Franz.Common.Messaging.Kafka 1.7.8

Franz.Common.Messaging.Kafka

A Kafka transport integration for the Franz Framework, designed to provide clean, deterministic, and production-grade interaction with Kafka topics, producers, and consumers.

This package focuses exclusively on Kafka transport concerns: configuration, producers, consumers, serialization, and transactions.

🧱 Hosting, background execution, and listeners are intentionally not handled here. They live in Franz.Common.Messaging.Hosting.Kafka.

✨ Features

Kafka Transport & Configuration

• Centralized Kafka configuration via MessagingOptions
• ConnectionProvider and ConnectionFactoryProvider for managing Kafka connections
• Deterministic, DI-friendly Kafka setup

Kafka Producers

• MessagingPublisher for publishing integration events
• MessagingSender for point-to-point messaging
• Automatic topic resolution and naming strategies

Kafka Consumers

• Native usage of Confluent.Kafka.IConsumer<string, string>
• IKafkaConsumerFactory as the single authority for consumer creation
• Correct lifetime management aligned with Kafka consumer group semantics

Modeling

• KafkaModel and ModelProvider for Kafka-based domain modeling
• Strong separation between messaging models and business logic

Serialization

• IMessageDeserializer
• JsonMessageDeserializer
• Deterministic JSON serialization using Franz messaging contracts

Transactions

• MessagingTransaction for Kafka-backed transactional workflows

Utilities

• ExchangeNamer and TopicNamer for consistent topic naming
• Messaging helpers shared across Franz transports

Dependency Injection

• Fluent ServiceCollectionExtensions for Kafka transport registration
• No accidental hosting or background execution side effects

🧭 Architectural Scope

This package is transport-only.

This separation ensures:

• Testability with Testcontainers
• Clean CI/CD pipelines
• No hidden threads or background services
• Reuse in CLI tools, workers, APIs, and serverless contexts

📦 Dependencies

This package depends on:

• Confluent.Kafka (2.3.0)
  Core Kafka client implementation

• Franz.Common.Messaging
  Core messaging abstractions and contracts

• Franz.Common.Annotations
  Messaging and modeling annotations

⚠️ Hosting integration is intentionally excluded. Use Franz.Common.Messaging.Hosting.Kafka for background listeners.

📥 Installation

From NuGet

dotnet add package Franz.Common.Messaging.Kafka

🚀 Usage

1️⃣ Register Kafka Transport

using Franz.Common.Messaging.Kafka.Extensions;

public void ConfigureServices(IServiceCollection services)
{
    services.AddKafkaMessaging(configuration);
}

This registers:

• Kafka producers
• Kafka senders
• Kafka consumers (transport only)

No hosted services are started.

2️⃣ Publish Messages

public class OrderPublisher
{
    private readonly IMessagingPublisher _publisher;

    public OrderPublisher(IMessagingPublisher publisher)
    {
        _publisher = publisher;
    }

    public async Task PublishAsync(OrderCreatedEvent evt)
    {
        await _publisher.PublishAsync(evt);
    }
}

3️⃣ Send Messages

public class PaymentSender
{
    private readonly IMessagingSender _sender;

    public PaymentSender(IMessagingSender sender)
    {
        _sender = sender;
    }

    public async Task SendAsync(PaymentCommand command)
    {
        await _sender.SendAsync(command);
    }
}

4️⃣ Kafka Consumers (Important)

Franz does not re-abstract Kafka consumers.

Consumers are provided directly by Confluent:

IConsumer<string, string>

They are:

• Created by IKafkaConsumerFactory
• Registered as long-lived singletons
• Fully compatible with Confluent.Kafka tooling and documentation

This avoids:

• Interface drift
• Partial re-implementations
• Subtle incompatibilities during upgrades

🧪 Testing & CI

This design is fully compatible with:

• Testcontainers (Kafka)
• Azure DevOps pipelines
• Docker-based integration tests
• Local developer environments

Because:

• No background services auto-start
• No implicit threads are created
• Kafka consumers are explicit and controlled

🔗 Integration with the Franz Framework

This package integrates with:

• Franz.Common.Messaging
• Franz.Common.Messaging.Hosting.Kafka (optional, for background execution)
• Franz.Common.Mediator
• Franz.Common.EntityFramework
• Franz.Common.Business

Kafka is treated as a transport, not an execution model.

🧾 Versioning & Changelog

Current Version: 1.7.8

Version 1.7.01

• 🧱 Corrected transport vs hosting separation
• 🔌 Removed Kafka consumer re-abstraction
• 🏭 Centralized consumer creation via IKafkaConsumerFactory
• ♻️ Fixed DI lifetimes for Kafka consumers
• 🧩 Clean separation between messaging and hosting layers
• 🧪 Improved Testcontainers and CI reliability

📄 License

MIT License See the LICENSE file for details.

🧠 Final Note

This package intentionally mirrors enterprise messaging frameworks (MassTransit, NServiceBus, Brighter) by enforcing:

Transport ≠ Hosting

That separation is what makes Franz:

• Predictable
• Testable
• Scalable
• Production-safe