Service 1 registers v1 and v2 with Eureka
Service 2 discovers and sends requests to Service 1's v1 and v2 using different Ribbon clients
I got this demo to work and will blog about it in the next couple of days.
http://tech.asimio.net/2017/03/06/Multi-version-Service-Discovery-using-Spring-Cloud-Netflix-Eureka-and-Ribbon.html
The idea I followed was for RestTemplate to use a different Ribbon client for each version because each client has its own ServerListFilter.
Service 1
application.yml
...
eureka:
client:
registerWithEureka: true
fetchRegistry: true
serviceUrl:
defaultZone: http://localhost:8000/eureka/
instance:
hostname: ${hostName}
statusPageUrlPath: ${management.context-path}/info
healthCheckUrlPath: ${management.context-path}/health
preferIpAddress: true
metadataMap:
instanceId: ${spring.application.name}:${server.port}
---
spring:
profiles: v1
eureka:
instance:
metadataMap:
versions: v1
---
spring:
profiles: v1v2
eureka:
instance:
metadataMap:
versions: v1,v2
...
Service 2
application.yml
...
eureka:
client:
registerWithEureka: false
fetchRegistry: true
serviceUrl:
defaultZone: http://localhost:8000/eureka/
demo-multiversion-registration-api-1-v1:
ribbon:
# Eureka vipAddress of the target service
DeploymentContextBasedVipAddresses: demo-multiversion-registration-api-1
NIWSServerListClassName: com.netflix.niws.loadbalancer.DiscoveryEnabledNIWSServerList
# Interval to refresh the server list from the source (ms)
ServerListRefreshInterval: 30000
demo-multiversion-registration-api-1-v2:
ribbon:
# Eureka vipAddress of the target service
DeploymentContextBasedVipAddresses: demo-multiversion-registration-api-1
NIWSServerListClassName: com.netflix.niws.loadbalancer.DiscoveryEnabledNIWSServerList
# Interval to refresh the server list from the source (ms)
ServerListRefreshInterval: 30000
...
Application.java
...
@SpringBootApplication(scanBasePackages = {
"com.asimio.api.multiversion.demo2.config",
"com.asimio.api.multiversion.demo2.rest"
})
@EnableDiscoveryClient
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
AppConfig.java (See how the Ribbon client name matches the Ribbon key found in application.yml
...
@Configuration
@RibbonClients(value = {
@RibbonClient(name = "demo-multiversion-registration-api-1-v1", configuration = RibbonConfigDemoApi1V1.class),
@RibbonClient(name = "demo-multiversion-registration-api-1-v2", configuration = RibbonConfigDemoApi1V2.class)
})
public class AppConfig {
@Bean(name = "loadBalancedRestTemplate")
@LoadBalanced
public RestTemplate loadBalancedRestTemplate() {
return new RestTemplate();
}
}
RibbonConfigDemoApi1V1.java
...
public class RibbonConfigDemoApi1V1 {
private DiscoveryClient discoveryClient;
@Bean
public ServerListFilter<Server> serverListFilter() {
return new VersionedNIWSServerListFilter<>(this.discoveryClient, RibbonClientApi.DEMO_REGISTRATION_API_1_V1);
}
@Autowired
public void setDiscoveryClient(DiscoveryClient discoveryClient) {
this.discoveryClient = discoveryClient;
}
}
RibbonConfigDemoApi1V2.java is similar but using RibbonClientApi.DEMO_REGISTRATION_API_1_V2
RibbonClientApi.java
...
public enum RibbonClientApi {
DEMO_REGISTRATION_API_1_V1("demo-multiversion-registration-api-1", "v1"),
DEMO_REGISTRATION_API_1_V2("demo-multiversion-registration-api-1", "v2");
public final String serviceId;
public final String version;
private RibbonClientApi(String serviceId, String version) {
this.serviceId = serviceId;
this.version = version;
}
}
VersionedNIWSServerListFilter.java
...
public class VersionedNIWSServerListFilter<T extends Server> extends DefaultNIWSServerListFilter<T> {
private static final String VERSION_KEY = "versions";
private final DiscoveryClient discoveryClient;
private final RibbonClientApi ribbonClientApi;
public VersionedNIWSServerListFilter(DiscoveryClient discoveryClient, RibbonClientApi ribbonClientApi) {
this.discoveryClient = discoveryClient;
this.ribbonClientApi = ribbonClientApi;
}
@Override
public List<T> getFilteredListOfServers(List<T> servers) {
List<T> result = new ArrayList<>();
List<ServiceInstance> serviceInstances = this.discoveryClient.getInstances(this.ribbonClientApi.serviceId);
for (ServiceInstance serviceInstance : serviceInstances) {
List<String> versions = this.getInstanceVersions(serviceInstance);
if (versions.isEmpty() || versions.contains(this.ribbonClientApi.version)) {
result.addAll(this.findServerForVersion(servers, serviceInstance));
}
}
return result;
}
private List<String> getInstanceVersions(ServiceInstance serviceInstance) {
List<String> result = new ArrayList<>();
String rawVersions = serviceInstance.getMetadata().get(VERSION_KEY);
if (StringUtils.isNotBlank(rawVersions)) {
result.addAll(Arrays.asList(rawVersions.split(",")));
}
return result;
}
...
AggregationResource.java
...
@RestController
@RequestMapping(value = "/aggregation", produces = "application/json")
public class AggregationResource {
private static final String ACTORS_SERVICE_ID_V1 = "demo-multiversion-registration-api-1-v1";
private static final String ACTORS_SERVICE_ID_V2 = "demo-multiversion-registration-api-1-v2";
private RestTemplate loadBalancedRestTemplate;
@RequestMapping(value = "/v1/actors/{id}", method = RequestMethod.GET)
public com.asimio.api.multiversion.demo2.model.v1.Actor findActorV1(@PathVariable(value = "id") String id) {
String url = String.format("http://%s/v1/actors/{id}", ACTORS_SERVICE_ID_V1);
return this.loadBalancedRestTemplate.getForObject(url, com.asimio.api.multiversion.demo2.model.v1.Actor.class, id);
}
@RequestMapping(value = "/v2/actors/{id}", method = RequestMethod.GET)
public com.asimio.api.multiversion.demo2.model.v2.Actor findActorV2(@PathVariable(value = "id") String id) {
String url = String.format("http://%s/v2/actors/{id}", ACTORS_SERVICE_ID_V2);
return this.loadBalancedRestTemplate.getForObject(url, com.asimio.api.multiversion.demo2.model.v2.Actor.class, id);
}
@Autowired
public void setLoadBalancedRestTemplate(RestTemplate loadBalancedRestTemplate) {
this.loadBalancedRestTemplate = loadBalancedRestTemplate;
}
}
