public OracleFetchedJob(OracleStorage storage, IDbConnection connection, FetchedJob fetchedJob)
{
if (fetchedJob == null)
{
throw new ArgumentNullException(nameof(fetchedJob));
}
_storage = storage ?? throw new ArgumentNullException(nameof(storage));
_connection = connection ?? throw new ArgumentNullException(nameof(connection));
_id = fetchedJob.Id;
JobId = fetchedJob.JobId.ToString(CultureInfo.InvariantCulture);
Queue = fetchedJob.Queue;
}
public IFetchedJob Dequeue(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));
}
FetchedJob fetchedJob = null;
IDbConnection connection;
do
{
cancellationToken.ThrowIfCancellationRequested();
connection = _storage.CreateAndOpenConnection();
try
{
using (new OracleDistributedLock(_storage, "JobQueue", TimeSpan.FromSeconds(30)))
{
var token = Guid.NewGuid().ToString();
var nUpdated = connection.Execute(@"
UPDATE HF_JOB_QUEUE
SET FETCHED_AT = SYS_EXTRACT_UTC (SYSTIMESTAMP), FETCH_TOKEN = :FETCH_TOKEN
WHERE (FETCHED_AT IS NULL OR FETCHED_AT < SYS_EXTRACT_UTC (SYSTIMESTAMP) + numToDSInterval(:TIMEOUT, 'second' )) AND (QUEUE IN :QUEUES) AND ROWNUM = 1
",
new
{
QUEUES = queues,
TIMEOUT = _options.InvisibilityTimeout.Negate().TotalSeconds,
FETCH_TOKEN = token
});
if (nUpdated != 0)
{
fetchedJob =
connection
.QuerySingle <FetchedJob>(
@"
SELECT ID as Id, JOB_ID as JobId, QUEUE as Queue
FROM HF_JOB_QUEUE
WHERE FETCH_TOKEN = :FETCH_TOKEN
",
new
{
FETCH_TOKEN = token
});
}
}
}
catch (DbException ex)
{
Logger.ErrorException(ex.Message, ex);
_storage.ReleaseConnection(connection);
throw;
}
if (fetchedJob == null)
{
_storage.ReleaseConnection(connection);
cancellationToken.WaitHandle.WaitOne(_options.QueuePollInterval);
cancellationToken.ThrowIfCancellationRequested();
}
} while (fetchedJob == null);
return(new OracleFetchedJob(_storage, connection, fetchedJob));
}