一次.net core异步线程设置超时时间的实战记录

public static class TaskHelper
{

    // 有返回值
    public static async Task<TResult> TimeoutAfter<TResult>(this Task<TResult> task, TimeSpan timeout)
    {
        using (var timeoutCancellationTokenSource = new CancellationTokenSource())
        {
            var completedTask = await Task.WhenAny(task, Task.Delay(timeout, timeoutCancellationTokenSource.Token));
            if (completedTask == task)
            {
                timeoutCancellationTokenSource.Cancel();
                return await task;  // Very important in order to propagate exceptions
            }
            else
            {
                throw new TimeoutException("The operation has timed out.");
            }
        }
    }

    // 无返回值
    public static async Task TimeoutAfter(this Task task, TimeSpan timeout)
    {
        using (var timeoutCancellationTokenSource = new CancellationTokenSource())
        {
            var completedTask = await Task.WhenAny(task, Task.Delay(timeout, timeoutCancellationTokenSource.Token));
            if (completedTask == task)
            {
                timeoutCancellationTokenSource.Cancel();
                await task;  // Very important in order to propagate exceptions
            }
            else
            {
                throw new TimeoutException("The operation has timed out.");
            }
        }
    }
}

    [TestMethod]
    public async Task TestMethod1()
    {
        //A 任务必须在指定时间内完成,否则任务失败
        //A 任务依赖B,C任务,B,C可以并行,任何一个失败,则A任务失败
        //A任务
        try
        {
            //有效时间3s
            var timeOut = TimeSpan.FromSeconds(3);
            await Task.Run(async () =>
            {
                List<Task<(string, bool)>> tasks = new List<Task<(string, bool)>>();
                //B任务
                tasks.Add(Task.Run(async () =>
                {
                    return ("B", await TestTask("B"));
                }).TimeoutAfter(timeOut));

                //C任务
                tasks.Add(Task.Run(async () =>
                {
                    return ("C", await TestTask("C"));
                }).TimeoutAfter(timeOut));

                var res = await Task.WhenAll(tasks);

                //两个任务,任何一个失败,则A任务失败
                foreach (var item in res)
                {
                    Console.WriteLine(item);
                }

            }).TimeoutAfter(timeOut);

        }
        catch (Exception ex)
        {
            Console.WriteLine("A任务执行超时了");
        }

        //await Task.Delay(3000);


    }

    public async Task<bool> TestTask(string name) 
    {
        var startTime = DateTime.Now;
        Console.WriteLine($"{startTime}---->{name}任务开始执行");
        //随机堵塞1-5s
        var t = new Random().Next(1, 5);
        await Task.Delay(t * 1000);

        var endTime = DateTime.Now; ;
        var time = (endTime - startTime).TotalSeconds;

        //随机数,模拟业务是否成功
        var res = new Random().Next(1, 10);
        Console.WriteLine($"{endTime}---->{name}任务执行完毕,耗时{time} s");
        return res <= 7;
    }