RetryHelper.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Collections.Generic;
using System.Threading;

namespace System.Device.Gpio.Tests;

public static class RetryHelper
{
    private static readonly Func<int, int> s_DefaultBackoffFunc = i => Math.Min(i * 100, 60_000);

    /// <summary>
    /// Executes the <paramref name="test"/> action up to a maximum of <paramref name="maxAttempts"/> times.
    /// </summary>
    /// <param name="test">The test to invoke.</param>
    /// <param name="maxAttempts">The maximum number of times to invoke <paramref name="test"/>.</param>
    /// <param name="backoffFunc">After a failure, invoked to determine how many milliseconds to wait before the next attempt. It's passed the number of iterations attempted.</param>
    public static void Execute(Action test, int maxAttempts = 5, Func<int, int>? backoffFunc = null)
    {
        if (maxAttempts < 1)
        {
            throw new ArgumentOutOfRangeException(nameof(maxAttempts));
        }

        if (test == null)
        {
            throw new ArgumentNullException(nameof(test));
        }

        // Execute the test until it either passes or we run it maxAttempts times
        var exceptions = new List<Exception>();
        for (int i = 1; i <= maxAttempts; i++)
        {
            try
            {
                test();
                return;
            }
            catch (Exception e)
            {
                exceptions.Add(e);
                if (i == maxAttempts)
                {
                    throw new AggregateException(exceptions);
                }
            }

            Thread.Sleep((backoffFunc ?? s_DefaultBackoffFunc)(i));
        }
    }
}