如何将akka streams kafka（reactive-kafka）集成到akka http应用程序中？

Question

我有一个基本的 scala akka http CRUD 应用程序。请参阅下面的相关类.

我只想将实体 ID 和一些数据（如 json）写入 Kafka 主题，例如，实体是 created/updated。

我正在查看 http://doc.akka.io/docs/akka-stream-kafka/current/producer.html，但我是 scala 和 akka 的新手，不确定如何将其集成到我的应用程序中？

例如，从上面的文档来看，这是一个生产者写入kafka的例子，所以我想我需要类似的东西，但是我的应用程序应该去哪里呢？我可以在创建用户后在我的服务的创建方法中添加另一个地图调用吗？

非常感谢！

val done = Source(1 to 100)
  .map(_.toString)
  .map { elem =>
    new ProducerRecord[Array[Byte], String]("topic1", elem)
  }
  .runWith(Producer.plainSink(producerSettings))

或者我是否需要在 Server.scala 的 bindAndHandle() 方法中执行此处 https://github.com/hseeberger/accessus 示例之类的操作？

网络Server.scala

object System {

  implicit val system = ActorSystem()
  implicit val dispatcher = system.dispatcher
  implicit val actorMaterializer = ActorMaterializer()

}

object WebServer extends App {

  import System._

  val config = new ApplicationConfig() with ConfigLoader
  ConfigurationFactory.setConfigurationFactory(new LoggingConfFileConfigurationFactory(config.loggingConfig))
  val injector = Guice.createInjector(new MyAppModule(config))
  val routes = injector.getInstance(classOf[Router]).routes
  Http().bindAndHandle(routes, config.httpConfig.interface, config.httpConfig.port)

}

Router.scala

def routes(): Route = {
    post {
      entity(as[User]) { user =>
        val createUser = userService.create(user)
        onSuccess(createUser) {
          case Invalid(y: NonEmptyList[Err]) =>  {
            throw new ValidationException(y)
          }
          case Valid(u: User) => {
              complete(ToResponseMarshallable((StatusCodes.Created, u)))
          }
        }
      }
    } ~
    // More routes here, left out for example  
}

Service.scala

def create(user: User): Future[MaybeValid[User]] = {
    for {
      validating <- userValidation.validateCreate(user)
      result <- validating match {
        case Valid(x: User) =>
          userRepo.create(x)
            .map(dbUser => Valid(UserConverters.fromUserRow(x)))
        case y: DefInvalid =>
          Future{y}
      }
    } yield result
  }

Repo.scala

def create(user: User): Future[User] = {
    mutateDbProvider.db.run(
      userTable returning userTable.map(_.userId)
        into ((user, id) => user.copy(userId = id)) +=
        user.copy(createdDate = Some(Timestamp.valueOf(LocalDateTime.now())))
    )
  }

Answer 1

既然你已经写了你的 Route 从 Entity 中解组 1 User，我认为你不需要 Producer.plainSink。相反，我认为 Producer.send 也可以。另外，作为旁注，抛出异常不是 "idiomatic" scala。所以我更改了无效用户的逻辑：

val producer : KafkaProducer = new KafkaProducer(producerSettings)

val routes : Route = 
  post {
    entity(as[User]) { user =>
      val createUser = userService.create(user)
      onSuccess(createUser) {
        case Invalid(y: NonEmptyList[Err]) =>  
          complete(BadRequest -> "invalid user")
        case Valid(u: User) => { 
          val producerRecord = 
            new ProducerRecord[Array[Byte], String]("topic1",s"""{"userId" : ${u.userId}, "entity" : "User"}""")

          onComplete(producer send producerRecord) { _ =>
            complete(ToResponseMarshallable((StatusCodes.Created, u)))
          }
        }
      }
    }
  }

如何将akka streams kafka（reactive-kafka）集成到akka http应用程序中？

How to integrate akka streams kafka (reactive-kafka) into akka http application?

scala

apache-kafka

akka

akka-stream

reactive-kafka