Переход на Scala: босиком по граблям

Data Processing Team

Java / Scala / Clojure / Groovy / ?

JVM

“Во-первых, это красиво…” *

Почему Scala?

akka-http / spray / finagle / play

REST & HTTP

Spray

Implicits

def strangeIdea(n: Int)(implicit s: String) = s * n

package spray.routing

...

trait HttpServiceBase extends Directives {

/** * Supplies the actor behavior for executing the given route. */ def runRoute(route: Route)(implicit eh: ExceptionHandler, rh: RejectionHandler, ac: ActorContext, rs: RoutingSettings, log: LoggingContext): Actor.Receive = {...}

def createOrUpdateCookieProfileRoute(): Route = post { pathPrefix(ApiVersion) { pathPrefix("cookies" / Segment) { cookieId => path("cookieProfiles" / IntNumber) { trackingSetupId => parameters('cookieSetTime.as[DateTime].?, 'cookieLastSeenTime.as[DateTime].?) { (cookieSetTime, cookieLastSeenTime) => entity(as[CookieProfile]) { cookieProfile => traceName("POST COOKIE PROFILE") { ctx => val serviceActor: ActorRef = newStorageServiceActor() val message = MergeCookieProfile(ctx, cookieProfile, cookieSetTime, cookieLastSeenTime) serviceActor.tell(message, ActorRef.noSender) } } } } } } }

trait JsonSerializerSupport {

implicit val formats = DefaultFormats ++ BinaryTypeSerializers.all ++ JodaTimeSerializers.all}

https://github.com/gettyimages/spray-swagger

Swagger

@ApiOperation( httpMethod = "POST", value = "Create/Update CookieProfile by cookieId and trackingSetupId", notes = "Creates new CookieProfile if it doesn't exists or updates old one if it exists in storage.”) @ApiImplicitParams(Array( new ApiImplicitParam( name = Fields.CookieId, value = Description.CookieId, required = true, dataType = DataTypes.String, paramType = ParamType.Path), new ApiImplicitParam( name = Fields.TrackingSetupId, value = Description.TrackingSetupId, required = true, dataType = DataTypes.Integer, paramType = ParamType.Path), new ApiImplicitParam( name = Fields.CookieSetTime, value = Description.CookieSetTime, dataType = DataTypes.String, paramType = ParamType.Query), new ApiImplicitParam( name = Fields.CookieLastSeenTime, value = Description.CookieLastSeenTime, dataType = DataTypes.String, paramType = ParamType.Query), new ApiImplicitParam( name = Fields.Body, value = Description.Body, required = true, dataType = DataTypes.CookieProfile, paramType = ParamType.Body))) @ApiResponses(Array( new ApiResponse(code = 200, message = Responses.Ok, response = classOf[SuccessResponse]), new ApiResponse(code = 400, message = Responses.BadRequest, response = classOf[ErrorResponse]), new ApiResponse(code = 500, message = Responses.InternalError, response = classOf[ErrorResponse]), new ApiResponse(code = 503, message = Responses.ServiceUnavailable))) @Path("/{cookieId}/cookieProfiles/{trackingSetupId}")

Akka

“blocking problem”

Shared state

Как это тестировать?

test("return 404 code for not existing cookie with cookieProfiles") { Get("/v1/cookies/777/cookieProfiles") ~> route ~> check { handled should be(right = true) response.status should be(StatusCodes.NotFound) } }

http://gatling.io/

Нагрузочные тесты

DevOps

Отличное решение

Kamonhttp://kamon.io/

Если вы сами готовы его допиливать

ELK & Grafana

Maven & sbt

Что бы могло пойти не так?

Итак, вы решили перейти на Scala

Сложность и академичность

IDE

OOP & FP

Explicit is better than implicit

Много споров о стиле

Take it easy

Плавный переход к Scala

Инкрементальное внедрение языка

Постоянное изучение

“Технологии идеальны, а люди – *удаки” **

Svetlana Bozhko aka @SBozhkos.bozhko@adform.comsvt.bozhko@gmail.com

http://devzen.ru

Спасибо!

* — Старый анекдот** — Baruch Sadogursky aka @jbaruch

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