ApplicationBuilder (generic - includes worker services)

.NET Generic Host - .NET

Learn about the .NET Generic Host, which is responsible for app startup and lifetime management.

https://learn.microsoft.com/en-us/dotnet/core/extensions/generic-host?tabs=appbuilder

On how to implement a worker service look at

Template

• Calls a CreateApplicationBuilder method to create and configure a builder object.

• Calls Build() to create an IHost instance.

• Calls Run or RunAsync method on the host object.

using Example.WorkerService;

HostApplicationBuilder builder = Host.CreateApplicationBuilder(args);
builder.Services.AddHostedService<Worker>(); // registered via DI

IHost host = builder.Build();
host.Run();

Settings

When you build the following settings are made

• Sets the content root to the path returned by GetCurrentDirectory().

• Loads host configuration from:
  • Environment variables prefixed with DOTNET_.
  • Command-line arguments.

• Loads app configuration from:
  • appsettings.json.
  • appsettings.{Environment}.json.
  • Secret Manager when the app runs in the Development environment.
  • Environment variables.
  • Command-line arguments.

• Adds the following logging providers:
  • Console
  • Debug
  • EventSource
  • EventLog (only when running on Windows)

• Enables scope validation and dependency validation when the environment is Development.

Framework-Provided Services

The following services are registered on build

• IHostApplicationLifetime - interface to handle lifecycle events of service

• IHostLifetime - determines when the host starts and stops

• IHostEnvironment - get metadata on the environment such as isProduction or app name