Does Eureka and Ribbon work for non spring boot application?

Question

I am rewriting a Spring MVC system.

The system is something like this in simple: [Gateway<->Backend Services<->Databases], where Gateway is a controller simply for authentication and forwarding the requests to Backend services.

The Backend services will be refactored to micro-services. I will use Eureka service to do registration for each of them. So eventually the architecture will be: [Gateway <-> Eureka <-> Backend micro-services <-> Databases]. The Gateway will lookup the registries from Eureka server and call the micro services.

However, the Gateway is not a spring boot application(and will NOT be rewritten as Spring boot), thus I don't believe Spring's eureka features (@EnableEurekaClient , DiscoveryClient, ect.) can be adopted easily as the examples do. Actually I tried adding the eureka client annotation to Gateway's controller, which caused my application collapsed.

Moreover, Ribbon is needed in the Gateway for client side loading balancing. But the same concern is as above.

//Update on 1st Nov. I have set up an Eureka server and a client, both of which are written in spring boot. I am using these two application for my Spring MVC testing. The server and client are running well.

Server's configuration application.properties is as below

server.port=8761

spring.application.name=service-itself

eureka.client.service-url.default-zone=http://localhost:8761/eureka/
eureka.client.register-with-eureka=true
eureka.client.fetch-registry=false

logging.level.com.netflix.eureka=OFF
logging.level.com.netflix.discovery=OFF

client's is as below: application.yml

spring:
  application:
    name: say-hello

server:
  port: 8090

eureka:
  client:
    service-url:
      defaultZone: http://${eureka.host:localhost}:${eureka.port:8761}/eureka/

When accessing the Eureka dashboard localhost:8761, I can see that client has been registered.

For my Spring MVC gateway, as it is not a Spring boot project, so I copied the example to my project simply for testing whether it can connect to the Eureka server and retrieve the registered the instance of "say-hello" client. Unfortunately, it cannot do so with saying "Cannot get an instance of example service to talk to from eureka" which is printed at line 76 in the example class.

Here is the eureka-client.properties placed in gateway's classpath. I can confirmed that the Client class is reading the config file.

eureka.name=gatewayEurekaClient
eureka.vipAddress=say-hello
eureka.port=8761
eureka.preferSameZone=true
eureka.preferSameZone=true
eureka.shouldUseDns=false
eureka.serviceUrl.default=http://localhost:8761/eureka
eureka.serviceUrl.defaultZone=http://localhost:8761/eureka

Moreover, this is the debug information when new DiscoveryClient(applicationInfoManager, clientConfig); is being executed

instanceInfo    InstanceInfo  (id=234)  
    actionType  null    
    appGroupName    "UNKNOWN" (id=246)  
    appName "GATEWAYEUREKACLIENT" (id=247)  
    asgName null    
    countryId   1   
    dataCenterInfo  PropertiesInstanceConfig$1  (id=248)    
    healthCheckExplicitUrl  null    
    healthCheckRelativeUrl  "/healthcheck" (id=253) 
    healthCheckSecureExplicitUrl    null    
    healthCheckUrl  "http://A156N7AB89AXNZQ:8761/healthcheck" (id=254)  
    homePageUrl "http://A156N7AB89AXNZQ:8761/" (id=255) 
    hostName    "A156N7AB89AXNZQ" (id=256)  
    instanceId  "A156N7AB89AXNZQ" (id=256)  
    ipAddr  "10.209.66.64" (id=257) 
    isCoordinatingDiscoveryServer   Boolean  (id=258)   
    isInstanceInfoDirty false   
    isSecurePortEnabled false   
    isUnsecurePortEnabled   true    
    lastDirtyTimestamp  Long  (id=260)  
    lastUpdatedTimestamp    Long  (id=263)  
    leaseInfo   LeaseInfo  (id=264) 
    metadata    ConcurrentHashMap<K,V>  (id=266)    
    overriddenstatus    InstanceInfo$InstanceStatus  (id=267)   
    port    8761    
    secureHealthCheckUrl    null    
    securePort  443 
    secureVipAddress    null    
    secureVipAddressUnresolved  null    
    sid "na" (id=270)   
    status  InstanceInfo$InstanceStatus  (id=271)   
    statusPageExplicitUrl   null    
    statusPageRelativeUrl   "/Status" (id=272)  
    statusPageUrl   "http://A156N7AB89AXNZQ:8761/Status" (id=273)   
    version "unknown" (id=274)  
    vipAddress  "say-hello" (id=275)    
    vipAddressUnresolved    "say-hello" (id=275)    

I am running out of idea. Can anyone please give a hand on this problem?

Answer 1

Support for Ribbon and Eureka in Spring is part of the Spring Cloud project (and mvn group id), not Spring Boot. I don't think boot is mandatory. Ribbon and Eureka themselves are provided by Netflix.

For ribbon, you need to define your own @LoadBalanced RestTemplate @Bean anyway. @EnableDiscoveryClient should work as long as the dependencies have spring cloud eureka and your class is a @Configuration class.

Short answer is - why not try a quick test? :).

Answer 2

Ribbon (https://github.com/Netflix/ribbon) and Eureka (https://github.com/Netflix/eureka) can work without Spring (and that is the way they were developed in the first place) but you will need to put a bit more effort into configuring everything to your needs.