⚠️ v0.1.0 Limitations

The following features exist as contracts only or have limitations in v0.1.0:

Bottom line: v0.1.0 provides complete transport abstraction with Azure providers. Applications must implement:

• IOutboxStore if using transactional outbox pattern (database-specific)
• Health endpoint wiring for contributor aggregation
• Custom IMessageSerializer if JSON is not suitable

🚀 Quick Start

Installation

# Azure Service Bus transport
dotnet add package HoneyDrunk.Transport.AzureServiceBus

# Or Azure Storage Queue transport
dotnet add package HoneyDrunk.Transport.StorageQueue

# Or InMemory transport (for testing)
dotnet add package HoneyDrunk.Transport.InMemory

# Or just the core abstractions (contracts only)
dotnet add package HoneyDrunk.Transport

Web API Setup

This example shows a web application with Kernel and Azure Service Bus. Simpler setups are possible—see package-specific documentation.

Registration order matters. Kernel must be registered before Transport. See DependencyInjection.md for details.

using HoneyDrunk.Kernel.DependencyInjection;
using HoneyDrunk.Transport.DependencyInjection;

var builder = WebApplication.CreateBuilder(args);

// 1. Kernel (required for Grid context)
builder.Services.AddHoneyDrunkCoreNode(nodeDescriptor);

// 2. Transport core (middleware pipeline, envelope factory)
builder.Services.AddHoneyDrunkTransportCore(options =>
{
    options.EnableTelemetry = true;
    options.EnableLogging = true;
});

// 3. Azure Service Bus provider
builder.Services.AddHoneyDrunkServiceBusTransport(options =>
{
    options.FullyQualifiedNamespace = "mynamespace.servicebus.windows.net";
    options.Address = "orders";
    options.EntityType = ServiceBusEntityType.Topic;
    options.SubscriptionName = "order-processor";
    options.MaxConcurrency = 10;
});

// 4. Register message handlers
builder.Services.AddMessageHandler<OrderCreatedEvent, OrderCreatedHandler>();

var app = builder.Build();
app.Run();

Abstractions-Only Usage

For libraries that only need contracts without runtime dependencies:

// Reference only HoneyDrunk.Transport
// No Kernel runtime, no broker SDK dependencies

public class OrderService
{
    private readonly ITransportPublisher _publisher;
    private readonly EnvelopeFactory _envelopeFactory;
    private readonly IMessageSerializer _serializer;

    public async Task PublishOrderCreatedAsync(Order order, CancellationToken ct)
    {
        var @event = new OrderCreatedEvent { OrderId = order.Id };
        var payload = _serializer.Serialize(@event);
        var envelope = _envelopeFactory.CreateEnvelope<OrderCreatedEvent>(payload);
        
        await _publisher.PublishAsync(
            envelope,
            EndpointAddress.Create("orders", "orders-topic"),
            ct);
    }
}

🎯 Key Features (v0.1.0)

📨 Transport Envelope Pattern

All messages are wrapped in immutable ITransportEnvelope for distributed tracing:

public interface ITransportEnvelope
{
    string MessageId { get; }
    string? CorrelationId { get; }
    string? CausationId { get; }
    string MessageType { get; }
    ReadOnlyMemory<byte> Payload { get; }
    IReadOnlyDictionary<string, string> Headers { get; }
    DateTimeOffset Timestamp { get; }
}

// Create envelopes via factory (integrates with TimeProvider and Grid context)
var envelope = envelopeFactory.CreateEnvelopeWithGridContext<OrderCreatedEvent>(
    payload, gridContext);

Note: Always use EnvelopeFactory to create envelopes. It integrates with TimeProvider for deterministic timestamps and IGridContext for distributed context propagation.

🔗 Grid Context Integration

Transport is fully integrated with Kernel's IGridContext for distributed context propagation:

public class OrderCreatedHandler : IMessageHandler<OrderCreatedEvent>
{
    public async Task<MessageProcessingResult> HandleAsync(
        OrderCreatedEvent message,
        MessageContext context,
        CancellationToken ct)
    {
        // Access Grid context directly from MessageContext
        var grid = context.GridContext;
        
        _logger.LogInformation(
            "Processing order {OrderId} with CorrelationId {CorrelationId} on Node {NodeId}",
            message.OrderId,
            grid?.CorrelationId,
            grid?.NodeId);
        
        return MessageProcessingResult.Success;
    }
}

Note: Grid context is extracted from envelope headers by GridContextPropagationMiddleware and populated in MessageContext automatically.

🧅 Middleware Pipeline

Message processing follows an onion-style middleware pattern:

// Built-in middleware (executed in order)
// 1. GridContextPropagationMiddleware - Extracts IGridContext from envelope
// 2. TelemetryMiddleware - Distributed tracing via OpenTelemetry
// 3. LoggingMiddleware - Structured logging of message processing

// Custom middleware registration
builder.Services.AddHoneyDrunkTransportCore()
    .AddMiddleware<CustomRetryMiddleware>()
    .AddMiddleware<CustomValidationMiddleware>();

Note: Middleware order matters. GridContextPropagation must run before telemetry to ensure correlation IDs are available for tracing.

📤 Transactional Outbox

For exactly-once processing with database transactions:

public class OrderService(
    IOutboxStore outboxStore,
    EnvelopeFactory factory,
    IMessageSerializer serializer,
    IDbContext dbContext)
{
    public async Task CreateOrderAsync(CreateOrderCommand command, CancellationToken ct)
    {
        await using var transaction = await dbContext.BeginTransactionAsync(ct);
        
        // Save order to database
        var order = new Order { /* ... */ };
        await dbContext.Orders.AddAsync(order, ct);
        
        // Save message to outbox (same transaction)
        var payload = serializer.Serialize(new OrderCreatedEvent { OrderId = order.Id });
        var envelope = factory.CreateEnvelope<OrderCreatedEvent>(payload);
        
        await outboxStore.SaveAsync(
            EndpointAddress.Create("orders", "orders-topic"),
            envelope, ct);
        
        await dbContext.SaveChangesAsync(ct);
        await transaction.CommitAsync(ct);
        
        // DefaultOutboxDispatcher publishes from outbox in background
    }
}

Note: IOutboxStore is a contract—application must implement against their database. DefaultOutboxDispatcher polls the store and publishes pending messages.

🏥 Health Contributors

Transport providers include health monitoring for Kubernetes probes:

public interface ITransportHealthContributor
{
    string Name { get; }
    ValueTask<TransportHealthResult> CheckHealthAsync(CancellationToken ct);
}

// Each transport registers its own contributor
// - ServiceBusHealthContributor
// - StorageQueueHealthContributor
// - InMemoryHealthContributor

Note: Health contributors are passive—invoked by host health system on demand. Applications wire contributors into their health check infrastructure.

⚖️ Storage Queue vs Service Bus

Choose Storage Queue for cost-effective, high-volume, simple queue scenarios.
Choose Service Bus for enterprise messaging with topics, sessions, or transactions.

📖 Documentation

Package Documentation

• Architecture - High-level architecture and design principles
• Abstractions - Core contracts: ITransportEnvelope, IMessageHandler, MessageContext
• Pipeline - Middleware pipeline and built-in middleware
• Configuration - All options: TransportCoreOptions, RetryOptions, error strategies
• Context - Grid context propagation and IGridContextFactory
• Primitives - EnvelopeFactory, TransportEnvelope, serialization
• Outbox - Transactional outbox pattern

Transport Providers

• AzureServiceBus - Service Bus transport: sessions, topics, blob fallback
• StorageQueue - Storage Queue transport: concurrency model, poison queues
• InMemory - InMemory transport for testing

Runtime & Observability

• Runtime - ITransportRuntime and consumer lifecycle
• Health - Health monitoring with ITransportHealthContributor
• Metrics - ITransportMetrics and OpenTelemetry integration
• Testing - Test patterns and helpers

🏗️ Project Structure

HoneyDrunk.Transport/
├── HoneyDrunk.Transport/                    # Core abstractions & pipeline
│   ├── Abstractions/                        # Publisher, consumer, handler contracts
│   ├── Pipeline/                            # Middleware execution engine
│   ├── Configuration/                       # TransportCoreOptions, RetryOptions
│   ├── Context/                             # Grid context factory and propagation
│   ├── Primitives/                          # EnvelopeFactory, TransportEnvelope
│   ├── Outbox/                              # IOutboxStore, DefaultOutboxDispatcher
│   ├── Runtime/                             # ITransportRuntime host
│   ├── Health/                              # ITransportHealthContributor
│   ├── Metrics/                             # ITransportMetrics
│   ├── Telemetry/                           # OpenTelemetry integration
│   └── DependencyInjection/                 # AddHoneyDrunkTransportCore()
│
├── HoneyDrunk.Transport.AzureServiceBus/    # Azure Service Bus provider
│   ├── Publishing/                          # ServiceBusTransportPublisher
│   ├── Consuming/                           # ServiceBusTransportConsumer
│   ├── BlobFallback/                        # Blob storage for failed publishes
│   ├── Health/                              # ServiceBusHealthContributor
│   └── DependencyInjection/                 # AddHoneyDrunkServiceBusTransport()
│
├── HoneyDrunk.Transport.StorageQueue/       # Azure Storage Queue provider
│   ├── Publishing/                          # StorageQueueTransportPublisher
│   ├── Consuming/                           # StorageQueueTransportConsumer
│   ├── Health/                              # StorageQueueHealthContributor
│   └── DependencyInjection/                 # AddHoneyDrunkTransportStorageQueue()
│
├── HoneyDrunk.Transport.InMemory/           # In-memory provider (testing)
│   ├── InMemoryBroker                       # Thread-safe in-memory message store
│   ├── Health/                              # InMemoryHealthContributor
│   └── DependencyInjection/                 # AddHoneyDrunkInMemoryTransport()
│
└── HoneyDrunk.Transport.Tests/              # xUnit test suite

🆕 What's New in v0.1.0

Core Transport

• ITransportPublisher and ITransportConsumer transport abstraction
• ITransportEnvelope immutable message wrapper with Grid context
• EnvelopeFactory integrating TimeProvider and IGridContext
• IMessagePipeline with onion-style middleware execution
• IMessageHandler<T> and MessageProcessingResult for handler contracts
• GridContextPropagationMiddleware, TelemetryMiddleware, LoggingMiddleware
• IOutboxStore and DefaultOutboxDispatcher for transactional outbox
• ITransportHealthContributor for health check participation
• ITransportMetrics for OpenTelemetry integration

Azure Service Bus Provider

• ServiceBusTransportPublisher with topic and queue support
• ServiceBusTransportConsumer with session and subscription support
• BlobFallbackPublisher for failed publish persistence
• ServiceBusHealthContributor for connectivity health checks
• AzureServiceBusOptions with retry and prefetch configuration

Azure Storage Queue Provider

• StorageQueueTransportPublisher with base64 encoding
• StorageQueueTransportConsumer with concurrent polling
• StorageQueueHealthContributor for connectivity health checks
• StorageQueueOptions with dequeue count and visibility timeout

InMemory Provider

• InMemoryBroker thread-safe message store for testing
• InMemoryTransportPublisher and InMemoryTransportConsumer
• InMemoryHealthContributor always-healthy contributor

🔗 Related Projects

Note: HoneyDrunk.Transport depends only on HoneyDrunk.Kernel.Abstractions (contracts, no runtime). Transport providers depend on their respective Azure SDKs.

📄 License

This project is licensed under the MIT License.

Built with 🍯 by HoneyDrunk Studios

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