Akka Streamsの縮退処理を用いた耐障害性の実現 〜 広告のリアルタイムオークションの事例 〜

「Scala将軍達の後の祭り」での発表資料です。

http://scala-syogun-matsuri.connpass.com/event/28124/

Transcript

1. Akka StreamsͷॖୀॲཧΛ༻͍ͨ
   ଱ো֐ੑͷ࣮ݱ
   ʙ ޿ࠂͷϦΞϧλΠϜΦʔΫγϣϯͷࣄྫ ʙ
   

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2. ࣗݾ঺հ
   @ikuo (Ikuo Matsumura)
   2008~ ૊ࠐܥͷ෼ࢄγϛϡϨʔγϣϯͷઃܭ։ൃͳͲ; C++, MATLAB
   IBM Research - Tokyo
   2011~ ϨγϐӫཆՁͷࣗಈܭࢉͷઃܭ։ൃͳͲ; Ruby/Rails, Treetop
   Cookpad, Inc.
   2014~ SSP/RTBΦʔΫγϣϯͷઃܭ։ൃͳͲ; Scala/Akka
   CyberAgent, Inc.
   CA ProFit-X team
   

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3. ޿ࠂͷϦΞϧλΠϜΦʔΫγϣϯ (RTB)
   ߴ͍Մ༻ੑཁ݅ɿࢭΊΒΕͳ͍ ˍ ଴ͬͯ͘Εͳ͍
   ෆ࣮֬ͳ؀ڥɿ֎෦ͷଟ਺ͷೖࡳݩ(DSP)ʹৗ࣌઀ଓ
   ೖࡳ͕શͯἧΘͳ͍͜ͱ͸ڐ༰Ͱ͖Δ
   

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4. ଟ਺ͷ֎෦઀ଓͷো֐͔ΒγεςϜΛकΓ͍ͨ
   * Photo by FEMA/Joselyne Augus5no; A home in Gilchrist, Texas, designed to resist flood
   waters survived Hurricane Ike in 2008.
   

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5. ֎෦઀ଓͷো֐ͱΞϓϩʔν
   ʮͪ͜Βʯͷҟৗɿ઀ଓͷ಺෦ঢ়ଶͷҟৗ
   ྫɿHTTP ΫϥΠΞϯτͷActorͷঢ়ଶҟৗ
   → SupervisorʹΑΔҟৗݕ஌ͱActorͷ࠶ىಈ
   ʮ͋ͪΒʯͷҟৗɿϨΠςϯγѱԽɾແԠ౴Խ
   ྫɿ઀ଓઌͷܭࢉࢿݯ΍ଳҬͷṧഭ
   → ॖୀ (fallback)ɿॏཁͰͳ͍ϝοηʔδΛࣺͯͯ
   ɹɹϝϞϦރׇ (OutOfMemoryError) Λ๷͙
   

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6. ରࡦ1: BoundedMailboxΛ࢖͏
   bounded-mailbox {
   mailbox-type = "akka.dispatch.NonBlockingBoundedMailbox"
   }
   ✅ ᷓΕͨΒϝοηʔδࣺͯΔͷͰϝϞϦރׇ๷͛Δ
   

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7. ❌ Ձ஋ͷߴ͍ϝοηʔδ͕ࣺͯΒΕΔ
   ؒʹ߹͏ݟࠐΈͷখ͍͞ೖࡳཁٻ͕࢒ͬͯ͠·͏
   

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8. ରࡦ2: ༏ઌ౓͖ͭͷBoundedMailboxΛ࢖͏
   bounded-mailbox {
   mailbox-type = "akka.dispatch.BoundedStablePriorityMailbox"
   mailbox-push-timeout-time = 0s
   }
   ✅ ᷓΕͨΒϝοηʔδࣺͯΔͷͰϝϞϦރׇ๷͛Δ
   ✅ Ձ஋ͷߴ͍ϝοηʔδΛ࢒ͤΔ
   

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9. ❌ ద༻࿙ΕͷActor͕͋ΔͱϝϞϦރׇ๷͛ͳ͍
   UnboundedͳϝʔϧϘοΫεͷActor͕͋Γɺ͕ͦ͜
   ཯଎ʹͳΔͱϝʔϧϘοΫε͕ᷓΕΔ
   

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10. ରࡦ3: Akka StreamsΛ࢖͏
    ϝοηʔδ͸ִนϊʔυ (bulkhead) Λհͯ͠௨৴ϊʔυ (subscriber) ʹBroadcastɻ
    ௨৴ϊʔυ͸֎෦ཁٻ׬ྃ·ͰϝοηʔδΛ্ྲྀʹཁٻ͠ͳ͍ɻ
    

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11. ִนϊʔυ (bulkhead)
    val bulkhead =
    Flow
    .apply[MyMessage]
    .buffer(
    bulkheadBufferSize,
    OverflowStrategy.dropHead
    )
    όοϑΝͷ࠷େαΠζΛ௒͑Δͱɺݹ͍ϝοηʔδ
    ΛࣺͯΔ ( dropHead )
    

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12. ௨৴ϊʔυ (subscriber)
    val subscriberA = Sink(ActorSubscriber[MyMessage](actorA))
    class ProxyA extends Actor with ActorSubscriber {
    def receive = {
    case OnNext(msg: MyMessage) =>
    hostConnector
    .ask(httpReq(msg))
    .map(...)
    .onComplete(request(1))
    ...
    ֎෦ཁٻͷ׬ྃΛ଴͔ͬͯΒ࣍ͷϝοηʔδΛ্ྲྀ
    (bulkhead) ʹཁٻ͢ΔͷͰɺ֎෦ཁٻͷաఔͷͲ͕͜
    ཯଎ʹͳͬͯ΋ϝʔϧϘοΫε͕ᷓΕͳ͍
    

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13. Akka StreamsΛ࢖͏
    ✅ ᷓΕͨΒϝοηʔδࣺͯΔͷͰϝϞϦރׇ๷͛Δ
    ✅ Ձ஋ͷߴ͍ϝοηʔδΛ࢒ͤΔ
    ✅ ཯଎ཁҼ͕Ҡಈͯ͠΋࣮֬ʹॖୀͰ͖Δ
    

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14. CA ProFit-X
    • 2015೥3݄ʹϦϦʔε
    • ౰ॳ͔ΒAkka StreamsʹΑΔ
    ॖୀॲཧΛ૊ࠐΈ
    • ݱࡏ͸ඵؒ໿1ສ݅ͷϦΞϧλ
    ΠϜΦʔΫγϣϯΛ҆ఆͯ͠
    ॲཧ
    

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15. ·ͱΊ
    Akka StreamsΛ֎෦઀ଓͷॖୀͷͨΊʹ࢖͏͜ͱ
    Ͱɺʮ଴ͬͯ͘Εͳ͍ʯ؀ڥͰ֎෦઀ଓͷো֐ʢੑ
    ೳྼԽ ) ͔ΒγεςϜΛकΔྫΛ঺հ͠·ͨ͠ɻ
    ॲཧ଎౓ͱ͸ผͷ ଱ো֐ੑ ͷଆ໘ͰAkka StreamsΛ
    ׆༻͢Δྫͷ1ͭͱͯ͠ɺࢀߟʹͳΕ͹޾͍Ͱ͢ɻ
    

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