SlimMessageBus <!-- omit in toc -->

SlimMessageBus is a lightweight, flexible, and extensible messaging framework for .NET, supporting multiple message brokers, including Kafka, RabbitMQ, Azure EventHubs, MQTT, Redis Pub/Sub, and more. It simplifies asynchronous communication and integrates seamlessly with modern .NET applications.

See how to migrate from MediatR or MassTransit

🚀 Quick Start

Installation

dotnet add package SlimMessageBus
# Add specific transport provider, e.g. Kafka
dotnet add package SlimMessageBus.Host.Kafka
# Add serialization plugin
dotnet add package SlimMessageBus.Host.Serialization.SystemTextJson

Basic Usage

Publishing Messages

IMessageBus bus; // injected

public record OrderCreatedEvent(int OrderId);

await bus.Publish(new OrderCreatedEvent(123));

Consuming Messages

public class OrderCreatedEventConsumer : IConsumer<OrderCreatedEvent>
{
    public async Task OnHandle(OrderCreatedEvent message, CancellationToken cancellationToken)
    {
        // Handle the event
    }
}

Request-Response Example

Sending a Request

public record CreateCustomerCommand(string Name) : IRequest<CreateCustomerCommandResult>;
public record CreateCustomerCommandResult(Guid CustomerId);

var result = await bus.Send(new CreateCustomerCommand("John Doe"));

Handling a Request

public class CreateCustomerCommandHandler : IRequestHandler<CreateCustomerCommand, CreateCustomerCommandResult>
{
    public async Task<CreateCustomerCommandResult> OnHandle(CreateCustomerCommand request, CancellationToken cancellationToken)
    {
        // Create customer logic
        return new(Guid.NewGuid());
    }
}

Configuration Example

services.AddSlimMessageBus(mbb =>
{
    mbb.AddChildBus("Bus1", builder =>
    {
         builder
               // the pub-sub events
               .Produce<OrderCreatedEvent>(x => x.DefaultPath("orders-topic"))
               .Consume<OrderCreatedEvent>(x => x.Path("orders-topic")
                  //.WithConsumer<OrderCreatedEventConsumer>() // Optional: can be skipped as IConsumer<OrderCreatedEvent> will be resolved from DI
                  //.KafkaGroup("kafka-consumer-group") // Kafka: Consumer Group
                  //.SubscriptionName("azure-sb-topic-subscription") // Azure ServiceBus: Subscription Name
               )

               // the request-response
               .Produce<CreateCustomerCommand>(x => x.DefaultPath("customer-requests"))
               .Handle<CreateCustomerCommand, CreateCustomerCommandResult>(x => x.Path("customer-requests"))

               // Use Kafka transport provider (requires SlimMessageBus.Host.Kafka package)
               .WithProviderKafka(cfg => cfg.BrokerList = "localhost:9092");

            // Use Azure Service Bus transport provider
            //.WithProviderServiceBus(cfg => { ... }) // requires SlimMessageBus.Host.AzureServiceBus package
            // Use Azure Event Hub transport provider
            //.WithProviderEventHub(cfg => { ... }) // requires SlimMessageBus.Host.AzureEventHub package
            // Use Redis transport provider
            //.WithProviderRedis(cfg => { ... }) // requires SlimMessageBus.Host.Redis package
            // Use RabbitMQ transport provider
            //.WithProviderRabbitMQ(cfg => { ... }) // requires SlimMessageBus.Host.RabbitMQ package

            // Use in-memory transport provider
            //.WithProviderMemory(cfg => { ... }) // requires SlimMessageBus.Host.Memory package
   })
   // Add other bus transports (as child bus for in memory domain events), if needed
   //.AddChildBus("Bus2", (builder) => {  })
   .AddJsonSerializer() // requires SlimMessageBus.Host.Serialization.SystemTextJson or SlimMessageBus.Host.Serialization.Json package
   .AddServicesFromAssemblyContaining<OrderCreatedEventConsumer>();
});

The configuration can be modularized (for modular monoliths).

📖 Documentation

• Introduction
• Transports:
  • Amazon SQS/SNS
  • Apache Kafka
  • Azure EventHubs
  • Azure ServiceBus
  • Hybrid
  • MQTT
  • Memory
  • NATS
  • RabbitMQ
  • Redis
  • SQL
• Plugins:
  • Serialization
  • Transactional Outbox
  • Validation using FluentValidation
  • AsyncAPI specification generation
  • Consumer Circuit Breaker
• Samples
• Use Cases

📦 NuGet Packages

| Name | Description | NuGet | | ------------------------------------ | ------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | SlimMessageBus | The core API for SlimMessageBus | | | Transports | | | | .Host.AmazonSQS | Transport provider for Amazon SQS / SNS | | | .Host.AzureEventHub | Transport provider for Azure Event Hubs | | | .Host.AzureServiceBus | Transport provider for Azure Service Bus | | | .Host.Kafka | Transport provider for Apache Kafka | | | .Host.MQTT | Transport provider for MQTT | | | .Host.Memory | Transport provider implementation for in-process (in memory) message passing (no messaging infrastructure required) | | | .Host.NATS | Transport provider for NATS |