/// <summary>
/// Specify a fallback value if all the tries fail.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="result"></param>
/// <param name="defaultValue"></param>
/// <returns></returns>
public static RetryResult <T> WithFallBackValue <T>(this RetryResult <T> result, T defaultValue)
{
if (defaultValue == null)
{
throw new ArgumentNullException(nameof(defaultValue));
}
if (!result.Successful)
{
try
{
result.ExecutedFallBack = true;
result.Result = defaultValue;
}
catch (Exception ex)
{
result.FallBackException = ex;
}
}
return(result);
}
/// <summary>
/// Configure a fallback function
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="result"></param>
/// <param name="fallback"></param>
/// <returns></returns>
public static RetryResult <T> WithFallBack <T>(this RetryResult <T> result, Func <T> fallback)
{
if (fallback == null)
{
throw new ArgumentNullException(nameof(fallback));
}
if (!result.Successful)
{
try
{
result.ExecutedFallBack = true;
result.Result = fallback();
}
catch (Exception ex)
{
result.FallBackException = ex;
}
}
return(result);
}
/// <summary>
/// Retry a function n times or until successful asynchronously.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="function"></param>
/// <param name="config"></param>
/// <returns></returns>
static async Task <RetryResult <T> > RetryFuncAsync <T>(Func <Task <T> > function, RetryConfig config)
{
var retryInfo = new RetryInfo();
var result = new RetryResult <T>(default(T), retryInfo);
var isOk = false;
var retriesRemaining = config.MaxRetries;
var timeoutAt = DateTime.Now.Add(config.TotalTimeout);
bool hasTimeout = config.HasTimeout;
while (!isOk && (retriesRemaining >= 0 || config.RetryForever) &&
(!hasTimeout || (config.HasTimeout && DateTime.Now < timeoutAt)))
{
result.RetryInfo.Executions++;
try
{
result.Result = await function();
isOk = true;
}
catch (Exception ex)
{
result.RetryInfo.Exceptions.Add(ex);
// Wait before retrying.
if (config.WaitBetweenRetries > TimeSpan.Zero)
{
Thread.Sleep(config.WaitBetweenRetries);
}
}
retriesRemaining--;
}
return(result);
}
