internal static async Task <TResponse> Retry <TRequest, TResponse>(
Func <TRequest, CallSettings, Task <TResponse> > fn,
TRequest request, CallSettings callSettings, IClock clock, IScheduler scheduler)
{
RetrySettings retrySettings = callSettings.Retry;
if (retrySettings == null)
{
return(await fn(request, callSettings).ConfigureAwait(false));
}
DateTime?overallDeadline = callSettings.Expiration.CalculateDeadline(clock);
// Every attempt should use the same deadline, calculated from the start of the call.
if (callSettings.Expiration?.Type == ExpirationType.Timeout)
{
callSettings = callSettings.WithDeadline(overallDeadline.Value);
}
// Remove retry from the call settings we pass into the function, so that the settings
// can be used even for a streaming call.
callSettings = callSettings.WithRetry(null);
foreach (var attempt in RetryAttempt.CreateRetrySequence(retrySettings, scheduler, overallDeadline, clock))
{
try
{
return(await fn(request, callSettings).ConfigureAwait(false));
}
catch (RpcException e) when(attempt.ShouldRetry(e))
{
await attempt.BackoffAsync(callSettings.CancellationToken.GetValueOrDefault()).ConfigureAwait(false);
}
}
throw new InvalidOperationException("Bug in GAX retry handling: finished sequence of attempts");
}