Spring Boot微服务中基于用户ID的动态日志控制策略

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <exclusions>
        <exclusion>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-logging</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-log4j2</artifactId>
</dependency>

import org.slf4j.MDC;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

/**
 * 用户上下文拦截器，用于将用户ID放入MDC。
 */
@Component
public class UserContextInterceptor implements HandlerInterceptor {

    public static final String USER_ID_KEY = "userId"; // 定义MDC中存储用户ID的键

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 实际应用中，用户ID可能从请求头、会话或安全上下文中获取。
        // 此处以从请求头获取为例。
        String userId = request.getHeader("X-User-ID"); 
        if (userId != null && !userId.isEmpty()) {
            MDC.put(USER_ID_KEY, userId);
        }
        return true;
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        // 确保在请求完成后清除MDC中的用户ID，防止线程池复用导致的数据混乱。
        MDC.remove(USER_ID_KEY);
    }
}

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * Web配置类，注册用户上下文拦截器。
 */
@Configuration
public class WebConfig implements WebMvcConfigurer {

    private final UserContextInterceptor userContextInterceptor;

    public WebConfig(UserContextInterceptor userContextInterceptor) {
        this.userContextInterceptor = userContextInterceptor;
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(userContextInterceptor);
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN" monitorInterval="30"> <!-- monitorInterval用于监控log4j2.xml自身的变化 -->
    <Appenders>
        <Console name="Console" target="SYSTEM_OUT">
            <!-- PatternLayout中加入 %X{userId} 以便在日志中输出MDC中的用户ID -->
            <PatternLayout pattern="%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} %X{userId} - %msg%n"/>
        </Console>
    </Appenders>

    <Loggers>
        <!-- Root Logger，设置默认日志级别，对所有未特殊配置的Logger生效 -->
        <Root level="info"> 
            <AppenderRef ref="Console"/>
        </Root>

        <!-- 针对特定包或类路径的Logger，此处以com.yourcompany.yourapp为例 -->
        <Logger name="com.yourcompany.yourapp" level="info" additivity="false">
            <AppenderRef ref="Console"/>
            <!-- 引入MutableThreadContextMapFilter 实现动态用户日志过滤 -->
            <Filters>
                <MutableThreadContextMapFilter onMismatch="DENY" onMatch="NEUTRAL">
                    <!-- path 指定动态配置文件的位置，file:前缀表示文件系统路径 -->
                    <KeyValuePair key="path" value="file:/path/to/your/config/users-to-log.json"/>
                    <!-- reloadIntervalMillis 指定轮询间隔，单位毫秒，此处为每5秒检查一次文件更新 -->
                    <KeyValuePair key="reloadIntervalMillis" value="5000"/> 
                </MutableThreadContextMapFilter>
            </Filters>
        </Logger>
    </Loggers>
</Configuration>

{
  "users": [
    {
      "id": "123",
      "level": "DEBUG"
    },
    {
      "id": "456",
      "level": "WARN"
    },
    {
      "id": "789",
      "level": "TRACE"
    }
  ],
  "defaultLevel": "INFO"
}