public Task StartReceive(CancellationToken cancellationToken = default)
{
maxConcurrency = limitations.MaxConcurrency;
var prefetchCount = maxConcurrency * transportSettings.PrefetchMultiplier;
if (transportSettings.PrefetchCount.HasValue)
{
prefetchCount = transportSettings.PrefetchCount.Value;
}
var receiveOptions = new ServiceBusReceiverOptions()
{
PrefetchCount = prefetchCount,
ReceiveMode = transportSettings.TransportTransactionMode == TransportTransactionMode.None
? ServiceBusReceiveMode.ReceiveAndDelete
: ServiceBusReceiveMode.PeekLock
};
receiver = serviceBusClient.CreateReceiver(ReceiveAddress, receiveOptions);
concurrencyLimiter = new SemaphoreSlim(maxConcurrency, maxConcurrency);
messageReceivingCancellationTokenSource = new CancellationTokenSource();
messageProcessingCancellationTokenSource = new CancellationTokenSource();
circuitBreaker = new RepeatedFailuresOverTimeCircuitBreaker($"'{receiveSettings.ReceiveAddress}'", transportSettings.TimeToWaitBeforeTriggeringCircuitBreaker, ex => criticalErrorAction("Failed to receive message from Azure Service Bus.", ex, messageProcessingCancellationTokenSource.Token));
// no Task.Run() here because ReceiveMessagesAndSwallowExceptions immediately yields with an await
messageReceivingTask = ReceiveMessagesAndSwallowExceptions(messageReceivingCancellationTokenSource.Token);
return(Task.CompletedTask);
}
public Task Init(Func <MessageContext, Task> pump, Func <ErrorContext, Task <ErrorHandleResult> > onError, CriticalError criticalError, PushSettings pushSettings)
{
topologyOperator = DetermineTopologyOperator(pushSettings.InputQueue);
messagePump = pump;
var name = $"MessagePump on the queue `{pushSettings.InputQueue}`";
circuitBreaker = new RepeatedFailuresOverTimeCircuitBreaker(name, timeToWaitBeforeTriggering, ex => criticalError.Raise("Failed to receive message from Azure Service Bus.", ex));
if (pushSettings.PurgeOnStartup)
{
throw new InvalidOperationException("Azure Service Bus transport doesn't support PurgeOnStartup behavior");
}
inputQueue = pushSettings.InputQueue;
topologyOperator.OnIncomingMessage(async(incoming, receiveContext) =>
{
if (circuitBreaker == null || throttler == null) /* can be disposed by fody injected logic, in theory */
{
return;
}
var tokenSource = new CancellationTokenSource();
receiveContext.CancellationToken = tokenSource.Token;
circuitBreaker.Success();
var transportTransaction = new TransportTransaction();
transportTransaction.Set(receiveContext);
await throttler.WaitAsync(receiveContext.CancellationToken).ConfigureAwait(false);
try
{
await messagePump(new MessageContext(incoming.MessageId, incoming.Headers, incoming.Body, transportTransaction, tokenSource, new ContextBag())).ConfigureAwait(false);
}
finally
{
throttler.Release();
}
});
topologyOperator.OnError(exception => circuitBreaker?.Failure(exception));
topologyOperator.OnProcessingFailure(onError);
topologyOperator.SetCriticalError(criticalError);
return(TaskEx.Completed);
}
public Task Init(Func <MessageContext, Task> onMessage, Func <ErrorContext, Task <ErrorHandleResult> > onError, CriticalError criticalError, PushSettings settings)
{
if (settings.PurgeOnStartup)
{
throw new Exception("Azure Service Bus transport doesn't support PurgeOnStartup behavior");
}
this.onMessage = onMessage;
this.onError = onError;
pushSettings = settings;
circuitBreaker = new RepeatedFailuresOverTimeCircuitBreaker($"'{settings.InputQueue}'", timeToWaitBeforeTriggeringCircuitBreaker, criticalError);
return(Task.CompletedTask);
}
