private Task[] CreateWaitTasks(string resource, int count, IDistributedLockMutex mutex)
{
var tasks = new Task[count];
for (int i = 0; i < count; i++)
{
tasks[i] = Task.Factory.StartNew(() =>
{
mutex.Wait(resource, TimeSpan.FromSeconds(2));
}, TaskCreationOptions.LongRunning);
}
do
{
// wait until all tasks are running
Thread.Sleep(100);
} while (tasks.Any(t => t.Status != TaskStatus.Running));
return(tasks);
}
private void Acquire(TimeSpan timeout)
{
try
{
// If result is null, then it means we acquired the lock
var isLockAcquired = false;
var now = DateTime.UtcNow;
var lockTimeoutTime = now.Add(timeout);
while (!isLockAcquired && (lockTimeoutTime >= now))
{
// Acquire the lock if it does not exist - Notice: ReturnDocument.Before
var filter = Builders <DistributedLockDto> .Filter.Eq(_ => _.Resource, _resource);
var update = Builders <DistributedLockDto> .Update.SetOnInsert(_ => _.ExpireAt, DateTime.UtcNow.Add(_storageOptions.DistributedLockLifetime));
var options = new FindOneAndUpdateOptions <DistributedLockDto>
{
IsUpsert = true,
ReturnDocument = ReturnDocument.Before
};
try
{
var result = _locks.FindOneAndUpdate(filter, update, options);
// If result is null, it means we acquired the lock
if (result == null)
{
if (Logger.IsTraceEnabled())
{
Logger.Trace($"{_resource} - Acquired");
}
isLockAcquired = true;
}
else
{
now = _mutex.Wait(_resource, CalculateTimeout(timeout));
}
}
catch (MongoCommandException)
{
// this can occur if two processes attempt to acquire a lock on the same resource simultaneously.
// unfortunately there doesn't appear to be a more specific exception type to catch.
now = _mutex.Wait(_resource, CalculateTimeout(timeout));
}
}
if (!isLockAcquired)
{
throw new DistributedLockTimeoutException($"{_resource} - Could not place a lock: The lock request timed out.");
}
}
catch (DistributedLockTimeoutException)
{
throw;
}
catch (Exception ex)
{
throw new MongoDistributedLockException($"{_resource} - Could not place a lock", ex);
}
}
