Excalibur.EventSourcing.DynamoDb 3.0.0-alpha.208

Excalibur.EventSourcing.DynamoDb

AWS DynamoDB event store implementation for Excalibur event sourcing.

Features

• Partition-aware event storage using {aggregateType}:{aggregateId} as partition key
• Transactional write support for atomic event appending (up to 100 events)
• DynamoDB Streams integration for event streaming
• Optimistic concurrency with conditional writes
• Auto-provisioning of tables with configurable capacity modes

Installation

dotnet add package Excalibur.EventSourcing.DynamoDb

Configuration

services.AddDynamoDbEventStore(options =>
{
 options.EventsTableName = "Events";
 options.PartitionKeyAttribute = "pk";
 options.SortKeyAttribute = "sk";
 options.UseTransactionalWrite = true;
 options.MaxBatchSize = 100;
 options.StreamsPollIntervalMs = 1000;
 options.CreateTableIfNotExists = true;
 options.UseOnDemandCapacity = true;
 options.EnableStreams = true;
});

Or via configuration:

services.AddDynamoDbEventStore(configuration.GetSection("DynamoDbEventStore"));

Usage

The package registers both IEventStore and ICloudNativeEventStore:

public class MyService
{
 private readonly IEventStore _eventStore;

 public MyService(IEventStore eventStore)
 {
 _eventStore = eventStore;
 }

 public async Task AppendEventsAsync(
 string aggregateId,
 IEnumerable<IDomainEvent> events,
 long expectedVersion,
 CancellationToken ct)
 {
 var result = await _eventStore.AppendAsync(
 aggregateId,
 "MyAggregate",
 events,
 expectedVersion,
 ct);

 if (!result.Success)
 {
 // Handle concurrency conflict or failure
 }
 }
}

DynamoDB Streams Subscription

Subscribe to event changes for projections or other event handlers:

var subscription = await _eventStore.SubscribeToChangesAsync(null, ct);
await subscription.StartAsync(ct);

await foreach (var change in subscription.ReadChangesAsync(ct))
{
 // Process event change
 Console.WriteLine($"Event: {change.Document?.EventType}");
}

Table Schema

The event store uses the following DynamoDB table schema:

Requirements

• .NET 9.0+
• AWS DynamoDB access (local or cloud)
• Excalibur.Data.DynamoDb for AWS SDK setup

License

See LICENSE files in repository root.