Event sourcing (laracon online)

Transcript

1. Getting started with event sourcing in Laravel

2. About me Freek Van der Herten Partner & developer at

   Spatie @freekmurze https://murze.be https://ohdear.app

3. Spatie Since 2003 Websites, applications and webshops Team 9 awesome

   human beings Specialisation Laravel, front-end development

4. Open Source 
 Software

5. We create a lot of it ± 200 packages on

   Packagist ± 2,000,000 downloads a month ± 25,000,000 total downloads All Postcardware!

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

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

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

9. Let's talk about event sourcing

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

    Eventsauce demo

11. Event Sourcing in short

12. Traditional application Write data in database An update means overwriting

    the old data The old data cannot be accessed anymore

13. APPLICATION DATABASE TABLE value X

14. APPLICATION DATABASE TABLE value X value Y

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...

16. APP EVENTS Event Event 1

17. APP EVENTS Event Event 1 Event 2

18. APP EVENTS Event Event 1 Event 2 Event 3

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

    3

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

    2 Event 3 ANOTHER PROJECTION

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

    2 Event 3 ANOTHER PROJECTION

22. APP CONSUMER CONSUMER 2 EVENTS PROJECTION Event Event 1 Event

    2 Event 3 Event 4 ANOTHER PROJECTION

23. Event Sourced Application Auditing requirements Extra reports needed Recording the

    unhappy path There is some setup required

24. Laravel 
 Event Projector

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

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

27. Demo

28. Eventsauce

29. Eventsauce Package made by Frank De Jonge Focuses on aggregates

    Framework agnostic Separate Laravel bindings package available Very powerful, adds complexity

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

31. APP Subtract $1000

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

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

    Subtract $1000 AGGREGATE ROOT (empty)

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)

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

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

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

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

39. Demo

40. In closing

41. Summary Laravel Event Projector Easy to use package to get

    started with projections Hooks into Laravel's native events Replay capabilities No aggregates

42. Summary EventSauce Framework agnostic Support for aggregates, process modelling No

    replay capabilities out of the box https://github.com/spatie/laravel-eventsauce

43. Writes are harder, reads are easier

44. Event sourcing makes the easy things harder… …and the harder

    things easier — Frank De Jonge

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

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

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