spring cloud gateway通过eureka服务发现路由，网关报500错误，
block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-nio-3
之前没有接触微服务，最近需要用到微服务了，所以先搭一个spring cloud测试一下，进行到服务网关的时候遇到了这个问题。
先上错误日志：
2020-09-02 10:08:05.979 INFO 53824 --- [ctor-http-nio-3] c.n.l.DynamicServerListLoadBalancer : Using serverListUpdater PollingServerListUpdater
2020-09-02 10:08:06.007 INFO 53824 --- [ctor-http-nio-3] c.netflix.config.ChainedDynamicProperty : Flipping property: my-service.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2020-09-02 10:08:06.009 INFO 53824 --- [ctor-http-nio-3] c.n.l.DynamicServerListLoadBalancer : DynamicServerListLoadBalancer for client my-service initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=my-service,current list of Servers=[192.168.1.52:8088],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone; Instance count:1; Active connections count: 0; Circuit breaker tripped count: 0; Active connections per server: 0.0;]
},Server stats: [[Server:192.168.1.52:8088; Zone:defaultZone; Total Requests:0; Successive connection failure:0; Total blackout seconds:0; Last connection made:Thu Jan 01 08:00:00 CST 1970; First connection made: Thu Jan 01 08:00:00 CST 1970; Active Connections:0; total failure count in last (1000) msecs:0; average resp time:0.0; 90 percentile resp time:0.0; 95 percentile resp time:0.0; min resp time:0.0; max resp time:0.0; stddev resp time:0.0]
]}ServerList:org.springframework.cloud.netflix.ribbon.eureka.DomainExtractingServerList@6e4b35d3
2020-09-02 10:08:06.024 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition ReactiveCompositeDiscoveryClient_CONFIG applying {pattern=/CONFIG/**} to Path
2020-09-02 10:08:06.025 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition ReactiveCompositeDiscoveryClient_CONFIG applying filter {regexp=/CONFIG/(?<remaining>.*), replacement=/${remaining}} to RewritePath
2020-09-02 10:08:06.026 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition matched: ReactiveCompositeDiscoveryClient_CONFIG
2020-09-02 10:08:06.027 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition ReactiveCompositeDiscoveryClient_MY-SERVICE applying {pattern=/MY-SERVICE/**} to Path
2020-09-02 10:08:06.027 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition ReactiveCompositeDiscoveryClient_MY-SERVICE applying filter {regexp=/MY-SERVICE/(?<remaining>.*), replacement=/${remaining}} to RewritePath
2020-09-02 10:08:06.028 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition matched: ReactiveCompositeDiscoveryClient_MY-SERVICE
2020-09-02 10:08:06.028 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition ReactiveCompositeDiscoveryClient_GATEWAY applying {pattern=/GATEWAY/**} to Path
2020-09-02 10:08:06.029 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition ReactiveCompositeDiscoveryClient_GATEWAY applying filter {regexp=/GATEWAY/(?<remaining>.*), replacement=/${remaining}} to RewritePath
2020-09-02 10:08:06.029 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition matched: ReactiveCompositeDiscoveryClient_GATEWAY
2020-09-02 10:08:06.030 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition test applying {_genkey_0=/myservice/**} to Path
2020-09-02 10:08:06.030 DEBUG 53824 --- [ctor-http-nio-3] o.s.c.g.r.RouteDefinitionRouteLocator : RouteDefinition matched: test
2020-09-02 10:08:06.074 ERROR 53824 --- [ctor-http-nio-3] a.w.r.e.AbstractErrorWebExceptionHandler : [7ecb6c86-3] 500 Server Error for HTTP GET "/myservice/demo/get"
java.lang.IllegalStateException: block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-nio-3
at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:83) ~[reactor-core-3.3.5.RELEASE.jar:3.3.5.RELEASE]
Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException:
Error has been observed at the following site(s):
|_ checkpoint ⇢ org.springframework.cloud.gateway.filter.WeightCalculatorWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ org.springframework.boot.actuate.metrics.web.reactive.server.MetricsWebFilter [DefaultWebFilterChain]
|_ checkpoint ⇢ HTTP GET "/myservice/demo/get" [ExceptionHandlingWebHandler]
Stack trace:
at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:83) ~[reactor-core-3.3.5.RELEASE.jar:3.3.5.RELEASE]
at reactor.core.publisher.Mono.block(Mono.java:1678) ~[reactor-core-3.3.5.RELEASE.jar:3.3.5.RELEASE]
at org.springframework.cloud.netflix.eureka.http.WebClientEurekaHttpClient.getApplicationsInternal(WebClientEurekaHttpClient.java:139) ~[spring-cloud-netflix-eureka-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.netflix.eureka.http.WebClientEurekaHttpClient.getApplications(WebClientEurekaHttpClient.java:124) ~[spring-cloud-netflix-eureka-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.netflix.eureka.config.EurekaConfigServerBootstrapConfiguration.lambda$eurekaConfigServerInstanceProvider$0(EurekaConfigServerBootstrapConfiguration.java:112) ~[spring-cloud-netflix-eureka-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.config.client.ConfigServerInstanceProvider.getConfigServerInstances(ConfigServerInstanceProvider.java:50) ~[spring-cloud-config-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration$HeartbeatListener.refresh(DiscoveryClientConfigServiceBootstrapConfiguration.java:120) ~[spring-cloud-config-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration$HeartbeatListener.startup(DiscoveryClientConfigServiceBootstrapConfiguration.java:106) ~[spring-cloud-config-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration$HeartbeatListener.onApplicationEvent(DiscoveryClientConfigServiceBootstrapConfiguration.java:98) ~[spring-cloud-config-client-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:403) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:409) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:409) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:360) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:897) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:553) ~[spring-context-5.2.6.RELEASE.jar:5.2.6.RELEASE]
at org.springframework.cloud.context.named.NamedContextFactory.createContext(NamedContextFactory.java:136) ~[spring-cloud-context-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.context.named.NamedContextFactory.getContext(NamedContextFactory.java:101) ~[spring-cloud-context-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.netflix.ribbon.SpringClientFactory.getContext(SpringClientFactory.java:131) ~[spring-cloud-netflix-ribbon-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.context.named.NamedContextFactory.getInstance(NamedContextFactory.java:145) ~[spring-cloud-context-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.netflix.ribbon.SpringClientFactory.getInstance(SpringClientFactory.java:121) ~[spring-cloud-netflix-ribbon-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.netflix.ribbon.SpringClientFactory.getLoadBalancer(SpringClientFactory.java:65) ~[spring-cloud-netflix-ribbon-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.getLoadBalancer(RibbonLoadBalancerClient.java:193) ~[spring-cloud-netflix-ribbon-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.choose(RibbonLoadBalancerClient.java:88) ~[spring-cloud-netflix-ribbon-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient.choose(RibbonLoadBalancerClient.java:78) ~[spring-cloud-netflix-ribbon-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.gateway.filter.LoadBalancerClientFilter.choose(LoadBalancerClientFilter.java:111) ~[spring-cloud-gateway-core-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.gateway.filter.LoadBalancerClientFilter.filter(LoadBalancerClientFilter.java:83) ~[spring-cloud-gateway-core-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.gateway.handler.FilteringWebHandler$GatewayFilterAdapter.filter(FilteringWebHandler.java:138) ~[spring-cloud-gateway-core-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.gateway.filter.OrderedGatewayFilter.filter(OrderedGatewayFilter.java:44) ~[spring-cloud-gateway-core-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at org.springframework.cloud.gateway.handler.FilteringWebHandler$DefaultGatewayFilterChain.lambda$filter$0(FilteringWebHandler.java:118) ~[spring-cloud-gateway-core-2.2.3.RELEASE.jar:2.2.3.RELEASE]
at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:44) [reactor-core-3.3.5.RELEASE.jar:3.3.5.RELEASE]
从错误看的话，gateway底层使用了netty和reactor响应式编程模式，
block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-nio-3
最后程序报错在这：
at reactor.core.publisher.BlockingSingleSubscriber.blockingGet
线程阻塞，它是不被reactor支持的，但这只是一个直接原因，具体的造成这个原因的还不知道。
接下来贴下yml
gateway的bootstrap.yml：
spring:
application:
name: gateway
profiles:
active: native
cloud:
config:
fail-fast: true
name: ${spring.application.name}
#profile: ${spring.profiles.active}
discovery:
enabled: true
service-id: config
eureka:
instance:
prefer-ip-address: true
client:
service-url:
defaultZone: http://eureka1:8080/eureka/
config中心的gateway.yml：
server:
port: 8082
Spring:
cloud:
gateway:
discovery:
locator:
enabled: true
routes:
- id: test
uri: lb://my-service
predicates:
- Path=/myservice/**
#暴露/actuator/bus-refresh接口
management:
endpoints:
web:
exposure:
include: "*"
hystrix:
command:
default:
execution:
isolation:
strategy: THREAD
thread:
timeoutInMilliseconds: 3000
interruptOnTimeout: true
ribbon:
ReadTimeout: 3000
ConnectTimeout: 3000
logging:
level:
org.springframework.cloud.gateway: debug
再贴一个my-service的bootstrap：
server:
port: 8088
spring:
application:
name: my-service
profiles:
active:
# 配置中心
cloud:
config:
fail-fast: true
name: ${spring.application.name}
#profile: ${spring.profiles.active}
discovery:
enabled: true
service-id: config
# 注册中心配置
eureka:
instance:
prefer-ip-address: false
client:
service-url:
defaultZone: http://eureka1:8080/eureka/
#registry-fetch-interval-seconds:
#instance-info-replication-interval-seconds:
#logging:
#level:
#io.swagger.models.parameters.AbstractSerializableParameter: error
浏览器访问
http://192.168.1.52:8082/myservice/demo/get
页面错误：
Whitelabel Error Page
This application has no configured error view, so you are seeing this as a fallback.
Wed Sep 02 10:08:06 CST 2020
[7ecb6c86-3] There was an unexpected error (type=Internal Server Error, status=500).
直接访问my-service：
http://192.168.1.52:8088/myservice/demo/get
没问题，可以正常访问