使用MDC实现日志链路跟踪

使用MDC实现日志链路跟踪

目录1.原理2.实现3.过滤器4.logback.xml5.返回体6.效果日志

前言:

在微服务环境中，我们经常使用Skywalking、CAT等去实现整体请求链路的追踪，但是这个整体运维成本高，架构复杂，我们来使用MDC通过Log来实现一个轻量级的会话事务跟踪功能。

1.原理

MDC org.sl4j.MDC其实内部就是ThreadLocal，MDC提供了put/get/clear等几个核心接口，用于操作ThreadLocal中的数据；ThreadLocal中的K-V，可以在logback.xml中声明，最终将会打印在日志中。

// java代码

MDC.put("userId","laker");

// logback.xml

%X{userId}

例如：

2.实现

整体流程如下：

用户登录系统，我们日志中记录userId:laker。用户发起请求，一个请求中可能实际产生多个http请求，这里可以前端生成一个requestId在返回体中，返回requestId。研发运维人员，可以根据 userId和requestId去日志中捞请求链路。

3.过滤器

@Order(value = Ordered.HIGHEST_PRECEDENCE + 100)

@Component

@WebFilter(filterName = "MDCFilter", urlPatterns = "/*")

public class MDCFilter extends OncePerRequestFilter {

@Override

protected void doFilterInternal(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, FilterChain filterChain) throws ServletException, IOException {

try {

MDC.put("userId", "laker");

MDC.put("requestId", IdUtil.fastUUID());

} catch (Exception e) {

//

}

try {

filterChain.doFilter(httpServletRequest, httpServletResponse);

} finally {

MDC.clear();

}

}

}

4.logback.xml

${LOG_HOME}/test.log

true

false

%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{50} %line - %m%n

${LOG_HOME}/test.log.%d{yyyy-MM-dd}

15

value="%d{HH:mm:ss.SSS} [%thread] %-5level [%X{userId}|%X{requestId}] %logger{20} - [%method,%line] - %msg%n"/>

${log.pattern}

%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{50} %line - %m%n

5.返回体

public class Response {

@ApiModelProperty(notes = "响应码，非200 即为异常", example = "200")

private final int code;

http:// @ApiModelProperty(notes = "响应消息", example = "提交成功")

private final String msg;

@ApiModelProperty(notes = "响应数据")

private final T data;

@ApiModelProperty(notes = "请求id")

private final String requestId;

public Response(int code, String msg, T data) {

this.code = code;

this.msg = msg;

this.data = data;

this.requestId = MDC.get("requestId");

}

6.效果日志

响应:

{

code: 200,

msg: "",

requestId: "74a269a8-3cb4-417e-853c-b968b77cce23"

}

日志:

18:37:15.997 [http-nio-8080-exec-1] INFO [laker|90717490-5ef4-4e46-bc2c-605952fc3803] c.l.m.c.InfoController - [v2Map,17] - null

18:37:38.980 [http-nio-8080-exec-2] INFO [laker|82bde351-f86e-466f-97a0-c857a0c4c1c9] c.l.m.c.InfoController - [v2Map,17] - null

18:37:39.992 [http-nio-8080-exec-3] INFO [laker|74a269a8-3cb4-417e-853c-b968b77cce23] c.l.m

value="%d{HH:mm:ss.SSS} [%thread] %-5level [%X{userId}|%X{requestId}] %logger{20} - [%method,%line] - %msg%n"/>

${log.pattern}

%d{yyyy-MM-dd HH:mm:ss.SSS} [%t] %-5level %logger{50} %line - %m%n

5.返回体

public class Response {

@ApiModelProperty(notes = "响应码，非200 即为异常", example = "200")

private final int code;

http:// @ApiModelProperty(notes = "响应消息", example = "提交成功")

private final String msg;

@ApiModelProperty(notes = "响应数据")

private final T data;

@ApiModelProperty(notes = "请求id")

private final String requestId;

public Response(int code, String msg, T data) {

this.code = code;

this.msg = msg;

this.data = data;

this.requestId = MDC.get("requestId");

}

6.效果日志

响应:

{

code: 200,

msg: "",

requestId: "74a269a8-3cb4-417e-853c-b968b77cce23"

}

日志:

18:37:15.997 [http-nio-8080-exec-1] INFO [laker|90717490-5ef4-4e46-bc2c-605952fc3803] c.l.m.c.InfoController - [v2Map,17] - null

18:37:38.980 [http-nio-8080-exec-2] INFO [laker|82bde351-f86e-466f-97a0-c857a0c4c1c9] c.l.m.c.InfoController - [v2Map,17] - null

18:37:39.992 [http-nio-8080-exec-3] INFO [laker|74a269a8-3cb4-417e-853c-b968b77cce23] c.l.m

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。