✉️ MyServiceBus

MyServiceBus (working title) is a lightweight, asynchronous service-bus runtime for Java and .NET, inspired by MassTransit.

It provides a consistent, opinionated broker-backed messaging model while remaining compatible with the documented MassTransit RabbitMQ and Azure Service Bus profiles. This makes it possible for Java and .NET services to send, publish, and consume messages across platforms, or interoperate with MassTransit in the verified compatibility scenarios.

See samples below.

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Getting started with .NET

Install the RabbitMQ transport for a broker-backed application. It brings in the core runtime and abstractions transitively:

dotnet add package Sundstrom.MyServiceBus.RabbitMq --version 0.1.0-preview.2

For an application that only needs the core runtime and its in-memory mediator, install the main package directly:

dotnet add package Sundstrom.MyServiceBus --version 0.1.0-preview.2

Continue with the .NET quick start to register the bus, configure RabbitMQ, add a consumer, and publish a message. The feature walkthrough covers the complete C# and Java APIs.

NuGet packages

Package	Purpose
Sundstrom.MyServiceBus	Core messaging runtime and in-memory mediator
Sundstrom.MyServiceBus.Abstractions	Portable message contracts, contexts, and endpoint abstractions
Sundstrom.MyServiceBus.RabbitMq	RabbitMQ transport and configuration integration
Sundstrom.MyServiceBus.AzureServiceBus	Verified-preview Azure Service Bus transport for direct send and publish/subscribe
Sundstrom.MyServiceBus.Testing	In-memory test harness and testing utilities

All packages currently use the same preview version. Install Sundstrom.MyServiceBus.Testing separately in test projects when the test harness is needed.

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Getting started with Java

Add the RabbitMQ module to a Gradle application. It brings in the Java runtime and its foundational modules transitively:

dependencies {
    implementation 'io.github.marinasundstrom.myservicebus:myservicebus-rabbitmq:0.1.0-preview.2'
}

For Maven applications:

<dependency>
  <groupId>io.github.marinasundstrom.myservicebus</groupId>
  <artifactId>myservicebus-rabbitmq</artifactId>
  <version>0.1.0-preview.2</version>
</dependency>

Continue with the Java quick start or the detailed Java guide.

Maven Central artifacts

Artifact	Purpose
io.github.marinasundstrom.myservicebus:myservicebus	Core messaging runtime and in-memory mediator
io.github.marinasundstrom.myservicebus:myservicebus-abstractions	Portable messaging contracts and abstractions
io.github.marinasundstrom.myservicebus:myservicebus-di	Dependency-injection abstractions
io.github.marinasundstrom.myservicebus:myservicebus-logging	Logging abstractions and adapters
io.github.marinasundstrom.myservicebus:myservicebus-tasks	Asynchronous task and cancellation abstractions
io.github.marinasundstrom.myservicebus:myservicebus-rabbitmq	RabbitMQ transport and configuration integration
io.github.marinasundstrom.myservicebus:myservicebus-azure-service-bus	Verified-preview Azure Service Bus transport for direct send and publish/subscribe
io.github.marinasundstrom.myservicebus:myservicebus-testing	In-memory test harness and testing utilities

All Java artifacts use the same version as the corresponding NuGet release.

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What is MyServiceBus?

MyServiceBus defines a stable messaging runtime with concepts such as:

• publish vs send
• consumers
• request/response
• retries and error handling
• middleware / pipeline behaviors
• scheduling
• in-memory testing

These portable concepts remain consistent across supported transport profiles, while broker-specific capabilities and guarantees remain explicit.

Unlike most Java messaging solutions, MyServiceBus does not require a framework-wide commitment (such as Spring). It can be used as a self-contained runtime, integrated into an existing application, or composed via factories and decorators—depending on project needs.

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Goals

• Provide a focused, community-driven alternative for basic MassTransit-style broker-backed messaging scenarios.
• Preserve a MassTransit-compatible messaging model across Java and .NET.
• Enable Java services to easily connect with .NET/C# services using shared messaging semantics.
• Offer a familiar experience for developers coming from .NET.
• Maintain feature parity and consistent behavior between the C# and Java implementations.
  See the design guidelines for architectural and behavioral parity.

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Features

• Fire-and-forget message sending
• Publish/subscribe pattern
• Request/response pattern (RequestClient and scoped client factory)
• RabbitMQ transport
• Verified-preview Azure Service Bus transport with corresponding C# and Java implementations
• In-memory mediator and test harness
• Compatibility with MassTransit message envelopes
• Raw JSON messages
• Fault and error handling semantics aligned with MassTransit
• Middleware / pipeline behaviors
• OpenTelemetry support
• Java and C# implementations with aligned semantics

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Specification

• MyServiceBus Specification
• ServiceBus Transport Specification
• Differences from MassTransit

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Building from source

Prerequisites

• .NET SDK
• Java (for the Java modules): JDK 17
• Gradle

Building

• .NET

  dotnet restore
  dotnet build

• Java Java build and run instructions are documented in src/Java/README.md.

Running tests

• .NET

  dotnet test

• Java

  gradle test

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Quick start

Minimal steps to configure MyServiceBus and publish a message. For a broader tour of the library, see the feature walkthrough, which covers both basic and advanced usage.

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C#

Register the bus with the ASP.NET host builder:

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddServiceBus(x =>
{
    x.AddConsumer<SubmitOrderConsumer>();

    x.UsingRabbitMq((context, cfg) =>
    {
        cfg.ConfigureEndpoints(context);
    });
});

var app = builder.Build();

await app.StartAsync();

var bus = app.Services.GetRequiredService<IMessageBus>();

Define the messages and consumer:

public record SubmitOrder(Guid OrderId);
public record OrderSubmitted(Guid OrderId);

class SubmitOrderConsumer : IConsumer<SubmitOrder>
{
    public Task Consume(ConsumeContext<SubmitOrder> context) =>
        context.Publish(new OrderSubmitted(context.Message.OrderId));
}

Publish the SubmitOrder message 🚀:

await bus.Publish(
    new SubmitOrder(Guid.NewGuid()),
    ctx => ctx.Headers["trace-id"] = Guid.NewGuid()
);

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Java

Register the bus:

ServiceCollection services = ServiceCollection.create();

services.from(MessageBusServices.class)
        .addServiceBus(cfg -> {
            cfg.addConsumer(SubmitOrderConsumer.class);
            cfg.using(
                RabbitMqFactoryConfigurator.class,
                (context, rbCfg) -> rbCfg.configureEndpoints(context)
            );
        });

ServiceProvider provider = services.buildServiceProvider();
MessageBus bus = provider.getService(MessageBus.class);

bus.start().join();

Define the messages and consumer:

record SubmitOrder(UUID orderId) { }
record OrderSubmitted(UUID orderId) { }

class SubmitOrderConsumer implements Consumer<SubmitOrder> {
    @Override
    public CompletableFuture<Void> consume(ConsumeContext<SubmitOrder> context) {
        return context.publish(
            new OrderSubmitted(context.getMessage().orderId())
        );
    }
}

Publish the SubmitOrder message:

bus.publish(
    new SubmitOrder(UUID.randomUUID()),
    ctx -> ctx.getHeaders().put("trace-id", UUID.randomUUID())
).join();

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Repository structure

• src/ – C# and Java source code
• test/ – Test projects
• docs/ – Documentation, including the feature walkthrough and specifications Development documents live in docs/development/
• docker-compose.yml – Docker configuration for local infrastructure

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Java Quickstart

See src/Java/README.md for detailed Java build and run instructions, including JDK 17 prerequisites and running the test application.

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Contributing

Contributions are welcome! Please run dotnet test before submitting a pull request and follow the coding conventions described in AGENTS.md.

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License

This project is licensed under the MIT License.