private Action<Task<CalculatorResult>> ErrorAction(AutoRenewLease autoRenew)
{
return (task) => {
task.Exception.Handle((inner) => {
if (inner is OperationCanceledException) {
autoRenew.Dispose();
Trace.WriteLine("Calculation Canceled");
}
else {
Trace.WriteLine("Unhandled exception when calculating the fibonacci sequence...", UnwindException(inner));
}
isCalculating = false;
return true;
});
};
}
public void Calculate()
{
CloudStorageAccount.SetConfigurationSettingPublisher((configName, configSetter) => {
configSetter(RoleEnvironment.GetConfigurationSettingValue(configName));
});
var acct = CloudStorageAccount.FromConfigurationSetting("StorageConnectionString");
var client = acct.CreateCloudBlobClient();
var taskBlob = client.GetBlobReference("dev-task-blobs/fib-task-blob");
var autoRenew = new AutoRenewLease(taskBlob);
if (autoRenew.HasLease) {
var cancellationSource = new CancellationTokenSource();
var cancellationToken = cancellationSource.Token;
var calculatorState = new CalculatorState { MaxNumbersInSequence = 48};
var calculatorTask = Task.Factory.StartNew<CalculatorResult>((state) => {
isCalculating = true;
cancellationToken.ThrowIfCancellationRequested();
var cs = (CalculatorState)state;
var calculatorResult = new CalculatorResult();
Func<int, int> fib = null;
fib = number => number > 1 ? fib(number - 1) + fib(number - 2) : number;
while (autoRenew.HasLease && isCalculating && !cancellationToken.IsCancellationRequested) {
for (int i = 0; i < cs.MaxNumbersInSequence; i++) {
if (!autoRenew.HasLease) {
isCalculating = false;
Trace.WriteLine("autoRenew.HasLease is false. Breaking out of calculation routine.");
cancellationSource.Cancel();
break;
}
else {
var nextNumber = fib(i);
calculatorResult.Numbers.Add(nextNumber);
Trace.WriteLine(String.Format("ix:{0} - {1}", (i + 1), nextNumber));
}
}
isCalculating = false;
}
autoRenew.Dispose();
cancellationToken.ThrowIfCancellationRequested();
return calculatorResult;
}, calculatorState, cancellationToken, TaskCreationOptions.LongRunning, TaskScheduler.Default);
calculatorTask.ContinueWith(CompletedAction(autoRenew), cancellationToken, TaskContinuationOptions.OnlyOnRanToCompletion, TaskScheduler.Default);
calculatorTask.ContinueWith(ErrorAction(autoRenew), TaskContinuationOptions.OnlyOnFaulted);
}
}
private Action<Task<CalculatorResult>> CompletedAction(AutoRenewLease autoRenew)
{
return (task) => {
autoRenew.Dispose();
Trace.WriteLine("Calculation is complete...");
Trace.WriteLine("Last number in the sequence is: " + task.Result.Numbers.Last());
isCalculating = false;
};
}