public void Track(SqlServerTimeoutJob item)
{
_items.TryAdd(item, null);
}
public void Untrack(SqlServerTimeoutJob item)
{
_items.TryRemove(item, out _);
}
private SqlServerTimeoutJob DequeueUsingSlidingInvisibilityTimeout(string[] queues, CancellationToken cancellationToken)
{
if (queues == null)
{
throw new ArgumentNullException(nameof(queues));
}
if (queues.Length == 0)
{
throw new ArgumentException("Queue array must be non-empty.", nameof(queues));
}
var useLongPolling = false;
var queuesString = String.Join("_", queues.OrderBy(x => x));
var resource = Tuple.Create(_storage, queuesString);
var pollingDelayMs = Math.Min(
Math.Max((int)_options.QueuePollInterval.TotalMilliseconds, MinPollingDelayMs),
PollingQuantumMs);
SqlServerTimeoutJob fetched = null;
using (var cancellationEvent = cancellationToken.GetCancellationEvent())
{
while (!cancellationToken.IsCancellationRequested)
{
var acquired = false;
try
{
if (useLongPolling)
{
DynamicMutex.Wait(resource, cancellationToken, out acquired);
}
fetched = _storage.UseConnection(null, connection =>
{
var parameters = new DynamicParameters();
parameters.Add("@queues", queues);
parameters.Add("@timeoutSs", (int)_options.SlidingInvisibilityTimeout.Value.Negate().TotalSeconds);
parameters.Add("@delayMs", pollingDelayMs);
parameters.Add("@endMs", PollingQuantumMs);
var query = useLongPolling ? GetBlockingFetchSql() : GetNonBlockingFetchSql();
using (var reader = connection.QueryMultiple(query, parameters, commandTimeout: _storage.CommandTimeout))
{
while (!reader.IsConsumed)
{
var fetchedJob = reader.Read <FetchedJob>().SingleOrDefault(x => x != null);
if (fetchedJob != null)
{
return(new SqlServerTimeoutJob(_storage, fetchedJob.Id, fetchedJob.JobId.ToString(CultureInfo.InvariantCulture), fetchedJob.Queue, fetchedJob.FetchedAt.Value));
}
}
}
return(null);
});
}
finally
{
if (acquired)
{
DynamicMutex.Release(resource);
}
}
if (fetched != null)
{
break;
}
if (_options.QueuePollInterval < LongPollingThreshold)
{
useLongPolling = true;
}
else
{
WaitHandle.WaitAny(new WaitHandle[] { cancellationEvent.WaitHandle, NewItemInQueueEvent }, _options.QueuePollInterval);
}
}
cancellationToken.ThrowIfCancellationRequested();
}
return(fetched);
}
