问题
I'm trying to use Feign client. Below is my feing client:
import com.eprogrammerz.examples.domain.Movie;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
/**
* Created by Yogen on 12/26/2016.
*/
@FeignClient(name = "movie-api")
public interface MovieApi {
@RequestMapping(method = RequestMethod.GET, value = "/movies/{id}")
Movie getMovie(@PathVariable("id") Long id);
}
I'm calling it from simple service as below:
@Service
public class MovieService {
@Autowired
MovieApi movieApi;
public Movie findMovie(Long id){
Movie movieOfTheDay = movieApi.getMovie(id);
return movieOfTheDay;
}
}
My spring boot app is as below:
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
@EnableFeignClients(basePackages = {"com.eprogrammerz.examples"})
@EnableCircuitBreaker
@SpringBootApplication
public class ClientAppApplication {
public static void main(String[] args) {
SpringApplication.run(ClientAppApplication.class, args);
}
}
build.gradle
buildscript {
ext {
springBootVersion = '1.4.3.RELEASE'
}
repositories {
jcenter()
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
jar {
baseName = 'client-app'
version = '0.0.1-SNAPSHOT'
}
sourceCompatibility = 1.8
targetCompatibility = 1.8
repositories {
jcenter()
mavenCentral()
maven { url "https://repo.spring.io/snapshot" }
maven { url "https://repo.spring.io/milestone" }
}
dependencies {
compile('org.springframework.cloud:spring-cloud-starter-feign')
// https://mvnrepository.com/artifact/com.netflix.hystrix/hystrix-core
compile('org.springframework.cloud:spring-cloud-starter-hystrix')
compile("org.springframework.boot:spring-boot-starter-web"){
exclude group: 'org.springframework.boot', module: 'spring-boot-starter-logging'
}
compileOnly('org.projectlombok:lombok')
testCompile('org.springframework.boot:spring-boot-starter-test')
}
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-dependencies:Camden.BUILD-SNAPSHOT"
mavenBom "org.springframework.boot:spring-boot-starter-parent:${springBootVersion}"
}
}
I'm getting error as below:
2016-12-30 13:07:16.894 INFO 6748 --- [nio-8082-exec-1] o.s.web.servlet.DispatcherServlet : FrameworkServlet 'dispatcherServlet': initialization completed in 39 ms
2016-12-30 13:07:16.939 INFO 6748 --- [nio-8082-exec-1] c.e.e.controllers.RequestController : Calling findMovie(1203)
2016-12-30 13:07:17.240 INFO 6748 --- [rix-movie-api-1] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@547496c2: startup date [Fri Dec 30 13:07:17 EST 2016]; parent: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@542e560f
2016-12-30 13:07:17.318 INFO 6748 --- [rix-movie-api-1] f.a.AutowiredAnnotationBeanPostProcessor : JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
2016-12-30 13:07:17.619 INFO 6748 --- [rix-movie-api-1] c.netflix.config.ChainedDynamicProperty : Flipping property: movie-api.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2016-12-30 13:07:17.670 INFO 6748 --- [rix-movie-api-1] c.n.u.concurrent.ShutdownEnabledTimer : Shutdown hook installed for: NFLoadBalancer-PingTimer-movie-api
2016-12-30 13:07:17.727 INFO 6748 --- [rix-movie-api-1] c.netflix.loadbalancer.BaseLoadBalancer : Client:movie-api instantiated a LoadBalancer:DynamicServerListLoadBalancer:{NFLoadBalancer:name=movie-api,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2016-12-30 13:07:17.739 INFO 6748 --- [rix-movie-api-1] c.n.l.DynamicServerListLoadBalancer : Using serverListUpdater PollingServerListUpdater
2016-12-30 13:07:17.746 INFO 6748 --- [rix-movie-api-1] c.n.l.DynamicServerListLoadBalancer : DynamicServerListLoadBalancer for client movie-api initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=movie-api,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:com.netflix.loadbalancer.ConfigurationBasedServerList@45bcfd5
2016-12-30 13:07:18.191 ERROR 6748 --- [nio-8082-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is com.netflix.hystrix.exception.HystrixRuntimeException: MovieApi#getMovie(Long) failed and no fallback available.] with root cause
com.netflix.client.ClientException: Load balancer does not have available server for client: movie-api
at com.netflix.loadbalancer.LoadBalancerContext.getServerFromLoadBalancer(LoadBalancerContext.java:468) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:184) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at com.netflix.loadbalancer.reactive.LoadBalancerCommand$1.call(LoadBalancerCommand.java:180) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:94) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeConcatMap.call(OnSubscribeConcatMap.java:42) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber$1.call(OperatorRetryWithPredicate.java:127) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.enqueue(TrampolineScheduler.java:73) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.schedulers.TrampolineScheduler$InnerCurrentThreadScheduler.schedule(TrampolineScheduler.java:52) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:79) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorRetryWithPredicate$SourceSubscriber.onNext(OperatorRetryWithPredicate.java:45) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.util.ScalarSynchronousObservable$WeakSingleProducer.request(ScalarSynchronousObservable.java:276) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Subscriber.setProducer(Subscriber.java:209) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:138) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.util.ScalarSynchronousObservable$JustOnSubscribe.call(ScalarSynchronousObservable.java:129) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.subscribe(Observable.java:10307) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.subscribe(Observable.java:10274) ~[rxjava-1.1.10.jar:1.1.10]
at rx.observables.BlockingObservable.blockForSingle(BlockingObservable.java:445) ~[rxjava-1.1.10.jar:1.1.10]
at rx.observables.BlockingObservable.single(BlockingObservable.java:342) ~[rxjava-1.1.10.jar:1.1.10]
at com.netflix.client.AbstractLoadBalancerAwareClient.executeWithLoadBalancer(AbstractLoadBalancerAwareClient.java:102) ~[ribbon-loadbalancer-2.2.0.jar:2.2.0]
at org.springframework.cloud.netflix.feign.ribbon.LoadBalancerFeignClient.execute(LoadBalancerFeignClient.java:63) ~[spring-cloud-netflix-core-1.2.4.BUILD-SNAPSHOT.jar:1.2.4.BUILD-SNAPSHOT]
at feign.SynchronousMethodHandler.executeAndDecode(SynchronousMethodHandler.java:97) ~[feign-core-9.3.1.jar:na]
at feign.SynchronousMethodHandler.invoke(SynchronousMethodHandler.java:76) ~[feign-core-9.3.1.jar:na]
at feign.hystrix.HystrixInvocationHandler$1.run(HystrixInvocationHandler.java:108) ~[feign-hystrix-9.3.1.jar:na]
at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:301) ~[hystrix-core-1.5.6.jar:1.5.6]
at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:297) ~[hystrix-core-1.5.6.jar:1.5.6]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:46) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) ~[rxjava-1.1.10.jar:1.1.10]
at rx.Observable.unsafeSubscribe(Observable.java:10211) ~[rxjava-1.1.10.jar:1.1.10]
at rx.internal.operators.OperatorSubscribeOn$1.call(OperatorSubscribeOn.java:94) ~[rxjava-1.1.10.jar:1.1.10]
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:56) ~[hystrix-core-1.5.6.jar:1.5.6]
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:47) ~[hystrix-core-1.5.6.jar:1.5.6]
at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:69) ~[hystrix-core-1.5.6.jar:1.5.6]
at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55) ~[rxjava-1.1.10.jar:1.1.10]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[na:1.8.0_51]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_51]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) ~[na:1.8.0_51]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) ~[na:1.8.0_51]
at java.lang.Thread.run(Thread.java:745) [na:1.8.0_51]
I tried different way. But couldn't figure out the solution. I couldn't find any information about this on Spring Cloud Netflix too. I couldn't find any information on discussion thread on StackOverflow too.
What I'm missing here? TIA.
Further Details:
application.yml for movie-api microservice is as below:
server:
port: 8090
logging:
config: classpath:log4j2.yml
spring:
application:
name: movie-api
Spring boot app on movie-api module:
@SpringBootApplication
public class MovieApiApplication {
public static void main(String[] args) {
SpringApplication.run(MovieApiApplication.class, args);
}
}
And controller is as below:
@RestController
@Slf4j
public class MovieController {
@Autowired
private MovieRepository movieRepository;
@RequestMapping("/movies/{id}")
public ResponseEntity<Movie> getBook(@PathVariable("id") Long id){
log.trace("getBook({})",id);
Optional<Movie> movie = Optional.of(movieRepository.findOneById(id));
if(movie.isPresent())
return new ResponseEntity(movie.get(), HttpStatus.OK);
return new ResponseEntity<Movie>(HttpStatus.NOT_FOUND);
}
}
回答1:
After doing research, and with help of @Bloodysock, I found that I was missing registration of remote server in 'client-app' micro-service. The document is at Spring Cloud Netflix.
I used Ribbon without Eureka with configuration in application.yml in 'client-app' micro-service as:
movie-api:
ribbon:
listOfServers: http://localhost:8090
回答2:
The problem is that your service doesn't know the host of requested service. If you are using Eureka, put this line on your .properties or .yml file:
eureka.client.fetchRegistry=true
OR
eureka:
client:
fetchRegistry: true
It'll make your service talk with Eureka and discovers host of requested service.
回答3:
If your Spring Cloud set up does not support specifying the servers in application.properties/application.yml, you have to configure the services URL in a Configuration class.
Pls, note the warning message in my application.properties [Spring Boot v2.0.0RELEASE, spring-cloud-starter-feign & spring-cloud-starter-ribbon v 1.4.3.RELEASE]
So what I did was to write a Configuration class as follows:
@Configuration
class LocalRibbonClientConfiguration {
@Bean
public ServerList<Server> ribbonServerList() {
// return new ConfigurationBasedServerList();
StaticServerList<Server> staticServerList = new StaticServerList<>((new Server("localhost", 8001)),
new Server("localhost", 8000));
return staticServerList;
}
}
Then, configured the Spring Boot Application to use this configuration as follows:
@SpringBootApplication
@EnableFeignClients("my-package.currencyconversionservice")
@RibbonClient(name = "currency-conversion-service", configuration = LocalRibbonClientConfiguration.class)
public class CurrencyConversionServiceApplication {
// nothing new here...
}
No need to change the Feign Proxy class. Posting just for this post to be served as a complete solution to the problem:
@FeignClient(name="currency-exchange-service")
@RibbonClient(name="currency-exchange-service")
public interface CurrencyExchangeServiceProxy {
@GetMapping("/currency-exchange/from/{from}/to/{to}")
public CurrencyConversionBean retrieveExchangeValue(@PathVariable("from") String from, @PathVariable("to") String to);
}
That's all. The problem was fixed.
回答4:
I nearly wasted 2 hours to find the root cause. I mistakenly imported EnableEurekaClient in client application, which was the root cause for the issue. I finally resolved this issue by removing the import. To my surprise @EnableDiscoveryClient does not require the below dependency. But if you are using Eureka Naming server than this has to be used.
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
<version>2.0.0.RELEASE</version>
</dependency>
回答5:
Make sure your ribbion client is correct.
package com.in28minutes.microservices.currencyconversionservice;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
@FeignClient(name="currency-exchange-service")
@RibbonClient(name="currency-exchange-service")
public interface CurrencyExchangeServiceProxy {
@GetMapping("/currency-exchange/from/{from}/to/{to}")
public CurrencyConversionBean retrieveExchangeValue
(@PathVariable("from") String from, @PathVariable("to") String to); //mention correct pathvariables
}
来源：https://stackoverflow.com/questions/41401009/load-balancer-does-not-have-available-server-for-client