content: /*
   * Copyright The OpenTelemetry Authors
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package io.opentelemetry.javaagent.instrumentation.spring.web.v6_0;
  
  import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.extendsClass;
  import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.hasClassesNamed;
  import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.implementsInterface;
  import static net.bytebuddy.matcher.ElementMatchers.isMethod;
  import static net.bytebuddy.matcher.ElementMatchers.named;
  import static net.bytebuddy.matcher.ElementMatchers.takesArgument;
  import static org.springframework.beans.factory.config.BeanDefinition.SCOPE_SINGLETON;
  
  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 org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
  import org.springframework.beans.factory.support.BeanDefinitionRegistry;
  import org.springframework.beans.factory.support.GenericBeanDefinition;
  
  /**
   * This instrumentation adds the OpenTelemetryHandlerMappingFilter definition to the spring context
   * When the context is created, the filter will be added to the beginning of the filter chain.
   */
  public class WebApplicationContextInstrumentation implements TypeInstrumentation {
  
    @Override
    public ElementMatcher<ClassLoader> classLoaderOptimization() {
      return hasClassesNamed(
          "org.springframework.context.support.AbstractApplicationContext",
          "org.springframework.web.context.WebApplicationContext");
    }
  
    @Override
    public ElementMatcher<TypeDescription> typeMatcher() {
      return extendsClass(named("org.springframework.context.support.AbstractApplicationContext"))
          .and(implementsInterface(named("org.springframework.web.context.WebApplicationContext")));
    }
  
    @Override
    public void transform(TypeTransformer transformer) {
      transformer.applyAdviceToMethod(
          isMethod()
              .and(named("postProcessBeanFactory"))
              .and(
                  takesArgument(
                      0,
                      named(
                          "org.springframework.beans.factory.config.ConfigurableListableBeanFactory"))),
          WebApplicationContextInstrumentation.class.getName() + "$FilterInjectingAdvice");
    }
  
    @SuppressWarnings("unused")
    public static class FilterInjectingAdvice {
  
      @Advice.OnMethodEnter(suppress = Throwable.class)
      public static void onEnter(@Advice.Argument(0) ConfigurableListableBeanFactory beanFactory) {
        if (beanFactory instanceof BeanDefinitionRegistry
            && !beanFactory.containsBean("otelAutoDispatcherFilter")) {
          // Explicitly loading classes allows to catch any class-loading issue or deal with cases
          // where the class is not visible.
          try {
            // Firstly check whether DispatcherServlet is present. We need to load an instrumented
            // class from spring-webmvc to trigger injection that makes
            // OpenTelemetryHandlerMappingFilter available.
            Class<?> dispatcherServletClass =
                beanFactory
                    .getBeanClassLoader()
                    .loadClass("org.springframework.web.servlet.DispatcherServlet");
  
            // Now attempt to load our injected instrumentation class from the same class loader as
            // DispatcherServlet
            Class<?> clazz =
                dispatcherServletClass
                    .getClassLoader()
                    .loadClass(
                        "org.springframework.web.servlet.v6_0.OpenTelemetryHandlerMappingFilter");
            GenericBeanDefinition beanDefinition = new GenericBeanDefinition();
            beanDefinition.setScope(SCOPE_SINGLETON);
            beanDefinition.setBeanClass(clazz);
  
            ((BeanDefinitionRegistry) beanFactory)
                .registerBeanDefinition("otelAutoDispatcherFilter", beanDefinition);
          } catch (ClassNotFoundException ignored) {
            // Ignore
          }
        }
      }
    }
  }
  