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：
代码语言：javascript复制{
"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
代码语言：javascript复制#dubbo
dubbo:
scan:
base-packages: com.example.dubboservicea.provider, com.example.dubboservicea.reference
protocol:
name: dubbo
port: 12101
registry:
address: zookeeper://192.168.0.150:20001
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
