How to build Spray How to build Akka How to Monitor them

1. Scala
{Culture}

2. Who Am I
• Now: Dynalyst
• Lang: Korean(30+ years)
Japanese(8+ years)
JAVA(8.2+ years)
Scala(a year)
• AdTech: AMoAd DSP
CAA Reward

3. What Dynalyst
• Dynamic Retargeting +
Analyst
• ユーザーの趣味嗜好に適した広告配
信を行う国内初のスマートフォンに
特化したダイナミックリターゲティ
ング広告

4. Scala USAGE

5. Today’s Talk
•How to build Spray
•How to build Akka
•How to Monitor them

6. continuous importing D
mark
ad
bid
imp
click
cv
redshift
request logging importing stored
tracking

7. continuous reporting D
redshift
date imp click cv
2014/09 10,000 500 10
2014/08 15,000 700 25
reporting &
stored summaring bidding optimization

8. Benchmark

9. What is Spray?
http://spray.io

10. What is Spray?
spray is an open-source toolkit for
building REST/HTTP-based
integration layers on top of Scala
and Akka. Being asynchronous,
actor-based, fast, lightweight,
modular and testable it's a great
way to connect your Scala
applications to the world.

11. Concurrency

12. Future[T]
implicit val ec: ExecutionContext
val f = Future { “hello world” }
// Future[String]

13. Future[T]
implicit val ec: ExecutionContext
for {
greeting ← Future(“hello world”)
name ← Future(“Han”)
} yield s”$greeting, $name”
// Future[String]

14. FutureDirectives
• spray-routing directives
• non-blocking actor thread

15. FutureDirectives
def onComplete[T]
(future: ⇒ Future[T])
(implicit ec: ExecutionContext)
:Directive1[Try[T]]

16. FutureDirectives
implicit val ec: ExecutionContext
def respondWithBidding = {
onComplete(bidding) {
case Success(bid: Bid) ⇒ …
case Success(noBid: NoBid) ⇒ …
case Failure(e) ⇒ …
}
}

17. Type of bidding
def bidding:Future[A<:BidResponse]

18. Implementation
def bidding:Future[A<:BidResponse]
!
• simple but bad implementation
Future {
// All bidding computations :(
}

19. Application Layers
Spray Router
Handle raw level http request & response
Bidding Business Logic
External Resources"
Fetch bidding candidates from data stores

20. Application Layers
Global Dispatcher
Spray Router
Handle raw level http request & response
Bidding Business Logic
External Resources"
Fetch bidding candidates from data stores

21. Application Layers
Spray Router
Handle raw level http request & response
Bidding Business Logic
External Resources"
Router Dispatcher
Service Dispatcher
Fetch bidding candidates from data stores
Repository Dispatcher

22. Implementation
trait Router {
implicit val ec = RouterDispatcher
def handle: Future[BidResponse]
}
trait Service {
implicit val ec = ServiceDispatcher
def bidding: Future[Bidder]
}
trait Repository {
implicit val ec = RepositoryDispatcher
def candidates: Future[List[Candidate]]
}

23. How to test those
Future[T] things
• Specs2 - Matcher[Future[T]]
bidding must beEqual(expected).await
bidding must beEqual(expected).await
(
retries = 2,
timeout = 100.millis
)

24. Abstract Future
http://logji.blogspot.jp/2014/02/
the-abstract-future.html

25. Abstract Future
trait Router[M[_]] {
implicit val M: Monad[M]
def handle: M[BidResponse]
}
trait Service[M[_]] {
implicit val M: Monad[M]
def bidding: M[Bidder] = M.point(bidder)
def bidder = …
}
trait Repository[M[_]] {
implicit val M: Monad[M]
def candidates: M[List[Candidate]]
}

26. Type class &
Implicit
object Service {
implicit def fs = new Service[Future] {
implicit val ec = ServiceDispatcher
val M = Monad[Future]
}
implicit def ids = new Service[Id] {
val M = Monad[Id]
}
} // type Id[+A] = A

27. Test Again
val s = Service.ids
s.bidding must beEqual(expected)

28. M[_] for Monad
• Monad is a structure that
represents computations defined
as sequences of steps
• Don’t dive into “Monad” here!

29. What about Akka?
http://akka.io

30. continuous importing D
redshift
mark
ad
bid
imp
click
cv
request logging importing stored
tracking

31. continuous reporting D
redshift
date imp click cv
2014/09 10,000 500 10
2014/08 15,000 700 25
reporting &
stored summaring bidding optimization

32. Master/Worker
http://letitcrash.com/post/
29044669086/balancing-workload-across-
nodes-with-akka-2

33. Overview

34. Overview

35. How to Monitor Akka
• Typesafe Console
http://resources.typesafe.com/docs/
console/manual/overview.html
• Kamon
http://kamon.io/

36. Typesafe console
• Great user interface
• Support by Typesafe
• Expensive

37. Kamon
• Open Source - Free
• Metrics: Akka, Spray, Play
(over 50 categories)
• StatsD, New Relic, Datadog
• Migration could be hard

38. Kamon meets Zabbix

39. Running Thread Count

40. Summary
• Future Directive on Spray
• Abstract Future
(Type class & Implicit)
• Akka master/worker pattern
• Monitoring Akka with Kamon

41. Best Practices?
• https://github.com/alexandru/
scala-best-practices
• So many “MUST NOT, SHOULD NOT”
• In my opinion, Trial and Error to
find right patterns

42. We are Hiring!
• 一緒に働く仲間を募集しています！
Scalaに興味のある方はぜひ！
adtech_scala@cyberagent.co.jp

43. Thanks
han_sangwon@cyberagent.co.jp