环境信息
- SpringCloudGateway 3.1.3
- Skywalking Agent 8.10.0
环境配置
Agent
由于SpringCloudGateway是基于WebFlux来实现的,需要进到skywalking的agent目录,将optional-plugins目录底下的以下两个jar包复制到plugins目录
- apm-spring-webflux-5.x-plugin-8.10.0.jar
- apm-spring-cloud-gateway-3.x-plugin-8.10.0.jar
Maven依赖配置
org.apache.skywalking
apm-toolkit-log4j-2.x
${skywalking.version}
org.apache.skywalking
apm-toolkit-trace
${skywalking.version}
日志pattern配置
[%d{yyyy-MM-dd HH:mm:ss.SSS}] [%traceId] [%logger{36}] [%thread] [%-5level] %msg%n
启动参数
新增启动参数
-javaagent:D:\work\skywalking-agent\skywalking-agent.jar=agent.service_name=xxx
-Dskywalking.collector.backend_service=xxx:11800
启动程序后,尝试通过网关进行接口调用,可以在Skywalking-ui上看到链路已经串起来了
调用链路
但是有个问题,日志里记录的日志始终不显示正确的TID
[2022-06-15 14:53:19.958] [TID: N/A]
问题处理过程
查看agent是怎么串联链路的
查看Skywalking-agent的源码,可以看到,在apm-spring-webflux-5.x-plugin-8.10.0.jar插件里,拦截了org.springframework.web.reactive.DispatcherHandler的handle方法
拦截器里往reactor的调用链路里,放入 < SKYWALKING_CONTEXT_SNAPSHOT - ContextSnapshot >
image.png
所以traceId可以从reactor的context里获取到
怎么让日志获取到traceId
网上找了下资料,在这里[https://github.com/reactor/reactor-core/blob/main/docs/asciidoc/faq.adoc#context.api]发现了相关信息
public static Consumer> logOnNext(Consumer logStatement) {
return signal -> {
if (!signal.isOnNext()) return; (1)
Optional toPutInMdc = signal.getContext().getOrEmpty("CONTEXT_KEY"); (2)
toPutInMdc.ifPresentOrElse(tpim -> {
try (MDC.MDCCloseable cMdc = MDC.putCloseable("MDC_KEY", tpim)) { (3)
logStatement.accept(signal.get()); (4)
}
},
() -> logStatement.accept(signal.get())); (5)
};
}
@GetMapping("/byPrice")
public Flux byPrice(@RequestParam Double maxPrice, @RequestHeader(required = false, name = "X-UserId") String userId) {
String apiId = userId == null ? "" : userId; (1)
return restaurantService.byPrice(maxPrice))
.doOnEach(logOnNext(r -> LOG.debug("found restaurant {} for ${}", (2)
r.getName(), r.getPricePerPerson())))
.contextWrite(Context.of("CONTEXT_KEY", apiId)); (3)
}
获取不到traceId的时候,怎么显示默认值
https://logging.apache.org/log4j/2.x/manual/layouts.html#PatternLayout
equals{pattern}{test}{substitution}
equalsIgnoreCase{pattern}{test}{substitution}
完整例子
- pattern改为 [%d{yyyy-MM-dd HH:mm:ss.SSS}] [TID: %equals{%X{traceId}}{}{N/A}] [%logger{36}] [%thread] [%-5level] %msg%n
- 注册onEachOperator的Hooks
@Component
public class LogHooks {
private static final String KEY = "logMdc";
@PostConstruct
@SuppressWarnings("unchecked")
public void setHook() {
reactor.core.publisher.Hooks.onEachOperator(KEY,
Operators.lift((scannable, coreSubscriber) -> new MdcSubscriber(coreSubscriber)));
}
@PreDestroy
public void resetHook() {
reactor.core.publisher.Hooks.resetOnEachOperator(KEY);
}
}
public class MdcSubscriber implements CoreSubscriber {
private static final String TRACE_ID = "traceId";
private static final String SKYWALKING_CTX_SNAPSHOT = "SKYWALKING_CONTEXT_SNAPSHOT";
private final CoreSubscriber