Kanject EventHub

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A strongly-typed, serverless event bus on AWS — publish typed events and fan them out to subscribers over SNS + SQS, without hand-writing topic and queue wiring. Deployed into your own account.

You'll learn
  • Provision EventHub into your AWS account
  • Register the client with AddServerlessEventHubClient
  • Publish typed [HubEvent] events
  • Subscribe with an IEventHubRequestHandler<T> bound to an SQS queue

Provision

bash 
kanject baas deploy eventhub --env dev

Register it in your service

Register the client with AddServerlessEventHubClient(serviceName, config). The serviceName scopes this service's topics and queues on the shared bus; the transport is SNS + SQS fan-out (EventBridge is used only for scheduled events).

csharp 
using Kanject.ServerlessEventHub.Provider.AwsSnsV4.Extensions;​var builder = WebApplication.CreateBuilder(args);​// serviceName scopes this service's topics/queues on the shared bus.builder.Services.AddServerlessEventHubClient(    serviceName: "orders",    new AwsServerlessEventHubConfiguration { /* region, schema, … */ });​var app = builder.Build();app.Run();

Publish typed events

Events are C# classes marked with [HubEvent(Topic, Version)]. Inject IServerlessEventHubClient (or IPublishEventAction) and call PublishAsync — the event goes to its SNS topic, and subscribed SQS queues fan out from there.

csharp 
using Kanject.ServerlessEventHub.Abstractions.Attributes;​// Events are typed classes, marked with a topic + version.[HubEvent(Topic = "order.completed", Version = 1)]public sealed class OrderCompleted{    public string OrderId { get; set; } = "";    public string UserId  { get; set; } = "";    public decimal Amount { get; set; }}​// Publish: inject IServerlessEventHubClient (or IPublishEventAction).public class OrderService(IServerlessEventHubClient hub){    public Task PublishAsync(OrderCompleted evt)        => hub.PublishAsync(evt);   // → SNS topic; SQS subscribers fan out}

Subscribe

A subscriber implements IEventHubRequestHandler<TEventArgs>. Register it with AddEventHubHandler<,>() and bind an SQS queue to the topics it consumes with SubscribeQueueToTopic — an explicit infrastructure wiring, not attribute auto-magic.

csharp 
// Subscribe: implement IEventHubRequestHandler<TEventArgs>, then register it// and bind an SQS queue to the topic(s) it consumes.public sealed class LedgerProjector : IEventHubRequestHandler<OrderCompletedArgs>{    public Task OnIncomingRequest(object sender, EventHubRequestHandlerArgs e)    {        // handle the delivered event        return Task.CompletedTask;    }}​// Composition root:services.AddEventHubHandler<LedgerProjector, OrderCompletedArgs>();services.SubscribeQueueToTopic("orders-ledger", "order.completed");

What you get

  • Typed events — a C# class per event, marked [HubEvent(Topic, Version)].
  • SNS + SQS fan-out — publish to a topic; each subscriber drains its own SQS queue.
  • Explicit subscriptions — IEventHubRequestHandler<T> + AddEventHubHandler<,>() + SubscribeQueueToTopic.
  • Service scoping — serviceName namespaces each service's topics and queues on the shared bus.
  • Scheduled events — an EventBridge scheduling extension for time-based publishes.
Recap
  • Provision with kanject baas deploy eventhub; register with AddServerlessEventHubClient(serviceName, config).
  • The real package is Kanject.ServerlessEventHub (brand: EventHub); transport is SNS + SQS fan-out.
  • Publish [HubEvent] classes via IServerlessEventHubClient.PublishAsync.
  • Subscribe with IEventHubRequestHandler<T> + AddEventHubHandler<,>() + SubscribeQueueToTopic.
Insights
Feed events into analytics.
NotificationHub
Notify on events.
Wallet
Drive posting profiles from transaction events.
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