content: /*
   * Copyright The OpenTelemetry Authors
   * SPDX-License-Identifier: Apache-2.0
   */
  
  package io.opentelemetry.javaagent.instrumentation.extannotations;
  
  import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.hasClassesNamed;
  import static io.opentelemetry.javaagent.instrumentation.extannotations.ExternalAnnotationSingletons.instrumenter;
  import static java.util.logging.Level.WARNING;
  import static net.bytebuddy.matcher.ElementMatchers.declaresMethod;
  import static net.bytebuddy.matcher.ElementMatchers.isAnnotatedWith;
  import static net.bytebuddy.matcher.ElementMatchers.isDeclaredBy;
  import static net.bytebuddy.matcher.ElementMatchers.isMethod;
  import static net.bytebuddy.matcher.ElementMatchers.namedOneOf;
  import static net.bytebuddy.matcher.ElementMatchers.none;
  import static net.bytebuddy.matcher.ElementMatchers.not;
  
  import io.opentelemetry.context.Context;
  import io.opentelemetry.context.Scope;
  import io.opentelemetry.instrumentation.api.incubator.config.internal.InstrumentationConfig;
  import io.opentelemetry.instrumentation.api.incubator.semconv.util.ClassAndMethod;
  import io.opentelemetry.javaagent.bootstrap.Java8BytecodeBridge;
  import io.opentelemetry.javaagent.bootstrap.internal.AgentInstrumentationConfig;
  import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
  import io.opentelemetry.javaagent.extension.instrumentation.TypeTransformer;
  import io.opentelemetry.javaagent.tooling.config.MethodsConfigurationParser;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.logging.Logger;
  import net.bytebuddy.asm.Advice;
  import net.bytebuddy.description.ByteCodeElement;
  import net.bytebuddy.description.NamedElement;
  import net.bytebuddy.description.method.MethodDescription;
  import net.bytebuddy.description.type.TypeDescription;
  import net.bytebuddy.matcher.ElementMatcher;
  import net.bytebuddy.matcher.ElementMatchers;
  
  public class ExternalAnnotationInstrumentation implements TypeInstrumentation {
  
    private static final Logger logger =
        Logger.getLogger(ExternalAnnotationInstrumentationModule.class.getName());
  
    private static final String PACKAGE_CLASS_NAME_REGEX = "[\\w.$]+";
  
    static final String CONFIG_FORMAT =
        "(?:\\s*"
            + PACKAGE_CLASS_NAME_REGEX
            + "\\s*;)*\\s*"
            + PACKAGE_CLASS_NAME_REGEX
            + "\\s*;?\\s*";
  
    // visible for testing
    static final List<String> DEFAULT_ANNOTATIONS =
        Arrays.asList(
            "com.appoptics.api.ext.LogMethod",
            "com.newrelic.api.agent.Trace",
            "com.signalfx.tracing.api.Trace",
            "com.tracelytics.api.ext.LogMethod",
            "datadog.trace.api.Trace",
            "io.opentracing.contrib.dropwizard.Trace",
            "kamon.annotation.Trace",
            "kamon.annotation.api.Trace",
            "org.springframework.cloud.sleuth.annotation.NewSpan");
  
    private static final String TRACE_ANNOTATIONS_CONFIG =
        "otel.instrumentation.external-annotations.include";
    private static final String TRACE_ANNOTATED_METHODS_EXCLUDE_CONFIG =
        "otel.instrumentation.external-annotations.exclude-methods";
  
    private final ElementMatcher.Junction<ClassLoader> classLoaderOptimization;
    private final ElementMatcher.Junction<NamedElement> traceAnnotationMatcher;
  
    /** This matcher matches all methods that should be excluded from transformation. */
    private final ElementMatcher.Junction<MethodDescription> excludedMethodsMatcher;
  
    public ExternalAnnotationInstrumentation() {
      Set<String> additionalTraceAnnotations =
          configureAdditionalTraceAnnotations(AgentInstrumentationConfig.get());
  
      if (additionalTraceAnnotations.isEmpty()) {
        classLoaderOptimization = none();
        traceAnnotationMatcher = none();
      } else {
        ElementMatcher.Junction<ClassLoader> classLoaderMatcher = none();
        for (String annotationName : additionalTraceAnnotations) {
          classLoaderMatcher = classLoaderMatcher.or(hasClassesNamed(annotationName));
        }
        this.classLoaderOptimization = classLoaderMatcher;
        this.traceAnnotationMatcher = namedOneOf(additionalTraceAnnotations.toArray(new String[0]));
      }
  
      excludedMethodsMatcher = configureExcludedMethods();
    }
  
    @Override
    public ElementMatcher<ClassLoader> classLoaderOptimization() {
      return classLoaderOptimization;
    }
  
    @Override
    public ElementMatcher<TypeDescription> typeMatcher() {
      return declaresMethod(isAnnotatedWith(traceAnnotationMatcher));
    }
  
    @Override
    public void transform(TypeTransformer transformer) {
      transformer.applyAdviceToMethod(
          isAnnotatedWith(traceAnnotationMatcher).and(not(excludedMethodsMatcher)).and(isMethod()),
          ExternalAnnotationInstrumentation.class.getName() + "$ExternalAnnotationAdvice");
    }
  
    // visible for testing
    static Set<String> configureAdditionalTraceAnnotations(InstrumentationConfig config) {
      String configString = config.getString(TRACE_ANNOTATIONS_CONFIG);
      if (configString == null) {
        return Collections.unmodifiableSet(new HashSet<>(DEFAULT_ANNOTATIONS));
      } else if (configString.isEmpty()) {
        return Collections.emptySet();
      } else if (!configString.matches(CONFIG_FORMAT)) {
        logger.log(
            WARNING,
            "Invalid trace annotations config \"{0}\". Must match 'package.Annotation$Name;*'.",
            configString);
        return Collections.emptySet();
      } else {
        Set<String> annotations = new HashSet<>();
        String[] annotationClasses = configString.split(";", -1);
        for (String annotationClass : annotationClasses) {
          if (!annotationClass.trim().isEmpty()) {
            annotations.add(annotationClass.trim());
          }
        }
        return Collections.unmodifiableSet(annotations);
      }
    }
  
    /**
     * Returns a matcher for all methods that should be excluded from auto-instrumentation by
     * annotation-based advices.
     */
    private static ElementMatcher.Junction<MethodDescription> configureExcludedMethods() {
      ElementMatcher.Junction<MethodDescription> result = none();
  
      Map<String, Set<String>> excludedMethods =
          MethodsConfigurationParser.parse(
              AgentInstrumentationConfig.get().getString(TRACE_ANNOTATED_METHODS_EXCLUDE_CONFIG));
      for (Map.Entry<String, Set<String>> entry : excludedMethods.entrySet()) {
        String className = entry.getKey();
        ElementMatcher.Junction<ByteCodeElement> classMather =
            isDeclaredBy(ElementMatchers.named(className));
  
        ElementMatcher.Junction<MethodDescription> excludedMethodsMatcher = none();
        for (String methodName : entry.getValue()) {
          excludedMethodsMatcher = excludedMethodsMatcher.or(ElementMatchers.named(methodName));
        }
  
        result = result.or(classMather.and(excludedMethodsMatcher));
      }
  
      return result;
    }
  
    @SuppressWarnings("unused")
    public static class ExternalAnnotationAdvice {
  
      @Advice.OnMethodEnter(suppress = Throwable.class)
      public static void onEnter(
          @Advice.Origin("#t") Class<?> declaringClass,
          @Advice.Origin("#m") String methodName,
          @Advice.Local("otelRequest") ClassAndMethod request,
          @Advice.Local("otelContext") Context context,
          @Advice.Local("otelScope") Scope scope) {
  
        Context parentContext = Java8BytecodeBridge.currentContext();
        request = ClassAndMethod.create(declaringClass, methodName);
        if (!instrumenter().shouldStart(parentContext, request)) {
          return;
        }
  
        context = instrumenter().start(parentContext, request);
        scope = context.makeCurrent();
      }
  
      @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)
      public static void stopSpan(
          @Advice.Local("otelRequest") ClassAndMethod request,
          @Advice.Local("otelContext") Context context,
          @Advice.Local("otelScope") Scope scope,
          @Advice.Thrown Throwable throwable) {
  
        if (scope == null) {
          return;
        }
        scope.close();
        instrumenter().end(context, request, null, throwable);
      }
    }
  }
  