pounard / php-eventsourcing

Event sourcing PHP library

Event Sourcing

This library is for now an purely educational project.

Idea behind this project is not to make assomptions about the user own business but still provide a set of optional features to help domain-driven development.

It will not implement a complete domain-driven development API, lots of libraries already exist to implement every bits, such as Symfony's Messenger component for communication buses.

If you are looking for a stable, production-ready, and mature alternative, please look at https://github.com/prooph/ instead. It has a complete coverage for the domain-driven, CQRS and Event Sourcing based devleopment, with a very well performing, very stable, and very well documented set of libraries.

Status

It implements the following:

• complete and functionnal event store interface with store and query abilities,
• in-memory array-based event store implementation allowing test-driven development,
• https://github.com/pounard/goat database connector implementation fully working with PDO MySQL, PDO PgSQL and ext_pgsql drivers.

Status

For now, this is a purely educational project, but if it ends up being performant and well tested enough, it might be one day a full-fledged production-ready project.

Roadmap

Wish-list, in order of preference and needs:

• add a 'type' column for aggregate identity, with no constraint at the store level,
• test it even more,
• implement a basic event emitter and event listener API,
• implement a basic aggregate-based event-driven domain oriented API layer implemented using generic store factory decorators,
• very large volume benchmarking,
• configuration-based event namespace storage partionning API implemented using generic store factory decorators,
• transaction support if the other databases are using the same driver as the event store,
• published/failed status in event table,
• Symfony bundle with a few dependency injection passes in order to register repositories,
• Symfony bundle: find a way to properly register or configure event store backend,
• Symfony bundle: provide configuration for namespaces,
• better configuration abilities for goat factory,
• snapshort storage and API,
• better serializer API for snapshot storage
• auto serializer instanciation depending on the event store
• helpers to use it along Symfony's Messenger component,
• provide more event store backends,
• Drupal 7 driver for event store,
• Drupal 8 driver for event store.

Additional arbitrary notes from concrete code

 *   - store in-memory event using a decorator over the event store/event store factory
 *     - if so, wrap with a transaction
 *     - write everything when it goes OK
 *   - namespace in event store should be an instance of Namespace object
 *      - if object is dynamic (tokens with, for example, date or able to partition)
 *        then the real end namespace will be dynamically computed on each run
 *      - NOT sure this is a good idea
 *   - write a generic implementation of aggregate that self-defines it fields (such as
 *     drupal 8 entity system)
 *       - use Symfony validation component for validation, base dynamic field definition
 *         upon object internal properties
 *       - allow read-only and read-write properties
 *       - define generic update event and when() handler that supports it with a dynamic
 *         event name
 *       - define a generic command implementation for updates that check for
 *         allowed values
 *       - define a generic handler implementation that validates the allowed values