Persistent Events: LiteDB

LiteDB is an embedded, serverless document database for .NET. It stores everything in a single .db file, with no SQL schema and no server to run. See Choosing a backend to compare the alternatives.

Install

dotnet add package M.EventBrokerSlim.PersistentEvents.LiteDb

Schema setup

None required. LiteDB creates the collection on first use.

Configuration

With a connection string

var registry = new EventRegistry()
    .Add<ArticlePublished>("article-published");

services
    .AddSingleton(registry)
    .AddEventBroker(x => x
        .WithLiteDbPersistence((db, settings) =>
        {
            db.ConnectionString = "Filename=events.db";
            db.Collection = "events"; // optional, default: "events"

            settings.PollingInterval = TimeSpan.FromSeconds(5);
        }))
    .AddEventHandlerPipeline<ArticlePublished>(pipeline, handlerName: "article-published-handler");

With an existing LiteDatabase instance

If your application already manages a LiteDatabase instance, pass it directly. The event broker uses it as-is:

var liteDb = new LiteDatabase("Filename=myapp.db");

services
    .AddSingleton(liteDb)
    .AddEventBroker(x => x
        .WithLiteDbPersistence((db, settings) =>
        {
            db.LiteDbInstance = liteDb;
            db.Collection = "broker_events"; // use a distinct collection name
        }));

Either db.ConnectionString or db.LiteDbInstance must be set; if both are set, LiteDbInstance wins and the connection string is ignored. db.Collection defaults to "events"; when several broker instances share one database file, give each a unique collection name. The settings argument exposes the shared PersistentEventBrokerSettings (polling interval, processing timeout, retention). For the full set, see the configuration reference.

Starting the broker

var provider = services.BuildServiceProvider();
provider.UsePersistentEventBroker(throwOnValidationErrors: true);

Full example

using FuncPipeline;
using M.EventBrokerSlim;
using M.EventBrokerSlim.DependencyInjection;
using M.EventBrokerSlim.Persistent;
using M.EventBrokerSlim.PersistentEvents.LiteDb;
using Microsoft.Extensions.DependencyInjection;

public record ArticlePublished(Guid ArticleId, string Slug);

var registry = new EventRegistry()
    .Add<ArticlePublished>("article-published");

IPipeline pipeline = PipelineBuilder.Create()
    .NewPipeline()
    .Execute(async (ArticlePublished e, CancellationToken ct) =>
    {
        Console.WriteLine($"Processing article {e.ArticleId}");
        await Task.CompletedTask;
    })
    .Build()
    .Pipelines[0];

var provider = new ServiceCollection()
    .AddSingleton(registry)
    .AddEventBroker(x => x
        .WithLiteDbPersistence((db, settings) =>
        {
            db.ConnectionString = "Filename=events.db";
        }))
    .AddEventHandlerPipeline<ArticlePublished>(pipeline, handlerName: "article-published-handler")
    .BuildServiceProvider();

provider.UsePersistentEventBroker(throwOnValidationErrors: true);

var broker = provider.GetRequiredService<IEventBroker>();
await broker.Publish(new ArticlePublished(Guid.NewGuid(), "my-first-article"));

await Task.Delay(TimeSpan.FromSeconds(15));
broker.Shutdown();