Allow minimal host to be created without default HostBuilder behavior · Issue #32485 · dotnet/aspnetcore (original) (raw)

Background and Motivation

The default host builder pulls in a ton of dependencies that are rooted for trimming by default. We should have a mode where the minimal host is dependency minimal as well.

These numbers are native AOT net8.0 compiled on linx-x64:

1. WebApplication.CreateBuilder() = 18.7 MB
2. With prototype changes of the proposed API - 12.9 MB

We can stick to the current naming convention and use the existing Create/CreateBuilder methods as the one with the defaults and CreateEmptyBuilder to be the empty one:

Proposed API

namespace Microsoft.AspNetCore.Builder { public class WebApplication { public static WebApplication Create(string[] args); public static WebApplicationBuilder CreateBuilder(); public static WebApplicationBuilder CreateBuilder(string[] args); public static WebApplicationBuilder CreateBuilder(WebApplicationOptions options);

•  public static WebApplicationBuilder CreateEmptyBuilder();

•  public static WebApplicationBuilder CreateEmptyBuilder(string[] args);

•  public static WebApplicationBuilder CreateEmptyBuilder(WebApplicationOptions options);

  } }

namespace Microsoft.Extensions.Hosting { public class GenericHostWebHostBuilderExtensions { public static IHostBuilder ConfigureWebHost(this IHostBuilder builder, Action configure) public static IHostBuilder ConfigureWebHost(this IHostBuilder builder, Action configure, Action configureWebHostBuilder)

•  public static IHostBuilder ConfigureEmptyWebHost(this IHostBuilder builder, Action<IWebHostBuilder> configure, Action<WebHostBuilderOptions> configureWebHostBuilder)

  } }

API Usage

WebApplicationBuilder builder = WebApplication.CreateEmptyBuilder(); builder.Logging.AddConsole();

WebApplication app = builder.Build();

app.MapGet("/", () => "Hello World");

app.Run();

Features

When creating an "empty" web application, the following features will be on (✅) or off (❌) by default. Note that these features can be enabled by the app explicitly after creating the builder/application. They just won't be enabled by default, in order to reduce app size.

• Features
  • StaticWebAssets ❌
  • IHostingStartup ❌
• Configuration
  • command line args ✅
  • appsetttings.json ❌
  • User secrets ❌
  • env variables ✅
• Middleware
  • Routing ✅
  • Auth ❌
  • HostFiltering ❌
  • ForwardedHeaders ❌
• Logging
  • Logging configuration support ❌
  • ConsoleLogger ❌
  • DebugLogger ❌
  • EventSourceLogger ❌
• Servers
  • IIS in proc ❌
  • IIS out of proc ❌
  • Kestrel
    * HTTP 1 ✅
    * HTTPS ❌
    * HTTP 2 ❌
    * HTTP 3 ❌

Alternative Designs

We could create whole new class names for another type of "Application" than a "WebApplication". Something like:

var apiBuilder = ApiApplication.CreateBuilder(args); var apiApp = builder.Builder();

Other possible names include:

• HttpApplication
• ContainerApplication
• CloudApplication
• WorkerApplication

Risks

Potential confusion about which one to call. The template should make it obvious that the "empty" builder doesn't have anything in it, and you need to add things like appsettings, console logging, etc.