Microsoft.Extensions.Http.Resilience: Using AddStandardResilienceHandler options with SlidingWindowRateLimiter

Question

Using Microsoft.Extensions.Http.Resilience is it possible to use precise RateLimiter options, such as SlidingWindowRateLimiter, with the AddStandardResilienceHandler. Alternatively apply the defaults from AddStandardResilienceHandler to a custom AddResilienceHandler definition for everything else other than the RateLimiter part?

Ideally I'd like to use the best practice defaults that are built-in to the resilience library, but override the RateLimiter part for specific API imposed limits.

For example I'd like to combine:

builder.AddStandardResilienceHandler(static options => {
    // Either apply RateLimiter options from below
});

with RateLimiter options such as:

services.AddHttpClient(Constants.StarshipitHttpClient)
    .AddResilienceHandler(Constants.StarshipitHttpClient, static builder =>
    {
        builder.AddRateLimiter(new SlidingWindowRateLimiter(
            new SlidingWindowRateLimiterOptions
            {
                PermitLimit = 2,
                Window = TimeSpan.FromSeconds(1),
                QueueLimit = int.MaxValue,
            }
        ));

        // Or add other default resiliency options from AddStandardResilienceHandler above  
    });

Does anyone know how to achieve this?

Answer 1

Ideally it should be as easy as this:

.AddStandardRResilienceHandler(options => 
{ 
   options.RateLimiter = yourRateLimiterOptions; 
})

But as far as I can see the the reported issue to alter default values is not yet fixed as of writing this answer.

---

For named HttpClient it works like this

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Http.Resilience;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Options;

var builder = Host.CreateApplicationBuilder(args);
builder.Services
    .AddHttpClient("test")
    .AddStandardResilienceHandler(options =>
    {
        options.AttemptTimeout.Timeout = TimeSpan.FromSeconds(11);
    });

var serviceProvider = builder.Services.BuildServiceProvider();
var monitor = serviceProvider.GetRequiredService<IOptionsMonitor<HttpStandardResilienceOptions>>();
var options = monitor.Get("test-standard");
Console.WriteLine(options.AttemptTimeout.Timeout);

using var host = builder.Build();

• It registers a named HttpClient with test name
• It adds the standard resilience handler to it
• It overrides the AttemptTimeout from 10 seconds (the default) to 11
• It retrieves an IOptionsMonitor from the DI
• It retrieves that HttpStandardResilienceOptions which is named to test-standard
  • This name is calculated like this $"{httpClientName}-{pipelineIdentifier}"
  • Where the pipelineIdentifier is standard

The printed output will be 11 seconds, see related dotnet fiddle

The same should work for the RateLimiter property.