一、概要

紧接上一篇，完成分析之后，就要具体的实现了。

service-a: 实现dubbo服务。

service-b: 实现web服务，并调用service-a实现的服务。

二、实现

2.1 日志采集及存储

本例直接使用【阿里云·日志服务】进行数据存储和检索，使用Aliyun Log Logback Appender进行日志收集及上传。

其实就是阿里自己实现了一个Logback Appender。当然我们也可以自己实现，比如上传至自建的ELK中。

2.2 项目中traceId生成、传递、销毁

2.2.1 traceId生成、销毁

2.2.1.1 客户端请求等触发(外部)

外部类请求触发情况，使用拦截器处理。

请求过来之后，生成traceId，并写入org.slf4j.MDC。

请求完成之后，将traceId从org.slf4j.MDC中移除。

package com.example.dubboserviceb.interceptor; import com.example.dubboserviceb.constants.Constants; import org.slf4j.MDC; import org.springframework.web.servlet.HandlerInterceptor; import org.springframework.web.servlet.ModelAndView; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.util.UUID; /** * @author lpe234 * @since 2019/5/25 14:43 */ public class TraceIdInterceptor implements HandlerInterceptor { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { // generate traceId String traceId = UUID.randomUUID().toString().replace("-", ""); // put traceId MDC.put(Constants.TRACE_ID, traceId); return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { // clear traceId MDC.remove(Constants.TRACE_ID); } } 

2.2.1.2 定时任务等触发(内部)

(略...)

2.2.1 traceId传递

2.2.1.1 WEB类传递

简单的接口返回类，增加traceId字段。

package com.example.dubboserviceb.utils; import lombok.Data; /** * @author lpe234 * @since 2019/5/25 14:55 */ @Data public class RestResponse<T> { private Integer code; private String msg; private T data; private String traceId; public RestResponse() { } public RestResponse(Integer code, String msg, T data) { this.code = code; this.msg = msg; this.data = data; } public static <T> RestResponse<T> ok(T data) { return new RestResponse<>(200, "ok", data); } public static <T> RestResponse<T> error(T data) { return new RestResponse<>(400, "error", data); } } 

当请求响应结果生成前，获取当前org.slf4j.MDC中的traceId，设置到RestResponse中。

package com.example.dubboserviceb.advice; import com.example.dubboserviceb.constants.Constants; import com.example.dubboserviceb.utils.RestResponse; import org.slf4j.MDC; import org.springframework.core.MethodParameter; import org.springframework.http.MediaType; import org.springframework.http.converter.HttpMessageConverter; import org.springframework.http.server.ServerHttpRequest; import org.springframework.http.server.ServerHttpResponse; import org.springframework.web.bind.annotation.ControllerAdvice; import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice; /** * @author lpe234 * @since 2019/5/25 15:03 */ @ControllerAdvice public class ResponseModifyAdvice implements ResponseBodyAdvice<Object> { @Override public boolean supports(MethodParameter methodParameter, Class<? extends HttpMessageConverter<?>> aClass) { return true; } @Override public Object beforeBodyWrite(Object o, MethodParameter methodParameter, MediaType mediaType, Class<? extends HttpMessageConverter<?>> aClass, ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse) { // put traceId to response ((RestResponse) o).setTraceId(MDC.get(Constants.TRACE_ID)); return o; } } 

最终，接口响应数据例如如下：

{ "code": 200, "msg": "ok", "data": "Hello apple", "traceId": "6c25de3422374d51be58555ae9c380e8" } 

2.2.1.2 Dubbo类传递

traceId的存储使用org.apache.dubbo.rpc.RpcContext(内部使用InternalThreadLocal实现)。

借助Dubbo的过滤器来实现，traceId在Dubbo服务间的读取、写入和清除。

package com.example.dubboservicea.filter; import com.example.dubboservicea.constants.Constants; import org.apache.dubbo.common.extension.Activate; import org.apache.dubbo.rpc.*; import org.slf4j.MDC; /** * @author lpe234 * @since 2019/5/25 15:24 */ @Activate(group = {org.apache.dubbo.common.Constants.PROVIDER, org.apache.dubbo.common.Constants.CONSUMER}) public class DubboTraceIdFilter implements Filter { @Override public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException { RpcContext rpcContext = RpcContext.getContext(); // before if (rpcContext.isProviderSide()) { // get traceId from dubbo consumer，and set traceId to MDC String traceId = rpcContext.getAttachment(Constants.TRACE_ID); MDC.put(Constants.TRACE_ID, traceId); } if (rpcContext.isConsumerSide()) { // get traceId from MDC, and set traceId to rpcContext String traceId = MDC.get(Constants.TRACE_ID); rpcContext.setAttachment(Constants.TRACE_ID, traceId); } Result result = invoker.invoke(invocation); // after if (rpcContext.isProviderSide()) { // clear traceId from MDC MDC.remove(Constants.TRACE_ID); } return result; } @Override public Result onResponse(Result result, Invoker<?> invoker, Invocation invocation) { return result; } } 

另，需要在resources/META-INF/dubbo/文件夹下，创建com.alibaba.dubbo.rpc.Filter文本文件。内容为dubboTraceIdFilter=com.example.dubboservicea.filter.DubboTraceIdFilter。

而后，spring-boot配置文件中 配置dubbo的过滤器

#dubbo dubbo: scan: base-packages: com.example.dubboservicea.provider, com.example.dubboservicea.reference protocol: name: dubbo port: 12101 registry: address: zookeeper://118.190.204.150:20084 provider: filter: dubboTraceIdFilter consumer: filter: dubboTraceIdFilter 

三、结果

3.1 HTTP请求结果返回

3.2 日志服务查询