using System;

using System.Net;

using System.Net.Http;

using System.Collections.Generic;

using System.Threading.Tasks;

​

using Polly;

using Polly.CircuitBreaker;

using Polly.Contrib.WaitAndRetry;

public class Program

{

    public static async Task Main()

    {

        var strategy = Policy.WrapAsync<HttpResponseMessage>(RetryScenario1(), RetryScenario2(), RetryScenario3(), CircuitBreaker());

        await strategy.ExecuteAsync(() => Task.FromResult(new HttpResponseMessage(HttpStatusCode.Unauthorized)));

    }

    static IAsyncPolicy<HttpResponseMessage> RetryScenario1() 

        => Policy<HttpResponseMessage>

        .HandleResult(r => r.StatusCode == HttpStatusCode.Unauthorized)

        .Or<BrokenCircuitException>()

        .WaitAndRetryAsync(sleepDurations: Backoff.ConstantBackoff(delay: TimeSpan.FromSeconds(1), retryCount: 3), 

                           onRetry: (ex, ts) => Console.WriteLine("OnRetry for 401"));

​

    static IAsyncPolicy<HttpResponseMessage> RetryScenario2() 

        => Policy<HttpResponseMessage>

        .HandleResult(r => r.StatusCode == HttpStatusCode.TooManyRequests)

        .Or<BrokenCircuitException>()

        .WaitAndRetryAsync(sleepDurations: Backoff.ExponentialBackoff(initialDelay: TimeSpan.FromSeconds(1), retryCount: 3), 

                       onRetry: (ex, ts) => Console.WriteLine("OnRetry for 429"));

    static IAsyncPolicy<HttpResponseMessage> RetryScenario3()   

        => Policy<HttpResponseMessage>

        .HandleResult(r => r.StatusCode == HttpStatusCode.BadGateway || r.StatusCode == HttpStatusCode.GatewayTimeout)

        .Or<BrokenCircuitException>()

        .WaitAndRetryAsync(sleepDurations: Backoff.ConstantBackoff(delay: TimeSpan.FromSeconds(5), retryCount: 3), 

                       onRetry: (ex, ts) => Console.WriteLine("OnRetry for 502, 504"));

    static List<HttpStatusCode> retryable = [ HttpStatusCode.Unauthorized, HttpStatusCode.TooManyRequests, HttpStatusCode.BadGateway, HttpStatusCode.GatewayTimeout ];

    static IAsyncPolicy<HttpResponseMessage> CircuitBreaker() 

        => Policy<HttpResponseMessage>

        .HandleResult(r => retryable.Contains(r.StatusCode))

        .CircuitBreakerAsync(handledEventsAllowedBeforeBreaking: 2,

          durationOfBreak: TimeSpan.FromSeconds(10),

          onBreak: (r, ts) => Console.WriteLine("OnBreak"), 

          onReset: () => Console.WriteLine("OnReset"), 

          onHalfOpen: () => Console.WriteLine("OnHalfOpen"));

}