为全局请求添加 TraceId ，看日志再也不懵逼

不知道大家有没有一堆日志就是定位不到那块是异常部分，接口错误无法复现，也找不到报错信息等比较棘手的问题。

其实解决上面的问题很简单，只要我们为每一个请求都分配一个唯一的 RequestId 或者叫 TraceId ，一旦出了问题，只需要拿着 Id 去日志里一搜，妖魔鬼怪立马原形毕露。

对于分布式链路追踪，有很多开源中间件，本文主要通过 logback 的 MDC 实现。

请求拦截器

@Component public class TraceIdInterceptor extends HandlerInterceptorAdapter { @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String traceId = String.format("%s - %s",request.getRequestURI(), UUID.fastUUID().toString(true));
        MDC.put("traceId", traceId); return true;
 }

注册拦截器

@Component @RequiredArgsConstructor public class GlobalWebMvcConfigurer implements WebMvcConfigurer { private final TraceIdInterceptor traceIdInterceptor; @Override public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(traceIdInterceptor);
    }
}

统一返回值

@Data @NoArgsConstructor @AllArgsConstructor public class CommonResponse<T> implements Serializable { /** 错误码 */ private Integer code; /** 错误消息 */ private String message; /** 泛型响应数据 */ private T Data; private String traceId; public CommonResponse(Integer code, String message) { this.code = code; this.message = message; this.traceId = MDC.get("traceId");
    }

}

日志配置

logback.xml

<?xml version="1.0" encoding="UTF-8"?> <configuration> <property name="LOG_PATTERN" value="%d{yyyy-MM-dd} %d{HH:mm:ss.SSS} [%highlight(%-5level)] [%boldYellow(%X{traceId})] [%boldYellow(%thread)] %boldGreen(%logger{36} %F.%L) %msg%n"> </property> <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"> <encoder> <pattern>${LOG_PATTERN}</pattern> </encoder> <!-- 控制台打印INFO及以上级别的日志 --> <filter class="ch.qos.logback.classic.filter.ThresholdFilter"> <level>INFO</level> </filter> </appender> <root> <appender-ref ref="STDOUT"/> </root> </configuration> 

测试

接口返回值

{ "code": 0, "message": "", "traceId": "/commerce-user/user/findById - 73e470120ef24d57a111de6b671d030b", "data": { "id": 1, "username": "test1", "password": "test", "extraInfo": "{}", "createTime": "2022-06-20T09:23:18.000+00:00", "updateTime": "2022-06-20T09:23:18.000+00:00", "balance": 0 }
}

日志

如此，如果线上有接口出现问题，拿着 traceId 到日志文件搜索，就能检索到该请求的日志调用链路，处理问题就变得简单了。

异步调用配置

因为是 ThreadLocal ，异步任务必然是获取不到 traceId 的，需要再线程池配置中手动添加。

线程池配置

@Configuration public class AsyncConfig implements AsyncConfigurer { @Bean @Override public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();

        executor.setCorePoolSize(10);
        executor.setMaxPoolSize(20);
        executor.setQueueCapacity(20);
        executor.setKeepAliveSeconds(60);
        executor.setThreadNamePrefix("user-async-"); // 等待所有任务结果候再关闭线程池 executor.setWaitForTasksToCompleteOnShutdown(true);
        executor.setAwaitTerminationSeconds(60); // 定义拒绝策略 executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy()); //设置线程装饰器 executor.setTaskDecorator(runnable -> ThreadMdcUtils.wrapAsync(runnable, MDC.getCopyOfContextMap())); // 初始化线程池, 初始化 core 线程 executor.initialize(); return executor;
    }
}

public class ThreadMdcUtils { public static Runnable wrapAsync(Runnable task, Map<String,String> context){ return () -> { if(context==null){
                MDC.clear();
            }else {
                MDC.setContextMap(context);
            } if(MDC.get("traceId")==null){
                MDC.put("traceId", UUID.fastUUID().toString(true));
            } try {
                task.run();
            }finally {
                MDC.clear();
            }
        };
    }
}

再次测试