前言

前陣子朋友他老大叫他實現(xiàn)這么一個功能杨凑，就是低侵入的記錄接口每次的請求響應(yīng)日志敷扫，然后并統(tǒng)計每次請求調(diào)用的成功刽宪、失敗次數(shù)以及響應(yīng)耗時厘贼，當(dāng)時朋友的實現(xiàn)思路是在每個業(yè)務(wù)的controller的方法上加一個自定義注解，然后寫一個aop圣拄，以這個自定義注解為pointcut來記錄日志嘴秸。

這種AOP+注解來實現(xiàn)日志記錄，應(yīng)該是很常見的實現(xiàn)方式。然而朋友在落地的時候岳掐，發(fā)現(xiàn)項目要加自定義注解的地方太多凭疮。后面我就跟他說，那就不寫注解岩四，直接以形如下

execution(* com.github.lybgeek.logaop.service..*.*(..))

這樣不行嗎？他說他這個功能他老大是希望給各個項目組使用哥攘，像我上面的方法剖煌，估計行不通，我就問他說為啥行不通逝淹，他說各個項目的包名都不一樣耕姊，如果我那種思路，他就說這樣在代碼里poincut不得要這么寫

execution(* com.github.lybgeek.a.service..*.*(..) 
|| * com.github.lybgeek.b.service..*.*(..) || * com.github.lybgeek.c.service..*.*(..) )

這樣每次新加要日志記錄栅葡，都得改切面代碼茉兰，還不如用自定注解來的好。聽完他的解釋欣簇，我一臉黑人問號臉规脸。于是就趁著5.1假期期間，寫個demo實現(xiàn)上面的需求

業(yè)務(wù)場景

低侵入的記錄接口每次的請求響應(yīng)日志熊咽，然后并統(tǒng)計每次請求調(diào)用的成功莫鸭、失敗次數(shù)以及響應(yīng)耗時

這個業(yè)務(wù)需求應(yīng)該算是很簡單，實現(xiàn)的難點就在于低侵入横殴，提到低侵入被因，我首先想到是使用者無需寫代碼，或者只需寫少量代碼或者僅需簡單配置一下衫仑，最好能做到業(yè)務(wù)無感知梨与。

實現(xiàn)手段

我這邊提供2種思路

• javaagent + byte-buddy
• springboot自動裝配 + AOP

javaagent

1、什么是javaagent

javaagent是一個簡單優(yōu)雅的java agent,利用java自帶的instrument特性+javassist/byte-buddy字節(jié)碼可以實現(xiàn)對類的攔截或者增強(qiáng)文狱。

javaAgent 是運(yùn)行在 main方法之前的攔截器粥鞋，它內(nèi)定的方法名叫 premain ，也就是說先執(zhí)行 premain 方法然后再執(zhí)行 main 方法

2瞄崇、如何實現(xiàn)一個javaagent

• a陷虎、必須實現(xiàn)premain方法

示例：

public class AgentDemo {

    public static void premain(String agentArgs, Instrumentation inst) {
        System.out.println("agentArgs : " + agentArgs);
        inst.addTransformer(new DefineTransformer(),true);
    }

    static class DefineTransformer implements ClassFileTransformer {

        @Override
        public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws IllegalClassFormatException {
            System.out.println("premain load Class:" + className);
            return classfileBuffer;
        }
    }
}

• b、在META-INF目錄添加MANIFEST.MF文檔杠袱，內(nèi)容形如下

Manifest-Version: 1.0
Implementation-Version: 0.0.1-SNAPSHOT
Premain-Class: com.github.lybgeek.agent.ServiceLogAgent
Can-Redefine-Classes: true

其中Premain-Class是必選項尚猿。MANIFEST.MF可以利用maven插件進(jìn)行生成，插件如下

 <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>3.2.0</version>
                <configuration>
                    <archive>
                        <manifest>
                            <addClasspath>true</addClasspath>
                        </manifest>
                        <manifestEntries>
                            <Premain-Class>com.github.lybgeek.agent.ServiceLogAgent</Premain-Class>
                            <Agent-Class>com.github.lybgeek.agent.ServiceLogAgent</Agent-Class>
                            <Can-Redefine-Classes>true</Can-Redefine-Classes>
                            <Can-Retransform-Classes>true</Can-Retransform-Classes>
                        </manifestEntries>
                    </archive>
                </configuration>
            </plugin>

3楣富、業(yè)務(wù)代碼如何使用javagent

java -javaagent:agentjar文件的位置 [= 傳入 premain的參數(shù) ] -jar 要運(yùn)行的jar文件

注：-javaagent一定要在-jar之前凿掂，不然不會生效

byte-buddy

1、什么是byte-buddy

Byte Buddy是一個JVM的運(yùn)行時代碼生成器，你可以利用它創(chuàng)建任何類庄萎，且不像JDK動態(tài)代理那樣強(qiáng)制實現(xiàn)一個接口踪少。Byte Buddy還提供了簡單的API，便于手工糠涛、通過Java Agent援奢，或者在構(gòu)建期間修改字節(jié)碼

2、byte-buddy教程

注： 如果再介紹byte-buddy使用忍捡，則篇幅會比較長集漾，因此提供以下2個byte-buddy學(xué)習(xí)鏈接，感興趣的朋友可以點擊查看

https://blog.gmem.cc/byte-buddy-study-note

https://notes.diguage.com/byte-buddy-tutorial/

如何利用javaagent + byte-buddy實現(xiàn)低侵入記錄日志

1砸脊、編寫agent入口類

public class ServiceLogAgent {


    public static String base_package_key = "agent.basePackage";

    public static void premain(String agentArgs, Instrumentation inst) {
        System.out.println("loaded agentArgs ：" + agentArgs);
        Properties properties = PropertiesUtils.getProperties(agentArgs);
        ServiceLogHelperFactory serviceLogHelperFactory = new ServiceLogHelperFactory(properties);
        serviceLogHelperFactory.getServiceLogHelper().initTable();

        AgentBuilder.Transformer transformer = (builder, typeDescription, classLoader, javaModule) -> {
            return builder
                    .method(ElementMatchers.<MethodDescription>any()) // 攔截任意方法
                    .intercept(MethodDelegation.to(new ServiceLogInterceptor(serviceLogHelperFactory))); // 委托
        };

        AgentBuilder.Listener listener = new AgentBuilder.Listener() {
            private Log log = LogFactory.getLog(AgentBuilder.Listener.class);

            @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) {
                log.error(throwable.getMessage(),throwable);
            }

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

        };

        new AgentBuilder
                .Default()
                // 指定需要攔截的類
                .type(ElementMatchers.nameStartsWith(properties.getProperty(base_package_key)))
                .and(ElementMatchers.isAnnotatedWith(Service.class))
                .transform(transformer)
                .with(listener)
                .installOn(inst);
    }


}

2具篇、編寫攔截器

public class ServiceLogInterceptor {
    private Log log = LogFactory.getLog(ServiceLogInterceptor.class);


    private ServiceLogHelperFactory serviceLogHelperFactory;

    public ServiceLogInterceptor(ServiceLogHelperFactory serviceLogHelperFactory) {
        this.serviceLogHelperFactory = serviceLogHelperFactory;
    }

    @RuntimeType
    public Object intercept(@AllArguments Object[] args, @Origin Method method, @SuperCall Callable<?> callable) {
        long start = System.currentTimeMillis();
        long costTime = 0L;
        String status = ServiceLog.SUCEESS;
        Object result = null;
        String respResult = null;
        try {
            // 原有函數(shù)執(zhí)行
            result = callable.call();
            respResult = JsonUtils.object2json(result);
        } catch (Exception e){
            log.error(e.getMessage(),e);
            status = ServiceLog.FAIL;
            respResult = e.getMessage();
        } finally{
            costTime = System.currentTimeMillis() - start;
            saveLog(args, method, costTime, status, respResult);
        }
        return result;
    }

    private void saveLog(Object[] args, Method method, long costTime, String status, String respResult) {
        if(!isSkipLog(method)){
            ServiceLog serviceLog = serviceLogHelperFactory.createServiceLog(args,method);
            serviceLog.setCostTime(costTime);
            serviceLog.setRespResult(respResult);
            serviceLog.setStatus(status);
            ServiceLogHelper serviceLogHelper = serviceLogHelperFactory.getServiceLogHelper();
            serviceLogHelper.saveLog(serviceLog);
        }
    }


    private boolean isSkipLog(Method method){
        ServiceLogProperties serviceLogProperties = serviceLogHelperFactory.getServiceLogProperties();
        List<String> skipLogServiceNameList = serviceLogProperties.getSkipLogServiceNameList();
        if(!CollectionUtils.isEmpty(skipLogServiceNameList)){
            String currentServiceName = method.getDeclaringClass().getName() + ServiceLogProperties.CLASS_METHOD_SPITE + method.getName();
            return skipLogServiceNameList.contains(currentServiceName);
        }
        return false;
    }



}

3、通過maven將agent打包成jar

4凌埂、效果演示

首先idea在啟動類的vm參數(shù)驱显，加入形如下內(nèi)容

 -javaagent:F:\springboot-learning\springboot-agent\springboot-javaagent-log\target\agent-log.jar=F:\springboot-learning\springboot-agent\springboot-javaagent-log\target\classes\agent.properties

效果圖

image.png

image.png

image.png

如何利用自動裝配+AOP實現(xiàn)低侵入記錄日志

注： 其實朋友那種方式也差不多可以了，只需把poincut的外移到配置文件文件即可

1瞳抓、編寫切面

@Slf4j
public class ServiceLogAdvice implements MethodInterceptor {

    private LogService logService;

    public ServiceLogAdvice(LogService logService) {
        this.logService = logService;
    }

    @Override
    public Object invoke(MethodInvocation invocation)  {

        long start = System.currentTimeMillis();
        long costTime = 0L;
        String status = ServiceLog.SUCEESS;
        Object result = null;
        String respResult = null;
        try {
            // 原有函數(shù)執(zhí)行
            result = invocation.proceed();
            respResult = JSON.toJSONString(result);
        } catch (Throwable e){
            log.error(e.getMessage(),e);
            status = ServiceLog.FAIL;
            respResult = e.getMessage();
        } finally{
            costTime = System.currentTimeMillis() - start;
            saveLog(invocation.getArguments(), invocation.getMethod(), costTime, status, respResult);
        }
        return result;

    }

    private void saveLog(Object[] args, Method method, long costTime, String status, String respResult) {
            ServiceLog serviceLog = ServiceLog.builder()
                                    .serviceName(method.getDeclaringClass().getName())
                                    .costTime(costTime)
                                    .methodName(method.getName())
                                    .status(status)
                                    .reqArgs(JSON.toJSONString(args))
                                    .respResult(respResult).build();
           logService.saveLog(serviceLog);
    }
}

2埃疫、注入切面bean

 @Bean
    @ConditionalOnMissingBean
    public AspectJExpressionPointcutAdvisor serviceLogAspectJExpressionPointcutAdvisor(AopLogProperties aopLogProperties) {
        AspectJExpressionPointcutAdvisor advisor = new AspectJExpressionPointcutAdvisor();
        advisor.setExpression(aopLogProperties.getPointcut());
        advisor.setAdvice(serviceLogAdvice());
        return advisor;
    }

3、編寫自動裝配類

@Configuration
@EnableConfigurationProperties(AopLogProperties.class)
@ConditionalOnProperty(prefix = "servicelog",name = "enabled",havingValue = "true",matchIfMissing = true)
public class AopLogAutoConfiguration {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Bean
    @ConditionalOnMissingBean
    public LogService logService(){
        return new LogServiceImpl(jdbcTemplate);
    }

    @Bean
    @ConditionalOnMissingBean
    public ServiceLogAdvice serviceLogAdvice(){
        return new ServiceLogAdvice(logService());
    }

    @Bean
    @ConditionalOnMissingBean
    public AspectJExpressionPointcutAdvisor serviceLogAspectJExpressionPointcutAdvisor(AopLogProperties aopLogProperties) {
        AspectJExpressionPointcutAdvisor advisor = new AspectJExpressionPointcutAdvisor();
        advisor.setExpression(aopLogProperties.getPointcut());
        advisor.setAdvice(serviceLogAdvice());
        return advisor;
    }


}

4孩哑、編寫spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
    com.github.lybgeek.logaop.config.AopLogAutoConfiguration

5熔恢、效果演示

在業(yè)務(wù)代碼做如下配置

• 5.1 在pom.xml引入starter

  <dependency>
            <groupId>com.github.lybgeek</groupId>
            <artifactId>aoplog-springboot-starter</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

• 5.2 在yml文件中配置pointcut

servicelog:
  pointcut: execution(* com.github.lybgeek.mock.service.client..*.*(..))
  enabled: true

• 5.3 效果圖

image.png

在這里插入圖片描述

總結(jié)

以上主要列舉了通過javaagent和aop加自動裝配2兩種方式來實現(xiàn)低侵入記錄日志。其實這兩種實現(xiàn)在一些開源的方案用得挺多的臭笆，比如byte-buddy在skywalking和arthas就有使用到叙淌，比如MethodInterceptor 在spring事務(wù)中就有用到。所以多看些源碼愁铺，在設(shè)計方案時鹰霍，有時候會產(chǎn)生意想不到的火花

demo鏈接

https://github.com/lyb-geek/springboot-learning/tree/master/springboot-agent