private async Task <bool> SendMessageAsync(MtaQueuedMessage msg)
{
// Check that the message next attempt after has passed.
if (msg.AttemptSendAfterUtc > DateTime.UtcNow)
{
RabbitMqOutboundQueueManager.Enqueue(msg);
await Task.Delay(50); // To prevent a tight loop within a Task thread we should sleep here.
return(false);
}
if (await MtaTransaction.HasBeenHandledAsync(msg.ID))
{
msg.IsHandled = true;
return(true);
}
// Get the send that this message belongs to so that we can check the send state.
Send snd = await SendManager.Instance.GetSendAsync(msg.InternalSendID);
switch (snd.SendStatus)
{
// The send is being discarded so we should discard the message.
case SendStatus.Discard:
await msg.HandleMessageDiscardAsync();
return(false);
// The send is paused, the handle pause state will delay, without deferring, the message for a while so we can move on to other messages.
case SendStatus.Paused:
msg.HandleSendPaused();
return(false);
// Send is active so we don't need to do anything.
case SendStatus.Active:
break;
// Unknown send state, requeue the message and log error. Cannot send!
default:
msg.AttemptSendAfterUtc = DateTime.UtcNow.AddMinutes(1);
RabbitMqOutboundQueueManager.Enqueue(msg);
Logging.Error("Failed to send message. Unknown SendStatus[" + snd.SendStatus + "]!");
return(false);
}
bool result;
// Check the message hasn't timed out. If it has don't attempt to send it.
// Need to do this here as there may be a massive backlog on the server
// causing messages to be waiting for ages after there AttemptSendAfter
// before picking up. The MAX_TIME_IN_QUEUE should always be enforced.
if (msg.AttemptSendAfterUtc - msg.QueuedTimestampUtc > new TimeSpan(0, MtaParameters.MtaMaxTimeInQueue, 0))
{
await msg.HandleDeliveryFailAsync(MtaParameters.TIMED_OUT_IN_QUEUE_MESSAGE, null, null);
result = false;
}
else
{
MailAddress mailAddress = new MailAddress(msg.RcptTo[0]);
MailAddress mailFrom = new MailAddress(msg.MailFrom);
MXRecord[] mXRecords = DNSManager.GetMXRecords(mailAddress.Host);
// If mxs is null then there are no MX records.
if (mXRecords == null || mXRecords.Length < 1)
{
await msg.HandleDeliveryFailAsync("550 Domain Not Found.", null, null);
result = false;
}
else if (IsMxBlacklisted(mXRecords))
{
await msg.HandleDeliveryFailAsync("550 Domain blacklisted.", null, mXRecords[0]);
result = false;
}
else
{
// The IP group that will be used to send the queued message.
VirtualMtaGroup virtualMtaGroup = VirtualMtaManager.GetVirtualMtaGroup(msg.VirtualMTAGroupID);
VirtualMTA sndIpAddress = virtualMtaGroup.GetVirtualMtasForSending(mXRecords[0]);
SmtpOutboundClientDequeueResponse dequeueResponse = await SmtpClientPool.Instance.DequeueAsync(sndIpAddress, mXRecords);
switch (dequeueResponse.DequeueResult)
{
case SmtpOutboundClientDequeueAsyncResult.Success:
case SmtpOutboundClientDequeueAsyncResult.NoMxRecords:
case SmtpOutboundClientDequeueAsyncResult.FailedToAddToSmtpClientQueue:
case SmtpOutboundClientDequeueAsyncResult.Unknown:
break; // Don't need to do anything for these results.
case SmtpOutboundClientDequeueAsyncResult.FailedToConnect:
await msg.HandleFailedToConnectAsync(sndIpAddress, mXRecords[0]);
break;
case SmtpOutboundClientDequeueAsyncResult.ServiceUnavalible:
await msg.HandleServiceUnavailableAsync(sndIpAddress);
break;
case SmtpOutboundClientDequeueAsyncResult.Throttled:
await msg.HandleDeliveryThrottleAsync(sndIpAddress, mXRecords[0]);
break;
case SmtpOutboundClientDequeueAsyncResult.FailedMaxConnections:
msg.AttemptSendAfterUtc = DateTime.UtcNow.AddSeconds(2);
RabbitMqOutboundQueueManager.Enqueue(msg);
break;
}
SmtpOutboundClient smtpClient = dequeueResponse.SmtpOutboundClient;
// If no client was dequeued then we can't currently send.
// This is most likely a max connection issue. Return false but don't
// log any deferal or throttle.
if (smtpClient == null)
{
result = false;
}
else
{
try
{
Action <string> failedCallback = delegate(string smtpResponse)
{
// If smtpRespose starts with 5 then perm error should cause fail
if (smtpResponse.StartsWith("5"))
{
msg.HandleDeliveryFailAsync(smtpResponse, sndIpAddress, smtpClient.MXRecord).Wait();
}
else
{
// If the MX is actively denying use service access, SMTP code 421 then we should inform
// the ServiceNotAvailableManager manager so it limits our attepts to this MX to 1/minute.
if (smtpResponse.StartsWith("421"))
{
ServiceNotAvailableManager.Add(smtpClient.SmtpStream.LocalAddress.ToString(), smtpClient.MXRecord.Host, DateTime.UtcNow);
msg.HandleDeliveryDeferral(smtpResponse, sndIpAddress, smtpClient.MXRecord, true);
}
else
{
// Otherwise message is deferred
msg.HandleDeliveryDeferral(smtpResponse, sndIpAddress, smtpClient.MXRecord, false);
}
}
throw new SmtpTransactionFailedException();
};
// Run each SMTP command after the last.
await smtpClient.ExecHeloOrRsetAsync(failedCallback);
await smtpClient.ExecMailFromAsync(mailFrom, failedCallback);
await smtpClient.ExecRcptToAsync(mailAddress, failedCallback);
await smtpClient.ExecDataAsync(msg.Message, failedCallback, async (response) => {
await msg.HandleDeliverySuccessAsync(sndIpAddress, smtpClient.MXRecord, response);
});
SmtpClientPool.Instance.Enqueue(smtpClient);
result = true;
}
catch (SmtpTransactionFailedException)
{
// Exception is thrown to exit transaction, logging of deferrals/failers already handled.
result = false;
}
catch (Exception ex)
{
Logging.Error("MessageSender error.", ex);
if (msg != null)
{
msg.HandleDeliveryDeferral("Connection was established but ended abruptly.", sndIpAddress, smtpClient.MXRecord, false);
}
result = false;
}
finally
{
if (smtpClient != null)
{
smtpClient.IsActive = false;
smtpClient.LastActive = DateTime.UtcNow;
}
}
}
}
}
return(result);
}
/// <summary>
/// Requeue the message in RabbitMQ.
/// </summary>
private void Requeue()
{
RabbitMqOutboundQueueManager.Enqueue(this);
IsHandled = true;
}
public void Start()
{
Thread t = new Thread(new ThreadStart(() => {
// Dictionary will hold a single int for each running task. The int means nothing.
ConcurrentDictionary <Guid, int> runningTasks = new ConcurrentDictionary <Guid, int>();
Action <MtaQueuedMessage> taskWorker = (qMsg) => {
// Generate a unique ID for this task.
Guid taskID = Guid.NewGuid();
// Add this task to the running list.
if (!runningTasks.TryAdd(taskID, 1))
{
return;
}
Task.Run(async() =>
{
try
{
// Loop while there is a task message to send.
while (qMsg != null && !_IsStopping)
{
// Send the message.
await SendMessageAsync(qMsg);
if (!qMsg.IsHandled)
{
Logging.Warn("Message not handled " + qMsg.ID);
qMsg.AttemptSendAfterUtc = DateTime.UtcNow.AddMinutes(1);
RabbitMq.RabbitMqOutboundQueueManager.Enqueue(qMsg);
}
// Acknowledge of the message.
RabbitMqOutboundQueueManager.Ack(qMsg);
// Try to get another message to send.
qMsg = RabbitMq.RabbitMqOutboundQueueManager.Dequeue();
}
}
catch (Exception ex)
{
// Log if we can't send the message.
Logging.Debug("Failed to send message", ex);
}
finally
{
// If there is still a acknowledge of the message.
if (qMsg != null)
{
if (!qMsg.IsHandled)
{
Logging.Warn("Message not handled " + qMsg.ID);
qMsg.AttemptSendAfterUtc = DateTime.UtcNow.AddMinutes(1);
RabbitMq.RabbitMqOutboundQueueManager.Enqueue(qMsg);
}
RabbitMqOutboundQueueManager.Ack(qMsg);
}
// Remove this task from the dictionary
int value;
runningTasks.TryRemove(taskID, out value);
}
});
};
Action startWorkerTasks = () => {
while ((runningTasks.Count < MAX_SENDING_WORKER_TASKS) && !_IsStopping)
{
MtaQueuedMessage qmsg = RabbitMq.RabbitMqOutboundQueueManager.Dequeue();
if (qmsg == null)
{
break; // Nothing to do, so don't start anymore workers.
}
taskWorker(qmsg);
}
};
while (!_IsStopping)
{
if (runningTasks.Count >= MAX_SENDING_WORKER_TASKS)
{
Thread.Sleep(100);
continue;
}
startWorkerTasks();
}
}));
t.Start();
}
private async Task SendMessageAsync(MtaQueuedMessage msg)
{
// Check that the message next attempt after has passed.
if (msg.AttemptSendAfterUtc > DateTime.UtcNow)
{
await RabbitMqOutboundQueueManager.Enqueue(msg);
await Task.Delay(50); // To prevent a tight loop within a Task thread we should sleep here.
return;
}
if (await Data.MtaTransaction.HasBeenHandledAsync(msg.ID))
{
msg.IsHandled = true;
return;
}
// Get the send that this message belongs to so that we can check the send state.
var snd = await SendManager.Instance.GetSendAsync(msg.InternalSendID);
switch (snd.SendStatus)
{
// The send is being discarded so we should discard the message.
case SendStatus.Discard:
await MtaMessageHelper.HandleMessageDiscardAsync(msg);
return;
// The send is paused, the handle pause state will delay, without deferring, the message for a while so we can move on to other messages.
case SendStatus.Paused:
await MtaMessageHelper.HandleSendPaused(msg);
return;
// Send is active so we don't need to do anything.
case SendStatus.Active:
break;
// Unknown send state, requeue the message and log error. Cannot send!
default:
msg.AttemptSendAfterUtc = DateTime.UtcNow.AddMinutes(1);
await RabbitMqOutboundQueueManager.Enqueue(msg);
Logging.Error("Failed to send message. Unknown SendStatus[" + snd.SendStatus + "]!");
return;
}
// Check the message hasn't timed out. If it has don't attempt to send it.
// Need to do this here as there may be a massive backlog on the server
// causing messages to be waiting for ages after there AttemptSendAfter
// before picking up. The MAX_TIME_IN_QUEUE should always be enforced.
if (msg.AttemptSendAfterUtc - msg.QueuedTimestampUtc > new TimeSpan(0, MtaParameters.MtaMaxTimeInQueue, 0))
{
await MtaMessageHelper.HandleDeliveryFailAsync(msg, MtaParameters.TIMED_OUT_IN_QUEUE_MESSAGE, null, null);
}
else
{
MailAddress rcptTo = new MailAddress(msg.RcptTo[0]);
MailAddress mailFrom = new MailAddress(msg.MailFrom);
MXRecord[] mXRecords = DNSManager.GetMXRecords(rcptTo.Host);
// If mxs is null then there are no MX records.
if (mXRecords == null || mXRecords.Length < 1)
{
await MtaMessageHelper.HandleDeliveryFailAsync(msg, "550 Domain Not Found.", null, null);
}
else if (IsMxBlacklisted(mXRecords))
{
await MtaMessageHelper.HandleDeliveryFailAsync(msg, "550 Domain blacklisted.", null, mXRecords[0]);
}
else
{
var vMtaGroup = VirtualMtaManager.GetVirtualMtaGroup(msg.VirtualMTAGroupID);
var sendResult = await MantaSmtpClientPoolCollection.Instance.SendAsync(mailFrom, rcptTo, vMtaGroup, mXRecords, msg.Message);
switch (sendResult.MantaOutboundClientResult)
{
case MantaOutboundClientResult.FailedToConnect:
await MtaMessageHelper.HandleFailedToConnectAsync(msg, sendResult.VirtualMTA, sendResult.MXRecord);
break;
case MantaOutboundClientResult.MaxConnections:
await RabbitMqOutboundQueueManager.Enqueue(msg);
break;
case MantaOutboundClientResult.MaxMessages:
await MtaMessageHelper.HandleDeliveryThrottleAsync(msg, sendResult.VirtualMTA, sendResult.MXRecord);
break;
case MantaOutboundClientResult.RejectedByRemoteServer:
if (string.IsNullOrWhiteSpace(sendResult.Message))
{
Logging.Error("RejectedByRemoteServer but no message!");
await MtaMessageHelper.HandleDeliveryDeferralAsync(msg, sendResult.Message, sendResult.VirtualMTA, sendResult.MXRecord);
}
if (sendResult.Message[0] == '4')
{
await MtaMessageHelper.HandleDeliveryDeferralAsync(msg, sendResult.Message, sendResult.VirtualMTA, sendResult.MXRecord);
}
else
{
await MtaMessageHelper.HandleDeliveryFailAsync(msg, sendResult.Message, sendResult.VirtualMTA, sendResult.MXRecord);
}
break;
case MantaOutboundClientResult.ServiceNotAvalible:
await MtaMessageHelper.HandleServiceUnavailableAsync(msg, sendResult.VirtualMTA);
break;
case MantaOutboundClientResult.Success:
await MtaMessageHelper.HandleDeliverySuccessAsync(msg, sendResult.VirtualMTA, sendResult.MXRecord, sendResult.Message);
break;
default:
// Something weird happening with this message, get it out of the way for a bit.
msg.AttemptSendAfterUtc = DateTime.UtcNow.AddMinutes(5);
await RabbitMqOutboundQueueManager.Enqueue(msg);
break;
}
}
}
}
