jakubhalun

@RestController
public class HelloController {

    private static final String template = "Hello, %s!";

    @RequestMapping("/hello")
    public String greeting(
            @RequestParam(value = "name", defaultValue = "World") String name) {
        return String.format(template, name);
    }

jakubhalun

public static void intercept(@AllArguments Object[] allArguments,
        @Origin Method method) {
    Logger logger = LoggerFactory.getLogger(method.getDeclaringClass());
    logger.info("Method {} of class {} called", method.getName(), method
            .getDeclaringClass().getSimpleName());

    for (Object argument : allArguments) {
        logger.info("Method {}, parameter type {}, value={}",
                method.getName(), argument.getClass().getSimpleName(),
                argument.toString());

jakubhalun

type(ElementMatchers.isAnnotatedWith(RestController.class))

jakubhalun

type(ElementMatchers.named(
  "pl.halun.demo.bytebuddy.instrumented.app.HelloController"))

jakubhalun

<dependency>
  <groupId>ch.qos.logback</groupId>
  <artifactId>logback-classic</artifactId>
  <version>1.1.7</version>
  <scope>provided</scope>
</dependency>

jakubhalun

return new AgentBuilder.Default().disableClassFormatChanges()
    .with(AgentBuilder.RedefinitionStrategy.RETRANSFORMATION)
    .type(named(className))
    .transform(new AgentBuilder.Transformer() {
    
    @Override
    public DynamicType.Builder<?> transform(
        DynamicType.Builder<?> builder, TypeDescription typeDescription,
        ClassLoader classLoader) {
            return builder.visit(Advice.to(LoggingAdvice.class).on(

jakubhalun

public class LoggingAdvice {
    @Advice.OnMethodEnter
    public static void intercept(@Advice.BoxedArguments Object[] allArguments,
            @Advice.Origin Method method) {
        Logger logger = LoggerFactory.getLogger(method.getDeclaringClass());
        logger.info("Method {} of class {} called", method.getName(), method
                .getDeclaringClass().getSimpleName());

        for (Object argument : allArguments) {
            logger.info("Method {}, parameter type {}, value={}",

jakubhalun

private static AgentBuilder createAgent(Class<? extends Annotation> annotationType,
        String methodName) {
    return new AgentBuilder.Default().type(
        ElementMatchers.isAnnotatedWith(annotationType)).transform(
            new AgentBuilder.Transformer() {
                @Override
                public DynamicType.Builder<?> transform(
                        DynamicType.Builder<?> builder,
                        TypeDescription typeDescription,
                        ClassLoader classLoader) {