Franz.Common.Messaging.Hosting.Kafka 1.6.19

Franz.Common.Messaging.Hosting.Kafka

A dedicated hosting library within the Franz Framework that provides Kafka-specific hosted services and dependency injection extensions.
This package bridges the Kafka transport layer (Franz.Common.Messaging.Kafka) with the .NET hosting infrastructure (Microsoft.Extensions.Hosting).

✨ Features

• Hosted Services

  • KafkaHostedService – continuously consumes Kafka messages and dispatches them.
  • OutboxHostedService – publishes stored outbox messages to Kafka in the background.
  • MessagingHostedService – general-purpose hosted message orchestrator.

• Dependency Injection Extensions

  • KafkaHostingServiceCollectionExtensions simplifies service registration in Startup/Program.cs.
  • Provides one-liners like AddKafkaHostedListener() and AddOutboxHostedListener().

• Separation of Concerns

  • Keeps transport logic (Franz.Common.Messaging.Kafka) separate from hosting concerns.
  • Makes testing listeners independent of the hosting runtime.

• Observability

  • Structured logging with emoji conventions (✅ success, ⚠️ retries, 🔥 DLQ).
  • Compatible with OpenTelemetry for distributed tracing.

📂 Project Structure

Franz.Common.Messaging.Hosting.Kafka/
├── Extensions/
│    └── KafkaHostingServiceCollectionExtensions.cs
├── HostedServices/
│    ├── KafkaHostedService.cs
│    ├── MessagingHostedService.cs
│    └── OutboxHostedService.cs
└── readme.md

⚙️ Dependencies

• Microsoft.Extensions.Hosting (8.0.0)
• Microsoft.Extensions.DependencyInjection.Abstractions (8.0.0)
• Franz.Common.Messaging – core messaging abstractions
• Franz.Common.Messaging.Kafka – Kafka transport adapter
• Franz.Common.Messaging.Hosting – base hosting abstractions

🚀 Usage

1. Register Kafka Hosted Services

In Program.cs or Startup.cs:

using Franz.Common.Messaging.Hosting.Kafka.Extensions;

var host = Host.CreateDefaultBuilder(args)
    .ConfigureServices((context, services) =>
    {
        services.AddKafkaHostedListener(context.Configuration);
        services.AddOutboxHostedListener(context.Configuration);
    })
    .Build();

await host.RunAsync();

2. Kafka Hosted Service

Runs in the background to consume Kafka messages and dispatch them via the mediator:

public class KafkaHostedService : BackgroundService
{
    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        // Consumes Kafka messages and dispatches
    }
}

3. Outbox Hosted Service

Ensures pending messages in MongoDB/SQL outbox are published to Kafka reliably:

public class OutboxHostedService : BackgroundService
{
    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        // Reads outbox, sends to Kafka, handles retries/DLQ
    }
}

📊 Observability

• Emoji logging (✅ processed, ⚠️ retry, 🔥 DLQ, 💤 idle).
• Integrated with MessageContextAccessor for correlation IDs.
• Tracing compatible with OpenTelemetry.

📝 Version Information

• Current Version: 1.6.19
• Part of the private Franz Framework ecosystem.

📜 License

This library is licensed under the MIT License. See the LICENSE file for details.

📖 Changelog

Version 1.6.2

• Introduced KafkaHostedService to run Kafka listeners inside .NET host.
• Added OutboxHostedService to bridge Mongo outbox with Kafka publishing.
• Added KafkaHostingServiceCollectionExtensions for simple DI registration.
• Unified hosted services with MessageContextAccessor and inbox idempotency support.
• Improved logging with emoji conventions and OpenTelemetry hooks.