public async Task Purge(TableBasedQueue queue, CancellationToken cancellationToken)
{
if (!enable)
{
Logger.DebugFormat("Purging expired messages on startup is not enabled for {0}.", queue);
return;
}
Logger.DebugFormat("Starting a new expired message purge task for table {0}.", queue);
var totalPurgedRowsCount = 0;
try
{
using (var connection = await openConnection(queue).ConfigureAwait(false))
{
var continuePurging = true;
while (continuePurging && !cancellationToken.IsCancellationRequested)
{
var purgedRowsCount = await queue.PurgeBatchOfExpiredMessages(connection, purgeBatchSize).ConfigureAwait(false);
totalPurgedRowsCount += purgedRowsCount;
continuePurging = purgedRowsCount == purgeBatchSize;
}
}
Logger.DebugFormat("{0} expired messages were successfully purged from table {1}", totalPurgedRowsCount, queue);
}
catch
{
Logger.WarnFormat("Purging expired messages from table {0} failed after purging {1} messages.", queue, totalPurgedRowsCount);
throw;
}
}
public virtual async Task <int> Purge(TableBasedQueue queue)
{
using (var connection = await connectionFactory.OpenNewConnection().ConfigureAwait(false))
{
return(await queue.Purge(connection).ConfigureAwait(false));
}
}
public void Init(TableBasedQueue inputQueue, TableBasedQueue errorQueue, Func <MessageContext, Task> onMessage, Func <ErrorContext, Task <ErrorHandleResult> > onError, CriticalError criticalError)
{
InputQueue = inputQueue;
ErrorQueue = errorQueue;
this.onMessage = onMessage;
this.onError = onError;
this.criticalError = criticalError;
}
async Task VerifyHeadersColumnType(TableBasedQueue queue)
{
try
{
using (var connection = await openConnection(queue).ConfigureAwait(false))
{
var columnType = await queue.CheckHeadersColumnType(connection).ConfigureAwait(false);
if (string.Equals(columnType, "varchar", StringComparison.OrdinalIgnoreCase))
{
Logger.Warn($"Table {queue.Name} stores headers in a non Unicode-compatible column (varchar).{Environment.NewLine}This may lead to data loss when sending non-ASCII characters in headers. SQL Server transport 3.1 and newer can take advantage of the nvarchar column type for headers. Please change the column type in the database.");
}
}
}
catch (Exception ex)
{
Logger.WarnFormat("Checking indexes on table {0} failed. Exception: {1}", queue, ex);
}
}
async Task VerifyExpiredIndex(TableBasedQueue queue)
{
try
{
using (var connection = await openConnection(queue).ConfigureAwait(false))
{
var indexExists = await queue.CheckExpiresIndexPresence(connection).ConfigureAwait(false);
if (!indexExists)
{
Logger.Warn($@"Table {queue.Name} does not contain index 'Index_Expires'.{Environment.NewLine}Adding this index will speed up the process of purging expired messages from the queue. Please consult the documentation for further information.");
}
}
}
catch (Exception ex)
{
Logger.WarnFormat("Checking indexes on table {0} failed. Exception: {1}", queue, ex);
}
}
public async Task <int> Peek(TableBasedQueue inputQueue, RepeatedFailuresOverTimeCircuitBreaker circuitBreaker, CancellationToken cancellationToken)
{
var messageCount = 0;
try
{
using (var scope = new TransactionScope(TransactionScopeOption.RequiresNew, new TransactionOptions {
IsolationLevel = IsolationLevel.ReadCommitted
}, TransactionScopeAsyncFlowOption.Enabled))
using (var connection = await connectionFactory.OpenNewConnection().ConfigureAwait(false))
{
messageCount = await inputQueue.TryPeek(connection, cancellationToken).ConfigureAwait(false);
circuitBreaker.Success();
if (messageCount == 0)
{
Logger.Debug($"Input queue empty. Next peek operation will be delayed for {settings.Delay}.");
await Task.Delay(settings.Delay, cancellationToken).ConfigureAwait(false);
}
scope.Complete();
}
}
catch (OperationCanceledException)
{
//Graceful shutdown
}
catch (SqlException e) when(cancellationToken.IsCancellationRequested)
{
Logger.Debug("Exception thown while performing cancellation", e);
}
catch (Exception ex)
{
Logger.Warn("Sql peek operation failed", ex);
await circuitBreaker.Failure(ex).ConfigureAwait(false);
}
return(messageCount);
}
public async Task PerformInspection(TableBasedQueue queue)
{
await VerifyExpiredIndex(queue).ConfigureAwait(false);
await VerifyHeadersColumnType(queue).ConfigureAwait(false);
}