content: /*
   * Copyright The OpenTelemetry Authors
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package io.opentelemetry.javaagent.instrumentation.spring.webflux.v5_0.server;
  
  import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.extendsClass;
  import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.hasClassesNamed;
  import static net.bytebuddy.matcher.ElementMatchers.isAbstract;
  import static net.bytebuddy.matcher.ElementMatchers.isMethod;
  import static net.bytebuddy.matcher.ElementMatchers.isPublic;
  import static net.bytebuddy.matcher.ElementMatchers.named;
  import static net.bytebuddy.matcher.ElementMatchers.not;
  import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
  import static net.bytebuddy.matcher.ElementMatchers.takesArguments;
  
  import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
  import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
  import net.bytebuddy.asm.Advice;
  import net.bytebuddy.asm.Advice.AssignReturned;
  import net.bytebuddy.description.type.TypeDescription;
  import net.bytebuddy.matcher.ElementMatcher;
  import org.springframework.web.reactive.function.server.HandlerFunction;
  import org.springframework.web.reactive.function.server.RouterFunction;
  import reactor.core.publisher.Mono;
  
  public class RouterFunctionInstrumentation implements TypeInstrumentation {
  
    @Override
    public ElementMatcher<ClassLoader> classLoaderOptimization() {
      return hasClassesNamed("org.springframework.web.reactive.function.server.ServerRequest");
    }
  
    @Override
    public ElementMatcher<TypeDescription> typeMatcher() {
      return not(isAbstract())
          .and(
              extendsClass(
                  // TODO: this doesn't handle nested routes (DefaultNestedRouterFunction)
                  named(
                      "org.springframework.web.reactive.function.server.RouterFunctions$DefaultRouterFunction")));
    }
  
    @Override
    public void transform(TypeTransformer transformer) {
      transformer.applyAdviceToMethod(
          isMethod()
              .and(isPublic())
              .and(named("route"))
              .and(
                  takesArgument(
                      0, named("org.springframework.web.reactive.function.server.ServerRequest")))
              .and(takesArguments(1)),
          this.getClass().getName() + "$RouteAdvice");
    }
  
    /**
     * This advice is responsible for setting additional span parameters for routes implemented with
     * functional interface.
     */
    @SuppressWarnings("unused")
    public static class RouteAdvice {
  
      @AssignReturned.ToReturned
      @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
      public static Mono<HandlerFunction<?>> methodExit(
          @Advice.This RouterFunction<?> thiz,
          @Advice.Return Mono<HandlerFunction<?>> result,
          @Advice.Thrown Throwable throwable) {
        if (throwable == null) {
          return result.doOnNext(new RouteOnSuccess(thiz));
        }
        return result;
      }
    }
  }
  