Question about how Eureka differentiates between a service provider and service consumer

[Vikash Dat]

Based on the example code found here: https://github.com/Netflix/eureka/tree/master/eureka-examples/src/main/java/com/netflix/eureka , it seems that both the service provider and client do the same initialization and registration steps:

 

// Register with Eureka
	DiscoveryManager.getInstance().initComponent(
	new MyDataCenterInstanceConfig(),
	new DefaultEurekaClientConfig());
	ApplicationInfoManager.getInstance().setInstanceStatus(InstanceStatus.UP);
	// this is the vip address for the example service to talk to as defined in conf/sample-eureka-service.properties
	String vipAddress = "sampleservice.mydomain.net";
	InstanceInfo nextServerInfo = null;
	try {
	nextServerInfo = DiscoveryManager.getInstance()
	.getEurekaClient()
	.getNextServerFromEureka(vipAddress, false);
	} catch (Exception e) {
	System.err.println("Cannot get an instance of example service to talk to from eureka");
	System.exit(-1);
	}

Even the service.properties and client.properties files are almost identical. The only difference I can see is that in the service.properties file, it includes a configuration for eureka.port. Does this mean that the only thing that tells the Eureka server that something is a service is if the eureka.port is in the config.file? 

Appreciate the clarification. 

[dl...@netflix.com]

Hi Vikash,

In the general case, if a server with an eureka client is configured to register with eureka servers, it is considered a service provider. Registration with the eureka servers is essentially an advertising of a server and the instanceInfo contains the contact details (ip, port etc) of the server. If a server with an eureka client is configured to read data from eureka servers, then this is a client use case.

A server with an eureka client can be both service provider and client, and the default configuration for eureka-client configures the eureka client to be both registering and reading from the eureka servers.

Thanks.

[Vikash Dat]

Thanks, but it seems the registration logic for both service provider and client are the same, at least from the sample code. Even the eureka-service.properties and eureka-client.properties file are almost identical, save for the fact that the eureka-service.properties files has the additional eureka.port config variable. We plan on utilizing some of netflix OSS in our platform, which included Eureka. I just want to make sure I understand how the registrations differ (from the sample code it is not apparent) so I can make sure that I never mistakenly register a consumer as a provider. 

Thanks

[dl...@netflix.com]

Hi Vikash,

I have updated the examples (pull https://github.com/Netflix/eureka/pull/522) to hopefully make this more clear. Would you mind taking a look and see if this answers your question? In general, the appName and vipAddress are what's used to differentiate different server(s) that provides different services.

[Vikash Dat]

+1 . Thanks for the promptness and the updated examples. They are much clearer now!