环境信息SpringCloudGateway 3.1.3Skywalking 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.jarapm-spring-cloud-gateway-3.x-plugin-8.10.0.jarMaven依赖配置

<dependency>  <groupId>org.apache.skywalking</groupId>    <artifactId>apm-toolkit-log4j-2.x</artifactId>    <version>${skywalking.version}</version></dependency><dependency>    <groupId>org.apache.skywalking</groupId>    <artifactId>apm-toolkit-trace</artifactId>    <version>${skywalking.version}</version></dependency>

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 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 >

所以traceId可以从reactor的context里获取到

怎么让日志获取到traceId

public static <T> Consumer<Signal<T>> logOnNext(Consumer<T> logStatement) {    return signal -> {        if (!signal.isOnNext()) return; (1)        Optional<String> 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<Restaurant> 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

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

@Componentpublic 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<Object> actual;        public MdcSubscriber(CoreSubscriber<Object> actual) {        this.actual = actual;    }        @Override    public void onSubscribe(Subscription s) {        actual.onSubscribe(s);    }        @Override    public void onNext(Object o) {        Context c = actual.currentContext();        Optional<String> traceIdOptional = Optional.empty();        if (!c.isEmpty() && c.hasKey(SKYWALKING_CTX_SNAPSHOT)) {            traceIdOptional = Optional.of(c.get(SKYWALKING_CTX_SNAPSHOT)).map(BeanUtil::beanToMap)                    .map(t -> t.get(TRACE_ID)).map(BeanUtil::beanToMap).map(t -> t.get("id")).map(Object::toString);        }        try (MDC.MDCCloseable cMdc = MDC.putCloseable(TRACE_ID, traceIdOptional.orElse("N/A"))) {            actual.onNext(o);        }    }        @Override    public void onError(Throwable throwable) {        actual.onError(throwable);    }        @Override    public void onComplete() {        actual.onComplete();    }        @Override    public Context currentContext() {        return actual.currentContext();    }}