My talk about our move to Scala. ScalaBy meetup, Minsk, April, 27, 2015

1. Переход на Scala:
босиком по граблям

2. Data Processing Team

3. Java / Scala / Clojure / Groovy / ?
JVM

4. “Во-первых, это красиво…” *
Почему Scala?

5. akka-http / spray / finagle / play
REST & HTTP

6. Spray

7. Implicits

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

9. 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 = {...}

10. 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)
}
}
}
}
}
}
}

11. trait JsonSerializerSupport {
implicit val formats =
DefaultFormats ++
BinaryTypeSerializers.all ++
JodaTimeSerializers.all
}

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

13. @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}")

14. Akka

15. “blocking problem”

16. Shared state

17. Как это тестировать?

18. 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)
}
}

19. http://gatling.io/
Нагрузочные тесты

20. DevOps

21. Отличное решение
Kamon
http://kamon.io/

22. Если вы сами готовы
его допиливать

23. ELK & Grafana

24. Maven & sbt

25. Что бы могло пойти не так?
Итак, вы решили
перейти на Scala

26. Сложность и
академичность

27. IDE

28. OOP & FP

29. Explicit is better than implicit
Много споров о стиле

31. Take it easy

32. Плавный переход к
Scala

33. Инкрементальное
внедрение языка

34. Постоянное изучение

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

36. Svetlana Bozhko aka @SBozhko
s.bozhko@adform.com
svt.bozhko@gmail.com
http://devzen.ru
Спасибо!

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