Event sourcing in Laravel (full stack brussels)

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 ± 30,000,000 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 Theory Laravel Event Projector demo Eventsauce demo
11. Theory
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 ABC-123 Subtract 1000 11:12 AM UUID PAYLOAD TIME APP Subtract $1000 RETRIEVE Subtract $1000 AGGREGATE ROOT ACCOUNTS CONSUMER -$1000 (empty) PERSIST
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
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
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
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
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-full-stack-brussels https://spatie.be/open-source https://murze.be https://ohdear.app