# SpringBoot全链路日志
SpringBoot全链路日志
# 1. MDC
一般是使用 MDC 实现全链路日志，如下
但是对于接口调用，异步线程，MQ 等处理实现是比较麻烦的，SpringCloud 可以使用 Sleuth 组件实现
# 2. Sleuth
引入对应 Jar 包
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-sleuth</artifactId>
</dependency>
Logback 加上 [%X{traceId:-}] [%X{spanId:-}] 即可
<property name="log.pattern" value="%d{yyyy-MM-dd HH:mm:ss:SSS} [%-3p] [%X{user:-}] [%thread] [%X{traceId:-}] [%X{spanId:-}] %C{5}.%method:%L: %m%n" />
可以输出当前 MDC 携带的参数
Map<String, String> mdcMap = MDC.getCopyOfContextMap();
{"traceId":"9324df3ca00d62ac","spanId":"9324df3ca00d62ac","spanExportable":"false","X-Span-Export":"false","X-B3-SpanId":"9324df3ca00d62ac","X-B3-TraceId":"9324df3ca00d62ac"}
Zipkin B3 Header标准，其格式如下
X-B3-TraceId: {TraceID}
X-B3-ParentSpanId: {ParentSpanID}
X-B3-SpanId: {SpanID}
X-B3-Sampled: {SampleFlag}
X-B3-TraceId:"5dbf140f59e8232f",
X-B3-ParentSpanId:"5dbf140f59e8232f",
X-B3-SpanId:"47a415c4317ffbdd",
X-B3-Sampled:"1",
参考