public async Task Init(Func <MessageContext, Task> onMessage, Func <ErrorContext, Task <ErrorHandleResult> > onError, CriticalError criticalError, PushSettings settings)
{
receiveStrategy = receiveStrategyFactory(settings.RequiredTransactionMode);
peekCircuitBreaker = new RepeatedFailuresOverTimeCircuitBreaker("SqlPeek", waitTimeCircuitBreaker, ex => criticalError.Raise("Failed to peek " + settings.InputQueue, ex));
receiveCircuitBreaker = new RepeatedFailuresOverTimeCircuitBreaker("ReceiveText", waitTimeCircuitBreaker, ex => criticalError.Raise("Failed to receive from " + settings.InputQueue, ex));
inputQueue = queueFactory(settings.InputQueue);
errorQueue = queueFactory(settings.ErrorQueue);
receiveStrategy.Init(inputQueue, errorQueue, onMessage, onError, criticalError);
if (settings.PurgeOnStartup)
{
try
{
var purgedRowsCount = await queuePurger.Purge(inputQueue).ConfigureAwait(false);
Logger.InfoFormat("{0:N} messages purged from queue {1}", purgedRowsCount, settings.InputQueue);
}
catch (Exception ex)
{
Logger.Warn("Failed to purge input queue on startup.", ex);
}
}
await schemaInspector.PerformInspection(inputQueue).ConfigureAwait(false);
}
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);
}