CQRS and Event Sourcing with PHP
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The document discusses Command Query Responsibility Segregation (CQRS) and Event Sourcing, clarifying common misconceptions and outlining their benefits and drawbacks. CQRS involves separating the models for reading and writing, allowing for independent scaling and multiple read models. Event Sourcing offers advantages like reliable audit logs and temporal queries but presents challenges such as a steep learning curve and complex schema changes.
CQRS and Event Sourcing with PHP
- 1. CQRS and Event Sourcing with PHP
- 3. Before we start ● Who knows what CQRS is? ● Who did already use CQRS in production? ● Who knows what Event Sourcing is? ● Who did already use Event Sourcing in production?
- 4. What CQRS is not? ● CQRS is not an architecture ● CQRS is not eventual consistency ● CQRS is not messaging ● CQRS is not eventing ● CQRS is not event sourcing ● CQRS is not CQS ● CQRS is not new ● CQRS is not hard to implement ● CQRS is not having separated models for reading and writing **
- 5. What is CQRS? ● Command and Query Responsibility Segregation ● It is essentially the creation of two objects where there was previously only one **
- 6. Before
- 7. After
- 8. Or...
- 9. ● Implement Event Sourcing CQRS makes it easier to... ● Implement task based UIs ● Scale the read and write models independently ● Have multiple read models (which helps reducing coupling)
- 10. ● Tactician Some libraries for CQRS ● SimpleBus ● Broadway ● Prooph ● Symfony Messenger
- 11. ● State is built from the events ● No state is stored, only events But what about Event Sourcing?
- 12. But what about Event Sourcing? Picture from: https://www.confluent.io
- 13. Event Sourcing benefits ● It is possible to create data-views specialized for certain cases ● It enables a 100% reliable audit log of the changes made to a business entity ● It decouples the representation of current state in the domain from the storage ● It facilitates the migration from monolithic applications into smaller pieces ● It enables temporal queries that determine the state of an entity at any point in time
- 14. Event Sourcing drawbacks ● It is a different and unfamiliar style of programming and so there is a learning curve ● You’ll also probably have to introduce a little more infrastructure to get up and running ● Not so simple onboarding of new team members ● Handling schema changes is not so simple as the events are immutable ● To handle entities with long and complex lifespans requires some “snapshot” strategy
- 23. What about Projections? Picture from: https://goo.gl/btBWH1
- 26. Some libraries for Event Sourcing ● Broadway ● Prooph ● EventSauce
- 27. Any questions?