Simplifying EventSourcing SFUGCGN 2024-07-04

Introduction into EventSourcing in PHP using the library patchlevel/event-sourcing. This talk exlcudes the reading side since on the event this was a separate talk held afterwards which was called "Exploring Projections and Processors in Event Sourcing" https://speakerdeck.com/davidbadura/exploring-projections-and-processors-in-event-sourcing-ca496e88-ea39-4fa5-97f1-62f110001de6.

Library: https://github.com/patchlevel/event-sourcing
Docs: https://event-sourcing.patchlevel.io/latest/

Symfony-Bundle: https://github.com/patchlevel/event-sourcing-bundle
Docs: https://event-sourcing-bundle.patchlevel.io/latest/

This Talk was held at the Symfony UserGroup in Cologne organized by QOSSMIC on the 4th of July 2024.

Transcript

2. Daniel Badura Freelance Software Engineer @danielbadura daniel.badura@patchlevel.de
6. • Enables state recreation by replaying events • Provides historical data by design • Simplifies auditing • Facilitates new data views • Models system behavior with events, not states
9. Event Bus Basics
13. • Hotel Created • Guest Reserved Room • Guest Payed Reserved Room • Guest Checked In • Guest Checked Out
17. • A Pattern from Domain-Driven-Design • An Aggregate is a cluster of multiple Domain objects • An Aggregate Root can be composed of multiple Aggregates • Every access should go through the Aggregate Root
26. • Which Aggregate • When it happened • In which order it happened • And more information defined by the user
30. • Is responsible for saving message in database • Everything happens transactional • Shipped Store is based on Doctrine DBAL • Own implementation possible
35. Event Bus Advanced Topics Quick run
50. Event Bus Projections aka. reading side Next Talk