字节码增强 - 初识链路追踪 - ByteBuddy

1. 简单介绍

1.1 背景

• 不能通过 -Javaagent 方式启动
• 需要增强非业务代码( Spring AOP 不够用)
• 业务方尽量少改动代码

1.2 效果

[Byte Buddy] BEFORE_INSTALL net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer@87f383f on sun.instrument.InstrumentationImpl@4eb7f003
[Byte Buddy] INSTALL net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer@87f383f on sun.instrument.InstrumentationImpl@4eb7f003
[Byte Buddy] TRANSFORM com.hisen.agent.util.Hisen [sun.misc.Launcher$AppClassLoader@18b4aac2, null, Thread[main,5,main], loaded=false]
name before:hisen
hello: hisen1677417020466
public static void com.hisen.agent.util.Hisen.hello(Java.lang.String): took 0 millisecond
HisenAdvice exit. time use:0

2. 代码逻辑

2.1 启动类

/**
 * @author hisenyuan
 * @date 2023/2/6 21:31
 */
public class Start {
    public static void main(String[] args) {
        startTraceAgent();
        Hisen.hello("hisen");
    }

    private static void startTraceAgent() {
        Instrumentation install = ByteBuddyAgent.install();
        HisenInterceptor.init(install);
        new HisenInstrumentation().init(install);
    }
}

2.2 拦截方式

会改变程序执行的堆栈

/**
 * @author hisenyuan
 * @date 2023/2/8 21:17
 */
public class HisenInterceptor {
    public static void init(Instrumentation instrumentation) {
        new AgentBuilder.Default()
                .type(ElementMatchers.nameEndsWith("Hisen"))
                .transform((builder, type, classLoader, module, protectionDomain) -> builder.method(ElementMatchers.any()).intercept(MethodDelegation.to(TimeInterceptor.class)))
                .installOn(instrumentation);
    }

    public static class TimeInterceptor {
        @RuntimeType
        public static Object intercept(@Origin Method method, @SuperCall Callable<?> callable) throws Exception {
            long start = System.currentTimeMillis();
            try {
                return callable.call();
            } catch (Exception e) {
                // 进行异常信息上报
                System.out.println("方法执行发生异常" + e.getMessage());
                throw e;
            } finally {
                System.out.println(method + ": took " + (System.currentTimeMillis() - start) + " millisecond");
            }
        }
    }
}

2.3 代码注入

不会改变代码堆栈流
这种方式也可以增强系统类

/**
 * @author hisenyuan
 * @date 2023/2/8 20:16
 */
public class HisenInstrumentation {
    public void init(Instrumentation instrumentation) {
        new AgentBuilder.Default()
                .disableClassFormatChanges()
                .with(RETRANSFORMATION)
                // Make sure we see helpful logs
                .with(AgentBuilder.RedefinitionStrategy.Listener.StreamWriting.toSystemError())
                .with(AgentBuilder.Listener.StreamWriting.toSystemError().withTransformationsOnly())
                .with(AgentBuilder.InstallationListener.StreamWriting.toSystemError())
                .ignore(none())
                // Ignore Byte Buddy and JDK classes we are not interested in
                .ignore(
                        nameStartsWith("net.bytebuddy.")
                                .or(nameStartsWith("jdk.internal.reflect."))
                                .or(nameStartsWith("Java.lang.invoke."))
                                .or(nameStartsWith("com.sun.proxy."))
                )
                .disableClassFormatChanges()
                .with(AgentBuilder.RedefinitionStrategy.RETRANSFORMATION)
                .with(AgentBuilder.InitializationStrategy.NoOp.INSTANCE)
                .with(AgentBuilder.TypeStrategy.Default.REDEFINE)
                .type(nameEndsWith("Hisen"))
                .transform(
                        (builder, type, classLoader, transformer, module) ->
                                builder.visit(Advice.to(HisenAdvice.class).on(isMethod().and(named("hello")))))
                .installOn(instrumentation);
    }

    public static class HisenAdvice {
        @Advice.OnMethodEnter
        static long enter(@Advice.Argument(value = 0, typing = DYNAMIC, readOnly = false) String name) {
            System.out.println("name before:" + name);
            // change name
            name += System.currentTimeMillis();
            return System.currentTimeMillis();
        }

        @Advice.OnMethodExit(onThrowable = RuntimeException.class)
        static void exit(
                @Advice.Enter
                long startTime) {
            System.out.println("HisenAdvice exit. time use:" + (System.currentTimeMillis() - startTime));
        }
    }
}