编写重试逻辑的最简洁方法? [英] Cleanest way to write retry logic?

问题描述

有时我需要在放弃之前重试几次操作.我的代码是这样的:

Occasionally I have a need to retry an operation several times before giving up. My code is like:

int retries = 3;
while(true) {
  try {
    DoSomething();
    break; // success!
  } catch {
    if(--retries == 0) throw;
    else Thread.Sleep(1000);
  }
}

我想在一个通用的重试函数中重写这个:

I would like to rewrite this in a general retry function like:

TryThreeTimes(DoSomething);

在 C# 中可以吗?TryThreeTimes() 方法的代码是什么?

Is it possible in C#? What would be the code for the TryThreeTimes() method?

推荐答案

简单地重试相同调用的一揽子 catch 语句如果用作一般异常处理机制可能是危险的.话虽如此，这里有一个基于 lambda 的重试包装器，您可以将其与任何方法一起使用.我选择将重试次数和重试超时作为参数考虑在内，以获得更大的灵活性:

Blanket catch statements that simply retry the same call can be dangerous if used as a general exception handling mechanism. Having said that, here's a lambda-based retry wrapper that you can use with any method. I chose to factor the number of retries and the retry timeout out as parameters for a bit more flexibility:

public static class Retry
{
    public static void Do(
        Action action,
        TimeSpan retryInterval,
        int maxAttemptCount = 3)
    {
        Do<object>(() =>
        {
            action();
            return null;
        }, retryInterval, maxAttemptCount);
    }

    public static T Do<T>(
        Func<T> action,
        TimeSpan retryInterval,
        int maxAttemptCount = 3)
    {
        var exceptions = new List<Exception>();

        for (int attempted = 0; attempted < maxAttemptCount; attempted++)
        {
            try
            {
                if (attempted > 0)
                {
                    Thread.Sleep(retryInterval);
                }
                return action();
            }
            catch (Exception ex)
            {
                exceptions.Add(ex);
            }
        }
        throw new AggregateException(exceptions);
    }
}

您现在可以使用此实用程序方法来执行重试逻辑:

You can now use this utility method to perform retry logic:

Retry.Do(() => SomeFunctionThatCanFail(), TimeSpan.FromSeconds(1));

或:

Retry.Do(SomeFunctionThatCanFail, TimeSpan.FromSeconds(1));

或:

int result = Retry.Do(SomeFunctionWhichReturnsInt, TimeSpan.FromSeconds(1), 4);

或者您甚至可以进行 async 重载.

Or you could even make an async overload.

这篇关于编写重试逻辑的最简洁方法?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！