ASP NET Core MVC to Azure functions without changing any code

[sjuarezgx]

Is there a tool or framework in the ASP.NET Core ecosystem that works identically to Spring's Cloud Function, allowing you to directly convert Controllers into Functions without the need to re-program them?

I have an API in ASP NET Core, with code like this:

[HttpGet] [Route("ListAirlines")] public async Task<ActionResult> gxep_listairlines( ) { //here my code }

I need to execute all my API as Azure functions without changing that code. I saw that now there is support for ASP NET Core integration with Azure functions. However, I do not see how to re-use my controllers code.

I tried creating a function "proxy" for all my controllers, by inyecting the ApplicationBuilder.

Program.cs:

    var host = new HostBuilder()
.ConfigureFunctionsWorkerDefaults()
.ConfigureServices(services =>
{
	services.AddControllers();
	IMvcBuilder builder = services.AddMvc(option => option.EnableEndpointRouting = false);
	
	services.AddSingleton<IApplicationBuilder>(sp =>
	{
		var appBuilder = new ApplicationBuilder(sp);
                   appBuilder.UseRouting();
		appBuilder.UseEndpoints(endpoints =>
		{
			endpoints.MapControllers();
		});
		return appBuilder;
	});
	AzureFunctionsStartup.ConfigureServices(services);
})
		

Azure function code:

          public class HttpTriggerHandler
          {
           private ICacheService2 _redis;
           private IApplicationBuilder _applicationBuilder;

           public HttpTriggerHandler(IApplicationBuilder applicationBuilder, ICacheService2 redis)
           {
       _applicationBuilder = applicationBuilder;
       if (redis != null && redis.GetType() == typeof(Redis))
	  _redis = redis;
            }

        public async Task<HttpResponseData> Run(
	[HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", "put", "delete", Route = "{*route}")] HttpRequestData 
         req,
	string route, FunctionContext executionContext)
     {
	
	var httpResponseData = req.CreateResponse();
	HttpContext httpAzureContextAccessor = new GXHttpAzureContextAccessor(req, httpResponseData, _redis);
	await _applicationBuilder.Build().Invoke(httpAzureContextAccessor);

	return httpResponseData;

	
       }
           }
           }

But it doesn't work. It seems to be executing the service twice.. I have the following runtime error.

An attempt was made to transition a task to a final state when it had already completed