Skip to main content

Documentation Index

Fetch the complete documentation index at: https://mintlify.com/Eventuous/eventuous/llms.txt

Use this file to discover all available pages before exploring further.

KurrentDB (formerly EventStoreDB) is the primary event store supported by Eventuous. The Eventuous.KurrentDB package provides a full IEventStore implementation backed by KurrentDB’s gRPC client, along with four subscription types — two catch-up and two persistent — and a producer for writing events back to streams.

​
Installation

dotnet add package Eventuous.KurrentDB

​
Event Store

KurrentDBEventStore implements IEventStore and is the recommended way to persist and load aggregate events in Eventuous. It accepts either a ready-made KurrentDBClient instance or KurrentDBClientSettings and will create the client itself. 
// Using an existing client
var store = new KurrentDBEventStore(client);

// Using connection settings directly
var store = new KurrentDBEventStore(
    KurrentDBClientSettings.Create("esdb://localhost:2113?tls=false")
);
EsdbEventStore is an obsolete alias that still compiles but will emit a warning. Migrate to KurrentDBEventStore.

​
Dependency injection

Register the KurrentDB client and the event store together: 
builder.Services.AddKurrentDBClient(
    builder.Configuration["KurrentDB:ConnectionString"]!
);
builder.Services.AddEventStore<KurrentDBEventStore>();
Your appsettings.json would contain: 
{
  "KurrentDB": {
    "ConnectionString": "esdb://localhost:2113?tls=false"
  }
}

​
Quick start with Docker

Spin up a local KurrentDB instance for development in seconds: 
docker run --rm -it \
  -p 2113:2113 \
  eventstore/eventstore:latest \
  --insecure \
  --run-projections=All
The HTTP and gRPC API is available on port 2113. Navigate to http://localhost:2113 to open the KurrentDB Admin UI.

​
Subscriptions

Eventuous ships four subscription classes for KurrentDB. All are registered through the standard AddSubscription<TSubscription, TOptions> extension.

​
Catch-up subscriptions

Catch-up subscriptions read all events from a stored checkpoint and continue in real time. They require an ICheckpointStore to persist their position.

​
AllStreamSubscription

Subscribes to the global $all stream and delivers every event written to the server.
  • Options type: AllStreamSubscriptionOptions
  • Key options: EventFilter (server-side filter), CheckpointInterval (default 10), StartFrom (InitialPosition.Earliest / Latest), ResolveLinkTos
services.AddSubscription<AllStreamSubscription, AllStreamSubscriptionOptions>(
    "BookingsProjections",
    builder => builder
        .UseCheckpointStore<MongoCheckpointStore>()
        .AddEventHandler<BookingStateProjection>()
        .AddEventHandler<MyBookingsProjection>()
        .WithPartitioningByStream(2)
);

​
StreamSubscription

Subscribes to a single, named stream.
  • Options type: StreamSubscriptionOptions
  • Key options: StreamName (required), IgnoreSystemEvents (default true), StartFrom, ResolveLinkTos
services.AddSubscription<StreamSubscription, StreamSubscriptionOptions>(
    "PaymentsStream",
    builder => builder
        .Configure(x => x.StreamName = "Payments")
        .UseCheckpointStore<InMemoryCheckpointStore>()
        .AddEventHandler<PaymentHandler>()
);

​
Persistent subscriptions

KurrentDB persistent subscriptions store their own checkpoints server-side. The consumer group is created automatically if it doesn’t exist yet.

​
AllPersistentSubscription

Server-managed persistent subscription against the $all stream.
  • Options type: AllPersistentSubscriptionOptions
  • Key options: EventFilter, BufferSize, Credentials, Deadline

​
StreamPersistentSubscription

Server-managed persistent subscription against a named stream.
  • Options type: StreamPersistentSubscriptionOptions
  • Key options: StreamName (required), BufferSize, Credentials
services.AddSubscription<StreamPersistentSubscription, StreamPersistentSubscriptionOptions>(
    "PaymentIntegration",
    builder => builder
        .Configure(x => x.StreamName = PaymentsIntegrationHandler.Stream)
        .AddEventHandler<PaymentsIntegrationHandler>()
);

​
Producer

KurrentDBProducer appends events to any stream and integrates with the Eventuous Gateway pattern. 
// Construct directly
var producer = new KurrentDBProducer(client);

// Or from client settings
var producer = new KurrentDBProducer(
    KurrentDBClientSettings.Create("esdb://localhost:2113?tls=false")
);
KurrentDBProduceOptions controls per-produce behaviour:
PropertyDefaultDescription
ExpectedStateStreamState.AnyOptimistic concurrency check
MaxAppendEventsCount500Maximum events per append batch
DeadlinenullgRPC deadline for the operation
CredentialsnullPer-call user credentials override

​
Complete registration example

The following shows the full Registrations.cs pattern taken from the Eventuous sample application: 
public static void AddEventuous(
    this IServiceCollection services,
    IConfiguration          configuration
) {
    DefaultEventSerializer.SetDefaultSerializer(
        new DefaultEventSerializer(
            new JsonSerializerOptions(JsonSerializerDefaults.Web)
                .ConfigureForNodaTime(DateTimeZoneProviders.Tzdb)
        )
    );

    services.AddKurrentDBClient(
        configuration["KurrentDB:ConnectionString"]!
    );
    services.AddEventStore<KurrentDBEventStore>();
    services.AddCommandService<BookingsCommandService, BookingState>();

    services.AddSingleton(Mongo.ConfigureMongo(configuration));

    services.AddSubscription<AllStreamSubscription, AllStreamSubscriptionOptions>(
        "BookingsProjections",
        builder => builder
            .UseCheckpointStore<MongoCheckpointStore>()
            .AddEventHandler<BookingStateProjection>()
            .AddEventHandler<MyBookingsProjection>()
            .WithPartitioningByStream(2)
    );

    services.AddSubscription<StreamPersistentSubscription, StreamPersistentSubscriptionOptions>(
        "PaymentIntegration",
        builder => builder
            .Configure(x => x.StreamName = PaymentsIntegrationHandler.Stream)
            .AddEventHandler<PaymentsIntegrationHandler>()
    );
}

Build docs developers (and LLMs) love

Get started for freeTalk to us