Document Missing Property To Use WebClient

Describe the bug Spring Cloud Config Client app running on Spring WebFlux reactive stack is unable to locate Cloud Config Server via Eureka Discovery, so it defaults to http://localhost:8888. (The Cloud Config Server is a traditional Spring MVC app running on servlet stack.) I’ve migrated my Config Client app from MVC to WebFlux, and Eureka Discovery of downstream services is still working (and I’m using ReactorLoadBalancerExchangeFilterFunction), but Cloud Config is no longer working.

Sample Stack trace:

WARN  2021-04-10 00:11:30,450 [main] org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration app=testapp version=2.0.1.0 : Could not locate configserver via discovery
org.springframework.web.client.UnknownContentTypeException: Could not extract response: no suitable HttpMessageConverter found for response type [class org.springframework.cloud.netflix.eureka.http.EurekaApplications] and content type [application/xml]
	at org.springframework.web.client.HttpMessageConverterExtractor.extractData(HttpMessageConverterExtractor.java:126) ~[spring-web-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:996) ~[spring-web-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.web.client.RestTemplate$ResponseEntityResponseExtractor.extractData(RestTemplate.java:979) ~[spring-web-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:739) ~[spring-web-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:672) ~[spring-web-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.web.client.RestTemplate.exchange(RestTemplate.java:581) ~[spring-web-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.cloud.netflix.eureka.http.RestTemplateEurekaHttpClient.getApplicationsInternal(RestTemplateEurekaHttpClient.java:158) ~[spring-cloud-netflix-eureka-client-2.2.7.RELEASE.jar!/:2.2.7.RELEASE]
	at org.springframework.cloud.netflix.eureka.http.RestTemplateEurekaHttpClient.getApplications(RestTemplateEurekaHttpClient.java:146) ~[spring-cloud-netflix-eureka-client-2.2.7.RELEASE.jar!/:2.2.7.RELEASE]
	at org.springframework.cloud.netflix.eureka.config.EurekaConfigServerBootstrapConfiguration.lambda$eurekaConfigServerInstanceProvider$0(EurekaConfigServerBootstrapConfiguration.java:112) ~[spring-cloud-netflix-eureka-client-2.2.7.RELEASE.jar!/:2.2.7.RELEASE]
	at org.springframework.cloud.config.client.ConfigServerInstanceProvider.getConfigServerInstances(ConfigServerInstanceProvider.java:50) ~[spring-cloud-config-client-2.2.7.RELEASE.jar!/:2.2.7.RELEASE]
	at org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration$HeartbeatListener.refresh(DiscoveryClientConfigServiceBootstrapConfiguration.java:123) ~[spring-cloud-config-client-2.2.7.RELEASE.jar!/:2.2.7.RELEASE]
	at org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration$HeartbeatListener.startup(DiscoveryClientConfigServiceBootstrapConfiguration.java:109) ~[spring-cloud-config-client-2.2.7.RELEASE.jar!/:2.2.7.RELEASE]
	at org.springframework.cloud.config.client.DiscoveryClientConfigServiceBootstrapConfiguration$HeartbeatListener.onApplicationEvent(DiscoveryClientConfigServiceBootstrapConfiguration.java:101) ~[spring-cloud-config-client-2.2.7.RELEASE.jar!/:2.2.7.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:404) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:361) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:898) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:554) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:758) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:750) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:405) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:140) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at org.springframework.cloud.bootstrap.BootstrapApplicationListener.bootstrapServiceContext(BootstrapApplicationListener.java:212) ~[spring-cloud-context-2.2.7.RELEASE.jar!/:2.2.7.RELEASE]
	at org.springframework.cloud.bootstrap.BootstrapApplicationListener.onApplicationEvent(BootstrapApplicationListener.java:117) ~[spring-cloud-context-2.2.7.RELEASE.jar!/:2.2.7.RELEASE]
	at org.springframework.cloud.bootstrap.BootstrapApplicationListener.onApplicationEvent(BootstrapApplicationListener.java:74) ~[spring-cloud-context-2.2.7.RELEASE.jar!/:2.2.7.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:127) ~[spring-context-5.2.13.RELEASE.jar!/:5.2.13.RELEASE]
	at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared(EventPublishingRunListener.java:80) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared(SpringApplicationRunListeners.java:53) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at org.springframework.boot.SpringApplication.prepareEnvironment(SpringApplication.java:345) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1237) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.3.9.RELEASE.jar!/:2.3.9.RELEASE]
	at com.company.testapp.Application.main(Application.java:21) ~[classes!/:?]
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
	at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
	at java.lang.reflect.Method.invoke(Method.java:566) ~[?:?]
	at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49) ~[app.jar:?]
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:107) ~[app.jar:?]
	at org.springframework.boot.loader.Launcher.launch(Launcher.java:58) ~[app.jar:?]
	at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:88) ~[app.jar:?]
 INFO  2021-04-10 00:11:30,667 [main] org.springframework.cloud.config.client.ConfigServicePropertySourceLocator app=testapp version=2.0.1.0 : Fetching config from server at : http://localhost:8888
 INFO  2021-04-10 00:11:30,676 [main] org.springframework.cloud.config.client.ConfigServicePropertySourceLocator app=testapp version=2.0.1.0 : Connect Timeout Exception on Url - http://localhost:8888. Will be trying the next url if available
 WARN  2021-04-10 00:11:30,676 [main] org.springframework.cloud.config.client.ConfigServicePropertySourceLocator app=testapp version=2.0.1.0 : Could not locate PropertySource: I/O error on GET request for "http://localhost:8888/testapp/test": Connection refused (Connection refused); nested exception is java.net.ConnectException: Connection refused (Connection refused)
 INFO  2021-04-10 00:11:30,679 [main] com.company.testapp.Application app=testapp version=2.0.1.0 : The following profiles are active: test

Versions:

springBootVersion = '2.3.9.RELEASE'
springCloudVersion = 'Hoxton.SR10'
reactorAddonsVersion = '3.3.5.RELEASE'
reactorCoreVersion = '3.3.13.RELEASE'
reactorNettyVersion = '0.9.16.RELEASE'

Dependencies:

implementation("org.springframework.boot:spring-boot-starter-actuator")
annotationProcessor("org.springframework.boot:spring-boot-starter-log4j2")
implementation("org.springframework.boot:spring-boot-starter-log4j2")
implementation('org.springframework.boot:spring-boot-starter-webflux')
implementation("org.springframework.cloud:spring-cloud-starter-loadbalancer")
implementation("org.springframework.cloud:spring-cloud-starter-netflix-eureka-client")
implementation("org.springframework.cloud:spring-cloud-starter-netflix-ribbon")
implementation("org.springframework.cloud:spring-cloud-config-client")
implementation("org.springframework.cloud:spring-cloud-starter-config")
implementation('org.springframework.cloud:spring-cloud-starter-hystrix'
compileOnly "org.springframework.boot:spring-boot-configuration-processor"
implementation("io.projectreactor.netty:reactor-netty:${reactorNettyVersion}")
implementation("io.projectreactor:reactor-core:${reactorCoreVersion}")
implementation("io.projectreactor.addons:reactor-extra:${reactorAddonsVersion}")

Bootstrap properties:

# Spring Cloud properties
spring.cloud.config.discovery.enabled=true
spring.cloud.config.discovery.serviceId=deliver-myconfigserver-v1
eureka.client.eurekaServerURLContext=eureka/v2
eureka.client.eurekaServerPort=8080
eureka.client.useDnsForFetchingServiceUrls=true
eureka.client.eurekaServerDNSName=eureka.\${CLOUD_ENVIRONMENT}.company.com

Application properties:

spring.cloud.loadbalancer.ribbon.enabled=false
spring.cloud.discovery.enabled=true
spring.cloud.discovery.reactive.enabled=true

[dibaggioj]

Ok, got it, thanks for the quick reply @ryanjbaxter.

[ryanjbaxter]

It would effect all WebClients.

You could provide your own Builder bean https://github.com/spring-cloud/spring-cloud-netflix/blob/98048189dd7ce85f503838abb58cf9fca8a78d1c/spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/config/DiscoveryClientOptionalArgsConfiguration.java#L114

But IDK if that helps in your case, it might depend on how you designed your application and where these services are getting a WebClient instance from.