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ModulesEventStoreDB

EventStoreDB

Griffin.EventStoreDB provides event-sourced aggregate storage, serialization, projections, subscriptions, and checkpoint support.

Installation

dotnet add package Griffin.EventStoreDB

An EventStoreDB server compatible with the package’s gRPC client is required at runtime.

Registration

using Griffin.EventStoreDB;
 
var builder = WebApplication.CreateBuilder(args);
 
builder.Services.AddEventStore(
    builder.Configuration,
    typeof(Program).Assembly);

AddEventStore registers options, the EventStoreDB client, aggregate repositories, and projection processors from the supplied assemblies. With no explicit assemblies, it scans the entry assembly.

Configuration

Use ConnectionStrings:eventstore, or the fallback EventStoreOptions:ConnectionString:

ConnectionStrings__eventstore=<EventStoreDB connection string>

Configure server TLS, credentials, and certificate trust for the target environment. Do not disable TLS in production to copy a local development connection string.

Event-Sourced Aggregates

The Griffin.EventStoreDB.Events namespace contains AggregateEventSourcing<TId> and IAggregateEventSourcing<TId>. The repository works with GUID-identified event-sourced aggregates, not arbitrary EF entities.

Inject IEventStoreDBRepository<YourAggregate> from Griffin.EventStoreDB.Repository, where YourAggregate is your application’s event-sourced aggregate type.

  • Find(id, cancellationToken) rehydrates an aggregate from its stream.
  • Add(aggregate, cancellationToken) expects a new stream.
  • Update(aggregate, expectedRevision, cancellationToken) appends pending events with optimistic concurrency.
  • Delete(...) currently delegates to Update; model deletion as an event rather than assuming the stream is removed.

Persisting clears pending aggregate events before append completion. Design failure recovery carefully; do not assume the same aggregate instance retains its pending events after a failed write.

Projections and Subscriptions

Projection registration scans for IProjectionProcessor implementations. Registration alone does not start a subscription worker.

Add the hosted subscription explicitly when your service should consume all-stream events:

using Griffin.EventStoreDB;
 
builder.Services.AddEventStoreDBSubscriptionToAll();

The default uses EventStoreDB-backed checkpoints. The lower-level AddEventStoreDB method accepts EventStoreDBOptions for checkpoint registration. If internal checkpoint registration is disabled, provide an ISubscriptionCheckpointRepository implementation yourself.

Provision permissions for the subscribed streams and checkpoint storage. Make projection handlers safe to replay and resilient to duplicate delivery.

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