Kanject.Core.CloudFunction.Abstractions 3.8.7

Kanject.Core.CloudFunction.Abstractions

Provider-neutral contracts for Kanject serverless function hosts: the ICloudFunction host lifecycle, the ICloudFunctionHealthCheck<T> health-check contract, the environment and configuration-source enums, and the [CloudFunctionHost] / [RequireConfigSection<T>] attributes that the Kanject Lambda source generator reads.

Most projects never reference this package directly: Kanject.Core.CloudFunction.Provider.AwsLambda depends on it, so every Lambda project already has it. Reference it on its own when a shared library needs these types without the AWS runtime (for example, a contracts assembly that exposes CloudFunctionEnvironment), or when you implement another host against the same lifecycle.

Installation

dotnet add package Kanject.Core.CloudFunction.Abstractions

Targets .NET 8, .NET 9 and .NET 10. Native AOT / trimming compatible. Depends on Kanject.Core.

Which packages do I need?

AWS Lambda is currently the only provider (CloudProvider.AwsLambda).

Quick start

The two attributes in this package describe a Lambda host declaratively. In a project that also references the AWS Lambda provider and the Kanject.Core.CloudFunction.Aws.Annotations generator, this is a complete host class:

using Kanject.Core.CloudFunction.Abstractions.Attributes;
using Kanject.Core.CloudFunction.Abstractions.Enums;
using Microsoft.Extensions.DependencyInjection;

namespace Orders.Lambda;

public sealed class AppSettings
{
    public string TableName { get; set; } = string.Empty;
}

[CloudFunctionHost(DebugEnvironment = CloudFunctionEnvironment.Development)]
[RequireConfigSection<AppSettings>("AppSettings")]
public partial class Functions
{
    public override void ConfigureServices(IServiceCollection services)
    {
        // AppSettings is a generated property, bound and validated before this method runs.
        services.AddSingleton(AppSettings);
    }
}

The generator supplies the base class, constructor, OnStartup and the assembly-level Lambda serializer. See the Kanject.Core.CloudFunction.Aws.Annotations package for exactly what it emits, and Kanject.Core.CloudFunction.Provider.AwsLambda for how the host runs.

Host lifecycle

ICloudFunction defines four members. The AWS Lambda provider calls them in this order the first time a function instance is constructed:

With [CloudFunctionHost], the generator writes OnStartup for you and you write ConfigureServices; Configure stays optional.

Environments

CloudFunctionEnvironment names the stage a function runs in: Development, Staging, Test, Qa, Production.

The AWS Lambda provider normally takes the environment name from the ASPNETCORE_LAMBDA_ENVIRONMENT or ASPNETCORE_ENVIRONMENT variable. Passing a CloudFunctionEnvironment to the base constructor, or setting DebugEnvironment on [CloudFunctionHost] (Debug builds only), pins it to the member name instead. The name selects appsettings.{Environment}.json.

Declarative host attributes

• [CloudFunctionHost] marks a partial class as a function host. Its properties (Provider, DebugEnvironment, ConfigurationSource, DebugFetchSecretPathFromAppSettings, EmitLambdaSerializer, EnableAot) choose what the generator emits. Use one per assembly.
• [RequireConfigSection<T>(sectionName)] declares that a configuration section must bind to T at cold start. You can apply it more than once. For each occurrence the generator emits a bind-or-throw check and a property that exposes the bound instance. It names that property from PropertyName if you set it, otherwise from the section name (when that is a valid C# identifier), otherwise from T's simple name. The attribute only validates: it does not register IOptions<T>.

ConfigurationSource has two values. None (the default) adds no source. AwsSystemManagerParameterStore wires AWS Systems Manager Parameter Store through the Kanject.Core.Api.Aws.Extensions package, which the consuming project must reference.

The generator package documents the full option reference and its analyzer rules.

Health-check contract

ICloudFunctionHealthCheck<TCloudFunction> is a fluent registration API for startup and on-demand health checks. The AWS Lambda CloudFunction implements it:

The registrations are stored as IHealthCheckEndpointModel / IHealthCheckFuncModel instances (both derive from IHealthCheckModel). HealthCheckEndpointModel and HealthCheckFuncWithModel are the concrete implementations.

Public surface at a glance

Namespaces: Kanject.Core.CloudFunction.Abstractions.Interfaces, .Attributes, .Enums and .Models.

Related packages

License

Licensed under the Kanject Code Libraries License Agreement (KCLLA); the full text ships in this package as LICENSE.md. Organizations whose trailing-twelve-month gross revenue and total funding raised are each below US$250,000 may use it at no cost under the Free Tier. At or above either threshold a commercial license is required — contact commercial@kanjectbusiness.com.