基于JavaAgent的全链路监控（2）
大约 3 分钟
《利用javaagent进行方法耗时的监控》
1、介绍
方法耗时利用前人轮子字节码操作工具ByteBuddy：Byte Buddy是一个代码生成和操作库，用于在Java应用程序运行时创建和修改Java类，而无需编译器的帮助。 除了Java类库附带的代码生成实用程序外，Byte Buddy还允许创建任意类，并且不限于实现用于创建运行时代理的接口。 此外，Byte Buddy提供了一个方便的API，可以使用Java代理或在构建过程中手动更改类。
2、pom.xml
引入ByteBuddy并打入到Agent包中
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>cn.edu.bjut</groupId>
<artifactId>checkpoint-agent</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<!-- Build args -->
<argline>-Xms512m -Xmx512m</argline>
<updateReleaseInfo>true</updateReleaseInfo>
<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>
<javassist.version>3.12.1.GA</javassist.version>
<guava.version>15.0</guava.version>
<byte-buddy.version>1.8.20</byte-buddy.version>
<maven-shade-plugin.version>2.4.3</maven-shade-plugin.version>
<maven-compiler-plugin.version>3.8.1</maven-compiler-plugin.version>
</properties>
<dependencies>
<dependency>
<groupId>javassist</groupId>
<artifactId>javassist</artifactId>
<version>${javassist.version}</version>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>${guava.version}</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>net.bytebuddy</groupId>
<artifactId>byte-buddy</artifactId>
<version>${byte-buddy.version}</version>
</dependency>
<dependency>
<groupId>net.bytebuddy</groupId>
<artifactId>byte-buddy-agent</artifactId>
<version>${byte-buddy.version}</version>
</dependency>
</dependencies>
<!-- 将javassist包打包到Agent中 -->
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>${maven-shade-plugin.version}</version>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
<configuration>
<transformers>
<transformer
implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
<manifestEntries>
<!--指明包含 premain 方法的类名，否则打包出来的文件会找不到 MANIFEST.MF -->
<Premain-Class>cn.edu.bjut.agent.MyAgent</Premain-Class>
</manifestEntries>
</transformer>
</transformers>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
<configuration>
<source>8</source>
<target>8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
3、MethodCostTime.java
package cn.edu.bjut.monitor;
import net.bytebuddy.implementation.bind.annotation.Origin;
import net.bytebuddy.implementation.bind.annotation.RuntimeType;
import net.bytebuddy.implementation.bind.annotation.SuperCall;
import java.lang.reflect.Method;
import java.util.concurrent.Callable;
/**
* @author zhengtianqi
*/
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");
}
}
}
4、MyAgent.java
package cn.edu.bjut.agent;
import cn.edu.bjut.monitor.JvmStack;
import cn.edu.bjut.monitor.MethodCostTime;
import com.google.common.util.concurrent.ThreadFactoryBuilder;
import net.bytebuddy.agent.builder.AgentBuilder;
import net.bytebuddy.description.type.TypeDescription;
import net.bytebuddy.dynamic.DynamicType;
import net.bytebuddy.implementation.MethodDelegation;
import net.bytebuddy.matcher.ElementMatchers;
import net.bytebuddy.utility.JavaModule;
import java.lang.instrument.Instrumentation;
import java.util.concurrent.*;
/**
* @author zhengtianqi
*/
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
// 拦截任意方法
.method(ElementMatchers.any())
// 委托
.intercept(MethodDelegation.to(MethodCostTime.class));
};
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()
// 指定需要拦截的类
.type(ElementMatchers.nameStartsWith("cn.edu.bjut"))
.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) {
}
}
5、MANIFEST.MF
Manifest-Version: 1.0
Premain-Class: cn.edu.bjut.agent.MyAgent
Can-Redefine-Classes: true
6、测试
VM options: -javaagent:D:\git\credible\checkpoint-agent\target\checkpoint-agent-1.0-SNAPSHOT.jar=testargs
结果：
