Hosting

Atom uses the standard .NET IHost / HostApplicationBuilder infrastructure under the hood. The AtomHost class provides convenience methods for setting up and running the host.

AtomHost.Run<T>(args)

The simplest way to start an Atom build:

AtomHost.Run<Build>(args);

This is what [GenerateEntryPoint] generates for you in Program.cs.

AtomHost.CreateAtomBuilder<T>(args)

For custom host configuration, use the builder pattern:

var builder = AtomHost.CreateAtomBuilder<Build>(args);

// Add your own services
builder.Services.AddSingleton<IMyService, MyService>();

// Add configuration sources
builder.Configuration.AddJsonFile("custom.json", optional: true);

builder.Build().UseAtom().Run();

The builder automatically:

• Loads appsettings.json and appsettings.{env}.json
• Reads the DOTNET_ENVIRONMENT / ASPNETCORE_ENVIRONMENT variable
• Registers all core Atom services

[GenerateEntryPoint]

Apply this attribute to your build definition class to have the source generator create the entry point:

[BuildDefinition]
[GenerateEntryPoint]
internal partial class Build : BuildDefinition { /* ... */ }

If you need full control over Main, omit this attribute and write your own.

[ConfigureHostBuilder] / [ConfigureHost]

Module interfaces can use [ConfigureHostBuilder] to have the source generator call a static ConfigureBuilder method when the interface is implemented:

[ConfigureHostBuilder]
public partial interface IGitVersion
{
    protected static partial void ConfigureBuilder(IHostApplicationBuilder builder) =>
        builder.Services
            .AddSingleton<IBuildIdProvider, GitVersionBuildIdProvider>()
            .AddSingleton<IBuildVersionProvider, GitVersionBuildVersionProvider>();
}

When your Build class implements IGitVersion, the generated code automatically calls ConfigureBuilder during host setup.

ConfigureDefinitionHost

Override this virtual method on your build class for one-off service registration:

public override void ConfigureDefinitionHost(IHostApplicationBuilder builder)
{
    base.ConfigureDefinitionHost(builder);
    builder.Services.AddSingleton<IMyService, MyService>();
}

Next Steps

→ Lifecycle Hooks