io.scalecube.services.examples.helloworld.Example1 Maven / Gradle / Ivy

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package io.scalecube.services.examples.helloworld;

import static io.scalecube.services.discovery.ClusterAddresses.toAddress;

import io.scalecube.services.Microservices;
import io.scalecube.services.discovery.ScalecubeServiceDiscovery;
import io.scalecube.services.examples.ServiceTransports;
import io.scalecube.services.examples.helloworld.service.GreetingServiceImpl;
import io.scalecube.services.examples.helloworld.service.api.GreetingsService;

/**
 * The Hello World project is a time-honored tradition in computer programming. It is a simple
 * exercise that gets you started when learning something new. Let’s get started with ScaleCube!
 *
 * the example starts 2 cluster member nodes. 1. seed is a member node and holds no services of
 * its own. 2. The microservices variable is a member that joins seed member and
 * provision GreetingService instance.
 */
public class Example1 {

  /**
   * Start the example.
   *
   * @param args ignored
   */
  public static void main(String[] args) {
    // ScaleCube Node node with no members
    Microservices seed =
        Microservices.builder()
            .discovery(ScalecubeServiceDiscovery::new)
            .transport(ServiceTransports::rsocketServiceTransport)
            .startAwait();

    // Construct a ScaleCube node which joins the cluster hosting the Greeting Service
    Microservices microservices =
        Microservices.builder()
            .discovery(
                serviceEndpoint ->
                    new ScalecubeServiceDiscovery(serviceEndpoint)
                        .options(opts -> opts.seedMembers(toAddress(seed.discovery().address()))))
            .transport(ServiceTransports::rsocketServiceTransport)
            .services(new GreetingServiceImpl())
            .startAwait();

    // Create service proxy
    GreetingsService service = seed.call().api(GreetingsService.class);

    // Execute the services and subscribe to service events
    service
        .sayHello("joe")
        .subscribe(
            consumer -> {
              System.out.println(consumer.message());
            });

    // shut down the nodes
    seed.shutdown().block();
    microservices.shutdown().block();
  }
}