The sample uses the Generic Host and the Microsoft.
NuGet package to host NServiceBus as a Windows Service.
Code walk-through
The builder configures NServiceBus using the NServiceBus.
package, including the critical error action that will shut down the application or service in case of a critical error.
var endpointConfiguration = new EndpointConfiguration("Samples.Hosting.GenericHost");
var routing = endpointConfiguration.UseTransport(new LearningTransport());
endpointConfiguration.UseSerialization<SystemJsonSerializer>();
endpointConfiguration.DefineCriticalErrorAction(OnCriticalError);
endpointConfiguration.EnableInstallers();
builder.UseNServiceBus(endpointConfiguration);
The critical error action:
static async Task OnCriticalError(ICriticalErrorContext context, CancellationToken cancellationToken)
{
var fatalMessage =
$"The following critical error was encountered:{Environment.NewLine}{context.Error}{Environment.NewLine}Process is shutting down. StackTrace: {Environment.NewLine}{context.Exception.StackTrace}";
try
{
await context.Stop(cancellationToken);
}
finally
{
Environment.FailFast(fatalMessage, context.Exception);
}
}
To simulate work, a BackgroundService called Worker
is registered as a hosted service:
builder.Services.AddHostedService<Worker>();
The IMessageSession
is injected into the Worker
constructor, and the Worker
sends messages when it is executed.
class Worker(IMessageSession messageSession) : BackgroundService
{
protected override async Task ExecuteAsync(CancellationToken cancellationToken)
{
try
{
var number = 0;
while (!cancellationToken.IsCancellationRequested)
{
await messageSession.SendLocal(new MyMessage { Number = number++ }, cancellationToken);
await Task.Delay(1000, cancellationToken);
}
}
catch (OperationCanceledException)
{
// graceful shutdown
}
}
}
Running the sample as a Windows Service
- Start PowerShell with elevated permissions
- Run
dotnet publish
in the directory of the sample; for example:C:\
samples\ generic-host - Run
New-Service -Name WorkerTest -BinaryPathName "C:\
samples\ generic-host\ bin\ Debug\ {framework}\ publish\ GenericHost. exe" - Run
Start-Service WorkerTest
- Go to the Event Viewer under
Windows Logs\
and observe event log entries from sourceApplications GenericHost
with the following content:
Category: MyMessageHandler
EventId: 0
Received message #{Number}
- Once done, run
Stop-Service WorkerTest
andRemove-Service WorkerTest