ThrottlingTroll.AzureFunctions

Rate limiting/throttling middleware for Azure Functions.

Install from NuGet:

dotnet add package ThrottlingTroll.AzureFunctions

IMPORTANT: if in your project you are using ASP.NET Core Integration, then you need to install and use ThrottlingTroll.AzureFunctionsAspNet package instead.

How to use (.NET Isolated)

Make sure you call one or another form of .UseThrottlingTroll() method at startup:

var builder = new HostBuilder();

// .....

builder.ConfigureFunctionsWorkerDefaults((hostBuilderContext, workerAppBuilder) => {

    workerAppBuilder.UseThrottlingTroll();

    // .....
});

All different ways of configuring, all other features and more code snippets are documented in our Wiki.

How to use (.NET InProc)

1. Use .AddThrottlingTroll() method to add ThrottlingTroll to your DI container at startup:

[assembly: WebJobsStartup(typeof(ThrottlingTrollSampleInProcFunction.Startup.Startup))]
namespace ThrottlingTrollSampleInProcFunction.Startup
{
    public class Startup : IWebJobsStartup
    {
        public void Configure(IWebJobsBuilder builder)
        {
            builder.Services.AddThrottlingTroll(options =>
            {
                // In InProc Functions config sections loaded from host.json have the "AzureFunctionsJobHost:" prefix in their names
                options.ConfigSectionName = "AzureFunctionsJobHost:ThrottlingTrollIngress";

                // .....
            });
        }
    }
}

2. Add InProc-specific implementation of IHttpRequestProxy to your project.

3. Wrap your Functions with .WithThrottlingTroll() method, like this:

public class MyFunctions
{
    private readonly IThrottlingTroll _thtr;

    public Functions(IThrottlingTroll thtr)
    {
        this._thtr = thtr;
    }

    [FunctionName("MyFunc")]
    public Task<IActionResult> MyFunc([HttpTrigger(AuthorizationLevel.Anonymous, "get")] HttpRequest req)
        => this._thtr.WithThrottlingTroll(new InProcHttpRequestProxy(req),
            async ctx =>
            {
                // Your code goes here ...

                return (IActionResult)new OkObjectResult("OK");
            },
            async ctx =>
            {
                return (IActionResult)new StatusCodeResult((int)HttpStatusCode.TooManyRequests);
            });
}

Samples

Sample Azure Functions projects (both InProc and Isolated) are located in this separate repo.