SpringCloud官网中关于Sleuth链路添加额外传播字段的描述如下:
有时需要传播额外的字段，例如请求 ID 或备用跟踪上下文。例如，如果你在 Cloud Foundry 环境中，可能希望传递请求 ID，如下例所示：
// when you initialize the builder, define the extra field you want to propagate
Tracing.newBuilder().propagationFactory(
ExtraFieldPropagation.newFactory(B3Propagation.FACTORY, "x-vcap-request-id")
);
// later, you can tag that request ID or use it in log correlation
requestId = ExtraFieldPropagation.get("x-vcap-request-id");
即在初始化时，添加需要额外传播的字段。在之后需要用到的地方可以通过ExtraFieldPropagation.get("x-vcap-request-id")的方式来获取。
在具体项目中的用法:
我们公司的需求是：链路追踪不止可以记录后台微服务的的调用链，也要把前端用户的操作单元给记录下来。
实现方式：由前端传两个标识参数来记录用户操作的链路，在网关时，获取到传递过来的参数，然后通过Brave的额外传播字段进行链路捆绑，并在客户端（具体的微服务应用）进行配置，将 baggage 值设置为 Slf4j 的 MDC，然后即可在日志中输出该参数信息。
一.定义额外传播的字段:
在网关中定义传播的额外字段，经测试，有两种方式可以添加额外的字段
方式一：
@Configuration
@Order(TraceWebServletAutoConfiguration.TRACING_FILTER_ORDER - 2)
public class SleuthPropagateConfig {
/** 前端操作ID */
public static final String OPERATION_ID = "X-Operation-ID";
/** 前端操作名称 如:行政区划/保存 */
public static final String OPERATION_NAME = "X-Operation-Name";
@Bean
public SleuthProperties sleuthProperties() {
SleuthProperties sleuthProperties = new SleuthProperties();
//会加baggage-前缀
// List dkBaggageKeys = new ArrayList<>();
// dkBaggageKeys.add(OPERATION_ID);
// List baggageKeys = sleuthProperties.getBaggageKeys();
// if (CollectionUtils.isEmpty(baggageKeys)) {
// sleuthProperties.setBaggageKeys(dkBaggageKeys);
// return sleuthProperties;
// }
// if (!baggageKeys.contains(OPERATION_ID)) {
// sleuthProperties.getBaggageKeys().add(OPERATION_ID);
// }
// if (!baggageKeys.contains(OPERATION_NAME)) {
// sleuthProperties.getBaggageKeys().add(OPERATION_NAME);
// }
//不会加前缀
List frontTraceKeys = new ArrayList<>();
frontTraceKeys.add(OPERATION_ID);
frontTraceKeys.add(OPERATION_NAME);
List propagationKeys = sleuthProperties.getPropagationKeys();
if (CollectionUtils.isEmpty(propagationKeys)) {
sleuthProperties.setPropagationKeys(frontTraceKeys);
return sleuthProperties;
}
if (!propagationKeys.contains(OPERATION_ID)) {
sleuthProperties.getPropagationKeys().add(OPERATION_ID);
}
if (!propagationKeys.contains(OPERATION_NAME)) {
sleuthProperties.getPropagationKeys().add(OPERATION_NAME);
}
return sleuthProperties;
}
}
但是这种方式不是很优雅，本人用的是第二种方式
方式二：
@Configuration
@Order(TraceWebServletAutoConfiguration.TRACING_FILTER_ORDER - 2)
public class SleuthPropagateConfig {
/** 前端操作ID */
public static final String OPERATION_ID = "X-Operation-ID";
/** 前端操作名称 如:行政区划/保存 */
public static final String OPERATION_NAME = "X-Operation-Name";
/**
* 定义链路追踪额外传播字段
* @return
*/
@Bean
public Tracing tracing() {
return Tracing.newBuilder().propagationFactory(
ExtraFieldPropagation.newFactoryBuilder(B3Propagation.FACTORY)
.addField(OPERATION_NAME)
.addField(OPERATION_ID)
//.addPrefixedFields("x-baggage-", Arrays.asList(OPERATION_NAME, OPERATION_ID))
.build()
).build();
}
}
二.在网关过滤器中设置传播字段的信息
@Component
public class FrontTraceFilter implements GlobalFilter, Ordered {
@Override
public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) {
String operationId = exchange.getRequest().getQueryParams().getFirst(SleuthPropagateConfig.OPERATION_ID);
String operationName = exchange.getRequest().getQueryParams().getFirst(SleuthPropagateConfig.OPERATION_NAME);
if (!StringUtils.isEmpty(operationId)
&& StringUtils.isEmpty(ExtraFieldPropagation.get(SleuthPropagateConfig.OPERATION_ID))) {
ExtraFieldPropagation.set(SleuthPropagateConfig.OPERATION_ID, operationId);
}
if (!StringUtils.isEmpty(operationName)
&& StringUtils.isEmpty(ExtraFieldPropagation.get(SleuthPropagateConfig.OPERATION_NAME))) {
ExtraFieldPropagation.set(SleuthPropagateConfig.OPERATION_NAME, operationName);
}
return chain.filter(exchange);
}
@Override
public int getOrder() {
return 0;
}
}
三.在客户端(微服务应用)添加配置
在application.yml中添加额外传播字段的相关配置，sleuth2.0后必须配置，否则在客户端获取不到字段信息
spring:
application:
name: demo-feign2
sleuth:
sampler:
#调用链信息采样率
probability: 1.0
# 注意, Sleuth2.0.0之后, baggage的 key 必须在这里配置才能生效
# baggage-keys:
# - X-Operation-ID
# - X-Operation-Name
propagation-keys:
- X-Operation-ID
- X-Operation-Name
log:
slf4j:
#自动额外传播字段设置为 Slf4j 的 MDC
whitelisted-mdc-keys:
- X-Operation-ID
- X-Operation-Name
四.在客户端中使用额外的传播字段
ExtraFieldPropagation.get("key");
五.logback日志配置
%date [%thread] %-5level %logger{80} - %msg%n
${LOG_FILE}.json
${LOG_FILE}/${APP_NAME}.json.%d{yyyy-MM-dd}.gz
7
UTC
{
"level": "%level",
"service": "${APP_NAME:-}",
"traceId": "%X{X-B3-TraceId:-}",
"spanId": "%X{X-B3-SpanId:-}",
"parentSpanId": "%X{X-B3-ParentSpanId:-}",
"exportable": "%X{X-Span-Export:-}",
"pid": "${PID:-}",
"thread": "%thread",
"class": "%logger{40}",
"method": "%M",
"line": "%L",
"message": "%message",
"operationId": "%X{X-Operation-ID}"
"operationName": "%X{X-Operation-Name}"
}
六.logback日志输出结果
{"@timestamp":"2019-11-27T04:00:33.233+00:00","level":"INFO","service":"demo-feign2","traceId":"04f1bfb59beb7053","spanId":"c7ba04760057c6f2","parentSpanId":"04f1bfb59beb7053","exportable":"true","pid":"43252","thread":"http-nio-8302-exec-2","class":"com.caihua.demo.feign.web.HiController","method":"sayHi","line":"19","message":"this is feign2 controller, begin to call the feign service","operationId":"123","operationName":"save"}
{"@timestamp":"2019-11-27T04:00:33.243+00:00","level":"INFO","service":"demo-producer2","traceId":"04f1bfb59beb7053","spanId":"9ece8de790d6ad9e","parentSpanId":"c7ba04760057c6f2","exportable":"true","pid":"7968","thread":"http-nio-8301-exec-4","class":"com.caihua.demo.DemoProducer2Application","method":"home","line":"29","message":"this is producer controller, begin to call producer2 service ","operationId":"123","operationName":"save"}
{"@timestamp":"2019-11-27T04:00:33.244+00:00","level":"INFO","service":"demo-producer2","traceId":"04f1bfb59beb7053","spanId":"9ece8de790d6ad9e","parentSpanId":"c7ba04760057c6f2","exportable":"true","pid":"7968","thread":"http-nio-8301-exec-4","class":"com.caihua.demo.producer.HiService","method":"sayHi","line":"21","message":"this is producer2 HiService, i will call private method","operationId":"123","operationName":"save"}
{"@timestamp":"2019-11-27T04:00:33.244+00:00","level":"INFO","service":"demo-producer2","traceId":"04f1bfb59beb7053","spanId":"9ece8de790d6ad9e","parentSpanId":"c7ba04760057c6f2","exportable":"true","pid":"7968","thread":"http-nio-8301-exec-4","class":"com.caihua.demo.producer.HiService","method":"sayHello","line":"28","message":"hello: cai, this is private method","operationId":"123","operationName":"save"}