internal MySqlDistributedLock Acquire()
{
Logger.TraceFormat("Acquire resource={0}, timeout={1}", _resource, _timeout);
int insertedObjectCount;
do
{
_cancellationToken.ThrowIfCancellationRequested();
var timeLeft = _start.Add(_timeout).Subtract(DateTime.UtcNow);
using (ResourceLock.AcquireOne(
_connection, _storageOptions.TablesPrefix,
timeLeft, _cancellationToken,
LockableResource.Lock))
{
insertedObjectCount = AcquireLock();
}
if (ContinueCondition(insertedObjectCount))
{
_cancellationToken.WaitHandle.WaitOne(DelayBetweenPasses);
_cancellationToken.ThrowIfCancellationRequested();
}
}
while (ContinueCondition(insertedObjectCount));
if (insertedObjectCount == 0)
{
throw new MySqlDistributedLockException("cannot acquire lock");
}
return this;
}
private int AggregateCounter(MySqlConnection connection)
{
using (ResourceLock.AcquireOne(
connection, _options.TablesPrefix, LockableResource.Counter))
{
return(connection.Execute(
GetAggregationQuery(),
new { now = DateTime.UtcNow, count = NumberOfRecordsInSinglePass }));
}
}
public IFetchedJob Dequeue(string[] queues, CancellationToken cancellationToken)
{
if (queues is null || !queues.Any())
{
throw new ArgumentException("Queue array must be non-empty.", nameof(queues));
}
var token = Guid.NewGuid().ToString();
// I'm not sure if this is used correctly...
var expiration = _options.InvisibilityTimeout;
// the connection variable is mutable, it job is claimed then this connection
// is passed to job itself, and variable is set to null so it does not get
// disposed here in such case
var connection = _storage.CreateAndOpenConnection();
try
{
while (true)
{
cancellationToken.ThrowIfCancellationRequested();
using (ResourceLock.AcquireOne(
connection, _options.TablesPrefix, LockableResource.Queue))
{
var updated = ClaimJob(connection, queues, expiration, token);
if (updated != 0)
{
var fetchedJob = FetchJobByToken(connection, token);
return(new MySqlFetchedJob(
_storage, _options,
Interlocked.Exchange(ref connection, null),
fetchedJob));
}
}
cancellationToken.WaitHandle.WaitOne(_options.QueuePollInterval);
cancellationToken.ThrowIfCancellationRequested();
}
}
catch (MySqlException ex)
{
Logger.ErrorException(ex.Message, ex);
throw;
}
finally
{
if (connection != null)
{
_storage.ReleaseConnection(connection);
}
}
}
public void Requeue()
{
Logger.TraceFormat("Requeue JobId={0}", JobId);
using (ResourceLock.AcquireOne(
_connection, _options.TablesPrefix, LockableResource.Queue))
{
_connection.Execute(
$"update `{_options.TablesPrefix}JobQueue` set FetchedAt = null where Id = @id",
new { id = _id });
}
_requeued = true;
}
public void RemoveFromQueue()
{
Logger.TraceFormat("RemoveFromQueue JobId={0}", JobId);
using (ResourceLock.AcquireOne(
_connection, _options.TablesPrefix, LockableResource.Queue))
{
_connection.Execute(
$"delete from `{_options.TablesPrefix}JobQueue` where Id = @id",
new { id = _id });
}
_removed = true;
}
internal void Release()
{
Logger.TraceFormat("Release resource={0}", _resource);
using (ResourceLock.AcquireOne(
_connection, _storageOptions.TablesPrefix,
_timeout, CancellationToken.None,
LockableResource.Lock))
{
_connection.Execute(
$"DELETE FROM `{_storageOptions.TablesPrefix}DistributedLock` " +
"WHERE Resource = @resource",
new { resource = _resource });
}
}
private void Enqueue(
IDbConnection connection, IDbTransaction transaction, string queue, string jobId)
{
Logger.TraceFormat("Enqueue JobId={0} Queue={1}", jobId, queue);
using (ResourceLock.AcquireOne(
connection, transaction, _options.TablesPrefix, LockableResource.Queue))
{
connection.Execute(
$@"/* MySqlJobQueue.Enqueue */
insert into `{_options.TablesPrefix}JobQueue` (JobId, Queue)
values (@jobId, @queue)",
new { jobId, queue },
transaction);
}
}
public static void Upgrade(MySqlConnection connection, string tablesPrefix = null)
{
if (connection == null)
{
throw new ArgumentNullException(nameof(connection));
}
var prefix = tablesPrefix ?? string.Empty;
using (ResourceLock.AcquireOne(
connection, prefix,
MigrationTimeout, CancellationToken.None,
LockableResource.Migration))
{
var resourceName = $"{typeof(MySqlObjectsInstaller).Namespace}.Migrations.xml";
var document = XElement.Parse(GetStringResource(resourceName));
EnsureMigrationsTable(connection, prefix);
var migrations = document
.Elements("migration")
.Select(e => new { id = e.Attribute("id")?.Value, script = e.Value })
.ToArray();
foreach (var migration in migrations)
{
var alreadyApplied = IsMigrationApplied(connection, prefix, migration.id);
if (alreadyApplied)
{
continue;
}
ApplyMigration(connection, migration.script, prefix, migration.id);
}
}
}
