Attributes reference

Attributes reference

ResourceKit ships two public attributes in the Purview.Aspire.ResourceKit namespace. Both are generated into the consuming compilation by the bundled source generator, so you do not reference a separate attribute package.

HostKitAttribute ([HostKit])

Marks the single host kit class per compilation. Exactly one host kit may exist per compilation (SG0004).

[HostKit]
sealed partial class ShopHostKit;

Optional named arguments:

Argument	Type	Default	Purpose
Name	string?	null	Controls generated naming.
ExtensionMethodName	string?	Derived from host kit name	Overrides the generated builder extension name (for example AddAspireResourceKit()).
GenerateOptions	bool	true	Enables/disables generated host options.

ResourceDefinitionAttribute ([ResourceDefinition])

Marks a resource kit class that participates in generation.

[ResourceDefinition<ProjectResource>("api", PropertyName = "API")]
partial class APIResourceKit;

Options:

Argument	Type	Default	Purpose
Name	string?	Derived from class name (suffix trimmed)	Logical Aspire resource name.
PropertyName	string?	Derived from class name	Generated host property name. Must be a valid C# identifier (SG0008).
AspireResourceType	generic type argument	null	The Aspire IResource type (generic style only).

ResourceDefinition vs ResourceDefinition<TResource>

ResourceKit supports two declaration styles with different base-type behavior.

Generic attribute (recommended)

Use [ResourceDefinition<TResource>] when you want the resource type declared directly on the attribute.

[ResourceDefinition<ProjectResource>("api")]
partial class APIResourceKit
{
    protected override IResourceBuilder<ProjectResource> BuildResource(IDistributedApplicationBuilder builder)
        => builder.AddProject<Projects.Example_Service>(Name);
}

• Do not declare an explicit base type on the class (SG0015).
• The generator supplies the host-specific base in generated partial code.

The type argument may be:

• an Aspire resource type implementing IResource (used as-is), or
• an IProjectMetadata type (the type accepted by AddProject<TProject>()), which is mapped to ProjectResource for the generated base class.

Anything else is rejected (SG0016).

Non-generic attribute

Use [ResourceDefinition] when you prefer (or need) to specify the resource type through an explicit base type.

[ResourceDefinition("api")]
partial class APIResourceKit : ResourceKitBase<ProjectResource>
{
    protected override IResourceBuilder<ProjectResource> BuildResource(IDistributedApplicationBuilder builder)
        => builder.AddProject<Projects.Example_Service>(Name);
}

• You must declare an explicit valid base type (SG0014).
• The base must derive from the generated ResourceKitBase<TResource> or the runtime ResourceKitBase<THostKit, TResource> (SG0006).

Rules summary

Situation	Diagnostic	Severity
Both styles on one class	SG0013	Error
Generic style with explicit base	SG0015	Error
Non-generic style without explicit base	SG0014	Error
Explicit base not derived from a valid Resource Kit base	SG0006	Error
Resource type cannot be inferred/found	SG0016	Error

Constructors

Attributed classes must not declare constructors with parameters or executable constructor bodies (SG0012). The generator supplies the constructor wiring in generated partial code; the primary constructor of a resource kit receives the host kit and options. In the manual (non-generated) pattern you declare it yourself — see Examples.

See also

• Generated Output — what the generator emits from these attributes.
• Diagnostics — full diagnostic reference.