Polly Policy.TimeoutAsync 没有给出 TimeoutRejected 异常 要执行的委托超时政策用法输出要执行的委托超时政策用法输出

编程问答 2022-05-30

问题描述

这是我的示例代码：

var timeoutPolicy = Policy.TimeoutAsync(TimeSpan.FromMilliseconds(_configOptions.ResponseTimeout),TimeoutStrategy.pessimistic);
            
try
{
    return await timeoutPolicy.ExecuteAsync(async ct => await Somemethod(request,ct),CancellationToken.None);
}
catch (TimeoutRejectedException ex)
{
    _//Some logging to go here/
}

configOptions.ResponseTimeout 在配置文件中配置，我期待方法 await Somemethod(request,ct)，CancellationToken.None 应该根据配置中给出的值抛出 TimeoutRejectedException。

但它没有抛出任何异常。 谁能帮我找出我哪里出错了？

非常感谢您的帮助。

解决方法

乐观超时

代表确实支持取消。

要执行的委托

private static async Task SomeMethodAsync(CancellationToken ct = default)
{
    Console.WriteLine($"{nameof(SomeMethodAsync)} has been called.");
    await Task.Delay(15000,ct); //It is aware of the CancellationToken
}

超时政策

 private static AsyncTimeoutPolicy GetTimeoutPolicy
    => Policy
        .TimeoutAsync(
            TimeSpan.FromMilliseconds(1000),TimeoutStrategy.Optimistic,(context,timeout,_,exception) =>
            {
                Console.WriteLine($"{"Timeout",-10}{timeout,-10:ss\\.fff}: {exception.GetType().Name}");
                return Task.CompletedTask;
            });

用法

var strategy = GetTimeoutPolicy;
var result = await strategy.ExecuteAsync(async (ct) => await SomeMethodAsync(ct),CancellationToken.None);

输出

SomeMethodAsync has been called.
Timeout   01.000    : TaskCanceledException
Unhandled exception. Polly.Timeout.TimeoutRejectedException: The delegate executed asynchronously through TimeoutPolicy did not complete within the timeout.
 ---> System.Threading.Tasks.TaskCanceledException: A task was canceled.
...

悲观超时

委托不支持取消。

要执行的委托

private static async Task SomeMethodAsync(CancellationToken ct = default)
{
    Console.WriteLine($"{nameof(SomeMethodAsync)} has been called.");
    await Task.Delay(15000); //It is NOT aware of the CancellationToken
}

超时政策

 private static AsyncTimeoutPolicy GetTimeoutPolicy
    => Policy
        .TimeoutAsync(
            TimeSpan.FromMilliseconds(1000),TimeoutStrategy.Pessimistic,-10:ss\\.fff}: {exception.GetType().Name}");
                return Task.CompletedTask;
            });

用法

var strategy = GetTimeoutPolicy;
var result = await strategy.ExecuteAsync(async () => await SomeMethodAsync());

输出

SomeMethodAsync has been called.
Timeout   01.000    : TaskCanceledException
Unhandled exception. Polly.Timeout.TimeoutRejectedException: The delegate executed asynchronously through TimeoutPolicy did not complete within the timeout.
 ---> System.Threading.Tasks.TaskCanceledException: A task was canceled.
...
c#c#dotnet-httpclientpolly