Event sourcing in Laravel (full stack brussels)

Transcript

1. Getting started with
   event sourcing in Laravel
   

   View Slide

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

   View Slide

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

   View Slide

4. Open Source 

   Software
   

   View Slide

5. We create a lot of it
   ± 200 packages on Packagist
   ± 2,000,000 downloads a month
   ± 30,000,000 total downloads
   All Postcardware!
   

   View Slide

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

   View Slide

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

   View Slide

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

   View Slide

9. Let's talk about
   event sourcing
   

   View Slide

10. Talk overview
    Theory
    Laravel Event Projector demo
    Eventsauce demo
    

    View Slide

11. Theory
    

    View Slide

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

    View Slide

13. APPLICATION
    DATABASE
    TABLE
    value X
    

    View Slide

14. APPLICATION
    DATABASE
    TABLE
    value X
    value Y
    

    View Slide

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...
    

    View Slide

16. APP EVENTS
    Event
    Event 1
    

    View Slide

17. APP EVENTS
    Event
    Event 1
    Event 2
    

    View Slide

18. APP EVENTS
    Event
    Event 1
    Event 2
    Event 3
    

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

24. Laravel 

    Event Projector
    

    View Slide

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
    

    View Slide

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

    View Slide

27. Demo
    

    View Slide

28. Eventsauce
    

    View Slide

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

    View Slide

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

    View Slide

31. APP
    Subtract $1000
    

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

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

    View Slide

38. AGGREGATE ROOT REPOSITORY
    ABC-123 Subtract 1000 11:12 AM
    ABC-124 Subtract 750 01:17 PM
    ABC-125 Subtract 1250 05:51 PM
    ABC-126 More Money Needed 05:51 PM
    UUID PAYLOAD TIME
    ACCOUNTS
    APP
    CONSUMER
    CONSUMER 2
    PROPOSED LOANS
    Subtract $1250
    -$3000
    RETRIEVE
    PERSIST
    Subtract $1000
    Subtract $750
    Subtract $1250
    More Money Needed
    AGGREGATE ROOT
    

    View Slide

39. Demo
    

    View Slide

40. In closing
    

    View Slide

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

    View Slide

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

    View Slide

43. Writes are harder, reads are easier
    

    View Slide

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

    View Slide

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

    View Slide

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
    

    View Slide

47. Thank you!
    https://speakerdeck.com/freekmurze/event-sourcing-full-stack-brussels
    https://spatie.be/open-source
    https://murze.be
    https://ohdear.app
    

    View Slide