Discovering unknown with EventStorming ConFoo

Transcript

1. Mariusz Gil DISCOVERING UNKNOWN WITH @mariuszgil

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3. https://www.tripled.io/img/DDD-books.jpg

4. CAPTURE The knowledge @mariuszgil

5. Embed Into code @mariuszgil

6. Protect From the world @mariuszgil

7. The critical complexity of most software projects is in understanding

   the domain itself Eric Evans @mariuszgil

8. Given… when… then… @mariuszgil

9. Initial idea

10. Reality

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13. Meet& tELL your STORY @mariuszgil

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16. @mariuszgil

17. @mariuszgil

18. Reservation requested @mariuszgil

19. Reservation requested Reservation accepted @mariuszgil

20. Reservation requested Reservation accepted Availability and Limits checked @mariuszgil

21. Reservation requested Reservation accepted Availability and Limits checked @mariuszgil

22. Reservation requested Reservation accepted Availability and Limits checked @mariuszgil

23. Reservation requested Reservation accepted Availability and Limits checked customer @mariuszgil

24. Reservation requested Reservation accepted Availability and Limits checked customer Reservation

    rejected How to handle rejections? @mariuszgil

25. Reservation requested Reservation accepted Availability and Limits checked customer Reservation

    rejected How to handle rejections? Similar offer Proposed @mariuszgil

26. Reservation requested Reservation accepted Availability and Limits checked customer Reservation

    rejected How to handle rejections? Similar offer Proposed agent @mariuszgil

27. Airline ticket Api gateway Reservation requested Reservation accepted Availability and

    Limits checked customer Reservation rejected How to handle rejections? Similar offer Proposed agent @mariuszgil

28. Airline ticket Api gateway Reservation requested Availability and Limits checked

    customer Reservation rejected How to handle rejections? Similar offer Proposed agent Email gateway Reservation accepted @mariuszgil

29. Airline ticket Api gateway Reservation requested Availability and Limits checked

    customer Reservation rejected How to handle rejections? Similar offer Proposed agent Email gateway Confirmation Delivered Reservation accepted @mariuszgil

30. Airline ticket Api gateway Reservation requested Availability and Limits checked

    customer Reservation rejected How to handle rejections? Similar offer Proposed agent Email gateway Confirmation Delivered Reservation accepted $ $ @mariuszgil

31. Airline ticket Api gateway Reservation requested Availability and Limits checked

    customer Reservation rejected How to handle rejections? Similar offer Proposed agent Email gateway Confirmation Delivered Reservation accepted $ $ How to handle service Downtimes? @mariuszgil

32. Airline ticket Api gateway Reservation requested Availability and Limits checked

    customer Reservation rejected How to handle rejections? Similar offer Proposed agent Email gateway Confirmation Delivered Reservation accepted $ $ How to handle service Downtimes? Some customers Have phones Only! @mariuszgil
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41. Bad decisions Cost a lot… @mariuszgil

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48. It’s DEVELoper (mis)understanding Not expert knowledge That get’s released in

    production Alberto Brandolini @mariuszgil

49. Big picture Event storming @mariuszgil

50. Design level Event storming @mariuszgil

51. Aggregate Event Actor Command / Decision Read model External System

    Policy @mariuszgil Command Query

52. @mariuszgil https://docs.axoniq.io/reference-guide/v/3.3/part-i-getting-started/architecture-overview

53. Payment Registered Loyalty points registered Loyalty points calculated Upgrade limits

    reached Account upgraded to higher status @mariuszgil

54. Payment Registered Loyalty points registered Loyalty points calculated Upgrade limits

    reached Account upgraded to higher status Register loyalty points @mariuszgil

55. Payment Registered Loyalty points registered Loyalty points calculated Upgrade limits

    reached Account Status upgraded Register loyalty points Upgrade account status @mariuszgil

56. Payment Registered Loyalty points registered Loyalty points calculated Upgrade limits

    reached Account Status upgraded Register loyalty points Upgrade account status required points Levels Account upgrading policy @mariuszgil

57. Payment Registered Loyalty points registered Loyalty points calculated Upgrade limits

    reached Account Status upgraded Register loyalty points Upgrade account status required points Levels Account upgrading policy Reservations and payments history c.service @mariuszgil

58. Payment Registered Loyalty points calculated Upgrade limits reached Account Status

    upgraded Upgrade account status required points Levels Account upgrading policy Loyalty account Loyalty points registered Register loyalty points Reservations and payments history c.service @mariuszgil

59. Payment Registered Loyalty points calculated Upgrade limits reached Account Status

    upgraded Upgrade account status required points Levels Account upgrading policy Loyalty account Loyalty points registered Register loyalty points Reservations and payments history c.service @mariuszgil

60. Outcomes @mariuszgil

61. Possible implementation Solution @mariuszgil There are many of them!!!!!!

62. business domain logic application logic infrastructure

63. business logic application logic infrastructure

64. business logic application logic infrastructure aggregate Event publishing command domain

    event

65. @Entity // Mark this aggregate as a JPA Entity public

    class MyAggregate { @Id private String id; // fields containing state... @CommandHandler public MyAggregate(CreateMyAggregateCommand command) { // ... update state apply(new MyAggregateCreatedEvent(...)); } // constructor needed by JPA protected MyAggregate() { } } Event Command / Decision

66. domain event domain event business logic application logic infrastructure domain

    event aggregate domain event event sourcing

67. public class MyAggregateRoot { @AggregateIdentifier private String aggregateIdentifier; // fields

    containing state... @CommandHandler public MyAggregateRoot(CreateMyAggregate cmd) { apply(new MyAggregateCreatedEvent(cmd.getId())); } // constructor needed for reconstruction protected MyAggregateRoot() { } @EventSourcingHandler private void handleMyAggregateCreatedEvent(MyAggregateCreatedEvent event) { // make sure identifier is always initialized properly this.aggregateIdentifier = event.getMyAggregateIdentifier(); // ... update state } } Aggregate

68. domain event domain event domain event domain event business logic

    application logic infrastructure domain event domain event command domain event policy process managers

69. business logic application logic infrastructure domain event command saga domain

    event command domain event Compensate command policy policy

70. public class OrderManagementSaga { private boolean paid = false; private

    boolean delivered = false; @Inject private transient CommandGateway commandGateway; @StartSaga @SagaEventHandler(associationProperty = "orderId") public void handle(OrderCreatedEvent event) { // client generated identifiers ShippingId shipmentId = createShipmentId(); InvoiceId invoiceId = createInvoiceId(); // associate the Saga with these values, before sending the commands SagaLifecycle.associateWith("shipmentId", shipmentId); SagaLifecycle.associateWith("invoiceId", invoiceId); // send the commands commandGateway.send(new PrepareShippingCommand(...)); commandGateway.send(new CreateInvoiceCommand(...)); } @SagaEventHandler(associationProperty = "shipmentId") public void handle(ShippingArrivedEvent event) { delivered = true; if (paid) { SagaLifecycle.end(); } } @SagaEventHandler(associationProperty = "invoiceId") public void handle(InvoicePaidEvent event) { paid = true; if (delivered) { SagaLifecycle.end(); } } // ... } Reactive Policy

71. read model business logic application logic infrastructure read models domain

    event domain event domain event domain event read model read model read model

72. business logic application logic infrastructure

73. business logic application logic infrastructure

74. business logic application logic infrastructure BUS Event

75. Event Command / Decision Event Event Aggregate

76. public class MyCommandComponentTest { private FixtureConfiguration<MyAggregate> fixture; @Before public void

    setUp() { fixture = new AggregateTestFixture<>(MyAggregate.class); } @Test public void testFirstFixture() { fixture.given(new MyEvent(1)) .when(new TestCommand()) .expectSuccessfulHandlerExecution() .expectEvents(new MyEvent(2)); /* } } Event Command / Decision Event Event Aggregate Given When Then

77. Command / Decision Read model Event Event Given When Then

78. Event Command / Decision Aggregate Read model Given When Then

    Event

79. DDD is not for you? @mariuszgil

80. Event Command / Decision Aggregate Read model Reactive Policy

81. Event Command / Decision Aggregate Read model Reactive Policy Record

    Inserted / Changed / Deleted Insert / Update / Delete / Truncate / … Record / Table Select / View Trigger / Procedure

82. Takeaways @mariuszgil

83. Big Picture Events Processes & Flows Hot Spots Systems Boundaries

    People @mariuszgil

84. Process Modeling Commands Policies Read Models Value Propositions Personas Metrics

    & Alerts @mariuszgil

85. Software Design Aggregates Policies Reactive Logic Read Models @mariuszgil

86. Communication! @mariuszgil

87. Building common understanding @mariuszgil

88. From production session

89. From production session

90. From alberto bandolino workshop

91. From production session

92. Software development is learning process Working code is a side

    effect Alberto Brandolini @mariuszgil
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94. What’s next? @mariuszgil

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98. THANK YOU! @mariuszgil