/// <summary>
/// Dequeue messages
/// </summary>
private async Task DeQueueMessagesAsync(CancellationToken ct)
{
try
{
if (_defaultSendIntervalSeconds > 0 && _maxSizeOfIoTHubMessageBytes > 0)
{
// send every x seconds
Trace($"Start timer to send data to IoTHub in {_defaultSendIntervalSeconds} seconds.");
_sendTimer = new Timer(async state => await SendToIoTHubAsync(), null, TimeSpan.FromSeconds(_defaultSendIntervalSeconds), TimeSpan.FromSeconds(_defaultSendIntervalSeconds));
}
WaitHandle[] waitHandles = { _sendQueueEvent, ct.WaitHandle };
while (true)
{
// wait till some work needs to be done
WaitHandle.WaitAny(waitHandles);
// do we need to stop
if (ct.IsCancellationRequested)
{
Trace($"Cancellation requested. Sending {_sendQueue.Count} remaining messages.");
await SendToIoTHubAsync();
break;
}
if (_sendQueue.Count > 0)
{
bool isPeekSuccessful = false;
bool isDequeueSuccessful = false;
string messageInJson = string.Empty;
int nextMessageSizeBytes = 0;
// perform a TryPeek to determine size of next message
// and whether it will fit. If so, dequeue message and add it to the list.
// if it cannot fit, send current message to IoTHub, reset it, and repeat.
isPeekSuccessful = _sendQueue.TryPeek(out messageInJson);
// get size of next message in the queue
if (isPeekSuccessful)
{
nextMessageSizeBytes = Encoding.UTF8.GetByteCount(messageInJson);
// sanity check that the user has set a large enough IoTHub messages size.
if (nextMessageSizeBytes > _maxSizeOfIoTHubMessageBytes && _maxSizeOfIoTHubMessageBytes > 0)
{
Trace(Utils.TraceMasks.Error, $"There is a telemetry message (size: {nextMessageSizeBytes}), which will not fit into an IoTHub message (max size: {_maxSizeOfIoTHubMessageBytes}].");
Trace(Utils.TraceMasks.Error, $"Please check your IoTHub message size settings. The telemetry message will be discarded silently. Sorry:(");
_sendQueue.TryDequeue(out messageInJson);
continue;
}
}
// determine if it will fit into remaining space of the IoTHub message or if we do not batch at all
// if so, dequeue it
if (_currentSizeOfIotHubMessageBytes + nextMessageSizeBytes < _maxSizeOfIoTHubMessageBytes || _maxSizeOfIoTHubMessageBytes == 0)
{
isDequeueSuccessful = _sendQueue.TryDequeue(out messageInJson);
// add dequeued message to list
if (isDequeueSuccessful)
{
OpcUaMessage msgPayload = JsonConvert.DeserializeObject <OpcUaMessage>(messageInJson);
_messageListSemaphore.Wait();
_messageList.Add(msgPayload);
_messageListSemaphore.Release();
_currentSizeOfIotHubMessageBytes = _currentSizeOfIotHubMessageBytes + nextMessageSizeBytes;
Trace(Utils.TraceMasks.OperationDetail, $"Added new message with size {nextMessageSizeBytes} to IoTHub message (size is now {_currentSizeOfIotHubMessageBytes}). {_sendQueue.Count} message(s) in send queue.");
// fall through, if we should send immediately
if (_maxSizeOfIoTHubMessageBytes != 0)
{
continue;
}
}
}
// the message needs to be sent now.
Trace(Utils.TraceMasks.OperationDetail, $"IoTHub message complete. Trigger send of message with size {_currentSizeOfIotHubMessageBytes} to IoTHub.");
await SendToIoTHubAsync();
}
}
}
catch (Exception e)
{
Trace(e, "Error while dequeuing messages.");
}
}
/// <summary>
/// Dequeue messages
/// </summary>
private static async Task DeQueueMessagesAsync(CancellationToken ct)
{
try
{
//Send every x seconds, regardless if IoT Hub message is full.
Timer sendTimer = new Timer(async state => await SendToIoTHubAsync(), null, 0, m_defaultSendIntervalInMilliSeconds);
while (true)
{
if (ct.IsCancellationRequested)
{
Trace("Cancellation requested. Sending remaining messages.");
sendTimer.Dispose();
await SendToIoTHubAsync();
break;
}
if (m_sendQueue.Count > 0)
{
bool isPeekSuccessful = false;
bool isDequeueSuccessful = false;
string messageInJson = string.Empty;
int nextMessageSizeBytes = 0;
//Perform a TryPeek to determine size of next message
//and whether it will fit. If so, dequeue message and add it to the list.
//If it cannot fit, send current message to IoT Hub, reset it, and repeat.
isPeekSuccessful = m_sendQueue.TryPeek(out messageInJson);
//Get size of next message in the queue
if (isPeekSuccessful)
{
nextMessageSizeBytes = System.Text.Encoding.UTF8.GetByteCount(messageInJson);
}
//Determine if it will fit into remaining space of the IoT Hub message.
//If so, dequeue it
if (m_currentSizeOfIoTHubMessageBytes + nextMessageSizeBytes < m_maxSizeOfIoTHubMessageBytes)
{
isDequeueSuccessful = m_sendQueue.TryDequeue(out messageInJson);
//Add dequeued message to list
if (isDequeueSuccessful)
{
OpcUaMessage msgPayload = JsonConvert.DeserializeObject <OpcUaMessage>(messageInJson);
m_messageList.Add(msgPayload);
m_currentSizeOfIoTHubMessageBytes = m_currentSizeOfIoTHubMessageBytes + nextMessageSizeBytes;
}
}
else
{
//Message is full. Send it to IoT Hub
await SendToIoTHubAsync();
}
}
}
}
catch (Exception exception)
{
Console.WriteLine("Error dequeuing message: " + exception.ToString());
}
}