spring boot 2+feign+eureka客户端不能将服务名称解析为URL

Question

我正在使用spring-cloud(Finchley.sr1)尝试spring-boot(2.0.5)，并尝试使用Eureka作为发现服务器，使用Feign/Ribbon作为客户机建立两个服务之间的通信。设置相当简单（尽管我尝试的各种事情和其他答案让我有点困惑）：

尤里卡应用程序

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

第二个服务的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

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

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

@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??
}

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

问题是，这会抛出一个404，当然是因为它试图命中的url是http://secondservice/dummy，而不是这样。如果我在FeignClient上设置URL，这可能会有所帮助，但是Eureka的意义是什么呢？另外，当这种方法起作用时，fiegn客户机会自动使用上下文路径吗？或者我必须在客户端的每个url中指定它？

Answer 1

找到了！它与发现或一般配置无关，这是因为feign不支持上下文路径！

为了“哑”下来，我继续删除每一个配置到最低限度，以保持服务的正常运行。当我移除第二个服务的上下文路径时，它突然起作用了。如果其他服务设置了feign+ribbon不支持自定义上下文路径。这是一个老bug，仍然没有修复。

有两种可能的解决方案：

null

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

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