How to build a crypto trading platform with Spring 5 and Reactor 3

In the talk, we will look at Reactive approaches with Spring 5 and Reactor 3 and see how to build a Reactive System using Spring Reactive Stack in details. In turn, we will discuss the common business needs, where these techniques fit well and how they may help you in solving complex problems in the most elegant and efficient way.

During the talk, we are going to build a Reactive Crypto-Trading Platform.

The central point which will be covered during the talk:

* Analyze of how to build a simple WebSocket API for data transfer;
* Analyze of existing Crypto-Platforms and the ways of integration with them using Reactor 3 and Spring WebFlux;
* Implementation of Trading and a Customer’s Wallet features;
* Security in Reactive solution with Reactive Spring Security;

What will be skipped:

* Blockchain mechanism;
* Purchasing/Sales mechanism of crypto-currencies in detail;
* Kotlin, obviously :);

Throughout all the talk, we will try to understand whether Reactor 3 and New Reactive Spring 5 helps us or not in solving of common business needs. Try to find out where Reactor 3 shines brightly, what works in WebFlux and what does not. Finally, we will be capable of making the decision whether we can already start working with Spring Boot 2 without fear.

Transcript

1. Строим
   крипто-трейдинг
   платформу
   Олег Докука
   

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8. Чего НЕ будет?
   !4
   

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9. А не будет
   !5
   

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10. А не будет
    •Blockchain
    •Kotlin
    •Тестирования
    !5
    

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11. Что будет?
    !6
    

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12. А будет
    !7
    

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13. А будет
    •Как построить крипто-трейдинг
    платформу
    !7
    

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14. А будет
    •Как построить крипто-трейдинг
    платформу
    •Spring +
    !7
    

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15. А будет
    •Как построить крипто-трейдинг
    платформу
    •Spring +
    •Разбор подходов и особенностей с
    Reactor 3
    !7
    

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16. А будет
    •Как построить крипто-трейдинг
    платформу
    •Spring +
    •Разбор подходов и особенностей с
    Reactor 3
    !8
    

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17. Какие требования?
    !9
    

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18. Функциональные
    !10
    

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19. Функциональные
    •RealTime стоимость Битка
    !10
    

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20. Функциональные
    •RealTime стоимость Битка
    •Графики, лента продаж и прочее
    !10
    

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21. Функциональные
    •RealTime стоимость Битка
    •Графики, лента продаж и прочее
    •Пользовательский кошелек
    !10
    

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22. Функциональные
    •RealTime стоимость Битка
    •Графики, лента продаж и прочее
    •Пользовательский кошелек
    •Торговля биткоином
    !10
    

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23. Нефункциональные
    !11
    

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24. Нефункциональные
    •Высокая пропускная способность и
    быстрота ответа
    !11
    

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25. Нефункциональные
    •Высокая пропускная способность и
    быстрота ответа
    •Эффективная утилизация железа
    !11
    

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26. Нефункциональные
    •Высокая пропускная способность и
    быстрота ответа
    •Эффективная утилизация железа
    •Отказоустойчивость
    !11
    

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27. Нефункциональные
    •Высокая пропускная способность и
    быстрота ответа
    •Эффективная утилизация железа
    •Отказоустойчивость
    •Java + Spring Stack
    !11
    

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28. Какой сервер?
    !12
    

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29. View Slide

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31. View Slide

32. 14
    Асинхронный, event-driven фреймворк
    

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33. View Slide

34. !15
    

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35. •Асинхронные, Не блокирующие
    операции
    !15
    

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36. •Асинхронные, Не блокирующие
    операции
    •Event-Loop
    !15
    

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37. !16
    

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38. •Высокая пропускная способность
    !16
    

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39. •Высокая пропускная способность
    •Эффективная утилизация ресурсов
    !16
    

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40. 1 Netty ≈ 2 Tomcat
    !17
    

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41. !18
    

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42. !18
    

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43. !18
    

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44. WebFlux
    WebMVC на реактивных стероидах
    !19
    

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45. Reactive Stack (WebFlux)
    @Controller, @RequestMapping,…
    Spring MVC
    Servlet API
    Servlet Container
    Default Stack (WebMVC)
    !20
    

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46. Reactive Stack (WebFlux)
    @Controller, @RequestMapping,…
    Spring WebFlux
    HTTP/Reactive-Streams
    Servlet 3.1, Netty, Undertow
    !20
    

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47. 21
    Project Reactor
    

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48. 22
    Flux.just(1, 2, 3, 4)
    .map(mapFunction())
    .filter(filterFunction())
    .map(mapFunction())
    .doOnNext(someAction())
    .subscribe()
    

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49. Reactive Types
    !23
    

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50. •Mono
    •
    Reactive Types
    !23
    

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51. •Mono
    •
    Reactive Types
    !23
    

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52. •Mono
    Reactive Types
    !24
    

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53. •Mono
    •Flux
    Reactive Types
    !24
    

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54. •Mono
    •Flux
    Reactive Types
    !24
    

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55. Reactive Types
    abstract class Flux
    implements Publisher {
    ...
    }
    

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56. Reactive Types
    abstract class Flux
    implements Publisher {
    ...
    }
    abstract class Flux
    implements Publisher {
    ...
    }
    

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57. Flux.just(1, 2, 3, 4)
    .map(…)
    .filter(…)
    .map(…)
    .doOnNext(…)
    .subscribe()
    

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58. Flux.just(1, 2, 3, 4)
    .map(…)
    .filter(…)
    .map(…)
    .doOnNext(…)
    .subscribe()
    Операторы
    

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59. То есть
    !27
    

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60. То есть
    •Netty
    !27
    

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61. То есть
    •Netty
    •Spring WebFlux
    !27
    

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62. То есть
    •Netty
    •Spring WebFlux
    •Project Reactor 3
    !27
    

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63. То есть
    •Netty
    •Spring WebFlux
    •Project Reactor 3
    •Spring Boot 2
    !27
    

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64. Начнем с API
    !28
    

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65. Что нужно?
    !29
    

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66. Что нужно?
    •Вернуть HTML trade.io/
    !29
    

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67. Что нужно?
    •Вернуть HTML trade.io/
    •WebSocket trade.io/stream
    !29
    

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68. Для WebSocket
    !30
    

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69. Для WebSocket
    •Реализовать WebSocketHandler
    •
    !30
    

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70. interface WebSocketHandler {
    Mono handle(WebSocketSession session);
    }
    !31
    

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71. interface WebSocketHandler {
    Mono handle(WebSocketSession session);
    }
    interface WebSocketHandler {
    Mono handle(WebSocketSession session);
    }
    !31
    

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72. interface WebSocketHandler {
    Mono handle(WebSocketSession session);
    }
    interface WebSocketHandler {
    Mono handle(WebSocketSession session);
    }
    interface WebSocketHandler {
    Mono handle(WebSocketSession session);
    }
    !31
    

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73. interface WebSocketSession {
    Flux receive();
    Mono send(Publisher messages);
    }
    !32
    

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74. interface WebSocketSession {
    Flux receive();
    Mono send(Publisher messages);
    }
    interface WebSocketSession {
    Flux receive();
    Mono send(Publisher messages);
    }
    !32
    

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75. interface WebSocketSession {
    Flux receive();
    Mono send(Publisher messages);
    }
    interface WebSocketSession {
    Flux receive();
    Mono send(Publisher messages);
    }
    interface WebSocketSession {
    Flux receive();
    Mono send(Publisher messages);
    }
    !32
    

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76. interface WebSocketSession {
    Flux receive();
    Mono send(Publisher messages);
    }
    interface WebSocketSession {
    Flux receive();
    Mono send(Publisher messages);
    }
    interface WebSocketSession {
    Flux receive();
    Mono send(Publisher messages);
    }
    interface WebSocketSession {
    Flux receive();
    Mono send(Publisher messages);
    }
    !32
    

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77. class WebSocketMessage {
    DataBuffer getPayload()
    String getPayloadAsText()
    WebSocketMessage retain()
    void release()
    }
    !33
    

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78. class WebSocketMessage {
    DataBuffer getPayload()
    String getPayloadAsText()
    WebSocketMessage retain()
    void release()
    }
    !33
    class WebSocketMessage {
    DataBuffer getPayload()
    String getPayloadAsText()
    WebSocketMessage retain()
    void release()
    }
    

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79. class WebSocketMessage {
    DataBuffer getPayload()
    String getPayloadAsText()
    WebSocketMessage retain()
    void release()
    }
    !33
    class WebSocketMessage {
    DataBuffer getPayload()
    String getPayloadAsText()
    WebSocketMessage retain()
    void release()
    }
    class WebSocketMessage {
    DataBuffer getPayload()
    String getPayloadAsText()
    WebSocketMessage retain()
    void release()
    }
    

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80. Для WebSocket
    •Реализовать WebSocketHandler
    !34
    

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81. Для WebSocket
    •Реализовать WebSocketHandler
    •Добавить конфигурацию
    !34
    

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82. Для WebSocket
    •Реализовать WebSocketHandler
    •Добавить конфигурацию
    •Протокол - JSON
    !35
    

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83. Что создадим?
    !36
    

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84. Что создадим?
    •IndexController.java
    !36
    

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85. Что создадим?
    •IndexController.java
    •CryptoChannel.java
    !36
    

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86. Что создадим?
    •IndexController.java
    •CryptoChannel.java
    •WebSocketConfiguration.java
    !36
    

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87. Что создадим?
    •IndexController.java
    •CryptoChannel.java
    •WebSocketConfiguration.java
    •Message.java
    !36
    

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88. Что создадим?
    •IndexController.java
    •CryptoChannel.java
    •WebSocketConfiguration.java
    •Message.java
    •WebSocketMessageMapper.java
    !36
    

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89. Что создадим?
    •IndexController.java
    •CryptoChannel.java
    •WebSocketConfiguration.java
    •Message.java
    •WebSocketMessageMapper.java
    !37
    

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90. !38
    Talk is cheap. Show me the code.
    - Linus Torvalds
    

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91. s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    !39
    

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92. s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    !39
    

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93. s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    !39
    

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94. s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    .map(…)
    .publishOn(…)
    .onBackpressure()
    .tranform(…)
    .tranform(…)
    .map(…)
    !39
    

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95. s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    .map(…)
    .publishOn(…)
    .onBackpressure()
    .tranform(…)
    .tranform(…)
    .map(…)
    !40
    

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96. s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    .map(…)
    .publishOn(…)
    .onBackpressure()
    .tranform(…)
    .tranform(…)
    .map(…)
    !40
    

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97. s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    .map(…)
    .publishOn(…)
    .onBackpressure()
    .tranform(…)
    .tranform(…)
    .map(…)
    !40
    

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98. s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    .map(…)
    .publishOn(…)
    .onBackpressure()
    .tranform(…)
    .tranform(…)
    .map(…)
    !41
    

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99. s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    s.receive()
    .map(WebSocketMessage::retain)
    .map(WebSocketMessage::getPayload)
    .publishOn(Schedulers.parallel())
    .transform(mapper::decode)
    .transform(this::doHandle)
    .onBackpressureBuffer()
    .transform(s -> mapper.encode(…))
    .map(db -> new WebSocketMessage(…))
    .as(session::send);
    .map(…)
    .publishOn(…)
    .onBackpressure()
    .tranform(…)
    .tranform(…)
    .map(…)
    !41
    

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100. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !41
     

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101. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !42
     

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102. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !42
     

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103. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !43
     

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104. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !43
     

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105. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !43
     

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106. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !44
     

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107. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !44
     

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108. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !45
     

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109. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !45
     

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110. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !46
     

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111. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !46
     

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112. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !47
     

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113. s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     s.receive()
     .map(WebSocketMessage::retain)
     .map(WebSocketMessage::getPayload)
     .publishOn(Schedulers.parallel())
     .transform(mapper::decode)
     .transform(this::doHandle)
     .onBackpressureBuffer()
     .transform(s -> mapper.encode(…))
     .map(db -> new WebSocketMessage(…))
     .as(session::send);
     .map(…)
     .publishOn(…)
     .onBackpressure()
     .tranform(…)
     .tranform(…)
     .map(…)
     !47
     

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114. Что запомнить!?
     !48
     

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115. Что запомнить!?
     •WebSocketMessage.retain/
     release для подсчёта ссылок
     !48
     

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116. Что запомнить!?
     •WebSocketMessage.retain/
     release для подсчёта ссылок
     •.publishOn() для переноса
     работу с Event-Loop
     !48
     

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117. Помогает
     !49
     

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118. Помогает
     •Работать с Netty
     !49
     

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119. Помогает
     •Работать с Netty
     •Построить чистый асинхронный код
     !49
     

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120. Помогает
     •Работать с Netty
     •Построить чистый асинхронный код
     •Управлять потоками
     !49
     

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121. Помогает
     •Работать с Netty
     •Построить чистый асинхронный код
     •Управлять потоками
     •Управлять Backpressure
     !49
     

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122. Не очень
     !50
     

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123. Не очень
     •Конфигурировать WebSocket API
     !50
     

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124. Не очень
     •Конфигурировать WebSocket API
     •Конвертировать bytes java
     !50
     

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125. Не очень
     •Конфигурировать WebSocket API
     •Конвертировать bytes java
     •Управлять ссылками
     !50
     

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126. Первые данные
     !51
     

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127. Откуда брать?
     !52
     

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128. Откуда брать?
     •Bitmex - WebSocket API
     !52
     

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129. Откуда брать?
     •Bitmex - WebSocket API
     •Bitfinex - WebSocket API
     !52
     

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130. Что нужно?
     !53
     

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131. Что нужно?
     •WebSocket Client
     !53
     

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132. interface WebSocketClient {
     Mono execute(URI url,
     WebSocketHandler handler);
     }
     !54
     

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133. interface WebSocketClient {
     Mono execute(URI url,
     WebSocketHandler handler);
     }
     interface WebSocketClient {
     Mono execute(URI url,
     WebSocketHandler handler);
     }
     !54
     

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134. interface WebSocketClient {
     Mono execute(URI url,
     WebSocketHandler handler);
     }
     interface WebSocketClient {
     Mono execute(URI url,
     WebSocketHandler handler);
     }
     !54
     interface WebSocketClient {
     Mono execute(URI url,
     WebSocketHandler handler);
     }
     

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135. Что создадим?
     !55
     

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136. Что создадим?
     •CryptoService.java
     !55
     

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137. Что создадим?
     •CryptoService.java
     •BitmexMessage.java
     !55
     

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138. Что создадим?
     •CryptoService.java
     •BitmexMessage.java
     •BitmexMessageMapper.java
     !55
     

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139. Что создадим?
     •CryptoService.java
     •BitmexMessage.java
     •BitmexMessageMapper.java
     •BitmexService.java
     !55
     

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140. Что создадим?
     •CryptoService.java
     •BitmexMessage.java
     •BitmexMessageMapper.java
     •BitmexService.java
     !56
     

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141. !57
     Talk is cheap. Show me the code.
     - Linus Torvalds
     

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142. map(…) Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     publishOn(…)
     then()
     flatMapIterable(…)
     !58
     

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143. map(…) Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     publishOn(…)
     then()
     flatMapIterable(…)
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     !58
     

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144. map(…) Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     publishOn(…)
     then()
     flatMapIterable(…)
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     !58
     

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145. Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     map(…)
     publishOn(…)
     then()
     flatMapIterable(…)
     !59
     

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146. Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     doOnNext(sink::next)
     map(…)
     publishOn(…)
     then()
     flatMapIterable(…)
     !59
     

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147. Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     doOnNext(sink::next)
     map(…)
     publishOn(…)
     then()
     flatMapIterable(…)
     !59
     

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148. Flux.create(sink ->
     ...
     s -> s.receive()
     .skip(6)
     .map(WSM::getPayloadAsText)
     .publishOn(…)
     .flatMapIterable(…)
     .doOnNext(sink::next)
     .then();
     ...
     );
     doOnNext(sink::next)
     map(…)
     publishOn(…)
     then()
     flatMapIterable(…)
     !60
     

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149. BitmexWebSocketConnection
     ClientWebSocketConnection
     !60
     

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150. !61
     BitmexWebSocketConnection
     ClientWebSocketConnection
     

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151. !61
     BitmexWebSocketConnection
     ClientWebSocketConnection
     

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152. !62
     BitmexWebSocketConnection
     ClientWebSocketConnection
     

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153. BitmexWebSocketConnection
     ClientWebSocketConnection
     BitmexWebSocketConnection
     ClientWebSocketConnection
     BitmexWebSocketConnection
     ClientWebSocketConnection
     BitmexWebSocketConnection
     ClientWebSocketConnection
     !62
     BitmexWebSocketConnection
     ClientWebSocketConnection
     

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154. !63
     Talk is cheap. Show me the code.
     - Linus Torvalds
     

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155. BitmexWebSocketConnection
     BitmexWebSocketConnection
     BitmexWebSocketConnection
     BitmexWebSocketConnection
     BitmexWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     !64
     

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156. BitmexWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     !64
     

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157. BitmexWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     !64
     

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158. А как же Bitfinex?
     

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159. !66
     Talk is cheap. Show me the code.
     - Linus Torvalds
     

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160. .publish() DirectProcessor
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     !67
     

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161. .publish() DirectProcessor
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     !67
     

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162. .publish() DirectProcessor
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     !67
     

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163. DirectProcessor
     .publish()
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     !68
     

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164. DirectProcessor
     .publish()
     ClientWebSocketConnection
     ClientWebSocketConnection
     ClientWebSocketConnection
     !68
     

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165. DirectProcessor
     .publish()
     ClientWebSocketConnection
     ClientWebSocketConnection
     !68
     

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166. Что запомнить!?
     !69
     

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167. Что запомнить!?
     •FluxSink для перенаправления
     !69
     

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168. Что запомнить!?
     •FluxSink для перенаправления
     •.publish() для уравниловки
     !69
     

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169. Что запомнить!?
     •FluxSink для перенаправления
     •.publish() для уравниловки
     !69
     

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170. Что запомнить!?
     •FluxSink для перенаправления
     •.publish() для уравниловки
     •DirectProcessor для push
     !69
     

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171. Что запомнить!?
     •FluxSink для перенаправления
     •.publish() для уравниловки
     •DirectProcessor для push
     !69
     

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172. Помогает
     !70
     

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173. Помогает
     •Работать с WebSocket
     !70
     

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174. Помогает
     •Работать с WebSocket
     •Перенаправлять данные
     !70
     

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175. Помогает
     •Работать с WebSocket
     •Перенаправлять данные
     •Мультикастить данные
     !70
     

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176. Помогает
     •Работать с WebSocket
     •Перенаправлять данные
     •Мультикастить данные
     •Объединять данные
     !70
     

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177. !71
     Не очень
     

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178. !71
     Не очень
     

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179. Строим Кошелёк
     !72
     

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180. Что нужно?
     !73
     

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181. Что нужно?
     •MongoDB - реактивная база данных
     •
     !73
     

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182. Что нужно?
     •MongoDB - реактивная база данных
     •Spring Data Mongo Reactive
     •
     !74
     

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183. interface ReactiveCrudRepository extends Repository
     Mono save(S entity);
     Flux saveAll(Iterable entities);
     Flux saveAll(Publisher entityStream);
     Mono findById(ID id);
     Mono findById(Mono id);
     Mono existsById(ID id);
     Mono existsById(Mono id);
     Flux findAll();
     Flux findAllById(Iterable ids);
     Flux findAllById(Publisher idStream);
     Mono count();
     Mono deleteById(ID id);
     Mono delete(T entity);
     Mono deleteAll(Iterable extends T> entities);
     Mono deleteAll(Publisher extends T> entityStream);
     Mono deleteAll();
     } 75
     

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184. interface ReactiveCrudRepository extends Repository
     Mono save(S entity);
     Flux saveAll(Iterable entities);
     Flux saveAll(Publisher entityStream);
     Mono findById(ID id);
     Mono findById(Mono id);
     Mono existsById(ID id);
     Mono existsById(Mono id);
     Flux findAll();
     Flux findAllById(Iterable ids);
     Flux findAllById(Publisher idStream);
     Mono count();
     Mono deleteById(ID id);
     Mono delete(T entity);
     Mono deleteAll(Iterable extends T> entities);
     Mono deleteAll(Publisher extends T> entityStream);
     Mono deleteAll();
     } 76
     

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185. Что нужно?
     •MongoDB - реактивная база данных
     •Spring Data Mongo Reactive
     •Конфигурация SpringSecurity - для
     пользовательского доступа
     !77
     

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186. class ReactiveSecurityContextHolder {
     static Mono getContext()
     }
     !78
     

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187. class ReactiveSecurityContextHolder {
     static Mono getContext()
     }
     class ReactiveSecurityContextHolder {
     static Mono getContext()
     }
     !78
     

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188. Что создадим?
     !79
     

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189. Что создадим?
     •Wallet.java
     !79
     

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190. Что создадим?
     •Wallet.java
     •WalletRepository.java
     !79
     

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191. Что создадим?
     •Wallet.java
     •WalletRepository.java
     •WalletService.java
     !79
     

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192. Что создадим?
     •Wallet.java
     •WalletRepository.java
     •WalletService.java
     •LocalWalletService.java
     !79
     

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193. Что создадим?
     •Wallet.java
     •WalletRepository.java
     •WalletService.java
     •LocalWalletService.java
     •LocalMessageMapper.java
     !79
     

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194. Что создадим?
     •Wallet.java
     •WalletRepository.java
     •WalletService.java
     •LocalWalletService.java
     •LocalMessageMapper.java
     !80
     

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195. !81
     Talk is cheap. Show me the code.
     - Linus Torvalds
     

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196. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     !82
     

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197. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscribe(out::println)
     !82
     

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198. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscribe(out::println)
     null
     !82
     

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199. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscribe(out::println)
     !82
     {emptyMap}
     

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200. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscribe(out::println)
     !82
     {emptyMap}
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscribe(out::println)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscribe(out::println)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscribe(out::println)
     

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201. null
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscribe(out::println)
     !82
     

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202. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     !83
     

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203. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     !83
     

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204. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     !83
     

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205. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     !83
     {emptyMap}
     

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206. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     !83
     {emptyMap}
     

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207. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     !83
     {security}
     

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208. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     !83
     {security}
     

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209. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName)
     .subscriberContext(security)
     .subscribe(out::println)
     Admin
     !83
     

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210. !84
     

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211. !84
     ReactorContextWebFilter
     

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212. !84
     ReactorContextWebFilter
     

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213. stateStreamSecurityProxy
     stateStream()
     !84
     ReactorContextWebFilter
     

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214. stateStreamSecurityProxy
     stateStream()
     !84
     ReactorContextWebFilter
     

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215. stateStreamSecurityProxy
     stateStream()
     !84
     ReactorContextWebFilter
     subscriberContext()
     

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216. stateStreamSecurityProxy
     stateStream()
     !84
     ReactorContextWebFilter
     subscriberContext()
     

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217. stateStreamSecurityProxy
     stateStream()
     !84
     ReactorContextWebFilter
     subscriberContext()
     

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218. stateStreamSecurityProxy
     stateStream()
     !84
     ReactorContextWebFilter
     subscriberContext()
     

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219. stateStreamSecurityProxy
     stateStream()
     !84
     ReactorContextWebFilter
     subscriberContext()
     

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220. stateStreamSecurityProxy
     stateStream()
     !84
     ReactorContextWebFilter
     subscriberContext()
     

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221. stateStreamSecurityProxy
     stateStream()
     !85
     ReactorContextWebFilter
     subscriberContext()
     

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222. stateStreamSecurityProxy
     stateStream()
     !85
     ReactorContextWebFilter
     subscriberContext()
     

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223. stateStreamSecurityProxy
     stateStream()
     !85
     ReactorContextWebFilter
     subscriberContext()
     

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224. stateStreamSecurityProxy
     stateStream()
     !85
     ReactorContextWebFilter
     subscriberContext()
     

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225. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     

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226. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ...
     ReactorContextWebFilter…
     

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227. ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     admin
     ReactiveSecurityContextHolder
     .getContext()
     .map(getAuthentication)
     .map(getName);
     ...
     ReactorContextWebFilter…
     

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228. Что запомнить!?
     !87
     

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229. Что запомнить!?
     •Замыкаем что бы получить
     Context
     !87
     

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230. Что запомнить!?
     •Замыкаем что бы получить
     Context
     •Context задом наперед
     !87
     

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231. Что запомнить!?
     •Замыкаем что бы получить
     Context
     •Context задом наперед
     •SecurityContext живет в
     Context
     !87
     

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232. Помогает
     !88
     

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233. Помогает
     •Работать реактивно с MongoDB
     !88
     

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234. Помогает
     •Работать реактивно с MongoDB
     •Защищать API просто
     !88
     

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235. !89
     Не очень
     

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236. !89
     Не очень
     

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237. Механика торговли
     !90
     

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238. Что нужно?
     •Сохранять результаты торгов в
     базу
     !91
     

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239. Бизнес механизм
     •Снять деньги с кошелька
     •Провести торги
     •В случае успеха - добавить деньги в кошелек
     •В случае неудачных торгов - вернуть деньги
     •В случае нехватки средств - ничего не делать
     !92
     

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240. Что измениться?
     •Wallet.java
     •CryptoService.java
     •WalletService.java
     !93
     

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241. class Wallet {
     ...
     Wallet withdraw(float amount)
     Wallet adjust(float amount)
     }
     !94
     

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242. Что измениться?
     •Wallet.java
     •CryptoService.java
     •WalletService.java
     !95
     

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243. interface CryptoService {
     Flux> stream();
     default Mono trade(…)
     }
     !96
     

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244. Что измениться?
     •Wallet.java
     •CryptoService.java
     •WalletService.java
     !97
     

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245. interface WalletService {
     Flux> changesStream();
     Mono withdraw(Message trade);
     Mono adjust(Message trade);
     Mono rollback(Message trade);
     }
     !98
     

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246. Что создадим?
     !99
     

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247. Что создадим?
     •Trade.java
     !99
     

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248. Что создадим?
     •Trade.java
     •TradeRepository.java
     !99
     

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249. Что создадим?
     •Trade.java
     •TradeRepository.java
     •LocalCryptoService.java
     !99
     

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250. Что создадим?
     •Trade.java
     •TradeRepository.java
     •LocalCryptoService.java
     !100
     

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251. !101
     Talk is cheap. Show me the code.
     - Linus Torvalds
     

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252. tradeOffer
     .onBackpressureBuffer()
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     )
     .map(LocalMessageMapper::tradeToMessage)
     .doOnNext(stream.sink()::next)
     .then(); !102
     

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253. tradeOffer
     .onBackpressureBuffer()
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     )
     .map(LocalMessageMapper::tradeToMessage)
     .doOnNext(stream.sink()::next)
     .then(); !102
     

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254. tradeOffer
     .onBackpressureBuffer()
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     )
     .map(LocalMessageMapper::tradeToMessage)
     .doOnNext(stream.sink()::next)
     .then(); !102
     

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255. tradeOffer
     .onBackpressureBuffer()
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     )
     .map(LocalMessageMapper::tradeToMessage)
     .doOnNext(stream.sink()::next)
     .then();!102
     

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256. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     !103
     

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257. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     !103
     

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258. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !103
     

     View Slide

259. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !104
     

     View Slide

260. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !104
     

     View Slide

261. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !104
     

     View Slide

262. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !104
     

     View Slide

263. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !105
     

     View Slide

264. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !105
     

     View Slide

265. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !105
     

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266. !106
     

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267. !106
     

     View Slide

268. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !107
     

     View Slide

269. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !107
     

     View Slide

270. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !107
     

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271. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !108
     

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272. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !108
     

     View Slide

273. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !108
     

     View Slide

274. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     !109
     

     View Slide

275. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     !109
     

     View Slide

276. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !109
     

     View Slide

277. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !110
     

     View Slide

278. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !110
     

     View Slide

279. !111
     

     View Slide

280. !111
     

     View Slide

281. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(NEME)
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !112
     

     View Slide

282. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(NEME)
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !112
     

     View Slide

283. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     !113
     

     View Slide

284. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     !113
     

     View Slide

285. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !113
     

     View Slide

286. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !114
     

     View Slide

287. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !114
     

     View Slide

288. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !114
     

     View Slide

289. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !115
     

     View Slide

290. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(rollback())
     onErrorResume(NEME)
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     !115
     

     View Slide

291. !116
     

     View Slide

292. !116
     

     View Slide

293. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(NEME)
     onErrorResume(rollback())
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     onErrorResume(rollback())
     !117
     

     View Slide

294. .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     .flatMap(trade ->
     ws.withdraw(trade)
     .then(doTrade(trade))
     .then(ws.adjust(trade))
     .then(doStoreTrade(trade))
     .onErrorResume(
     NotEnoughMoneyException.class,
     t -> Mono.empty()
     )
     .onErrorResume(t ->
     ws.rollback(trade)
     .then(Mono.empty())
     )
     }
     onErrorResume(NEME)
     onErrorResume(rollback())
     adjust()
     doTrade()
     .withdraw()
     doStoreTrade()
     onErrorResume(rollback())
     !117
     

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295. Есть БУГ
     

     View Slide

296. View Slide

297. Что запомнить!?
     !120
     

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298. Что запомнить!?
     •.onErrorXXX для ошибок
     !120
     

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299. Что запомнить!?
     •.onErrorXXX для ошибок
     •.then для последовательности
     операций
     !120
     

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300. Что запомнить!?
     •.onErrorXXX для ошибок
     •.then для последовательности
     операций
     •Request/Session scope -
     своими руками
     !120
     

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301. Помогает
     !121
     

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302. Помогает
     •Работать с ошибками
     !121
     

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303. Помогает
     •Работать с ошибками
     •Строить сложное - просто
     !121
     

     View Slide

304. Не очень
     !122
     

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305. Не очень
     •Конфигурировать Request/
     Session scope
     !122
     

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306. А как же
     отказоустойчивость?
     !123
     

     View Slide

307. Что нужно?
     !124
     

     View Slide

308. Что нужно?
     •Стабильно работать в случае
     отказа внешних сервисов
     !124
     

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309. Что нужно?
     •Стабильно работать в случае
     отказа внешних сервисов
     •Стабильно работать в случае не
     авторизованного доступа
     !124
     

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310. !125
     Talk is cheap. Show me the code.
     - Linus Torvalds
     

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311. Что запомнить!?
     !126
     

     View Slide

312. Что запомнить!?
     •Изолируем отдельные компоненты
     !126
     

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313. Что запомнить!?
     •Изолируем отдельные компоненты
     •.timeout - чтобы долго не
     ждать
     !126
     

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314. Что запомнить!?
     •Изолируем отдельные компоненты
     •.timeout - чтобы долго не
     ждать
     •.retryWhen - для повторных
     попыток
     !126
     

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315. Помогает
     !127
     

     View Slide

316. Помогает
     •Изолировать компоненты
     !127
     

     View Slide

317. Помогает
     •Изолировать компоненты
     •Работать с переподключением
     !127
     

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318. !128
     Не очень
     

     View Slide

319. !128
     Не очень
     

     View Slide

320. Итожим
     !129
     

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321. View Slide

322. View Slide

323. View Slide

324. View Slide

325. 130
     ?
     

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326. С чем уйти?
     !131
     

     View Slide

327. WebFlux - тот же
     WebMVC но работает с
     Netty
     !132
     

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328. WebFlux + Reactor
     Чистый асинхронный
     код
     !133
     

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329. Ивентам - Event-Loop
     Бизнес логике -
     отдельный Thread Pool
     !134
     

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330. Экономь сокеты
     - .publish() данные
     !135
     

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331. Реактивная
     интеграция с Базой с -
     Spring Data Reactive
     !136
     

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332. Замыкаем потоки для
     общего Context
     !137
     

     View Slide

333. Грустим (пока что) изза
     Request/Session Scopes
     !138
     

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334. Отлавливаем ошибки с -
     .onErrorXXX
     !139
     

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335. Остаемся
     непоколебимыми с -
     .retryWhen
     !140
     

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336. Экономим время с -
     .timeout
     !141
     

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337. Что еще упустили?
     !142
     

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338. Что еще упустили?
     •Дебажить сложно - но просто
     тестить с StepVerifier
     !142
     

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339. Что еще упустили?
     •Дебажить сложно - но просто
     тестить с StepVerifier
     •Нет реактивного JDBC (пока что)
     !142
     

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340. Что еще упустили?
     •Дебажить сложно - но просто
     тестить с StepVerifier
     •Нет реактивного JDBC (пока что)
     •Императивный код никто не
     отменял
     !142
     

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341. Где применять?
     !143
     

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342. Где применять?
     •Системы с высокой нагрузкой
     !143
     

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343. Где применять?
     •Системы с высокой нагрузкой
     •Там где нужно экономить на
     железе
     !143
     

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344. Где применять?
     •Системы с высокой нагрузкой
     •Там где нужно экономить на
     железе
     •Microservices orchestration
     !143
     

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345. На посмотреть
     •WebFlux воркшоп - https://bclozel.github.io/webflux-
     workshop/
     •Играем с Reactor 3 - https://tech.io/playgrounds/929/
     reactive-programming-with-reactor-3/Intro
     •JDBC? Смотреть тут - https://www.youtube.com/watch?
     v=OiXu05WU7zI
     •Все еще не уверены? - Netflix вещает - https://goo.gl/
     dMBUC7
     !144
     

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346. https://goo.gl/JZHhrq
     Код живет тут
     !145
     

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347. Олег Докука
     /oleh.dokuka /OlegDokuka
     /OlehDokuka
     

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348. View Slide

349. View Slide