/// <summary>Executes a function and applies retry logic, if enabled.</summary>
public override async Task <TResult> ExecuteAsync <TResult>(object sender, Func <Task <TResult> > function, CancellationToken cancellationToken = default)
{
if (function == null)
{
throw SqlReliabilityUtil.ArgumentNull(nameof(function));
}
SqlRetryLogicBase retryLogic = null;
var exceptions = new List <Exception>();
retry:
try
{
TResult result = await function.Invoke();
RetryLogicPoolAdd(retryLogic);
return(result);
}
catch (Exception e)
{
if (RetryLogic.RetryCondition(sender) && RetryLogic.TransientPredicate(e))
{
retryLogic = retryLogic ?? GetRetryLogic();
SqlClientEventSource.Log.TryTraceEvent("<sc.{0}.ExecuteAsync<TResult>|INFO> Found an action eligible for the retry policy (retried attempts = {1}).",
TypeName, retryLogic.Current);
exceptions.Add(e);
if (retryLogic.TryNextInterval(out TimeSpan intervalTime))
{
// The retrying event raises on each retry.
ApplyRetryingEvent(sender, retryLogic, intervalTime, exceptions, e);
await Task.Delay(intervalTime, cancellationToken);
goto retry;
}
else
{
throw CreateException(exceptions, retryLogic);
}
}
else
{
RetryLogicPoolAdd(retryLogic);
throw;
}
}
}
/// <summary>Executes a function and applies retry logic, if enabled.</summary>
public override TResult Execute <TResult>(object sender, Func <TResult> function)
{
if (function == null)
{
throw new ArgumentNullException(nameof(function));
}
SqlRetryLogicBase retryLogic = null;
var exceptions = new List <Exception>();
retry:
try
{
TResult result = function.Invoke();
RetryLogicPoolAdd(retryLogic);
return(result);
}
catch (Exception e)
{
if (enableRetryLogic && RetryLogic.RetryCondition(sender) && RetryLogic.TransientPredicate(e))
{
retryLogic = retryLogic ?? GetRetryLogic();
SqlClientEventSource.Log.TryTraceEvent("<sc.{0}.Execute<TResult>|INFO> Found an action eligible for the retry policy (retried attempts = {1}).",
TypeName, retryLogic.Current);
exceptions.Add(e);
if (retryLogic.TryNextInterval(out TimeSpan intervalTime))
{
// The retrying event raises on each retry.
ApplyRetryingEvent(sender, retryLogic, intervalTime, exceptions, e);
Thread.Sleep(intervalTime);
goto retry;
}
else
{
throw CreateException(exceptions, retryLogic);
}
}
else
{
RetryLogicPoolAdd(retryLogic);
throw;
}
}
}
public override TResult Execute <TResult>(object sender, Func <TResult> function)
{
// Create a list to save transient exceptions to report later if necessary
IList <Exception> exceptions = new List <Exception>();
// Prepare it before reusing
RetryLogic.Reset();
// Create an infinite loop to attempt the defined maximum number of tries
do
{
try
{
// Try to invoke the function
return(function.Invoke());
}
// Catch any type of exception for further investigation
catch (Exception e)
{
// Ask the RetryLogic object if this exception is a transient error
if (RetryLogic.TransientPredicate(e))
{
// Add the exception to the list of exceptions we've retried on
exceptions.Add(e);
// Ask the RetryLogic for the next delay time before the next attempt to run the function
if (RetryLogic.TryNextInterval(out TimeSpan gapTime))
{
Console.WriteLine($"Wait for {gapTime} before next try");
// Wait before next attempt
Thread.Sleep(gapTime);
}
else
{
// Number of attempts has exceeded the maximum number of tries
throw new AggregateException("The number of retries has exceeded the maximum number of attempts.", exceptions);
}
}
else
{
// If the exception wasn't a transient failure throw the original exception
throw;
}
}
} while (true);
}