ASP.NET Core hosting extensions for AWS Lambda, providing timeout-aware cancellation tokens and graceful request handling. Links Lambda timeout detection with HTTP request cancellation for improved reliability and proper resource cleanup in serverless applications.
LayeredCraft Lambda ASP.NET Core Hosting Extensions
Extensions and middleware for Amazon.Lambda.AspNetCoreServer.Hosting. Provides ASP.NET Core components designed specifically for AWS Lambda hosting, delivering improved reliability, observability, and developer experience.
Features
⏱️ Lambda Timeout Handling: Intelligent timeout middleware that links Lambda execution limits with HTTP request cancellation
🔄 Graceful Shutdown: Proper handling of approaching Lambda timeouts with configurable safety buffers
🛠️ Developer Experience: Standard CancellationToken patterns work seamlessly in Lambda environments
🧪 Local Development: Pass-through behavior when running outside Lambda (Kestrel, IIS Express)
📊 Observability: Structured logging with detailed timeout and cancellation telemetry
using LayeredCraft.Lambda.AspNetCore.Hosting.Extensions;
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
// Add Lambda timeout-aware cancellation early in the pipeline
app.UseLambdaTimeoutLinkedCancellation();
// Your other middleware
app.UseRouting();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
With Custom Safety Buffer
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
// Custom safety buffer of 500ms for cleanup operations
app.UseLambdaTimeoutLinkedCancellation(TimeSpan.FromMilliseconds(500));
app.UseRouting();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
Using Cancellation in Controllers
[ApiController]
[Route("api/[controller]")]
public class DataController : ControllerBase
{
private readonly IDataService _dataService;
public DataController(IDataService dataService)
{
_dataService = dataService;
}
[HttpGet]
public async Task<IActionResult> GetData(CancellationToken cancellationToken)
{
try
{
// This will be cancelled if Lambda timeout approaches
var data = await _dataService.GetDataAsync(cancellationToken);
return Ok(data);
}
catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
{
// Lambda timeout occurred - return appropriate response
return StatusCode(504, "Request timeout");
}
}
}
The LambdaTimeoutLinkMiddleware creates a sophisticated cancellation token that triggers when either:
Client disconnects or the server aborts the request (standard ASP.NET Core behavior)
Lambda timeout approaches (calculated from ILambdaContext.RemainingTime with safety buffer)
The middleware replaces HttpContext.RequestAborted with this linked token, enabling downstream code to respond to Lambda timeouts through standard CancellationToken patterns.
Safety Buffer
The configurable safety buffer (default: 250ms) ensures your application has time to:
Complete cleanup operations
Write final log entries
Return appropriate HTTP status codes
Flush telemetry data
Local Development
When running locally (Kestrel, IIS Express) where ILambdaContext is unavailable, the middleware operates as a pass-through with only standard client disconnect cancellation active.
Status Codes
The middleware automatically sets appropriate HTTP status codes on timeout:
# Clone the repository
git clone https://github.com/LayeredCraft/lambda-aspnetcore-hosting-extensions.git
cd lambda-aspnetcore-hosting-extensions
# Restore dependencies
dotnet restore
# Build the project
dotnet build
# Run tests
dotnet test
