content: /*
   * Copyright The OpenTelemetry Authors
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package io.opentelemetry.javaagent.instrumentation.hystrix;
  
  import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.extendsClass;
  import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.hasClassesNamed;
  import static io.opentelemetry.javaagent.instrumentation.hystrix.HystrixSingletons.instrumenter;
  import static net.bytebuddy.matcher.ElementMatchers.named;
  import static net.bytebuddy.matcher.ElementMatchers.namedOneOf;
  import static net.bytebuddy.matcher.ElementMatchers.returns;
  
  import com.netflix.hystrix.HystrixInvokableInfo;
  import io.opentelemetry.instrumentation.rxjava.v1_0.TracedOnSubscribe;
  import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
  import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
  import net.bytebuddy.asm.Advice;
  import net.bytebuddy.description.type.TypeDescription;
  import net.bytebuddy.matcher.ElementMatcher;
  import rx.Observable;
  
  public class HystrixCommandInstrumentation implements TypeInstrumentation {
    @Override
    public ElementMatcher<ClassLoader> classLoaderOptimization() {
      return hasClassesNamed(
          "com.netflix.hystrix.HystrixCommand", "com.netflix.hystrix.HystrixObservableCommand");
    }
  
    @Override
    public ElementMatcher<TypeDescription> typeMatcher() {
      return extendsClass(
          namedOneOf(
              "com.netflix.hystrix.HystrixCommand", "com.netflix.hystrix.HystrixObservableCommand"));
    }
  
    @Override
    public void transform(TypeTransformer transformer) {
      transformer.applyAdviceToMethod(
          named("getExecutionObservable").and(returns(named("rx.Observable"))),
          this.getClass().getName() + "$ExecuteAdvice");
      transformer.applyAdviceToMethod(
          named("getFallbackObservable").and(returns(named("rx.Observable"))),
          this.getClass().getName() + "$FallbackAdvice");
    }
  
    @SuppressWarnings("unused")
    public static class ExecuteAdvice {
  
      @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
      public static void stopSpan(
          @Advice.This HystrixInvokableInfo<?> command,
          @Advice.Return(readOnly = false) Observable<?> result,
          @Advice.Thrown Throwable throwable) {
  
        HystrixRequest request = HystrixRequest.create(command, "execute");
        result = Observable.create(new TracedOnSubscribe<>(result, instrumenter(), request));
      }
    }
  
    @SuppressWarnings("unused")
    public static class FallbackAdvice {
  
      @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
      public static void stopSpan(
          @Advice.This HystrixInvokableInfo<?> command,
          @Advice.Return(readOnly = false) Observable<?> result,
          @Advice.Thrown Throwable throwable) {
  
        HystrixRequest request = HystrixRequest.create(command, "fallback");
        result = Observable.create(new TracedOnSubscribe<>(result, instrumenter(), request));
      }
    }
  }
  