Rethinking Reactive Architectures

NDC Oslo 2021
Video: https://youtu.be/L1Zgfr6bFvA

Transcript

1. Rethinking Reactive
   Architectures
   @duffleit
   NCD London
   

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2. David Leitner
   @duffleit
   Coding Architect
   ✉ david@squer.at
   🐥 @duffleit
   

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3. Reactivity
   @duffleit
   and many more.
   “ Programming with, or designing upon,
   asynchronous data streams.
   

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4. It's about
   Streams.
   @duffleit
   

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5. @duffleit
   

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6. “ streams are just another data structure.
   @duffleit
   Time
   Space
   Value
   Getter Setter
   Collections
   Iterators Generators
   Promise
   Deferred Resolver
   Stream
   Subscriber Emitter
   

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7. “ streams are just another data structure.
   @duffleit
   

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8. @duffleit
   What has this to do
   with reactivity?
   🤔
   “ Programming with, or designing upon,
   asynchronous data streams.
   

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9. @duffleit
   var counter = 2;
   var doubled = counter * 2;
   1
   2
   

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10. @duffleit
    var counter = 2;
    var doubled = counter * 2;
    assert(doubled, 4);
    1
    2
    3
    4
    ✅
    

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11. @duffleit
    var counter = 2;
    var doubled = counter * 2;
    // updating the counter
    counter = 3;
    1
    2
    3
    4
    5
    

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12. @duffleit
    var counter = 2;
    var doubled = counter * 2;
    // updating the counter
    counter = 3;
    assert(doubled, 6)
    1
    2
    3
    4
    5
    6
    7
    💔
    

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13. @duffleit
    var counter = 2;
    var doubled = counter * 2;
    // updating the counter
    counter = 3;
    doubled = counter * 2;
    1
    2
    3
    4
    5
    6
    

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14. @duffleit
    var counter = 2;
    var doubled = counter * 2;
    // updating the counter
    counter = 3;
    doubled = counter * 2;
    assert(doubled, 6)
    1
    2
    3
    4
    5
    6
    7
    8
    

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15. @duffleit
    var counter = 2;
    var doubled = counter * 2;
    // updating the counter
    counter = 3;
    doubled = counter * 2;
    assert(doubled, 6)
    1
    2
    3
    4
    5
    6
    7
    8
    ✅
    doubled
    🔗
    counter
    paulstovell.com/reactive-programming/
    

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16. @duffleit
    var counter = 2;
    var doubled <= counter * 2;
    1
    2
    doubled
    🔗
    counter
    👆
    

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17. @duffleit
    var counter = 2;
    var doubled <= counter * 2;
    // updating the counter
    counter = 3;
    1
    2
    3
    4
    5
    doubled
    🔗
    counter
    

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18. @duffleit
    var counter = 2;
    var doubled <= counter * 2;
    // updating the counter
    counter = 3;
    assert(doubled, 6)
    1
    2
    3
    4
    5
    6
    7
    doubled
    🔗
    counter
    ✅
    

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19. @duffleit
    var counter = stream(2);
    1
    🔗
    = streams
    👈 counter: [2]
    

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20. @duffleit
    var counter = stream(2);
    var doubled = counter.map(x -> x * 2)
    1
    2
    👈 counter: [2]
    

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21. @duffleit
    var counter = stream(2);
    var doubled = counter.map(x -> x * 2)
    1
    2
    🔗
    = streams
    👆
    counter: [2]
    

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22. @duffleit
    var counter = stream(2);
    var doubled = counter.map(x -> x * 2)
    1
    2 👆
    counter: [2]
    doubled: [4]
    

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23. @duffleit
    var counter = stream(2);
    var doubled = counter.map(x -> x * 2)
    1
    2
    “ we project the data from our counter stream into
    our doubled stream.
    👆
    counter: [2]
    doubled: [4]
    

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24. @duffleit
    var counter = stream(2);
    var doubled = counter.map(x -> x * 2)
    // updating the counter
    1
    2
    3
    4
    👈
    counter: [2]
    doubled: [4]
    

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25. @duffleit
    var counter = stream(2);
    var doubled = counter.map(x -> x * 2)
    // updating the counter
    counter.emit(3);
    1
    2
    3
    4
    5
    👈
    counter: [2]
    doubled: [4]
    

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26. @duffleit
    var counter = stream(2);
    var doubled = counter.map(x -> x * 2)
    // updating the counter
    counter.emit(3);
    1
    2
    3
    4
    5
    counter: [2, 3]
    doubled: [4]
    👈
    

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27. @duffleit
    var counter = stream(2);
    var doubled = counter.map(x -> x * 2)
    // updating the counter
    counter.emit(3);
    1
    2
    3
    4
    5
    counter: [2, 3]
    doubled: [4, 6]
    👈
    

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28. @duffleit
    var counter = stream(2);
    var doubled = counter.map(x -> x * 2)
    // updating the counter
    counter.emit(3);
    assert(doubled.value, 6)
    1
    2
    3
    4
    5
    6
    7
    👈
    counter: [2, 3]
    doubled: [4, 6]
    ✅
    

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29. @duffleit
    

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30. @duffleit
    var counter = new BehaviorSubject(2);
    1
    👈
    

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31. @duffleit
    var counter = new BehaviorSubject(2);
    var doubled = counter.pipe(map(x -> x * 2));
    1
    2
    👈
    

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32. @duffleit
    var counter = new BehaviorSubject(2);
    var doubled = counter.pipe(map(x -> x * 2));
    // updating the counter
    counter.emit(3);
    1
    2
    3
    4
    5
    👈
    

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33. @duffleit
    var counter = new BehaviorSubject(2);
    var doubled = counter.pipe(map(x -> x * 2));
    // updating the counter
    counter.emit(3);
    assert(doubled.value, 6);
    1
    2
    3
    4
    5
    6
    7
    👈 ✅
    

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34. @duffleit
    

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35. @duffleit
    var counter = 2;
    1
    👈
    

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36. @duffleit
    var counter = 2;
    $: doubled = counter * 2;
    1
    2
    👈
    

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37. @duffleit
    var counter = 2;
    $: doubled = counter * 2;
    1
    2
    👈
    

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38. @duffleit
    var counter = 2;
    $: doubled = counter * 2;
    // updating the counter
    counter = 3;
    1
    2
    3
    4
    5
    👈
    

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39. @duffleit
    var counter = 2;
    $: doubled = counter * 2;
    // updating the counter
    counter = 3;
    assert(doubled, 6);
    1
    2
    3
    4
    5
    6
    7
    👈 ✅
    

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40. “ Programming with,
    or designing upon,
    asynchronous data
    streams.
    @duffleit
    

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41. @duffleit
    We can apply those
    Concepts of Reactive Programming
    on Architecture as well.
    * and hope they still make sense.
    

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42. @duffleit
    User
    
    Account
    
    Legder
    
    WebBanking
    New Payment
    💸
    Perform Payment
    € 20, 00
    👧
    Lisa
    to
    David
    from
    transferMoney
    triggerPayment
    createTransactions
    

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43. @duffleit
    User
    
    Account
    
    Legder
    
    WebBanking
    Your payment was
    successfully executed.
    transferMoney
    triggerPayment
    createTransactions
    ✅
    

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44. @duffleit
    User
    
    Account
    
    Legder
    
    WebBanking
    New Payment
    💸
    Perform Payment
    € 20, 00
    👧
    Lisa
    to
    David
    from
    transferMoney
    triggerPayment
    createTransactions
    Legder
    Legder
    
    

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45. @duffleit
    User
    
    Account
    
    Legder
    
    WebBanking
    Your payment was
    successfully executed.
    transferMoney
    triggerPayment
    createTransactions
    ✅
    Retries
    Timeouts
    Circuit Breakers
    Synchronise
    

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46. First Generation of MicroServices
    Synchronously Integrated
    @duffleit
    

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47. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    
    Legder
    

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48. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    
    Legder
    

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49. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Queue
    
    Legder
    

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50. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Queue
    
    Legder
    

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51. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Queue
    
    Legder
    

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52. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Queue
    
    Legder
    

    View Slide

53. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Queue
    
    Legder
    

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54. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions Queue
    
    Legder
    Your payment was
    accepted.
    ✅
    

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55. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions Queue
    
    Legder
    Your payment was
    accepted.
    ✅
    Legder
    
    

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56. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions Queue
    
    Legder
    Your payment was
    accepted.
    ✅
    Legder
    
    

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57. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions Queue
    
    Legder
    Your payment was
    accepted.
    ✅
    Legder
    
    Queue
    

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58. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions Queue
    
    Legder
    Your payment was
    accepted.
    ✅
    Legder
    
    Queue
    Queue
    

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59. Second Generation of MicroServices
    Asynchronously Integrated
    @duffleit
    

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60. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Legder
    
    Queue
    Queue
    Queue
    

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61. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Legder
    
    Queue
    Queue
    Queue
    As a Customer, I want my
    transaction to be booked
    by the ledger.
    

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62. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Legder
    
    Queue
    Queue
    Queue
    As a Customer, I want the
    account service to update
    my balance.
    

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63. @duffleit
    User
    
    Account
    
    WebBanking
    transferMoney
    triggerPayment
    createTransactions
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Legder
    
    Queue
    Queue
    Queue
    As a Customer, I want
    to transfer money to
    someone else.
    

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64. The Entity Service
    Antipattern.
    @duffleit
    

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65. Let's create Services along
    Customer Journeys.
    @duffleit
    

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66. @duffleit
    “ On the Criteria To Be Used in
    Decomposing Systems into Modules
    — Parnas, 1972
    

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67. Let's create Services along
    Customer Journeys.
    @duffleit
    

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68. @duffleit
    User
    
    Account
    
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Legder
    
    Payments
    
    Domain Services
    Journey Services
    As a Customer, I want
    to transfer money to
    someone else.
    

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69. @duffleit
    User
    
    Account
    
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Legder
    
    Web-BFF
    
    Domain Services
    Backend For Frontends
    As a Customer, I want
    to transfer money to
    someone else.
    Mobile-BFF
    
    Mobile Banking
    € 20, 00
    Pay
    Payment Flow
    Payment Flow
    

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70. @duffleit
    No Domain Logic in
    Backend For Frontends.
    It's about Ui-Specific Aggregation, to get rid
    of over-fetching and over-requesting.
    

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71. @duffleit
    Ok, but back to the problem
    with our Customer Journeys.
    

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72. @duffleit
    User
    
    Account
    
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Legder
    
    Payments
    
    Domain Services
    Journey Services
    

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73. @duffleit
    User
    
    Account
    
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Legder
    
    Payments
    
    Domain Services
    Journey Services
    Balance
    
    

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74. @duffleit
    ⚡
    Customer Journey and Entity Data
    Mismatch Problem
    

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75. @duffleit
    Users Accounts Transactions
    Entities
    Customer Journeys
    Payments
    Onboarding
    Fraud Detection
    ⚡
    

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76. @duffleit
    User Account
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Transactions
    Payments
    Domain Services
    Journey Services
    Onboarding Fraud Detection
    User Account
    Account Transactions
    

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77. @duffleit
    User Account
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Transactions
    Payments
    Domain Services
    Journey Services
    Onboarding Fraud Detection
    User Account
    Account Transactions
    ⚡
    ⚡ ⚡
    

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78. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User Account
    Account Transactions
    User
    Account
    Transactions
    Service Autnomy
    

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79. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User Account
    Account Transactions
    User
    Account
    Transactions
    Data Duplication
    ⚡
    

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80. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User Account
    Account Transactions
    User
    Account
    Transactions
    Data Syncronisation
    🤯
    ⚡
    

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81. @duffleit
    clarify who owns which Data.
    Always
    

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82. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User Account
    Account Transactions
    User
    Account
    Transactions
    

    View Slide

83. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Synchronous Calls
    😔
    

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84. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Synchronous Calls
    😔
    

    View Slide

85. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User Cache
    Account
    Transactions
    Synchronous Calls
    😔
    

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86. @duffleit
    “ we project data from our counter variable into our
    doubled variable.
    There must be a better solution
    🤔
    

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87. @duffleit
    “ we project the data from our onboarding service
    into our payments service.
    There must be a better solution
    🤔
    Payments
    User
    Onboarding
    User
    project
    

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88. @duffleit
    Payments
    Onboarding
    User Aggregate User Readmodel
    UserChangedEvent
    UserChange
    Command
    That's CQRS in a nutshell
    🥜
    updates
    

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89. @duffleit
    Payments
    Onboarding
    User Aggregate User Readmodel
    UserChangedEvent
    UserChange
    Command
    Stream
    

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90. @duffleit
    Payments
    Onboarding
    User Aggregate User Readmodel
    UserChange
    Command
    Stream
    UserChangedEvent
    transform
    apply
    

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91. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Stream
    

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92. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Stream
    

    View Slide

93. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Stream
    

    View Slide

94. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Stream
    

    View Slide

95. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Stream
    Projections
    

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96. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Stream
    Projections
    

    View Slide

97. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Stream
    Projections
    

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98. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Stream
    Projections
    

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99. @duffleit
    WebBanking
    New Payment
    💸
    € 20, 00
    👧
    Lisa
    to
    David
    from
    Perform Payment
    Payments
    Journey Services
    Onboarding Fraud Detection
    User
    Account
    Account
    Transactions
    User
    Account
    Transactions
    Stream
    

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100. @duffleit
     WebBanking
     New Payment
     💸
     € 20, 00
     👧
     Lisa
     to
     David
     from
     Perform Payment
     Payments
     Journey Services
     Onboarding Fraud Detection
     User
     Account
     Account
     Transactions
     User
     Account
     Transactions
     Stream
     Projections
     

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101. @duffleit
     But bro, didn't we just introduce
     Eventual Consistency?
     

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102. @duffleit
     Eventual Consistency
     Eventual Divergence
     Dashboard
     User (age: 22)
     UserChanged (age: 21)
     UserChanged (age: 22)
     Profile
     User (age: 21)
     ⚡
     timestamp
     timestamp
     

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103. @duffleit
     Eventual Consistency
     Eventual Divergence
     Eventual Variance
     Ledger
     Stream
     Transaction (+10€)
     🔥
     

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104. @duffleit
     Eventual Consistency
     Eventual Divergence
     Eventual Variance
     Ledger
     Dashboard
     Stream
     🔥 Transaction (+10€) Transaction (+10€)
     Balance: 20€
     

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105. @duffleit
     Eventual Consistency
     Eventual Divergence
     Eventual Variance
     Eventual Latency
     Service B
     Stream
     UserChanged (age: 21) UserChanged (age: 22)
     Profile
     User (age: 21)
     Dashboard
     User (age: 21)
     User (age: 22)
     

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106. Single User Context
     @duffleit
     Eventual Consistency
     Eventual Divergence
     Eventual Variance
     Eventual Latency
     Service B
     Stream
     UserChanged (age: 21) UserChanged (age: 22)
     Profile
     User (age: 21)
     Dashboard
     User (age: 21)
     User (age: 22)
     🕰
     

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107. @duffleit
     Eventual Consistency
     Eventual Divergence
     Eventual Variance
     Eventual Latency
     same events, different results.
     same events, different quantity.
     same events, different realisation.
     Ordering Guarantees
     Optimistic UIs
     At-Least-Once
     Delivery
     Deduplication
     Mechanisms
     

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108. @duffleit
     tl/dr:
     Eventual Consistency is
     often used as a
     knock-out argument
     but isn't, in most cases.
     

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109. @duffleit
     WebBanking
     New Payment
     💸
     € 20, 00
     👧
     Lisa
     to
     David
     from
     Perform Payment
     Payments
     Journey Services
     Onboarding Fraud Detection
     User
     Account
     Account
     Transactions
     User
     Account
     Transactions
     Stream
     Projections
     

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110. @duffleit
     Mobile Banking Usage
     93% — Show balance & last transactions
     3% — Initiate new payment
     4% — Any other functionality
     

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111. @duffleit
     Payments
     Journey Services
     Onboarding Overview
     User
     Account
     Account
     Transactions
     User
     Account
     Transactions
     Stream
     

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112. @duffleit
     Payments
     Journey Services
     Onboarding Overview
     User
     Account
     Account
     Transactions
     User
     Account
     Transactions
     Stream
     

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113. @duffleit
     Payments
     Journey Services
     Onboarding Overview
     User
     Account
     Account
     Transactions
     User
     Account
     Transactions
     Stream
     

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114. @duffleit
     Payments
     Journey Services
     Onboarding Overview
     User
     Account
     Account
     Transactions
     User
     Account
     Transactions
     Stream
     

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115. @duffleit
     Payments
     Journey Services
     Onboarding Overview
     User
     Account
     Account
     Transactions
     User
     Account
     Transactions
     Stream
     

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116. @duffleit
     Payments
     Journey Services
     Onboarding Overview
     User
     Account
     Account
     Transactions
     User
     Account
     Transactions
     Stream
     93% of what our users need
     can still be performed.
     WebBanking
     Current Balance: 200€
     👧
     You sent Lisa 100€
     Christoph sent you 300€
     

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117. @duffleit
     WebBanking
     Current Balance: 200€
     👧
     You sent Lisa 100€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     Overview
     Transactions
     We can easily scale
     horizontally.
     

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118. @duffleit
     WebBanking
     Current Balance: 200€
     👧
     You sent Lisa 100€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     Overview
     Transactions
     We can easily scale
     horizontally.
     

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119. @duffleit
     WebBanking of David
     Current Balance: 300€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     WebBanking of Lisa
     👧
     New Payment
     💸
     € 20, 00 David
     to
     👧
     Lisa
     from
     Perform Payment
     

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120. @duffleit
     WebBanking of David
     Current Balance: 300€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     WebBanking of Lisa
     👧
     New Payment
     💸
     € 20, 00 David
     to
     👧
     Lisa
     from
     Perform Payment
     

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121. @duffleit
     WebBanking of David
     Current Balance: 300€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     WebBanking of Lisa
     👧
     New Payment
     💸
     € 20, 00 David
     to
     👧
     Lisa
     from
     Perform Payment
     

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122. @duffleit
     WebBanking of David
     Current Balance: 300€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     WebBanking of Lisa
     👧
     New Payment
     💸
     € 20, 00 David
     to
     👧
     Lisa
     from
     Perform Payment
     

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123. @duffleit
     WebBanking of David
     Current Balance: 300€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     WebBanking of Lisa
     👧
     New Payment
     💸
     € 20, 00 David
     to
     👧
     Lisa
     from
     Perform Payment
     

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124. @duffleit
     WebBanking of David
     Current Balance: 300€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     WebBanking of Lisa
     👧
     New Payment
     💸
     € 20, 00 David
     to
     👧
     Lisa
     from
     Perform Payment
     

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125. @duffleit
     WebBanking of David
     Current Balance: 300€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     WebBanking of Lisa
     👧
     New Payment
     💸
     € 20, 00 David
     to
     👧
     Lisa
     from
     Perform Payment
     

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126. @duffleit
     WebBanking of David
     Current Balance: 300€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     WebBanking of Lisa
     👧
     New Payment
     💸
     € 20, 00 David
     to
     👧
     Lisa
     from
     Perform Payment
     👧
     Lisa sent you 20€
     

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127. @duffleit
     WebBanking of David
     Current Balance: 320€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     WebBanking of Lisa
     👧
     New Payment
     💸
     € 20, 00 David
     to
     👧
     Lisa
     from
     Perform Payment
     👧
     Lisa sent you 20€
     

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128. @duffleit
     WebBanking of David
     Current Balance: 320€
     Christoph sent you 300€
     Payments
     Journey Services
     Onboarding Overview
     User Account
     Transactions
     User
     Account
     Transactions
     Stream
     WebBanking of Lisa
     👧
     New Payment
     💸
     € 20, 00 David
     to
     👧
     Lisa
     from
     Perform Payment
     👧
     Lisa sent you 20€
     GraphQL
     subscriptions
     mutations
     Out-of-the-box
     real-time
     capabilities.
     

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129. @duffleit
     WebBanking of David
     Current Balance: 320€
     Christoph sent you 300€
     Payments
     Journey Services
     Legacy System
     Accounts
     Stream
     👧
     Lisa sent you 20€
     User
     😮 💨😮 💨
     😮 💨
     Change Data
     Capture (CDC) User User
     

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130. Third Generation of MicroServices
     Fully Reactive
     @duffleit
     High Resilience
     🔥
     Horizontal Scaling ↔
     Real Time Integration
     ⏱
     Good Integration with Legacy Systems
     🏚
     

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131. Dimensions of Scaling
     @duffleit
     Vertical
     Horizontal
     Service
     

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132. Dimensions of Scaling
     @duffleit
     Vertical
     Horizontal
     Service
     

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133. Dimensions of Scaling
     Vertical
     Horizontal
     Service Service Service
     Sharding
     

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134. Dimensions of Scaling
     Vertical
     Horizontal
     Service
     Service
     Service
     Sharding
     Users A-H
     Users I-P
     Users Q-Z
     

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135. Dimensions of Scaling
     Vertical
     Horizontal
     Service
     Service
     Service
     User from
     User from
     Users from
     Service Service
     Service
     Sharding
     

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136. @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     

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137. @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     

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138. @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     Payments Payments Payments
     

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139. @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     Payments Payments Payments
     ValidPaymentReceived
     

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140. @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     Payments Payments Payments
     Stream
     ValidPaymentReceived
     Partition 0 Partition 1 Partition 2
     

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141. Fraud Detection Fraud Detection
     @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     Payments Payments Payments
     Stream
     ValidPaymentReceived
     Partition 0 Partition 1 Partition 2
     Fraud Detection
     PaymentCheckedAgainstFraud
     

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142. Fraud Detection Fraud Detection
     @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     Payments Payments Payments
     Stream
     ValidPaymentReceived
     Partition 0 Partition 1 Partition 2
     Fraud Detection
     Stream
     PaymentChecked
     Partition 0 Partition 1 Partition 2
     

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143. Fraud Detection Fraud Detection
     @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     Payments Payments Payments
     Stream
     ValidPaymentReceived
     Partition 0 Partition 1 Partition 2
     Fraud Detection
     Stream
     PaymentChecked
     Partition 0 Partition 1 Partition 2
     Ledger Ledger Ledger
     TransactionBooked
     

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144. Fraud Detection Fraud Detection
     @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     Payments Payments Payments
     Stream
     ValidPaymentReceived
     Partition 0 Partition 1 Partition 2
     Fraud Detection
     Stream
     PaymentChecked
     Partition 0 Partition 1 Partition 2
     Ledger Ledger Ledger
     Partition 0 Partition 1 Partition 2
     Stream
     TransactionBooked
     Project
     Transactions
     Streams
     Flink
     

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145. Fraud Detection Fraud Detection
     @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     Payments Payments Payments
     Stream
     ValidPaymentReceived
     Partition 0 Partition 1 Partition 2
     Fraud Detection
     Stream
     PaymentChecked
     Partition 0 Partition 1 Partition 2
     Ledger Ledger Ledger
     Partition 0 Partition 1 Partition 2
     Stream
     TransactionBooked
     Project
     Transactions
     Shard 0 Shard 1 Shard 2
     DataSink
     WebBanking
     Current Balance: 200€
     👧
     You sent Lisa 100€
     Christoph sent you 300€
     Streams
     Flink
     

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146. Fraud Detection Fraud Detection
     @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     Payments Payments Payments
     Stream
     ValidPaymentReceived
     Partition 0 Partition 1 Partition 2
     Fraud Detection
     Stream
     PaymentChecked
     Partition 0 Partition 1 Partition 2
     Ledger Ledger Ledger
     Partition 0 Partition 1 Partition 2
     Stream
     TransactionBooked
     Project
     Transactions
     WebBanking
     Current Balance: 200€
     👧
     You sent Lisa 100€
     Christoph sent you 300€
     Shard 0 Shard 1 Shard 2
     DataSink
     Streams
     Flink
     

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147. Fraud Detection Fraud Detection
     @duffleit
     Stream
     UserTriggeredPayment Partition 0 Partition 1 Partition 2
     UserTriggeredPayment
     Payments Payments Payments
     Stream
     ValidPaymentReceived
     Partition 0 Partition 1 Partition 2
     Fraud Detection
     Stream
     PaymentChecked
     Partition 0 Partition 1 Partition 2
     Ledger Ledger Ledger
     Partition 0 Partition 1 Partition 2
     Stream
     TransactionBooked
     Project
     Transactions
     WebBanking
     Current Balance: 200€
     👧
     You sent Lisa 100€
     Christoph sent you 300€
     Shard 0 Shard 1 Shard 2
     DataSink
     🚀 We can scale
     nearly unlimited.
     

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148. Forth Generation of MicroServices
     Stream Based
     @duffleit
     Massive Throughput
     🚀
     Extremely Scalable ↔
     

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149. So many choices,
     Lets sum up.
     @duffleit
     

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150. Monolith
     @duffleit
     

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151. Monolith
     @duffleit
     

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152. Syncronously
     😩 Pain
     @duffleit
     

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153. Modulith
     @duffleit
     

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154. Asyncronously
     📦 Shared Data
     @duffleit
     

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155. Reactive
     ⚡ From Pull to Push
     @duffleit
     

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156. Streaming Massiv Throughput
     🚀
     @duffleit
     

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157. Monolith Reactive
     Push-Based
     Async
     Pull-Based
     Streamed
     Availability
     🟢
     , Resilience
     🦺
     , Scalability ↔ , Throughput
     🚀
     Complexity
     💰
     @duffleit
     

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158. Monolith Reactive
     Push-Based
     Async
     Pull-Based
     Streamed
     @duffleit
     The Rise of Reactive Microservices.
     And the future of fully Stream Based Architectures.
     

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159. David Leitner
     @duffleit
     Coding Architect
     ✉ david@squer.at
     🐥 @duffleit
     

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160. squer.link /
     slicing-microservices
     

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