public void SetupReceivers(ReceiveSettings[] receivers, Action <string, Exception, CancellationToken> criticalErrorAction)
{
var messagePumps = new Dictionary <string, IMessageReceiver>(receivers.Length);
foreach (var receiver in receivers)
{
if (receiver.UsePublishSubscribe)
{
throw new NotImplementedException("MSMQ does not support native pub/sub.");
}
// The following check avoids creating some sub-queues, if the endpoint sub queue has the capability to exceed the max length limitation for queue format name.
CheckEndpointNameComplianceForMsmq.Check(receiver.ReceiveAddress);
QueuePermissions.CheckQueue(receiver.ReceiveAddress);
var pump = new MessagePump(
transactionMode =>
SelectReceiveStrategy(transactionMode, transportSettings.TransactionScopeOptions.TransactionOptions),
transportSettings.MessageEnumeratorTimeout,
criticalErrorAction,
transportSettings,
receiver);
messagePumps.Add(pump.Id, pump);
}
Receivers = messagePumps;
}
// This is static to prevent the method from accessing feilds in the pump since that causes variable capturing and cause extra allocations
static async Task InnerReceiveMessages(MessagePump messagePump)
{
try
{
await messagePump.receiveStrategy.ReceiveMessage(messagePump.messageProcessingCancellationTokenSource.Token).ConfigureAwait(false);
messagePump.receiveCircuitBreaker.Success();
}
catch (OperationCanceledException) when(messagePump.messageProcessingCancellationTokenSource.IsCancellationRequested)
{
// Graceful shutdown
}
catch (Exception ex)
{
Logger.Warn("MSMQ receive operation failed", ex);
await messagePump.receiveCircuitBreaker.Failure(ex).ConfigureAwait(false);
}
finally
{
messagePump.concurrencyLimiter.Release();
}
}
// This is static to prevent the method from accessing fields in the pump since that causes variable capturing and cause extra allocations
static async Task ReceiveMessagesSwallowExceptionsAndReleaseConcurrencyLimiter(MessagePump messagePump, SemaphoreSlim localConcurrencyLimiter, CancellationToken messagePumpCancellationToken)
{
#pragma warning disable PS0021 // Highlight when a try block passes multiple cancellation tokens - justification:
// The message processing cancellation token is being used for the receive strategies,
// since we want those only to be canceled when the public token passed to Stop() is canceled.
// The message pump token is being used elsewhere, because we want those operations to be canceled as soon as Stop() is called.
// The catch clauses on the inner try are correctly filtered on the message processing cancellation token and
// the catch clause on the outer try is correctly filtered on the message pump cancellation token.
try
#pragma warning restore PS0021 // Highlight when a try block passes multiple cancellation tokens
{
try
{
// we are switching token here so we need to catch cancellation
await messagePump.receiveStrategy.ReceiveMessage(messagePump.messageProcessingCancellationTokenSource.Token).ConfigureAwait(false);
messagePump.receiveCircuitBreaker.Success();
}
catch (Exception ex) when(ex.IsCausedBy(messagePump.messageProcessingCancellationTokenSource.Token))
{
Logger.Warn("MSMQ receive operation canceled", ex);
}
catch (Exception ex)
{
Logger.Warn("MSMQ receive operation failed", ex);
await messagePump.receiveCircuitBreaker.Failure(ex, messagePumpCancellationToken).ConfigureAwait(false);
}
}
#pragma warning disable PS0019 // When catching System.Exception, cancellation needs to be properly accounted for - justification: see PS0021 suppression justification
catch (Exception ex) when(ex.IsCausedBy(messagePumpCancellationToken))
#pragma warning restore PS0019 // When catching System.Exception, cancellation needs to be properly accounted for
{
// private token, sender is being stopped, log the exception in case the stack trace is ever needed for debugging
Logger.Debug("Operation canceled while stopping message pump.", ex);
}
finally
{
localConcurrencyLimiter.Release();
}
}