dubbo下的异常统一处理

dubbo下的异常统一处理

ps:lz最近写了一个统一异常处理模块,按等级高低发送给对应的负责人(该异常发生的类对应的包对应的模块),跟大家分享一下.

异常统一处理需要类去实现javax.ws.rs的ExceptionMapper接口

public interface ExceptionMapper<E extends Throwable> {

/**
* Map an exception to a {@link javax.ws.rs.core.Response}. Returning
* {@code null} results in a {@link javax.ws.rs.core.Response.Status#NO_CONTENT}
* response. Throwing a runtime exception results in a
* {@link javax.ws.rs.core.Response.Status#INTERNAL_SERVER_ERROR} response.
*
* @param exception the exception to map to a response.
* @return a response mapped from the supplied exception.
*/
Response toResponse(E exception);
}

需要了解dubbo的ExceptionFilter的实现:

/*
* Copyright 1999-2011 Alibaba Group.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0 *
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.dubbo.rpc.filter;

import java.lang.reflect.Method;

import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.extension.Activate;
import com.alibaba.dubbo.common.logger.Logger;
import com.alibaba.dubbo.common.logger.LoggerFactory;
import com.alibaba.dubbo.common.utils.ReflectUtils;
import com.alibaba.dubbo.common.utils.StringUtils;
import com.alibaba.dubbo.rpc.Filter;
import com.alibaba.dubbo.rpc.Invocation;
import com.alibaba.dubbo.rpc.Invoker;
import com.alibaba.dubbo.rpc.Result;
import com.alibaba.dubbo.rpc.RpcContext;
import com.alibaba.dubbo.rpc.RpcException;
import com.alibaba.dubbo.rpc.RpcResult;
import com.alibaba.dubbo.rpc.service.GenericService;

/**
* ExceptionInvokerFilter
* <p>
* 功能：
* <ol>
* <li>不期望的异常打ERROR日志（Provider端）<br>
*     不期望的日志即是，没有的接口上声明的Unchecked异常。
* <li>异常不在API包中，则Wrap一层RuntimeException。<br>
*     RPC对于第一层异常会直接序列化传输(Cause异常会String化)，避免异常在Client出不能反序列化问题。
* </ol>
*
* @author william.liangf
* @author ding.lid
*/
@Activate(group = Constants.PROVIDER)
public class ExceptionFilter implements Filter {

private final Logger logger;

public ExceptionFilter() {
this(LoggerFactory.getLogger(ExceptionFilter.class));
}

public ExceptionFilter(Logger logger) {
this.logger = logger;
}

public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
try {
Result result = invoker.invoke(invocation);
if (result.hasException() && GenericService.class != invoker.getInterface()) {
try {
Throwable exception = result.getException();

// 如果是checked异常，直接抛出
if (! (exception instanceof RuntimeException) && (exception instanceof Exception)) {
return result;
}
// 在方法签名上有声明，直接抛出
try {
Method method = invoker.g
4000
etInterface().getMethod(invocation.getMethodName(), invocation.getParameterTypes());
Class<?>[] exceptionClassses = method.getExceptionTypes();
for (Class<?> exceptionClass : exceptionClassses) {
if (exception.getClass().equals(exceptionClass)) {
return result;
}
}
} catch (NoSuchMethodException e) {
return result;
}

// 未在方法签名上定义的异常，在服务器端打印ERROR日志
logger.error("Got unchecked and undeclared exception which called by " + RpcContext.getContext().getRemoteHost()
+ ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName()
+ ", exception: " + exception.getClass().getName() + ": " + exception.getMessage(), exception);

// 异常类和接口类在同一jar包里，直接抛出
String serviceFile = ReflectUtils.getCodeBase(invoker.getInterface());
String exceptionFile = ReflectUtils.getCodeBase(exception.getClass());
if (serviceFile == null || exceptionFile == null || serviceFile.equals(exceptionFile)){
return result;
}
// 是JDK自带的异常，直接抛出
String className = exception.getClass().getName();
if (className.startsWith("java.") || className.startsWith("javax.")) {
return result;
}
// 是Dubbo本身的异常，直接抛出
if (exception instanceof RpcException) {
return result;
}

// 否则，包装成RuntimeException抛给客户端
return new RpcResult(new RuntimeException(StringUtils.toString(exception)));
} catch (Throwable e) {
logger.warn("Fail to ExceptionFilter when called by " + RpcContext.getContext().getRemoteHost()
+ ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName()
+ ", exception: " + e.getClass().getName() + ": " + e.getMessage(), e);
return result;
}
}
return result;
} catch (RuntimeException e) {
logger.error("Got unchecked and undeclared exception which called by " + RpcContext.getContext().getRemoteHost()
+ ". service: " + invoker.getInterface().getName() + ", method: " + invocation.getMethodName()
+ ", exception: " + e.getClass().getName() + ": " + e.getMessage(), e);
throw e;
}
}

}

在此基础上,去实现ExceptionMapper<E extend throwable>抓取特定的异常,比如:

public class RpcExceptionMapperSupportWarning implements ExceptionMapper<RpcException>{
@Override
public Response toResponse(RpcException e) {
FailedResponse faild = null;

if (e.getCause() instanceof ConstraintViolationException) {
EExceptionLevel level = EExceptionLevel.LEVEL_LOW;
ExceptionWarningFilter.FILTER.warning(e, level);
return this.rpcMapperSupper.toResponse(e);
}//else if(){}...
else {//RPC Call Failure!!!
EExceptionLevel level = EExceptionLevel.LEVEL_HIGH;
ExceptionWarningFilter.FILTER.warning(e, level);
faild = FailedResponse.ILLEGAL_RPC_CALL;
}
return Response.status(Response.Status.OK).entity(faild).type("application/json; charset=UTF-8").build();
}
}

上述代码中的ExceptionWarningFilter类,便是处理异常的类:

public enum ExceptionWarningFilter {

FILTER;
private static Logger logger = LoggerFactory.getLogger(ExceptionWarningFilter.class);
private DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

public void warning(Throwable throwable,EExceptionLevel level){
Throwable exception = throwable.getCause();
if (exception == null) {
exception = throwable;
}
WarningMessage warningMessage = null;

Timestamp happenTimestamp =new Timestamp(new Date().getTime());

String exceptionStack = getExceptionStack(exception);//异常栈

String ip = RpcContext.getContext().getLocalHost();

if (exception instanceof RuntimeException) {
String message = exception.getLocalizedMessage();
if (message!=null) {
warningMessage = getWarningInfo(message,warningMessage);
}else{
for(StackTraceElement el : exception.getStackTrace()){
warningMessage = getWarningInfo(el,exception,warningMessage);
break;
}
}
}else {
for (StackTraceElement el : exception.getStackTrace()) {
if (el.getClassName().startsWith("com.java")) {
warningMessage = getWarningInfo(el,exception,warningMessage);
break;
}
}
if (warningMessage==null) {
for(StackTraceElement el : exception.getStackTrace()){
warningMessage = getWarningInfo(el,exception,warningMessage);
break;
}
}
}
callingTheExceptionNotificationService(level,happenTimestamp,warningMessage,exceptionStack,ip);

}

private String getExceptionStack(Throwable exception) {
String exceptionStack = null;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
exception.printStackTrace(new PrintStream(baos));
if (baos!=null) {
exceptionStack =  baos.toString();
}
return exceptionStack;

}

private void callingTheExceptionNotificationService(EExceptionLevel level, Timestamp happenTimestamp,
WarningMessage warningMessage, String exceptionStack, String ip) {
String happenTime = df.format(happenTimestamp==null?new Date().getTime():happenTimestamp);
FileSystemXmlApplicationContext fsxac = null;
try {
fsxac = new FileSystemXmlApplicationContext("/server-spring.xml");
IExceptionNotifyService exceptionNotifyService = (IExceptionNotifyService) fsxac.getBean("exceptionNotifyService");
exceptionNotifyService.exceptionNotify(level,
getWarningInfo(happenTimestamp,warningMessage,exceptionStack,ip));
logger.debug("发送异常报警信息(时间:{},info:{}",happenTime,warningMessage.toString());
} catch (Exception e) {
e.printStackTrace();
logger.debug(e.toString());
}finally {
if (fsxac!=null) {
fsxac.close();
}
}
}

lz只贴了主要的方法,其他的就是对bean的数据的封装,就不贴了
这里lz使用了一个枚举类来作为这个异常处理类,主要是想运用一个单例模式,这个用法可在efftive java中找到,这种写法在功能上与共有域方法相近，但是它更简洁，无偿地提供了序列化机制，绝对防止对此实例化，即使是在面对复杂的序列化或者反射攻击的时候。虽然这中方法还没有广泛采用，但是单元素的枚举类型已经成为实现Singleton的最佳方法。
lz主要碰到的问题是,这个实现了的异常mapper并不支持spring的antowired注释,大概的解释应该是他并不会被声明为一个bean?lz的解决方法是自己去配置文件里get一个,如果有更好的解决方法欢迎评论@,这里还有一个要注意的是,dubbo的异常处理中,不符合条件的,会包装成一个runtimeException再抛出,所以lz在处理类中对 instanceof runtimeException的异常做了处理,lz的处理其实说起来很白痴,就是获取他携带的LocalizedMessage然后对其做处理,获取异常发生的类,方法,行以及对应的包名.
之后就是根据业务需求将异常信息发送给对应负责人了,出去性能的考虑,lz和同事的方案为将该信息发送到消息队列上去,并设置该异常类型的redis缓存,用于判断相隔多少时间发送,而消费方则去收取消息队列上对应的topic数据去做处理.