Vert.x - Services Proxy

• codegen.generators : a comma separated list of generators, each expression is a regex, allow to filter undesired generators

• -proc: {none,only} : Controls whether annotation processing and/or compilation is done.
  • -proc:none means that compilation takes place without annotation processing.
  • -proc:only means that only annotation processing is done, without any subsequent compilation.

• You write your service as a Java interface and annotate it with the @ProxyGen annotation

@ProxyGen
public interface SomeDatabaseService {

 // A couple of static factory methods to create the instances (respectively implementation and proxy
 // Create is used when you deploy a vertical (ie you deploy the service)
 @GenIgnore
  static SomeDatabaseService create(arguments ..., Handler<AsyncResult<DatabaseServiceInterface>> readyHandler) {
    // The SomeDatabaseServiceImpl  class is an implementation class that you are creating
    return new SomeDatabaseServiceImpl(argument, readyHandler);
  }
 
 @GenIgnore
 // Proxy is used when you use/test the service as server client code
 static SomeDatabaseService createProxy(Vertx vertx, String address) {
   // The SomeDatabaseServiceVertxEBProxy class is generated by the annotation processor
   return new SomeDatabaseServiceVertxEBProxy(vertx, address);
 }

// Actual service operations here...
@Fluent
SomeDatabaseService doSomething(Arguments ..., Handler<AsyncResult<YourReturnType>> resultHandler);

}

• You give code generation metadata in the package-info.java file where groupPackage is the package of the generated class.

@ModuleGen(name = "database", groupPackage = "net.bytle.api.db")
package net.bytle.api.db;

import io.vertx.codegen.annotations.ModuleGen;

SomeServiceInterface.create(argument, ready -> {
  if (ready.succeeded()) {
	// ready result is the implementation (ie SomeServiceInterfaceImpl instance)
	ServiceBinder binder = new ServiceBinder(vertx).setAddress(IP_QUEUE_NAME);
	binder.register(SomeServiceInterface.class, ready.result());
	promise.complete();
  } else {
	promise.fail(ready.cause());
  }
});

SomeDatabaseService service = SomeDatabaseService.createProxy(vertx,
    "database-service-address");

// Save some data in the database - this time using the proxy
service.doSomething(Arguments ..., res2 -> {
  if (res2.succeeded()) {
    // done
  }
});

• deploy your verticle (service)
• and instantiate your service proxy (that you can use in every test)

@Before
  public void prepare(TestContext context) throws InterruptedException {
    vertx = Vertx.vertx();

    JsonObject conf = new JsonObject() 
      .put(DatabaseVerticle.KEY_JDBC_URL, "jdbc:hsqldb:mem:testdb;shutdown=true")
      .put(DatabaseVerticle.KEY_JDBC_MAX_POOL_SIZE, 4);

    vertx.deployVerticle(
      new DatabaseVerticle(), // The service
      new DeploymentOptions().setConfig(conf),
      context.asyncAssertSuccess(
        id -> { 
           // the deployment was successful, you get the deployment id (no needed)
           // but you can instantiate your service proxy
           service = DatabaseServiceInterface.createProxy(vertx, DatabaseVerticle.IP_QUEUE_NAME)) // The service proxy
        }
    );

  }

• https://vertx.io/docs/vertx-service-proxy/java/
• https://vertx.io/docs/guide-for-java-devs/#_refactoring_to_vert_x_services
• https://how-to.vertx.io/service-proxy-howto/