package io.opentelemetry.javaagent.instrumentation.netty.v4_1;
 
 import io.netty.handler.codec.http.HttpResponse;
-import io.netty.util.AttributeKey;
+import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
 import io.opentelemetry.instrumentation.netty.v4.common.internal.server.NettyServerInstrumenterFactory;
 import io.opentelemetry.javaagent.bootstrap.internal.CommonConfig;
 
 public final class NettyServerSingletons {
 
-  static final AttributeKey<HttpRequestAndChannel> HTTP_REQUEST =
-      AttributeKey.valueOf(NettyServerSingletons.class, "http-server-request");
-  static final AttributeKey<HttpResponse> HTTP_RESPONSE =
-      AttributeKey.valueOf(NettyServerSingletons.class, "http-server-response");
-
   private static final Instrumenter<HttpRequestAndChannel, HttpResponse> INSTRUMENTER =
       NettyServerInstrumenterFactory.create(
+          GlobalOpenTelemetry.get(),
           "io.opentelemetry.netty-4.1",
           CommonConfig.get().getServerRequestHeaders(),
           CommonConfig.get().getServerResponseHeaders());

instrumentation/netty/netty-4.1/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_1/client/HttpClientTracingHandler.java

@@ -1,17 +0,0 @@
-/*
- * Copyright The OpenTelemetry Authors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package io.opentelemetry.javaagent.instrumentation.netty.v4_1.client;
-
-import io.netty.channel.CombinedChannelDuplexHandler;
-
-public class HttpClientTracingHandler
-    extends CombinedChannelDuplexHandler<
-        HttpClientResponseTracingHandler, HttpClientRequestTracingHandler> {
-
-  public HttpClientTracingHandler() {
-    super(new HttpClientResponseTracingHandler(), new HttpClientRequestTracingHandler());
-  }
-}

instrumentation/netty/netty-4.1/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/netty/v4_1/server/HttpServerTracingHandler.java

@@ -1,17 +0,0 @@
-/*
- * Copyright The OpenTelemetry Authors
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package io.opentelemetry.javaagent.instrumentation.netty.v4_1.server;
-
-import io.netty.channel.CombinedChannelDuplexHandler;
-
-public class HttpServerTracingHandler
-    extends CombinedChannelDuplexHandler<
-        HttpServerRequestTracingHandler, HttpServerResponseTracingHandler> {
-
-  public HttpServerTracingHandler() {
-    super(new HttpServerRequestTracingHandler(), new HttpServerResponseTracingHandler());
-  }
-}

instrumentation/netty/netty-4.1/javaagent/src/test/groovy/ChannelPipelineTest.groovy

@@ -8,7 +8,7 @@ import io.netty.channel.DefaultChannelPipeline
 import io.netty.channel.embedded.EmbeddedChannel
 import io.netty.handler.codec.http.HttpClientCodec
 import io.opentelemetry.instrumentation.test.AgentInstrumentationSpecification
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.HttpClientTracingHandler
+import io.opentelemetry.instrumentation.netty.v4_1.internal.client.HttpClientTracingHandler
 import spock.lang.Unroll
 
 @Unroll
@@ -31,7 +31,7 @@ class ChannelPipelineTest extends AgentInstrumentationSpecification {
     channelPipeline.addLast("http", handler)
     channelPipeline.first() == handler
     // our handler was also added
-    channelPipeline.last().getClass() == HttpClientTracingHandler
+    channelPipeline.last().getClass().simpleName == "HttpClientTracingHandler"
 
     and:
     removeMethod.call(channelPipeline, handler)
@@ -70,7 +70,7 @@ class ChannelPipelineTest extends AgentInstrumentationSpecification {
     then: "noop handler was removed; http and instrumentation handlers were added"
     channelPipeline.size() == 2
     channelPipeline.first() == httpHandler
-    channelPipeline.last().getClass() == HttpClientTracingHandler
+    channelPipeline.last().getClass().simpleName == "HttpClientTracingHandler"
 
     when:
     def anotherNoopHandler = new NoopChannelHandler()
@@ -103,7 +103,7 @@ class ChannelPipelineTest extends AgentInstrumentationSpecification {
     then: "add http and instrumentation handlers"
     channelPipeline.size() == 2
     channelPipeline.first() == httpHandler
-    channelPipeline.last().getClass() == HttpClientTracingHandler
+    channelPipeline.last().getClass().simpleName == "HttpClientTracingHandler"
 
     when:
     def noopHandler = new NoopChannelHandler()
@@ -120,7 +120,7 @@ class ChannelPipelineTest extends AgentInstrumentationSpecification {
     then: "http and instrumentation handlers will be remained"
     channelPipeline.size() == 2
     channelPipeline.first() == httpHandler
-    channelPipeline.last().getClass() == HttpClientTracingHandler
+    channelPipeline.last().getClass().simpleName == "HttpClientTracingHandler"
 
     when:
     channelPipeline.removeLast()

instrumentation/netty/netty-4.1/javaagent/src/test/groovy/Netty41ClientTest.groovy

@@ -30,7 +30,6 @@ import io.opentelemetry.instrumentation.test.AgentTestTrait
 import io.opentelemetry.instrumentation.test.base.HttpClientTest
 import io.opentelemetry.instrumentation.testing.junit.http.AbstractHttpClientTest
 import io.opentelemetry.instrumentation.testing.junit.http.SingleConnection
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.HttpClientTracingHandler
 import io.opentelemetry.semconv.trace.attributes.SemanticAttributes
 import spock.lang.Shared
 import spock.lang.Unroll
@@ -253,7 +252,7 @@ class Netty41ClientTest extends HttpClientTest<DefaultFullHttpRequest> implement
 
     then:
     // The first one returns the removed tracing handler
-    pipeline.remove(HttpClientTracingHandler.getName()) != null
+    pipeline.remove("io.opentelemetry.javaagent.shaded.instrumentation.netty.v4_1.internal.client.HttpClientTracingHandler") != null
   }
 
   def "when a handler is added to the netty pipeline we add ONLY ONE tracing handler"() {
@@ -264,9 +263,9 @@ class Netty41ClientTest extends HttpClientTest<DefaultFullHttpRequest> implement
     when:
     pipeline.addLast("name", new HttpClientCodec())
     // The first one returns the removed tracing handler
-    pipeline.remove(HttpClientTracingHandler.getName())
+    pipeline.remove("io.opentelemetry.javaagent.shaded.instrumentation.netty.v4_1.internal.client.HttpClientTracingHandler")
     // There is only one
-    pipeline.remove(HttpClientTracingHandler.getName()) == null
+    pipeline.remove("io.opentelemetry.javaagent.shaded.instrumentation.netty.v4_1.internal.client.HttpClientTracingHandler") == null
 
     then:
     thrown NoSuchElementException
@@ -283,7 +282,7 @@ class Netty41ClientTest extends HttpClientTest<DefaultFullHttpRequest> implement
 
     then:
     // The first one returns the removed tracing handler
-    null != pipeline.remove(HttpClientTracingHandler.getName())
+    null != pipeline.remove("io.opentelemetry.javaagent.shaded.instrumentation.netty.v4_1.internal.client.HttpClientTracingHandler")
     null != pipeline.remove("some_handler")
     null != pipeline.remove("a_traced_handler")
   }
@@ -311,9 +310,9 @@ class Netty41ClientTest extends HttpClientTest<DefaultFullHttpRequest> implement
     channel.pipeline().addLast(new TracedHandlerFromInitializerHandler())
 
     then:
-    null != channel.pipeline().get(HttpClientTracingHandler.getName())
+    null != channel.pipeline().get("io.opentelemetry.javaagent.shaded.instrumentation.netty.v4_1.internal.client.HttpClientTracingHandler")
     null != channel.pipeline().remove("added_in_initializer")
-    null == channel.pipeline().get(HttpClientTracingHandler.getName())
+    null == channel.pipeline().get("io.opentelemetry.javaagent.shaded.instrumentation.netty.v4_1.internal.client.HttpClientTracingHandler")
   }
 
   def "request with trace annotated method #method"() {

instrumentation/netty/netty-4.1/library/build.gradle.kts

@@ -0,0 +1,9 @@
+plugins {
+  id("otel.library-instrumentation")
+}
+
+dependencies {
+  library("io.netty:netty-codec-http:4.1.0.Final")
+  implementation(project(":instrumentation:netty:netty-4-common:library"))
+  implementation(project(":instrumentation:netty:netty-common:library"))
+}

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/NettyClientTelemetry.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.netty.v4_1;
+
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.channel.ChannelOutboundHandlerAdapter;
+import io.netty.channel.CombinedChannelDuplexHandler;
+import io.netty.handler.codec.http.HttpResponse;
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.client.HttpClientRequestTracingHandler;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.client.HttpClientResponseTracingHandler;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.client.HttpClientTracingHandler;
+
+/** Entrypoint for instrumenting Netty HTTP clients. */
+public final class NettyClientTelemetry {
+
+  private final Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter;
+
+  NettyClientTelemetry(Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter) {
+    this.instrumenter = instrumenter;
+  }
+
+  /** Returns a new {@link NettyClientTelemetry} configured with the given {@link OpenTelemetry}. */
+  public static NettyClientTelemetry create(OpenTelemetry openTelemetry) {
+    return builder(openTelemetry).build();
+  }
+
+  /**
+   * Returns a new {@link NettyClientTelemetryBuilder} configured with the given {@link
+   * OpenTelemetry}.
+   */
+  public static NettyClientTelemetryBuilder builder(OpenTelemetry openTelemetry) {
+    return new NettyClientTelemetryBuilder(openTelemetry);
+  }
+
+  /**
+   * /** Returns a new {@link ChannelOutboundHandlerAdapter} that generates telemetry for outgoing
+   * HTTP requests. Must be paired with {@link #createResponseHandler()}.
+   */
+  public ChannelOutboundHandlerAdapter createRequestHandler() {
+    return new HttpClientRequestTracingHandler(instrumenter);
+  }
+
+  /**
+   * Returns a new {@link ChannelInboundHandlerAdapter} that generates telemetry for incoming HTTP
+   * responses. Must be paired with {@link #createRequestHandler()}.
+   */
+  public ChannelInboundHandlerAdapter createResponseHandler() {
+    return new HttpClientResponseTracingHandler(instrumenter);
+  }
+
+  /**
+   * Returns a new {@link CombinedChannelDuplexHandler} that generates telemetry for outgoing HTTP
+   * requests and incoming responses in a single handler.
+   */
+  public CombinedChannelDuplexHandler<
+          ? extends ChannelInboundHandlerAdapter, ? extends ChannelOutboundHandlerAdapter>
+      createCombinedHandler() {
+    return new HttpClientTracingHandler(instrumenter);
+  }
+}

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/NettyClientTelemetryBuilder.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.netty.v4_1;
+
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
+import io.netty.handler.codec.http.HttpResponse;
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.instrumentation.api.instrumenter.AttributesExtractor;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.internal.client.NettyClientInstrumenterFactory;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/** A builder of {@link NettyClientTelemetry}. */
+public final class NettyClientTelemetryBuilder {
+
+  private final OpenTelemetry openTelemetry;
+  private List<String> capturedRequestHeaders = Collections.emptyList();
+  private List<String> capturedResponseHeaders = Collections.emptyList();
+  private final List<AttributesExtractor<HttpRequestAndChannel, HttpResponse>>
+      additionalAttributesExtractors = new ArrayList<>();
+
+  NettyClientTelemetryBuilder(OpenTelemetry openTelemetry) {
+    this.openTelemetry = openTelemetry;
+  }
+
+  /**
+   * Configures the HTTP request headers that will be captured as span attributes.
+   *
+   * @param capturedRequestHeaders A list of HTTP header names.
+   */
+  @CanIgnoreReturnValue
+  public NettyClientTelemetryBuilder setCapturedRequestHeaders(
+      List<String> capturedRequestHeaders) {
+    this.capturedRequestHeaders = capturedRequestHeaders;
+    return this;
+  }
+
+  /**
+   * Configures the HTTP response headers that will be captured as span attributes.
+   *
+   * @param capturedResponseHeaders A list of HTTP header names.
+   */
+  @CanIgnoreReturnValue
+  public NettyClientTelemetryBuilder setCapturedResponseHeaders(
+      List<String> capturedResponseHeaders) {
+    this.capturedResponseHeaders = capturedResponseHeaders;
+    return this;
+  }
+
+  /**
+   * Adds an additional {@link AttributesExtractor} to invoke to set attributes to instrumented
+   * items.
+   */
+  @CanIgnoreReturnValue
+  public NettyClientTelemetryBuilder addAttributesExtractor(
+      AttributesExtractor<HttpRequestAndChannel, HttpResponse> attributesExtractor) {
+    additionalAttributesExtractors.add(attributesExtractor);
+    return this;
+  }
+
+  /** Returns a new {@link NettyClientTelemetry} with the given configuration. */
+  public NettyClientTelemetry build() {
+    return new NettyClientTelemetry(
+        new NettyClientInstrumenterFactory(
+                openTelemetry, "io.opentelemetry.netty-4.1", false, false, Collections.emptyMap())
+            .createHttpInstrumenter(
+                capturedRequestHeaders, capturedResponseHeaders, additionalAttributesExtractors));
+  }
+}

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/NettyServerTelemetry.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.netty.v4_1;
+
+import io.netty.channel.ChannelInboundHandlerAdapter;
+import io.netty.channel.ChannelOutboundHandlerAdapter;
+import io.netty.channel.CombinedChannelDuplexHandler;
+import io.netty.handler.codec.http.HttpResponse;
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.server.HttpServerRequestTracingHandler;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.server.HttpServerResponseTracingHandler;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.server.HttpServerTracingHandler;
+
+/** Entrypoint for instrumenting Netty HTTP servers. */
+public final class NettyServerTelemetry {
+
+  private final Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter;
+
+  NettyServerTelemetry(Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter) {
+    this.instrumenter = instrumenter;
+  }
+
+  /** Returns a new {@link NettyServerTelemetry} configured with the given {@link OpenTelemetry}. */
+  public static NettyServerTelemetry create(OpenTelemetry openTelemetry) {
+    return builder(openTelemetry).build();
+  }
+
+  /**
+   * Returns a new {@link NettyServerTelemetryBuilder} configured with the given {@link
+   * OpenTelemetry}.
+   */
+  public static NettyServerTelemetryBuilder builder(OpenTelemetry openTelemetry) {
+    return new NettyServerTelemetryBuilder(openTelemetry);
+  }
+
+  /**
+   * Returns a new {@link ChannelInboundHandlerAdapter} that generates telemetry for incoming HTTP
+   * requests. Must be paired with {@link #createResponseHandler()}.
+   */
+  public ChannelInboundHandlerAdapter createRequestHandler() {
+    return new HttpServerRequestTracingHandler(instrumenter);
+  }
+
+  /**
+   * Returns a new {@link ChannelOutboundHandlerAdapter} that generates telemetry for outgoing HTTP
+   * responses. Must be paired with {@link #createRequestHandler()}.
+   */
+  public ChannelOutboundHandlerAdapter createResponseHandler() {
+    return new HttpServerResponseTracingHandler(instrumenter);
+  }
+
+  /**
+   * Returns a new {@link CombinedChannelDuplexHandler} that generates telemetry for incoming HTTP
+   * requests and outgoing responses in a single handler.
+   */
+  public CombinedChannelDuplexHandler<
+          ? extends ChannelInboundHandlerAdapter, ? extends ChannelOutboundHandlerAdapter>
+      createCombinedHandler() {
+    return new HttpServerTracingHandler(instrumenter);
+  }
+}

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/NettyServerTelemetryBuilder.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.netty.v4_1;
+
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.instrumentation.netty.v4.common.internal.server.NettyServerInstrumenterFactory;
+import java.util.Collections;
+import java.util.List;
+
+/** A builder of {@link NettyServerTelemetry}. */
+public final class NettyServerTelemetryBuilder {
+
+  private final OpenTelemetry openTelemetry;
+  private List<String> capturedRequestHeaders = Collections.emptyList();
+  private List<String> capturedResponseHeaders = Collections.emptyList();
+
+  NettyServerTelemetryBuilder(OpenTelemetry openTelemetry) {
+    this.openTelemetry = openTelemetry;
+  }
+
+  /**
+   * Configures the HTTP request headers that will be captured as span attributes.
+   *
+   * @param capturedRequestHeaders A list of HTTP header names.
+   */
+  @CanIgnoreReturnValue
+  public NettyServerTelemetryBuilder setCapturedRequestHeaders(
+      List<String> capturedRequestHeaders) {
+    this.capturedRequestHeaders = capturedRequestHeaders;
+    return this;
+  }
+
+  /**
+   * Configures the HTTP response headers that will be captured as span attributes.
+   *
+   * @param capturedResponseHeaders A list of HTTP header names.
+   */
+  @CanIgnoreReturnValue
+  public NettyServerTelemetryBuilder setCapturedResponseHeaders(
+      List<String> capturedResponseHeaders) {
+    this.capturedResponseHeaders = capturedResponseHeaders;
+    return this;
+  }
+
+  /** Returns a new {@link NettyServerTelemetry} with the given configuration. */
+  public NettyServerTelemetry build() {
+    return new NettyServerTelemetry(
+        NettyServerInstrumenterFactory.create(
+            openTelemetry,
+            "io.opentelemetry.netty-4.1",
+            capturedRequestHeaders,
+            capturedResponseHeaders));
+  }
+}

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/internal/AttributeKeys.java

@@ -3,11 +3,15 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.javaagent.instrumentation.netty.v4_1;
+package io.opentelemetry.instrumentation.netty.v4_1.internal;
 
 import io.netty.util.AttributeKey;
 import io.opentelemetry.context.Context;
 
+/**
+ * This class is internal and is hence not for public use. Its APIs are unstable and can change at
+ * any time.
+ */
 public final class AttributeKeys {
 
   public static final AttributeKey<Context> WRITE_CONTEXT =

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/internal/client/HttpClientRequestTracingHandler.java

@@ -3,23 +3,37 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.javaagent.instrumentation.netty.v4_1.client;
+package io.opentelemetry.instrumentation.netty.v4_1.internal.client;
-
-import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.NettyClientSingletons.HTTP_REQUEST;
-import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.NettyClientSingletons.instrumenter;
 
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelOutboundHandlerAdapter;
 import io.netty.channel.ChannelPromise;
 import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpResponse;
 import io.netty.util.Attribute;
+import io.netty.util.AttributeKey;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.AttributeKeys;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.AttributeKeys;
 
+/**
+ * This class is internal and is hence not for public use. Its APIs are unstable and can change at
+ * any time.
+ */
 public class HttpClientRequestTracingHandler extends ChannelOutboundHandlerAdapter {
 
+  public static final AttributeKey<HttpRequestAndChannel> HTTP_REQUEST =
+      AttributeKey.valueOf(HttpClientRequestTracingHandler.class, "http-client-request");
+
+  private final Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter;
+
+  public HttpClientRequestTracingHandler(
+      Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter) {
+    this.instrumenter = instrumenter;
+  }
+
   @Override
   public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise prm) {
     if (!(msg instanceof HttpRequest)) {
@@ -27,13 +41,13 @@ public class HttpClientRequestTracingHandler extends ChannelOutboundHandlerAdapt
       return;
     }
 
-    Context parentContext = ctx.channel().attr(AttributeKeys.WRITE_CONTEXT).getAndRemove();
+    Context parentContext = ctx.channel().attr(AttributeKeys.WRITE_CONTEXT).getAndSet(null);
     if (parentContext == null) {
       parentContext = Context.current();
     }
 
     HttpRequestAndChannel request = HttpRequestAndChannel.create((HttpRequest) msg, ctx.channel());
-    if (!instrumenter().shouldStart(parentContext, request) || isAwsRequest(request)) {
+    if (!instrumenter.shouldStart(parentContext, request) || isAwsRequest(request)) {
       ctx.write(msg, prm);
       return;
     }
@@ -42,7 +56,7 @@ public class HttpClientRequestTracingHandler extends ChannelOutboundHandlerAdapt
     Attribute<Context> contextAttr = ctx.channel().attr(AttributeKeys.CLIENT_CONTEXT);
     Attribute<HttpRequestAndChannel> requestAttr = ctx.channel().attr(HTTP_REQUEST);
 
-    Context context = instrumenter().start(parentContext, request);
+    Context context = instrumenter.start(parentContext, request);
     parentContextAttr.set(parentContext);
     contextAttr.set(context);
     requestAttr.set(request);
@@ -51,8 +65,8 @@ public class HttpClientRequestTracingHandler extends ChannelOutboundHandlerAdapt
       ctx.write(msg, prm);
       // span is ended normally in HttpClientResponseTracingHandler
     } catch (Throwable throwable) {
-      instrumenter().end(contextAttr.getAndRemove(), requestAttr.getAndRemove(), null, throwable);
+      instrumenter.end(contextAttr.getAndSet(null), requestAttr.getAndSet(null), null, throwable);
-      parentContextAttr.remove();
+      parentContextAttr.set(null);
       throw throwable;
     }
   }

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/internal/client/HttpClientResponseTracingHandler.java

@@ -3,10 +3,9 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.javaagent.instrumentation.netty.v4_1.client;
+package io.opentelemetry.instrumentation.netty.v4_1.internal.client;
 
-import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.NettyClientSingletons.HTTP_RESPONSE;
+import static io.opentelemetry.instrumentation.netty.v4_1.internal.client.HttpClientRequestTracingHandler.HTTP_REQUEST;
-import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.client.NettyClientSingletons.instrumenter;
 
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
@@ -14,13 +13,29 @@ import io.netty.handler.codec.http.FullHttpResponse;
 import io.netty.handler.codec.http.HttpResponse;
 import io.netty.handler.codec.http.LastHttpContent;
 import io.netty.util.Attribute;
+import io.netty.util.AttributeKey;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.AttributeKeys;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.AttributeKeys;
 
+/**
+ * This class is internal and is hence not for public use. Its APIs are unstable and can change at
+ * any time.
+ */
 public class HttpClientResponseTracingHandler extends ChannelInboundHandlerAdapter {
 
+  private static final AttributeKey<HttpResponse> HTTP_RESPONSE =
+      AttributeKey.valueOf(HttpClientResponseTracingHandler.class, "http-client-response");
+
+  private final Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter;
+
+  public HttpClientResponseTracingHandler(
+      Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter) {
+    this.instrumenter = instrumenter;
+  }
+
   @Override
   public void channelRead(ChannelHandlerContext ctx, Object msg) {
     Attribute<Context> contextAttr = ctx.channel().attr(AttributeKeys.CLIENT_CONTEXT);
@@ -31,25 +46,24 @@ public class HttpClientResponseTracingHandler extends ChannelInboundHandlerAdapt
     }
 
     Attribute<Context> parentContextAttr = ctx.channel().attr(AttributeKeys.CLIENT_PARENT_CONTEXT);
-    Attribute<HttpRequestAndChannel> requestAttr =
+    Attribute<HttpRequestAndChannel> requestAttr = ctx.channel().attr(HTTP_REQUEST);
-        ctx.channel().attr(NettyClientSingletons.HTTP_REQUEST);
 
     Context parentContext = parentContextAttr.get();
     HttpRequestAndChannel request = requestAttr.get();
 
     if (msg instanceof FullHttpResponse) {
-      parentContextAttr.remove();
+      parentContextAttr.set(null);
-      contextAttr.remove();
+      contextAttr.set(null);
-      requestAttr.remove();
+      requestAttr.set(null);
     } else if (msg instanceof HttpResponse) {
       // Headers before body have been received, store them to use when finishing the span.
       ctx.channel().attr(HTTP_RESPONSE).set((HttpResponse) msg);
     } else if (msg instanceof LastHttpContent) {
       // Not a FullHttpResponse so this is content that has been received after headers. Finish the
       // span using what we stored in attrs.
-      parentContextAttr.remove();
+      parentContextAttr.set(null);
-      contextAttr.remove();
+      contextAttr.set(null);
-      requestAttr.remove();
+      requestAttr.set(null);
     }
 
     // We want the callback in the scope of the parent, not the client span
@@ -62,9 +76,9 @@ public class HttpClientResponseTracingHandler extends ChannelInboundHandlerAdapt
     }
 
     if (msg instanceof FullHttpResponse) {
-      instrumenter().end(context, request, (HttpResponse) msg, null);
+      instrumenter.end(context, request, (HttpResponse) msg, null);
     } else if (msg instanceof LastHttpContent) {
-      instrumenter().end(context, request, ctx.channel().attr(HTTP_RESPONSE).getAndRemove(), null);
+      instrumenter.end(context, request, ctx.channel().attr(HTTP_RESPONSE).getAndSet(null), null);
     }
   }
 }

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/internal/client/HttpClientTracingHandler.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.netty.v4_1.internal.client;
+
+import io.netty.channel.CombinedChannelDuplexHandler;
+import io.netty.handler.codec.http.HttpResponse;
+import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
+
+/**
+ * This class is internal and is hence not for public use. Its APIs are unstable and can change at
+ * any time.
+ */
+public class HttpClientTracingHandler
+    extends CombinedChannelDuplexHandler<
+        HttpClientResponseTracingHandler, HttpClientRequestTracingHandler> {
+
+  public HttpClientTracingHandler(Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter) {
+    super(
+        new HttpClientResponseTracingHandler(instrumenter),
+        new HttpClientRequestTracingHandler(instrumenter));
+  }
+}

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/internal/server/HttpServerRequestTracingHandler.java

@@ -3,27 +3,42 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.javaagent.instrumentation.netty.v4_1.server;
+package io.opentelemetry.instrumentation.netty.v4_1.internal.server;
-
-import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.server.NettyServerSingletons.instrumenter;
 
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelInboundHandlerAdapter;
 import io.netty.handler.codec.http.HttpRequest;
+import io.netty.handler.codec.http.HttpResponse;
 import io.netty.util.Attribute;
+import io.netty.util.AttributeKey;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.AttributeKeys;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.AttributeKeys;
 
+/**
+ * This class is internal and is hence not for public use. Its APIs are unstable and can change at
+ * any time.
+ */
 public class HttpServerRequestTracingHandler extends ChannelInboundHandlerAdapter {
 
+  static final AttributeKey<HttpRequestAndChannel> HTTP_REQUEST =
+      AttributeKey.valueOf(HttpServerRequestTracingHandler.class, "http-server-request");
+
+  private final Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter;
+
+  public HttpServerRequestTracingHandler(
+      Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter) {
+    this.instrumenter = instrumenter;
+  }
+
   @Override
   public void channelRead(ChannelHandlerContext ctx, Object msg) {
     Channel channel = ctx.channel();
     Attribute<Context> contextAttr = channel.attr(AttributeKeys.SERVER_CONTEXT);
-    Attribute<HttpRequestAndChannel> requestAttr = channel.attr(NettyServerSingletons.HTTP_REQUEST);
+    Attribute<HttpRequestAndChannel> requestAttr = channel.attr(HTTP_REQUEST);
 
     if (!(msg instanceof HttpRequest)) {
       Context serverContext = contextAttr.get();
@@ -43,12 +58,12 @@ public class HttpServerRequestTracingHandler extends ChannelInboundHandlerAdapte
     }
     HttpRequestAndChannel request = HttpRequestAndChannel.create((HttpRequest) msg, channel);
 
-    if (!instrumenter().shouldStart(parentContext, request)) {
+    if (!instrumenter.shouldStart(parentContext, request)) {
       ctx.fireChannelRead(msg);
       return;
     }
 
-    Context context = instrumenter().start(parentContext, request);
+    Context context = instrumenter.start(parentContext, request);
     contextAttr.set(context);
     requestAttr.set(request);
 
@@ -57,7 +72,7 @@ public class HttpServerRequestTracingHandler extends ChannelInboundHandlerAdapte
       // the span is ended normally in HttpServerResponseTracingHandler
     } catch (Throwable throwable) {
       // make sure to remove the server context on end() call
-      instrumenter().end(contextAttr.getAndRemove(), requestAttr.getAndRemove(), null, throwable);
+      instrumenter.end(contextAttr.getAndSet(null), requestAttr.getAndSet(null), null, throwable);
       throw throwable;
     }
   }

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/internal/server/HttpServerResponseTracingHandler.java

@@ -3,9 +3,9 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.javaagent.instrumentation.netty.v4_1.server;
+package io.opentelemetry.instrumentation.netty.v4_1.internal.server;
 
-import static io.opentelemetry.javaagent.instrumentation.netty.v4_1.server.NettyServerSingletons.instrumenter;
+import static io.opentelemetry.instrumentation.netty.v4_1.internal.server.HttpServerRequestTracingHandler.HTTP_REQUEST;
 
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
@@ -16,15 +16,31 @@ import io.netty.handler.codec.http.FullHttpResponse;
 import io.netty.handler.codec.http.HttpResponse;
 import io.netty.handler.codec.http.LastHttpContent;
 import io.netty.util.Attribute;
+import io.netty.util.AttributeKey;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
+import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
 import io.opentelemetry.instrumentation.netty.common.internal.NettyErrorHolder;
-import io.opentelemetry.instrumentation.netty.v4.common.internal.HttpRequestAndChannel;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.AttributeKeys;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.AttributeKeys;
 import javax.annotation.Nullable;
 
+/**
+ * This class is internal and is hence not for public use. Its APIs are unstable and can change at
+ * any time.
+ */
 public class HttpServerResponseTracingHandler extends ChannelOutboundHandlerAdapter {
 
+  static final AttributeKey<HttpResponse> HTTP_RESPONSE =
+      AttributeKey.valueOf(HttpServerResponseTracingHandler.class, "http-server-response");
+
+  private final Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter;
+
+  public HttpServerResponseTracingHandler(
+      Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter) {
+    this.instrumenter = instrumenter;
+  }
+
   @Override
   public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise prm) {
     Attribute<Context> contextAttr = ctx.channel().attr(AttributeKeys.SERVER_CONTEXT);
@@ -59,14 +75,14 @@ public class HttpServerResponseTracingHandler extends ChannelOutboundHandlerAdap
             future ->
                 end(
                     ctx.channel(),
-                    ctx.channel().attr(NettyServerSingletons.HTTP_RESPONSE).getAndRemove(),
+                    ctx.channel().attr(HTTP_RESPONSE).getAndSet(null),
                     writePromise));
       }
     } else {
       writePromise = prm;
       if (msg instanceof HttpResponse) {
         // Headers before body has been sent, store them to use when finishing the span.
-        ctx.channel().attr(NettyServerSingletons.HTTP_RESPONSE).set((HttpResponse) msg);
+        ctx.channel().attr(HTTP_RESPONSE).set((HttpResponse) msg);
       }
     }
 
@@ -78,17 +94,16 @@ public class HttpServerResponseTracingHandler extends ChannelOutboundHandlerAdap
     }
   }
 
-  private static void end(Channel channel, HttpResponse response, ChannelFuture future) {
+  private void end(Channel channel, HttpResponse response, ChannelFuture future) {
     Throwable error = future.isSuccess() ? null : future.cause();
     end(channel, response, error);
   }
 
   // make sure to remove the server context on end() call
-  private static void end(
+  private void end(Channel channel, @Nullable HttpResponse response, @Nullable Throwable error) {
-      Channel channel, @Nullable HttpResponse response, @Nullable Throwable error) {
+    Context context = channel.attr(AttributeKeys.SERVER_CONTEXT).getAndSet(null);
-    Context context = channel.attr(AttributeKeys.SERVER_CONTEXT).getAndRemove();
+    HttpRequestAndChannel request = channel.attr(HTTP_REQUEST).getAndSet(null);
-    HttpRequestAndChannel request = channel.attr(NettyServerSingletons.HTTP_REQUEST).getAndRemove();
     error = NettyErrorHolder.getOrDefault(context, error);
-    instrumenter().end(context, request, response, error);
+    instrumenter.end(context, request, response, error);
   }
 }

instrumentation/netty/netty-4.1/library/src/main/java/io/opentelemetry/instrumentation/netty/v4_1/internal/server/HttpServerTracingHandler.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.netty.v4_1.internal.server;
+
+import io.netty.channel.CombinedChannelDuplexHandler;
+import io.netty.handler.codec.http.HttpResponse;
+import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
+import io.opentelemetry.instrumentation.netty.v4.common.HttpRequestAndChannel;
+
+/**
+ * This class is internal and is hence not for public use. Its APIs are unstable and can change at
+ * any time.
+ */
+public class HttpServerTracingHandler
+    extends CombinedChannelDuplexHandler<
+        HttpServerRequestTracingHandler, HttpServerResponseTracingHandler> {
+
+  public HttpServerTracingHandler(Instrumenter<HttpRequestAndChannel, HttpResponse> instrumenter) {
+    super(
+        new HttpServerRequestTracingHandler(instrumenter),
+        new HttpServerResponseTracingHandler(instrumenter));
+  }
+}

instrumentation/ratpack/ratpack-1.4/javaagent/build.gradle.kts

@@ -14,6 +14,7 @@ dependencies {
   library("io.ratpack:ratpack-core:1.4.0")
 
   implementation(project(":instrumentation:netty:netty-4.1:javaagent"))
+  implementation(project(":instrumentation:netty:netty-4.1:library"))
 
   testImplementation(project(":instrumentation:ratpack:ratpack-1.4:testing"))
 

instrumentation/ratpack/ratpack-1.4/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/ratpack/TracingHandler.java

@@ -11,8 +11,8 @@ import static io.opentelemetry.javaagent.instrumentation.ratpack.RatpackSingleto
 
 import io.netty.util.Attribute;
 import io.opentelemetry.context.Scope;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.AttributeKeys;
 import io.opentelemetry.javaagent.bootstrap.Java8BytecodeBridge;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.AttributeKeys;
 import ratpack.handling.Context;
 import ratpack.handling.Handler;
 

instrumentation/reactor/reactor-netty/reactor-netty-0.9/javaagent/build.gradle.kts

@@ -21,6 +21,7 @@ muzzle {
 
 dependencies {
   implementation(project(":instrumentation:netty:netty-4.1:javaagent"))
+  implementation(project(":instrumentation:netty:netty-4.1:library"))
   library("io.projectreactor.netty:reactor-netty:0.9.0.RELEASE")
 
   testInstrumentation(project(":instrumentation:reactor:reactor-netty:reactor-netty-1.0:javaagent"))

instrumentation/reactor/reactor-netty/reactor-netty-0.9/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/reactornetty/v0_9/DecoratorFunctions.java

@@ -8,7 +8,7 @@ package io.opentelemetry.javaagent.instrumentation.reactornetty.v0_9;
 import io.netty.channel.Channel;
 import io.opentelemetry.context.Context;
 import io.opentelemetry.context.Scope;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.AttributeKeys;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.AttributeKeys;
 import java.util.function.BiConsumer;
 import javax.annotation.Nullable;
 import reactor.netty.Connection;

instrumentation/reactor/reactor-netty/reactor-netty-0.9/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/reactornetty/v0_9/OnRequest.java

@@ -6,7 +6,7 @@
 package io.opentelemetry.javaagent.instrumentation.reactornetty.v0_9;
 
 import io.opentelemetry.context.Context;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.AttributeKeys;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.AttributeKeys;
 import java.util.function.BiConsumer;
 import reactor.netty.Connection;
 import reactor.netty.http.client.HttpClientRequest;

instrumentation/reactor/reactor-netty/reactor-netty-1.0/javaagent/build.gradle.kts

@@ -24,6 +24,7 @@ dependencies {
   annotationProcessor("com.google.auto.value:auto-value")
 
   implementation(project(":instrumentation:netty:netty-4.1:javaagent"))
+  implementation(project(":instrumentation:netty:netty-4.1:library"))
   implementation(project(":instrumentation:netty:netty-4-common:library"))
   implementation(project(":instrumentation:netty:netty-common:library"))
   implementation(project(":instrumentation:reactor:reactor-3.1:library"))

instrumentation/reactor/reactor-netty/reactor-netty-1.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/reactornetty/v1_0/HttpResponseReceiverInstrumenter.java

@@ -11,8 +11,8 @@ import static io.opentelemetry.javaagent.instrumentation.reactornetty.v1_0.React
 
 import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.context.Context;
+import io.opentelemetry.instrumentation.netty.v4_1.internal.AttributeKeys;
 import io.opentelemetry.instrumentation.reactor.ContextPropagationOperator;
-import io.opentelemetry.javaagent.instrumentation.netty.v4_1.AttributeKeys;
 import java.util.function.BiConsumer;
 import java.util.function.Function;
 import javax.annotation.Nullable;

instrumentation/reactor/reactor-netty/reactor-netty-1.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/reactornetty/v1_0/ReactorNettySingletons.java

@@ -72,11 +72,10 @@ public final class ReactorNettySingletons {
 
     NettyClientInstrumenterFactory instrumenterFactory =
         new NettyClientInstrumenterFactory(
+            GlobalOpenTelemetry.get(),
             INSTRUMENTATION_NAME,
             connectionTelemetryEnabled,
             false,
-            CommonConfig.get().getClientRequestHeaders(),
-            CommonConfig.get().getClientResponseHeaders(),
             CommonConfig.get().getPeerServiceMapping());
     CONNECTION_INSTRUMENTER = instrumenterFactory.createConnectionInstrumenter();
   }

settings.gradle.kts

@@ -351,6 +351,7 @@ include(":instrumentation:mongo:mongo-common:testing")
 include(":instrumentation:netty:netty-3.8:javaagent")
 include(":instrumentation:netty:netty-4.0:javaagent")
 include(":instrumentation:netty:netty-4.1:javaagent")
+include(":instrumentation:netty:netty-4.1:library")
 include(":instrumentation:netty:netty-4-common:javaagent")
 include(":instrumentation:netty:netty-4-common:library")
 include(":instrumentation:netty:netty-common:library")