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手写链路追踪优化-自动全局追踪代替局部手动追踪

web 2025/9/4 4:08:38

1. 前文回顾和优化需求分析

前文的demo已经具备了简单的日志追踪能力
前文：手写链路追踪
它的缺点也明显，它是API level的，也就是如果想全局追踪，每个API都需要手写一份，这就会产生很多重复代码，同时我们在API层面也不想见到跟业务无关的代码，该怎么优化呢？
要想全局有效，一劳永逸，你可能会想到放到filter或者aspect处理，让我们对比一下哪个更合适

特性	Filter	Aspect
作用范围	Web请求层面	方法调用层面
依赖关系	依赖Servlet容器	依赖AOP框架（如Spring AOP）
触发条件	所有HTTP请求	特定方法调用
配置方式	web.xml或注解	注解或XML配置
执行顺序	按注册顺序	按优先级
灵活性	相对较低	较高，可精确控制切入点

因为是从API转移，符合Web请求层面和http触发条件，跟filter情景一致，所以考虑把它转移到filter

2. 代码实现

2.1 创建一个filter

实现如下功能：

servletRequest拦截trace id的请求头
如果upstream没有传入trace id，系统内部自己随机生成一个
用trace id替换当前线程的线程名（这是利用了在传统的Spring MVC中，默认情况下是一个请求对应一个阻塞线程的原理，这里留个伏笔，请思考还有什么遗漏）
为了线程安全，直接修改线程名需要注意恢复

package com.sandwich.logtracing.filter;import com.sandwich.logtracing.util.RandomStrUtils;
import jakarta.servlet.*;
import lombok.extern.slf4j.Slf4j;
import org.apache.catalina.connector.RequestFacade;
import org.apache.commons.lang3.StringUtils;import java.io.IOException;/*** @Author 公众号： IT三明治* @Date 2025/8/30* @Description: log filter, to update the log thread name with a trace id*/
@Slf4j
public class LogFilter implements Filter {@Overridepublic void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {String traceId = ((RequestFacade) servletRequest).getHeader("x-request-correlation-id");//if the request header don't have a trace id，then generate a random oneif (StringUtils.isBlank(traceId)) {traceId = RandomStrUtils.generateRandomString(15);}// keep original thread nameThread currentThread = Thread.currentThread();String originalName = currentThread.getName();try {//replace current thread name with a trace idThread.currentThread().setName(traceId);filterChain.doFilter(servletRequest, servletResponse);} finally {//restore thread name before api request endThread.currentThread().setName(originalName);}}
}

2.2 注册filter

package com.sandwich.logtracing.config;import com.sandwich.logtracing.filter.LogFilter;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;/*** @Author 公众号： IT三明治* @Date 2025/8/30* @Description:*/
@Configuration
public class WebConfiguration {@Bean@ConditionalOnMissingBean(LogFilter.class)@Order(Ordered.HIGHEST_PRECEDENCE + 101)public FilterRegistrationBean<LogFilter> logFilterFilterRegistrationBean() {FilterRegistrationBean<LogFilter> bean = new FilterRegistrationBean<>();bean.setFilter(new LogFilter());bean.addUrlPatterns("/*");return bean;}
}

2.3 删除API中trace id的处理逻辑

package com.sandwich.logtracing.controller;import com.sandwich.logtracing.entity.ApiResponse;
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.*;/*** @Author 公众号： IT三明治* @Date 2025/8/29* @Description: login demo controller*/
@Slf4j
@RestController
@RequestMapping("/test")
public class LoginController {@PostMapping("/login")public ApiResponse<String> login(@RequestBody LoginRequest loginRequest) {for (int i=1; i<= 10; i++) {log.info("processing login for user {}, login step {} done", loginRequest.getUsername(), i);}log.info("user {} login success", loginRequest.getUsername());return ApiResponse.success("Sandwich login success", Thread.currentThread().getName());}@Datapublic static class LoginRequest {private String username;private String password;}
}

注意：Thread.currentThread().getName()已经变成trace id了。

2.4 为了显示API请求的所有内容，还是用shell的方式请求

#!/bin/bash# Define the API endpoint
API_URL="http://localhost:8080/test/login"function generate_random_string() {# 使用openssl生成随机字符串（如果已安装）if command -v openssl &> /dev/null; thenopenssl rand -base64 20 | tr -dc 'a-zA-Z0-9' | fold -w 15 | head -n 1else# 使用系统方法生成local chars="abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"local result=""result=$(printf "%s" "${chars:$((RANDOM % ${#chars})):1}"{1..15} | tr -d '\n')echo "$result"fi
}function normalLogin() {# 生成15位随机字符串作为traceIdtraceId=$(generate_random_string)echo "Generated traceId from client side: $traceId"response=$(curl -X POST $API_URL \-H "Content-Type: application/json" \-H "x-request-correlation-id: $traceId" \-d '{"username": "Sandwich", "password": "test"}')echo "Response from login API:"# 通过python工具将返回信息格式化成json格式echo "$response" | python -m json.tool
}normalLogin

3. 验证测试

启动项目
执行shell请求

Administrator@USER-20230930SH MINGW64 /d/git/java/log-tracing/shell (master)
$ ./login.sh
Generated traceId from client side: ubBKwVCauRVV78m% Total    % Received % Xferd  Average Speed   Time    Time     Time  CurrentDload  Upload   Total   Spent    Left  Speed
100   144    0   100  100    44   7636   3360 --:--:-- --:--:-- --:--:-- 11076
Response from login API:
{"responseCode": 200,"message": "success","data": "Sandwich login success","traceId": "ubBKwVCauRVV78m"
}