基于JavaAgent的全链路监控三《ByteBuddy操作监控方法字节码》

itstack-demo-agent-03
├── pom.xml
└── src
    ├── main
    │   ├── java
    │   │   └── org.itstack.demo.agent
    │   │       ├── MethodCostTime.java
    │   │       └── MyAgent.java
    │   └── resources
    │       └── META-INF
    │           └── MANIFEST.MF
    └── test
         └── java
             └── org.itstack.demo.test
                 └── ApiTest.java

<properties>
    <!-- Build args -->
    <argline>-Xms512m -Xmx512m</argline>
    <skip_maven_deploy>false</skip_maven_deploy>
    <updateReleaseInfo>true</updateReleaseInfo>
    <project.build.sourceEncoding>utf-8</project.build.sourceEncoding>
    <maven.test.skip>true</maven.test.skip>
    <!-- 自定义MANIFEST.MF -->
    <maven.configuration.manifestFile>src/main/resources/META-INF/MANIFEST.MF</maven.configuration.manifestFile>
</properties>

<dependencies>
    <dependency>
        <groupId>javassist</groupId>
        <artifactId>javassist</artifactId>
        <version>3.12.1.GA</version>
        <type>jar</type>
    </dependency>
    <dependency>
        <groupId>net.bytebuddy</groupId>
        <artifactId>byte-buddy</artifactId>
        <version>1.8.20</version>
    </dependency>
    <dependency>
        <groupId>net.bytebuddy</groupId>
        <artifactId>byte-buddy-agent</artifactId>
        <version>1.8.20</version>
    </dependency>
</dependencies>

<!-- 将javassist包打包到Agent中 -->
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-shade-plugin</artifactId>
    <executions>
        <execution>
            <phase>package</phase>
            <goals>
                <goal>shade</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <artifactSet>
            <includes>
                <include>javassist:javassist:jar:</include>
                <include>net.bytebuddy:byte-buddy:jar:</include>
                <include>net.bytebuddy:byte-buddy-agent:jar:</include>
            </includes>
        </artifactSet>
    </configuration>
</plugin>      

/**
 * 博客：http://itstack.org
 * 论坛：http://bugstack.cn
 * 公众号：bugstack虫洞栈  ｛获取学习源码｝
 * create by fuzhengwei on 2019
 */
public class MethodCostTime {

    @RuntimeType
    public static Object intercept(@Origin Method method, @SuperCall Callable<?> callable) throws Exception {
        long start = System.currentTimeMillis();
        try {
            // 原有函数执行
            return callable.call();
        } finally {
            System.out.println(method + " 方法耗时：" + (System.currentTimeMillis() - start) + "ms");
        }
    }

}

/**
 * javaagent
 * 博客：http://itstack.org
 * 论坛：http://bugstack.cn
 * 公众号：bugstack虫洞栈  ｛获取学习源码｝
 * create by fuzhengwei on 2019
 */
public class MyAgent {

    //JVM 首先尝试在代理类上调用以下方法
    public static void premain(String agentArgs, Instrumentation inst) {
        System.out.println("this is my agent：" + agentArgs);
        
        AgentBuilder.Transformer transformer = (builder, typeDescription, classLoader, javaModule) -> {
            return builder
                    .method(ElementMatchers.any()) // 拦截任意方法
                    .intercept(MethodDelegation.to(MethodCostTime.class)); // 委托
        };

        AgentBuilder.Listener listener = new AgentBuilder.Listener() {
            @Override
            public void onDiscovery(String s, ClassLoader classLoader, JavaModule javaModule, boolean b) {

            }

            @Override
            public void onTransformation(TypeDescription typeDescription, ClassLoader classLoader, JavaModule javaModule, boolean b, DynamicType dynamicType) {

            }

            @Override
            public void onIgnored(TypeDescription typeDescription, ClassLoader classLoader, JavaModule javaModule, boolean b) {

            }

            @Override
            public void onError(String s, ClassLoader classLoader, JavaModule javaModule, boolean b, Throwable throwable) {

            }

            @Override
            public void onComplete(String s, ClassLoader classLoader, JavaModule javaModule, boolean b) {

            }

        };

        new AgentBuilder
                .Default()
                .type(ElementMatchers.nameStartsWith("org.itstack.demo.test")) // 指定需要拦截的类
                .transform(transformer)
                .with(listener)
                .installOn(inst);
    }


    //如果代理类没有实现上面的方法，那么 JVM 将尝试调用该方法
    public static void premain(String agentArgs) {
    }

}

Manifest-Version: 1.0
Premain-Class: org.itstack.demo.agent.MyAgent
Can-Redefine-Classes: true

/**
 * 博客：http://itstack.org
 * 论坛：http://bugstack.cn
 * 公众号：bugstack虫洞栈  ｛获取学习源码｝
 * create by fuzhengwei on 2019
 *
 * VM options：
 * -javaagent:E:\itstack\GIT\itstack.org\itstack-demo-agent\itstack-demo-agent-03\target\itstack-demo-agent-03-1.0.0-SNAPSHOT.jar=testargs
 */
public class ApiTest {

    public static void main(String[] args) throws InterruptedException {
        ApiTest apiTest = new ApiTest();
        apiTest.echoHi();
    }

    private void echoHi() throws InterruptedException {
        System.out.println("hi agent");
        Thread.sleep((long) (Math.random() * 500));
    }

}

this is my agent：testargs
hi agent
private void org.itstack.demo.test.ApiTest.echoHi() throws java.lang.InterruptedException 方法耗时：329ms
public static void org.itstack.demo.test.ApiTest.main(java.lang.String[]) throws java.lang.InterruptedException 方法耗时：329ms

Process finished with exit code 0