Generated output

Generated output

From your [HostKit] and [ResourceDefinition] declarations, the generator emits all of the boilerplate that wires your resource kits together. The generated code is marked with [CompilerGenerated] and [GeneratedCode("HostKitGenerator", ...)] and is excluded from code coverage.

What gets generated

• a host resource base class (the concrete host kit deriving from HostKitBase<THostKit>),
• resource properties on the host (one per resource definition),
• host + per-resource options (when GenerateOptions is enabled),
• a typed ResourceKitBase<TResource> base per host kit,
• each resource kit’s sealed partial skeleton with a constructor and Options property,
• an AppHost extension method to build/configure/register the host kit.

Host kit members

For every [ResourceDefinition], the host kit gets a lazily initialized property. Accessing a property before Build throws, and setting it twice throws:

public Purview.Aspire.ResourceKit.Example.AppHost.AppModels.Resources.ExampleAPIKit ExampleAPI
{
    get
    {
        return field ?? throw new global::System.InvalidOperationException(
            "The 'ExampleAPI' resource has not been initialized. Call Build first.");
    }
    private set { ... }
}

Generated host Build/Configure

Build instantiates each resource kit from its options, registers it with the base class, invokes the optional onBuilt callback, then calls base.Build(builder):

public override void Build(global::Aspire.Hosting.IDistributedApplicationBuilder builder)
{
    // Creating ExampleAPIKit Resource Kit.
    ExampleAPI = new(this, Options.ExampleAPI);

    // Register the discovered app resources with the base class.
    AddResource(ExampleAPI);

    // Now the additional post-build func builder
    onBuilt?.Invoke(this, builder);

    base.Build(builder);
}

public override void Configure()
{
    base.Configure();
    onConfigured?.Invoke(this);
}

Generated resource kit skeleton

Each resource kit derives from the generated ResourceKitBase<TResource> and gains a constructor that accepts the host kit and its options:

internal sealed partial class ExampleAPIKit : global::Purview.Aspire.ResourceKit.ResourceKitBase<ProjectResource>
{
    public ExampleAPIKit(ExampleHostKit hostKit, ExampleAPIKitOptions options)
        : base(hostKit, (options ?? throw new global::System.ArgumentNullException(nameof(options))).Name)
    {
        Options = options;
        IsEnabled = options.IsEnabled;
    }

    public ExampleAPIKitOptions Options { get; }
}

Your partial class supplies BuildResource(...) and optionally ConfigureResource() and IsResourceEnabled(builder).

Generated options

Host options are nested under the host kit and expose a SectionName constant plus one nested options object per resource:

public sealed partial class ExampleHostKitOptions
{
    public const string SectionName = "ExampleHostKit";

    public ExampleAPIKitOptions ExampleAPI { get; init; } = new();
}

Each resource options type carries Name (defaulting to the logical resource name) and IsEnabled:

public sealed partial class ExampleAPIKitOptions
{
    [global::System.ComponentModel.DataAnnotations.Required(AllowEmptyStrings = false)]
    public string Name { get; set; } = "api";

    public bool IsEnabled { get; set; } = true;
}

Name is decorated with [Required(AllowEmptyStrings = false)]; the generated extension method calls ValidateOnStart().

Generated extension method

The extension method binds host options from configuration, creates the host kit, and runs the full lifecycle:

public static global::Aspire.Hosting.IDistributedApplicationBuilder AddAspireResourceKit(
    this global::Aspire.Hosting.IDistributedApplicationBuilder builder,
    global::System.Action<ExampleHostKit, global::Aspire.Hosting.IDistributedApplicationBuilder>? onBuilt = null,
    global::System.Action<ExampleHostKit>? onConfigured = null,
    global::System.Action<global::Microsoft.Extensions.Options.OptionsBuilder<ExampleHostKitOptions>>? configureOptions = null
)
{
    var optionsBuilder = builder.Services
        .AddOptions<ExampleHostKitOptions>()
        .BindConfiguration(ExampleHostKitOptions.SectionName);

    configureOptions?.Invoke(optionsBuilder);
    optionsBuilder.ValidateOnStart();

    var hostKitOptions = builder.Configuration
        .GetSection(ExampleHostKitOptions.SectionName)
        .Get<ExampleHostKitOptions>() ?? new();

    ExampleHostKit hostKit = new(onBuilt, onConfigured, hostKitOptions);
    hostKit.Build(builder);
    hostKit.Configure();
    builder.Services.AddSingleton(hostKit);
    return builder;
}

The extension method name defaults to Add<HostKitName>() (for example AddAspireResourceKit() for ExampleHostKit) and can be overridden with HostKitAttribute.ExtensionMethodName.

See also

• Attributes Reference
• Lifecycle: Build vs Configure
• Configuration and Options