content: /*
   * Copyright The OpenTelemetry Authors
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package io.opentelemetry.javaagent.instrumentation.vertx.v5_0.client;
  
  import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.hasClassesNamed;
  import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.implementsInterface;
  import static io.opentelemetry.javaagent.instrumentation.vertx.v5_0.client.VertxClientSingletons.instrumenter;
  import static net.bytebuddy.matcher.ElementMatchers.isMethod;
  import static net.bytebuddy.matcher.ElementMatchers.isPrivate;
  import static net.bytebuddy.matcher.ElementMatchers.nameStartsWith;
  import static net.bytebuddy.matcher.ElementMatchers.named;
  import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
  
  import io.opentelemetry.context.Context;
  import io.opentelemetry.context.Scope;
  import io.opentelemetry.instrumentation.api.util.VirtualField;
  import io.opentelemetry.javaagent.bootstrap.Java8BytecodeBridge;
  import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
  import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
  import io.opentelemetry.javaagent.instrumentation.vertx.client.Contexts;
  import io.opentelemetry.javaagent.instrumentation.vertx.client.ExceptionHandlerWrapper;
  import io.vertx.core.Handler;
  import io.vertx.core.http.HttpClientRequest;
  import io.vertx.core.http.HttpClientResponse;
  import net.bytebuddy.asm.Advice;
  import net.bytebuddy.description.type.TypeDescription;
  import net.bytebuddy.matcher.ElementMatcher;
  
  /**
   * Two things happen in this instrumentation.
   *
   * <p>First, {@link EndRequestAdvice}, {@link HandleExceptionAdvice} and {@link
   * HandleResponseAdvice} deal with the common start span/end span functionality. As Vert.x is async
   * framework, calls to the instrumented methods may happen from different threads. Thus, correct
   * context is stored in {@code HttpClientRequest} itself.
   *
   * <p>Second, when HttpClientRequest calls any method that actually performs write on the underlying
   * Netty channel, {@link MountContextAdvice} scopes that method call into the context captured on
   * the first step. This ensures proper context transfer between the client who actually initiated
   * the http call and the Netty Channel that will perform that operation. The main result of this
   * transfer is a suppression of Netty CLIENT span.
   */
  public class HttpRequestInstrumentation implements TypeInstrumentation {
  
    @Override
    public ElementMatcher<ClassLoader> classLoaderOptimization() {
      return hasClassesNamed("io.vertx.core.http.HttpClientRequest");
    }
  
    @Override
    public ElementMatcher<TypeDescription> typeMatcher() {
      return implementsInterface(named("io.vertx.core.http.HttpClientRequest"));
    }
  
    @Override
    public void transform(TypeTransformer transformer) {
      transformer.applyAdviceToMethod(
          isMethod().and(nameStartsWith("end").or(named("sendHead"))),
          HttpRequestInstrumentation.class.getName() + "$EndRequestAdvice");
  
      transformer.applyAdviceToMethod(
          isMethod().and(named("handleException")),
          HttpRequestInstrumentation.class.getName() + "$HandleExceptionAdvice");
  
      transformer.applyAdviceToMethod(
          isMethod()
              .and(named("handleResponse"))
              .and(takesArgument(1, named("io.vertx.core.http.HttpClientResponse"))),
          HttpRequestInstrumentation.class.getName() + "$HandleResponseAdvice");
  
      transformer.applyAdviceToMethod(
          isMethod().and(isPrivate()).and(nameStartsWith("write").or(nameStartsWith("connected"))),
          HttpRequestInstrumentation.class.getName() + "$MountContextAdvice");
  
      transformer.applyAdviceToMethod(
          isMethod()
              .and(named("exceptionHandler"))
              .and(takesArgument(0, named("io.vertx.core.Handler"))),
          HttpRequestInstrumentation.class.getName() + "$ExceptionHandlerAdvice");
    }
  
    @SuppressWarnings("unused")
    public static class EndRequestAdvice {
  
      @Advice.OnMethodEnter(suppress = Throwable.class)
      public static void attachContext(
          @Advice.This HttpClientRequest request,
          @Advice.Local("otelContext") Context context,
          @Advice.Local("otelScope") Scope scope) {
        Context parentContext = Java8BytecodeBridge.currentContext();
  
        if (!instrumenter().shouldStart(parentContext, request)) {
          return;
        }
  
        context = instrumenter().start(parentContext, request);
        Contexts contexts = new Contexts(parentContext, context);
        VirtualField.find(HttpClientRequest.class, Contexts.class).set(request, contexts);
  
        scope = context.makeCurrent();
      }
  
      @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
      public static void endScope(
          @Advice.This HttpClientRequest request,
          @Advice.Local("otelContext") Context context,
          @Advice.Local("otelScope") Scope scope,
          @Advice.Thrown Throwable throwable) {
        if (scope != null) {
          scope.close();
        }
        if (throwable != null) {
          instrumenter().end(context, request, null, throwable);
        }
      }
    }
  
    @SuppressWarnings("unused")
    public static class HandleExceptionAdvice {
  
      @Advice.OnMethodEnter(suppress = Throwable.class)
      public static void handleException(
          @Advice.This HttpClientRequest request,
          @Advice.Argument(0) Throwable t,
          @Advice.Local("otelScope") Scope scope) {
        Contexts contexts = VirtualField.find(HttpClientRequest.class, Contexts.class).get(request);
  
        if (contexts == null) {
          return;
        }
  
        instrumenter().end(contexts.context, request, null, t);
  
        // Scoping all potential callbacks etc to the parent context
        scope = contexts.parentContext.makeCurrent();
      }
  
      @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
      public static void handleResponseExit(@Advice.Local("otelScope") Scope scope) {
        if (scope != null) {
          scope.close();
        }
      }
    }
  
    @SuppressWarnings("unused")
    public static class HandleResponseAdvice {
  
      @Advice.OnMethodEnter(suppress = Throwable.class)
      public static void handleResponseEnter(
          @Advice.This HttpClientRequest request,
          @Advice.Argument(1) HttpClientResponse response,
          @Advice.Local("otelScope") Scope scope) {
        Contexts contexts = VirtualField.find(HttpClientRequest.class, Contexts.class).get(request);
  
        if (contexts == null) {
          return;
        }
  
        instrumenter().end(contexts.context, request, response, null);
  
        // Scoping all potential callbacks etc to the parent context
        scope = contexts.parentContext.makeCurrent();
      }
  
      @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
      public static void handleResponseExit(@Advice.Local("otelScope") Scope scope) {
        if (scope != null) {
          scope.close();
        }
      }
    }
  
    @SuppressWarnings("unused")
    public static class MountContextAdvice {
  
      @Advice.OnMethodEnter(suppress = Throwable.class)
      public static void mountContext(
          @Advice.This HttpClientRequest request, @Advice.Local("otelScope") Scope scope) {
        Contexts contexts = VirtualField.find(HttpClientRequest.class, Contexts.class).get(request);
        if (contexts == null) {
          return;
        }
  
        scope = contexts.context.makeCurrent();
      }
  
      @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
      public static void unmountContext(@Advice.Local("otelScope") Scope scope) {
        if (scope != null) {
          scope.close();
        }
      }
    }
  
    @SuppressWarnings("unused")
    public static class ExceptionHandlerAdvice {
  
      @Advice.OnMethodEnter(suppress = Throwable.class)
      public static void wrapExceptionHandler(
          @Advice.This HttpClientRequest request,
          @Advice.Argument(value = 0, readOnly = false) Handler<Throwable> handler) {
        if (handler != null) {
          VirtualField<HttpClientRequest, Contexts> virtualField =
              VirtualField.find(HttpClientRequest.class, Contexts.class);
          handler = ExceptionHandlerWrapper.wrap(instrumenter(), request, virtualField, handler);
        }
      }
    }
  }
  