spring boot 2 + feign + eureka client wont resolve service-name to URL

Question

I am trying spring-boot (2.0.5) with spring-cloud (Finchley.SR1) and trying to setup communication between two services using Eureka as discovery server and Feign/Ribbon as clients. The setup is quite straightforward (although a bit muddied by the various things and other answers I tried):

Eureka's application.yml

spring:
  application:
    name: eureka-service
server:
  port: 8761
eureka:
  instance:
    hostname: localhost
    preferIpAddress: true
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka

second service's bootstrap.yml

spring:
  application:
    name: secondservice
eureka:
  instance:
    hostname: ${spring.application.name}
    preferIpAddress: true
    instanceId: ${spring.application.name}:${spring.application.instance_id:${random.value}}
    statusPageUrlPath: ${server.servlet.context-path}/actuator/info
    healthCheckUrlPath: ${server.servlet.context-path}/actuator/health
    leaseRenewalIntervalInSeconds: 15
    leaseExpirationDurationInSeconds: 45
    metadata-map:
      server.servlet.context-path: ${server.servlet.context-path}
  client:
    enabled: true
    serviceUrl:
      defaultZone: http://localhost:8761/eureka

my test/template service's bootstrap.yml

spring:
  application:
    name: templateservice
eureka:
  instance:
    hostname: ${spring.application.name}
    preferIpAddress: true
    instanceId: ${spring.application.name}:${spring.application.instance_id:${random.value}}
    statusPageUrlPath: ${server.servlet.context-path}/actuator/info
    healthCheckUrlPath: ${server.servlet.context-path}/actuator/health
    leaseRenewalIntervalInSeconds: 15
    leaseExpirationDurationInSeconds: 45
    metadata-map:
      server.servlet.context-path: ${server.servlet.context-path}
  client:
    enabled: true
    serviceUrl:
      defaultZone: http://localhost:8761/eureka
logging:
  level:
    com...MessageServiceClient: DEBUG

My Feign client

@FeignClient(name = "secondservice", configuration = FeignConfig.class)
public interface MessageServiceClient {
    @RequestMapping(method = RequestMethod.GET, value = "/dummy")
    public String getMessage();
}

My Service class:

@Autowired MessageServiceClient messageServiceClient;
@Autowired private LoadBalancerClient loadBalancer;
public String getDummyMessage() {
    ServiceInstance instance = loadBalancer.choose("secondservice");
    URI secondServiceUri = URI.create(String.format("http://%s:%s", instance.getHost(), instance.getPort()));

    System.out.println(secondServiceUri); // logs http://192.168.0.205:8090, check log below

    return messageServiceClient.getMessage(); // throws 404??
}

In FeignConfig, only thing being done is setting log level to FULL. The log looks like this:

2018-10-08 11:14:59.511  INFO [templateservice,,,] 16801 --- [onPool-worker-2] s.c.a.AnnotationConfigApplicationContext : Refreshing SpringClientFactory-secondservice: startup date [Mon Oct 08 11:14:59 IST 2018]; parent: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@451f35ad
2018-10-08 11:14:59.683  INFO [templateservice,,,] 16801 --- [onPool-worker-2] f.a.AutowiredAnnotationBeanPostProcessor : JSR-330 'javax.inject.Inject' annotation found and supported for autowiring
2018-10-08 11:15:00.042  INFO [templateservice,,,] 16801 --- [onPool-worker-2] c.netflix.config.ChainedDynamicProperty  : Flipping property: secondservice.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2018-10-08 11:15:00.095  INFO [templateservice,,,] 16801 --- [onPool-worker-2] c.n.u.concurrent.ShutdownEnabledTimer    : Shutdown hook installed for: NFLoadBalancer-PingTimer-secondservice
2018-10-08 11:15:00.146  INFO [templateservice,,,] 16801 --- [onPool-worker-2] c.netflix.loadbalancer.BaseLoadBalancer  : Client: secondservice instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=secondservice,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2018-10-08 11:15:00.189  INFO [templateservice,,,] 16801 --- [onPool-worker-2] c.n.l.DynamicServerListLoadBalancer      : Using serverListUpdater PollingServerListUpdater
2018-10-08 11:15:00.287  INFO [templateservice,,,] 16801 --- [onPool-worker-2] c.netflix.config.ChainedDynamicProperty  : Flipping property: secondservice.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2018-10-08 11:15:00.291  INFO [templateservice,,,] 16801 --- [onPool-worker-2] c.n.l.DynamicServerListLoadBalancer      : DynamicServerListLoadBalancer for client secondservice initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=secondservice,current list of Servers=[192.168.0.205:8090, 192.168.0.205:8090],Load balancer stats=Zone stats: {defaultzone=[Zone:defaultzone; Instance count:2;   Active connections count: 0;    Circuit breaker tripped count: 0;   Active connections per server: 0.0;]
},Server stats: [[Server:192.168.0.205:8090;    Zone:defaultZone;   Total Requests:0;   Successive connection failure:0;    Total blackout seconds:0;   Last connection made:Thu Jan 01 05:30:00 IST 1970;  First connection made: Thu Jan 01 05:30:00 IST 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@3625959e
http://192.168.0.205:8090
2018-10-08 11:15:01.215  INFO [templateservice,,,] 16801 --- [erListUpdater-0] c.netflix.config.ChainedDynamicProperty  : Flipping property: secondservice.ribbon.ActiveConnectionsLimit to use NEXT property: niws.loadbalancer.availabilityFilteringRule.activeConnectionsLimit = 2147483647
2018-10-08 11:15:07.951 DEBUG [templateservice,,,] 16801 --- [onPool-worker-2] c.e.m.t.clients.MessageServiceClient     : [MessageServiceClient#getMessage] ---> GET http://secondservice/dummy HTTP/1.1
2018-10-08 11:15:12.527 DEBUG [templateservice,,,] 16801 --- [onPool-worker-2] c.e.m.t.clients.MessageServiceClient     : [MessageServiceClient#getMessage] <--- HTTP/1.1 404 (4575ms)
2018-10-08 11:15:12.559 ERROR [templateservice,7004692c56b2e643,7004692c56b2e643,false] 16801 --- [nio-8080-exec-4] o.s.c.s.i.web.ExceptionLoggingFilter     : Uncaught exception thrown

The issue is, this throws a 404, of course cause the url it is trying to hit is http://secondservice/dummy, and there is no such thing. It might help noting, that if I set url on the FeignClient, it works, but then what is the point of Eureka? Also, for when this works, would fiegn clients automatically use the context path? or I have to specify it in every url on client?

UPDATE 1: Response to: http://localhost:8761/eureka/apps/secondservice

Answer 1

Found it! Its nothing to do with discovery, or config in general, it is because feign does not support context path!

In an attempt to 'dumb' down, I went on removing every single config to bare-minimum to keep the services up. It suddenly worked when I removed the context path of the second service. Thing is Feign+Ribbon do not support custom context path if set by other service. This is an old bug, still not fixed.

There are two possible solutions:

1. Remove context path.
2. Add context path in your Feign clients. So basically your Feign client becomes:

// This needs to be here for the formatting below to be right

@FeignClient(name = "secondservice/secondservice", configuration = FeignConfig.class)
public interface MessageServiceClient {
    @RequestMapping(method = RequestMethod.GET, value = "/dummy")
    public String getMessage();
}

I personally don't like either of the solutions. I like to have context path, well, to give context to a url, it becomes self-explanatory with a context. But it is a property of the other service (secondservice) and should be chosen/changed by that service. And so should not be hardcoded in dependent services. I would have liked it to be supported, but meanwhile, I am going to go for:

@FeignClient(name = "${dependencies.secondservice.url}")
public interface MessageServiceClient {....}

And in application.properties: dependencies.secondservice.url=secondservice/secondservice. This makes it clear that the property is owned by the dependency and not by this service.

Few more notes: 1. I could trace the request to SynchronousMethodHandler#executeAndDecode, response = client.execute(request, options);. Till here the url is note resolved. 2. The url being logged: GET http://secondservice/secondservice/dummy is in fact the correct URL, the first secondservice string gets replaced with IP after the log statement. Here is the documentation supporting that: https://cloud.spring.io/spring-cloud-static/Finchley.SR1/single/spring-cloud.html#_using_ribbon. Notice the url passed to restTemplate. This is what triggered the search for alternative causes.

Answer 2

I change the value of eureka.client.serviceUrl.defaultZone, from both services properties file. Then I replaced localhost with IP Address and it worked for me.

Hope it helps?