Event sourcing using Laravel

Who am I?

Damiano Petrungaro

Italy

source: www.vidiani.com

Tivoli (RM)

Tivoli (RM)

source: www.romaest.org

Tivoli (RM)

Tivoli (RM)

Tivoli (RM)

Me everyday:

Event sourcing

Capture all changes to an application state as a sequence of events.

CQRS

It's a pattern that I first heard described by Greg Young.
At its heart is the notion that you can use a different model to update information than the model you use to read information.
 

command query responsibility segregation

Command
vs
Query

Events

It's an immutable object used to represent something important that occurred in the domain.

Events

let's code

Domain model

It's a mutable object with an identity, it can be represented in different ways.

 

It's comparable to other entities by its ID.

Aggregate root

A DDD aggregate is a cluster of domain objects that can be treated as a single unit.
An example may be an order and its line-items, these will be separate objects, but it's useful to treat the order (together with its line items) as a single aggregate.

aka: write model

Value Object

It's an immutable object representing a value in a domain.
 

It's comparable to other value objects by its own values.

Domain Model

let's code

Command

It's a write operation!

Command

let's code

Extra: Repository

It's an abstraction layer to provide access to all the entities and the value objects related to an aggregate.

Extra: Repository

let's code

Read Model

A read model is a model specialized for reads, that is, queries.
It takes events produced by the domain and uses them to build and maintain a model that is suitable for answering the client's queries.
It can draw on events from different aggregates and even different types of aggregate.

Projection

Projection is a specialized representation of the state derivated from of our system

Read Model

&
Projector

let's code

Discussions & Questions

101

Let's do some homework

Event sourcing using Laravel

By Damiano Petrungaro

Event sourcing using Laravel

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