Configuration

Aggregate

A path must be specified for Event Sourcing to know where to look for your aggregates. If you want you can use glob patterns to specify multiple paths.

patchlevel_event_sourcing:
  aggregates: '%kernel.project_dir%/src/*/Domain'

Or use an array to specify multiple paths.

patchlevel_event_sourcing:
  aggregates:
    - '%kernel.project_dir%/src/Hotel/Domain'
    - '%kernel.project_dir%/src/Room/Domain'

Events

A path must be specified for Event Sourcing to know where to look for your events. If you want you can use glob patterns to specify multiple paths.

patchlevel_event_sourcing:
  events: '%kernel.project_dir%/src/*/Domain/Event'

Or use an array to specify multiple paths.

patchlevel_event_sourcing:
  events:
    - '%kernel.project_dir%/src/Hotel/Domain/Event'
    - '%kernel.project_dir%/src/Room/Domain/Event'

Custom Headers

If you want to implement custom headers for your application, you must specify the paths to look for those headers. If you want you can use glob patterns to specify multiple paths.

patchlevel_event_sourcing:
  headers: '%kernel.project_dir%/src/*/Domain/Header'

Or use an array to specify multiple paths.

patchlevel_event_sourcing:
  headers:
    - '%kernel.project_dir%/src/Hotel/Domain/Header'
    - '%kernel.project_dir%/src/Room/Domain/Header'

Connection

You have to specify the connection url to the event store.

patchlevel_event_sourcing:
  connection:
    url: '%env(EVENTSTORE_URL)%'

Connection for Projections

Per default, our event sourcing connection is not available to use in your application. But you can create a dedicated connection that you can use for your projections.

patchlevel_event_sourcing:
  connection:
    url: '%env(EVENTSTORE_URL)%'
    provide_dedicated_connection: true

use Doctrine\DBAL\Connection;

class YourService
{
    public function __construct(
        private readonly Connection $projectionConnection,
    ) {
    }
}

Doctrine Bundle

If you have installed the doctrine bundle, you can also define the connection via doctrine and then use it in the store.

doctrine:
    dbal:
        connections:
            eventstore:
                url: '%env(EVENTSTORE_URL)%'

patchlevel_event_sourcing:
    connection:
        service: doctrine.dbal.eventstore_connection

If you are using Doctrine for your projections too, you need to create a dedicated connection for this. You can do this by defining a new connection named projection in the doctrine.yaml file and use the same connection url as for the event store.

doctrine:
    dbal:
        connections:
            eventstore:
                url: '%env(EVENTSTORE_URL)%'
            projection:
                url: '%env(EVENTSTORE_URL)%'

patchlevel_event_sourcing:
    connection:
        service: doctrine.dbal.eventstore_connection

doctrine:
    dbal:
        schema_filter: ~^(projection_)~

Then you can use this connection in your projections. If you are using autowiring you can inject the right connection Connection $projectionConnection parameter name. The prefix projection is used to identify the connection.

namespace App\Projection;

use Doctrine\DBAL\Connection;
use Patchlevel\EventSourcing\Attribute\Projector;

#[Projector('my_projection')]
class MyProjection
{
    public function __construct(
        private readonly Connection $projectionConnection,
    ) {
    }
}

Store

The store and schema is configurable.

Change Store type

You can change the store type of the event store.

patchlevel_event_sourcing:
    store:
        type: 'in_memory'

Following store types are available:

• dbal_aggregate default (deprecated)
• dbal_stream recommended
• in_memory
• custom

Change table Name

You can change the table name of the event store.

patchlevel_event_sourcing:
    store:
        options:
            table_name: 'my_event_store'

Read Only Mode

For dbal_aggregate and dbal_stream store types you can activate the read only mode. Readings are possible, but if you try to write, an exception StoreIsReadOnly is thrown.

patchlevel_event_sourcing:
    store:
        read_only: true

Merge ORM Schema

You can also merge the schema with doctrine orm. You have to set the following flag for this:

patchlevel_event_sourcing:
    store:
        merge_orm_schema: true

Kernel Reset

Only available in in_memory store. If you want to reset the store after each kernel request, you can activate this option. So you can avoid side effects between the tests.

patchlevel_event_sourcing:
    store:
        kernel_reset: true

Data Migration

If you want to migrate from your current store to a new store, you can use the following configuration. This register a new store and a new cli command event-sourcing:store:migrate. You can define translators to translate the old events to the new store. Here is an example for a migration from dbal_aggregate to dbal_stream.

patchlevel_event_sourcing:
    store:
        migrate_to_new_store:
            type: 'dbal_stream'
            options:
                table_name: 'my_stream_store'
            translators:
              - Patchlevel\EventSourcing\Message\Translator\AggregateToStreamHeaderTranslator

Migration

You can use doctrine migrations to manage the schema.

patchlevel_event_sourcing:
    migration:
        namespace: EventSourcingMigrations
        path: "%kernel.project_dir%/migrations"

Subscription

Store

You can change where the subscription engine stores its necessary information about the subscription. Default is dbal, which means it stores it in the same DB that is used by the dbal event store.

Otherwise you can choose between the following stores:

• dbal default
• in_memory
• static_in_memory
• custom

patchlevel_event_sourcing:
  subscription:
    store: 
      type: 'custom' # default is 'dbal'
      service: 'my_subscription_store'
      options:
        table_name: 'my_subscription_store'

Catch Up

If aggregates are used in the processors and new events are generated there, then they are not part of the current subscription engine run and will only be processed during the next run or boot. This is usually not a problem in dev or prod environment because a worker is used and these events will be processed at some point. But in testing it is not so easy. For this reason, you can activate the catch_up option.

patchlevel_event_sourcing:
    subscription:
        catch_up: true

Throw on Error

You can activate the throw_on_error option to throw an exception if a subscription engine run has an error. This is useful for testing or development to get directly feedback if something is wrong.

patchlevel_event_sourcing:
    subscription:
        throw_on_error: true

Run After Aggregate Save

If you want to run the subscription engine after an aggregate is saved, you can activate this option. This is useful for testing or development, so you don't have run a worker to process the events.

patchlevel_event_sourcing:
    subscription:
        run_after_aggregate_save: true

Auto Setup

If you want to automatically setup the subscription engine, you can activate this option. This is useful for development, so you don't have to setup the subscription engine manually.

patchlevel_event_sourcing:
    subscription:
        auto_setup: true

Rebuild After File Change

If you want to rebuild the subscription engine after a file change, you can activate this option. This is also useful for development, so you don't have to rebuild the projections manually.

patchlevel_event_sourcing:
    subscription:
        rebuild_after_file_change: true

Gap Detection

Depending on the database you are using for the eventstore it may be happening that your subscriptions are skipping some events. This is due to how auto-increments work in these databases in combination with e.g. longer open transactions. Even when not working with longer open transactions, this may occur if load is high on the database. We already have a locking mechanism in place to prevent this behaviour which throttles write speed. Gap Detection operates different, it checks if a gap between the last message handled and the current message is present. If so it waits a reasonable amount of time and re-fetches the message. This results into slower updates for the subscriptions but creates more resilience.

patchlevel_event_sourcing:
    subscription:
        gap_detection: ~

You can also define how often the gap detection should re-check the gap and how long it should wait, in this example we instantly retry the first time, then we wait 500ms and after that we check a last time after 1 second.

patchlevel_event_sourcing:
    subscription:
        gap_detection:
            retries_in_ms: [0, 500, 1000]

Another config option is to define the detection window. The option defines the timeframe from now if we should check for a gap. It's defined as an DateInterval so you need to provide a valid string for it.

patchlevel_event_sourcing:
    subscription:
        gap_detection:
            detection_window: 'PT5M'

Command Bus

You can enable the command bus integration to use your aggregates as command handlers. For this bundle we provide only a symfony messenger integration, so you have to define the bus in the messenger configuration.

framework:
    messenger:
        default_bus: command.bus
        buses:
            command.bus: ~

After this, you need to define the command bus in the event sourcing configuration. This will automatically register the aggregate handlers for the symfony messenger, so you can handle commands with your aggregates.

patchlevel_event_sourcing:
    command_bus:
        service: command.bus

Instant Retry

You can define the default instant retry configuration for the command bus. This will be used if you don't define a retry configuration for a specific command.

patchlevel_event_sourcing:
    command_bus:
        instant_retry:
            default_max_retries: 3
            default_exceptions:
                - Patchlevel\EventSourcing\Repository\AggregateOutdated

Query Bus

You can enable the query bus integration to use queries to retrieve data from your system. For this bundle we provide only a symfony messenger integration, so you have to define the bus in the messenger configuration.

framework:
    messenger:
        buses:
            query.bus: ~

After this, you need to define the query bus in the event sourcing configuration. This will automatically register the handlers for the symfony messenger, so you can handle queries in your services.

patchlevel_event_sourcing:
    query_bus:
        service: query.bus

Event Bus

You can enable the event bus to listen for events and messages synchronously. But you should consider using the subscription engine for this.

patchlevel_event_sourcing:
    event_bus: ~

Patchlevel (Default) Event Bus

First of all we have our own default event bus. This works best with the library, as the #[Subscribe] attribute is used there, among other things.

patchlevel_event_sourcing:
    event_bus:
        type: default

Symfony Event Bus

But you can also use Symfony Messenger. To do this, you first have to define a suitable message bus. This must be "allow_no_handlers" so that this messenger can be an event bus according to the definition.

# messenger.yaml
framework:
    messenger:
        buses:
            event.bus:
                default_middleware: allow_no_handlers

We can then use this messenger or event bus in event sourcing:

patchlevel_event_sourcing:
    event_bus:
        type: symfony
        service: event.bus

Since the event bus was replaced, event sourcing own attributes no longer work. You use the Symfony attributes instead.

use Patchlevel\EventSourcing\EventBus\Message;
use Symfony\Component\Messenger\Attribute\AsMessageHandler;

#[AsMessageHandler('event.bus')]
class SmsNotificationHandler
{
    public function __invoke(Message $message): void
    {
        if (!$message instanceof GuestIsCheckedIn) {
            return;
        }

        // ... do some work - like sending an SMS message!
    }
}

PSR-14 Event Bus

You can also use any other event bus that implements the PSR-14 standard.

patchlevel_event_sourcing:
    event_bus:
        type: psr14
        service: my.event.bus.service

Custom Event Bus

You can also use your own event bus that implements the Patchlevel\EventSourcing\EventBus\EventBus interface.

patchlevel_event_sourcing:
    event_bus:
        type: custom
        service: my.event.bus.service

Snapshot

You can use symfony cache to define the target of the snapshot store.

framework:
    cache:
        default_redis_provider: 'redis://localhost'
        pools:
            event_sourcing.cache:
                adapter: cache.adapter.redis

After this, you need define the snapshot store. Symfony cache implement the psr6 interface, so we need choose this type and enter the id from the cache service.

patchlevel_event_sourcing:
    snapshot_stores:
        default:
            service: event_sourcing.cache

Finally, you have to tell the aggregate that it should use this snapshot store.

namespace App\Profile\Domain;

use Patchlevel\EventSourcing\Aggregate\BasicAggregateRoot;
use Patchlevel\EventSourcing\Attribute\Aggregate;
use Patchlevel\EventSourcing\Attribute\Snapshot;

#[Aggregate(name: 'profile')]
#[Snapshot('default')]
final class Profile extends BasicAggregateRoot
{
    // ...
}

Cryptography

You can use the library to encrypt and decrypt personal data. For this you need to enable the crypto shredding.

patchlevel_event_sourcing:
    cryptography:
      use_encrypted_field_name: true

If you want to use another algorithm, you can specify this here:

patchlevel_event_sourcing:
    cryptography:
        algorithm: 'aes-256-gcm'

Clock

The clock is used to return the current time as DateTimeImmutable.

Freeze Clock

You can freeze the clock for testing purposes:

when@test:
    patchlevel_event_sourcing:
        clock:
            freeze: '2020-01-01 22:00:00'

Symfony Clock

Since symfony 6.2 there is a clock implementation based on psr-20 that you can use.

composer require symfony/clock

patchlevel_event_sourcing:
    clock:
        service: 'clock'

PSR-20

You can also use your own implementation of your choice. They only have to implement the interface of the psr-20. You can then specify this service here:

patchlevel_event_sourcing:
    clock:
        service: 'my_own_clock_service'