content: /*
   * Copyright The OpenTelemetry Authors
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package io.opentelemetry.javaagent.instrumentation.netty.v4_0.client;
  
  import static io.opentelemetry.javaagent.instrumentation.netty.v4_0.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.util.Attribute;
  import io.netty.util.AttributeKey;
  import io.opentelemetry.context.Context;
  import io.opentelemetry.context.Scope;
  import io.opentelemetry.instrumentation.netty.common.v4_0.HttpRequestAndChannel;
  import io.opentelemetry.javaagent.instrumentation.netty.v4_0.AttributeKeys;
  
  public class HttpClientRequestTracingHandler extends ChannelOutboundHandlerAdapter {
  
    public static final AttributeKey<HttpRequestAndChannel> HTTP_CLIENT_REQUEST =
        AttributeKeys.attributeKey(AttributeKeys.class.getName() + ".http-client-request");
  
    @Override
    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise prm) throws Exception {
      if (!(msg instanceof HttpRequest)) {
        super.write(ctx, msg, prm);
        return;
      }
  
      Context parentContext = Context.current();
  
      HttpRequestAndChannel request = HttpRequestAndChannel.create((HttpRequest) msg, ctx.channel());
      if (!instrumenter().shouldStart(parentContext, request)) {
        super.write(ctx, msg, prm);
        return;
      }
  
      Attribute<Context> parentContextAttr = ctx.channel().attr(AttributeKeys.CLIENT_PARENT_CONTEXT);
      Attribute<Context> contextAttr = ctx.channel().attr(AttributeKeys.CLIENT_CONTEXT);
      Attribute<HttpRequestAndChannel> requestAttr = ctx.channel().attr(HTTP_CLIENT_REQUEST);
  
      Context context = instrumenter().start(parentContext, request);
      parentContextAttr.set(parentContext);
      contextAttr.set(context);
      requestAttr.set(request);
  
      try (Scope ignored = context.makeCurrent()) {
        super.write(ctx, msg, prm);
      } catch (Throwable throwable) {
        instrumenter().end(contextAttr.getAndRemove(), requestAttr.getAndRemove(), null, throwable);
        parentContextAttr.remove();
        throw throwable;
      }
      // span is ended normally in HttpClientResponseTracingHandler
    }
  }
  