Hosting

Component: NServiceBus
Nuget Package: NServiceBus Version: 5.x

At its core NServiceBus is a library, as such it can be hosted in any .NET process.

There are several approaches to hosting.

Self-hosting

"Self-hosting" is a general term used to refer to when the application code takes full control over all facets of hosting NServiceBus. This includes the following actions:

Related:

When self-hosting, the user is responsible for creating and starting the endpoint instance

var busConfiguration = new BusConfiguration();
// Apply configuration
var startableBus = Bus.Create(busConfiguration);
var bus = startableBus.Start();

The user is also responsible for properly shutting down the endpoint when it is no longer needed (usually when the application terminates).

bus.Dispose();

Windows Service Hosting

A Windows Service is the most common way NServiceBus is hosted.

Related:

Send-only hosting

A "Send-only endpoint" is used when the only purpose is sending messages and no message processing is required in that endpoint. Common use cases include websites, console application and windows application. This is the code for starting an endpoint in send only mode.

var busConfiguration = new BusConfiguration();
var sendOnlyBus = Bus.CreateSendOnly(busConfiguration);

The only configuration when running in this mode is the destination when Sending a message.

Web Hosting

NServiceBus can be hosted in any web technology that support .NET. See Web Application Hosting.

Multi-Hosting

"Multi-hosting" refers to hosing multiple NServiceBus endpoints in a single .NET process.

It is safe for multiple endpoints can share the same AppDomain or, alternatively use a multiple AppDomains approach.

Related:

Accessing the bus

Most usages of the bus will occur where the NServiceBus APIs are used. For example Handlers and Sagas. However there are other scenarios that may require an alternative approach where the user needs to directly access the bus from outside of the framework.

Using a Container

NServiceBus support dependency injection via use Containers. At startup, the instance of a bus session will be injected into the configured container and can be access via that container.

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Static variable

For many scenarios a container is not required. In these cases a simple public static variable on the startup class will suffice. This variable can then be access globally in the application. For example:

  • In windows service or console the variable would be placed on the Program.cs
  • In a Website the variable would be placed on the Global.cs.

Alternatively the static variable could be placed on a (more appropriately named) helper class.

public static class EndpointInstance
{
    public static IBus Endpoint { get; private set; }
    public static void SetInstance(IBus endpoint)
    {
        if (Endpoint != null)
        {
            throw new Exception("Endpoint already set.");
        }
        Endpoint = endpoint;
    }
}

"Custom Host" Solutions

A "Custom Host" refers to a process or library that wraps the NServiceBus library to take partial control of configuration, startup and shutdown. This Host then exposes extension points for common activities and uses conventions and/or sensible defaults for many other configuration options.

NServiceBus Host

The NServiceBus Host takes a more opinionated approach to hosting. It allows the execution as both a windows service and a console application (for development). It also adds the concepts of Profiles and Custom installation.

Related:

Hosting in Azure

There are a variety of ways to host in Azure. Depending on the requirements self-hosting may be an option or, alternatively, a custom Azure host may be required. See Hosting in Azure Cloud Services for more information.

Related:

Samples

Related Articles

Hosting in Azure Cloud Services

Using Azure Cloud Services to host NServiceBus.

NServiceBus Host

Avoid writing repeat configuration code, host the endpoints in a Windows Service, and change technologies without code.


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