.NET Standart library for subscribing/publishing messages to RabbitMq. Under the hood uses official RabbitMq .NET client, but provides more abstract interface.
| Package Name | NuGet Package | Description |
|---|---|---|
| tRebbit.Abstractions |  |
This package contains abstractions over low level implementations as connections, channels and others. Recommended to be used in Domain or Application layers of an application. |
| tRebbit |  |
This package contains implementations of types defined in tRebbit.Abstractions and DI extensions to wire them up. Recommended to be used only inside Infrastructure layer to avoid other layers coupling with low level details. |
- Simplify publising/subscribing to events, without referring to RabbitMq building blocks.
- Provide basic implementation wich could be extended.
- Separated abstractions and implementations into different libraries. It allows you to use interfaces only inside Application/Domain Layer and bind them to implemenrations only inside Infrastructure Layer.
- Dead-lettering is optional and could help to keep track of failures during original event processing.
- IServiceCollection.AddEventBus helps to hook up everything in single place to be good to go.
- In-memory subscription management keeps track of events/handles registered by your app.
- IIntegrationEventHandler is a basic interface to implement for particular type of event to handle.
- Is not opinionated about resillience library or approach you use by accepting delegates for this from client code.
- Define event message by inheriting IntegrationEvent type:
public class PaymentCompletedEvent : IntegrationEvent
{
public decimal PayAmount { get; private set; }
public string UserId { get; private set; }
public PaymentCompletedEvent(decimal payAmount, string userId)
{
PayAmount = payAmount;
UserId = userId;
}
}
- Define event handles by implementing IIntegrationEventHandler interface:
public class PaymentCompletedIntegrationEventHandler :
IIntegrationEventHandler<PaymentCompletedEvent>
{
public Task Handle(PaymentCompletedEvent @event, bool isFirstDispatch)
{
// uncomment to see how event flows into DLX
//throw new ArgumentNullException();
Console.WriteLine("Payment completed");
Console.WriteLine(System.Text.Json.JsonSerializer.Serialize(@event));
return Task.CompletedTask;
}
}
- Register event handles with DI:
services.AddScoped<PaymentCompletedIntegrationEventHandler>();
- Wire up everything by calling .AddEventBus:
services.AddEventBus(
exchangeName: "your_exchange_name",
queueName: "your_task_queue_name",
config: new RabbitMqConfig
{
Connection = "localhost",
UserName = "guest",
Password = "guest"
},
resillientConnectionPolicyAction: , // here place reference to resillience action which will handle connections, for example RetryPolicy.Execute
resillientPublishPolicyAction: , // here place reference to resillience action which will handle publishes, for example RetryPolicy.Execute
preprocessAction: // any preprocess action before event is actually handled by your custom event handles
);
- Usage:
static void Main(string[] args)
{
var host = CreateHostBuilder(args).Build();
var serviceProvider = host.Services;
var eventBus = serviceProvider.GetRequiredService<IEventBus>();
// subscribe
eventBus.Subscribe<PaymentCompletedEvent,
PaymentCompletedIntegrationEventHandler>();
eventBus.ActivateSubscriptionChannel();
// publish
eventBus.Publish(new PaymentCompletedEvent(100.0m, "bchornii"));
Console.Read();
}
static IHostBuilder CreateHostBuilder(string[] args) =>
Host.CreateDefaultBuilder(args)
.ConfigureServices((_, services) =>
{
var connectionRetryPolicy = RetryPolicy.Handle<SocketException>()
.Or<BrokerUnreachableException>()
.WaitAndRetry(5, retryAttempt =>
TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)), (ex, time) =>
{
Console.WriteLine($"RabbitMQ Client could not connect after {time.TotalSeconds:n1}s ({ex.Message})");
});
var publishRetryPolicy = RetryPolicy.Handle<SocketException>()
.Or<BrokerUnreachableException>()
.WaitAndRetry(5, retryAttempt =>
TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)), (ex, time) =>
{
Console.WriteLine($"RabbitMQ Client could not connect after {time.TotalSeconds:n1}s ({ex.Message})");
});
services.AddScoped<PaymentCompletedIntegrationEventHandler>();
services.AddEventBus(
exchangeName: "bc_exchange",
queueName: "bc_default_queue",
config: new RabbitMqConfig
{
Connection = "localhost",
UserName = "guest",
Password = "guest"
},
resillientConnectionPolicyAction: connectionRetryPolicy.Execute,
resillientPublishPolicyAction: publishRetryPolicy.Execute,
preprocessAction: (s, o) => Task.CompletedTask);
});