Event sourcing (laracon online)

Transcript

1. Getting started with
   event sourcing in Laravel
   

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2. About me
   Freek Van der Herten
   Partner & developer at Spatie
   @freekmurze
   https://murze.be
   https://ohdear.app
   

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3. Spatie
   Since 2003
   Websites, applications and webshops
   Team
   9 awesome human beings
   Specialisation
   Laravel, front-end development
   

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4. Open Source 

   Software
   

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5. We create a lot of it
   ± 200 packages on Packagist
   ± 2,000,000 downloads a month
   ± 25,000,000 total downloads
   All Postcardware!
   

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6. Highlights
   Popular
   laravel-backup
   laravel-medialibrary
   laravel-permission
   New
   laravel-query-builder
   laravel-blade-x
   

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7. https://spatie.be/open-source
   

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8. https://spatie.be/open-source/postcards
   

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9. Let's talk about
   event sourcing
   

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10. Talk overview
    Projecting events in short
    Laravel Event Projector demo
    Eventsauce demo
    

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11. Event Sourcing
    in short
    

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12. Traditional application
    Write data in database
    An update means overwriting the old data
    The old data cannot be accessed anymore
    

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13. APPLICATION
    DATABASE
    TABLE
    value X
    

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14. APPLICATION
    DATABASE
    TABLE
    value X
    value Y
    

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15. Event Sourced Application
    The application will fire off events
    Events will get written in a dedicated store
    Events are passed to consumers that create projections
    Aggregate, Aggregate Root...
    

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16. APP EVENTS
    Event
    Event 1
    

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17. APP EVENTS
    Event
    Event 1
    Event 2
    

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18. APP EVENTS
    Event
    Event 1
    Event 2
    Event 3
    

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19. APP
    CONSUMER
    EVENTS
    PROJECTION
    Event
    Event 1
    Event 2
    Event 3
    

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20. APP
    CONSUMER
    CONSUMER 2
    EVENTS
    PROJECTION
    Event
    Event 1
    Event 2
    Event 3
    ANOTHER PROJECTION
    

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21. APP
    CONSUMER
    CONSUMER 2
    EVENTS
    PROJECTION
    Event
    Event 1
    Event 2
    Event 3
    ANOTHER PROJECTION
    

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22. APP
    CONSUMER
    CONSUMER 2
    EVENTS
    PROJECTION
    Event
    Event 1
    Event 2
    Event 3
    Event 4
    ANOTHER PROJECTION
    

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23. Event Sourced Application
    Auditing requirements
    Extra reports needed
    Recording the unhappy path
    There is some setup required
    

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24. Laravel 

    Event Projector
    

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25. Laravel Event Projector
    Package made by Spatie
    It's not full event sourcing, it focuses on projections
    Beautifully integrated into Laravel
    Easy to get started with
    

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26. https://docs.spatie.be/laravel-event-projector
    

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27. Demo
    

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28. Eventsauce
    

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29. Eventsauce
    Package made by Frank De Jonge
    Focuses on aggregates
    Framework agnostic
    Separate Laravel bindings package available
    Very powerful, adds complexity
    

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30. https://eventsauce.io/docs/
    

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31. APP
    Subtract $1000
    

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32. AGGREGATE ROOT REPOSITORY
    UUID PAYLOAD TIME
    APP
    Subtract $1000
    

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33. AGGREGATE ROOT REPOSITORY
    UUID PAYLOAD TIME
    APP
    Subtract $1000
    RETRIEVE
    Subtract $1000
    AGGREGATE ROOT
    (empty)
    

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34. AGGREGATE ROOT REPOSITORY
    UUID PAYLOAD TIME
    APP
    Subtract $1000
    RETRIEVE
    PERSIST
    Subtract $1000
    AGGREGATE ROOT
    ACCOUNTS
    CONSUMER
    -$1000
    ABC-123 Subtract 1000 11:12 AM
    (empty)
    

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35. AGGREGATE ROOT REPOSITORY
    UUID PAYLOAD TIME
    APP
    RETRIEVE
    PERSIST
    Subtract $750
    AGGREGATE ROOT
    ACCOUNTS
    -$1000
    CONSUMER
    ABC-123 Subtract 1000 11:12 AM
    Subtract $750
    Subtract $1000
    

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36. AGGREGATE ROOT REPOSITORY
    UUID PAYLOAD TIME
    APP
    RETRIEVE
    PERSIST
    Subtract $750
    AGGREGATE ROOT
    ACCOUNTS
    -$1750
    CONSUMER
    ABC-123 Subtract 1000 11:12 AM
    Subtract $750
    Subtract $1000
    ABC-124 Subtract 750 01:17 PM
    

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37. AGGREGATE ROOT REPOSITORY
    UUID PAYLOAD TIME
    APP
    RETRIEVE
    PERSIST
    AGGREGATE ROOT
    ACCOUNTS
    -$1750
    CONSUMER
    ABC-123 Subtract 1000 11:12 AM
    ABC-124 Subtract 750 01:17 PM
    Subtract $1250
    Subtract $1000
    Subtract $750
    Subtract $1250
    Propose loan
    

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38. AGGREGATE ROOT REPOSITORY
    ABC-123 Subtract 1000 11:12 AM
    ABC-124 Subtract 750 01:17 PM
    ABC-125 Subtract 1250, Propose loan 05:51 PM
    UUID PAYLOAD TIME
    ACCOUNTS
    APP
    CONSUMER
    CONSUMER 2
    PROPOSED LOANS
    Subtract $1250
    -$3000
    RETRIEVE
    PERSIST
    Subtract $1000
    Subtract $750
    Subtract $1250
    Propose loan
    AGGREGATE ROOT
    

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39. Demo
    

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40. In closing
    

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41. Summary
    Laravel Event Projector
    Easy to use package to get started with projections
    Hooks into Laravel's native events
    Replay capabilities
    No aggregates
    

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42. Summary
    EventSauce
    Framework agnostic
    Support for aggregates, process modelling
    No replay capabilities out of the box
    https://github.com/spatie/laravel-eventsauce
    

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43. Writes are harder, reads are easier
    

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44. Event sourcing makes the easy things harder…
    …and the harder things easier
    — Frank De Jonge
    

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45. Larabank
    https://github.com/spatie/larabank-traditional
    https://github.com/spatie/larabank-event-projector
    https://github.com/spatie/larabank-eventsauce
    

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46. Resources
    https://kickstarter.engineering/event-sourcing-made-simple-4a2625113224
    https://github.com/spatie/laravel-event-projector
    https://github.com/eventsaucephp/eventsauce
    https://github.com/prooph
    

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47. Thank you!
    https://speakerdeck.com/freekmurze/event-sourcing-laracon-online
    https://spatie.be/open-source
    https://murze.be
    https://ohdear.app
    https://fullstackeurope.com
    

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