/// <summary>
/// Enqueue the SmtpOutboundClient for use by another message.
/// </summary>
/// <param name="client">The client to queue.</param>
public void Enqueue(SmtpOutboundClient client)
{
SmtpClientMxRecords mxConnections = this._OutboundConnections.GetOrAdd(client.SmtpStream.LocalAddress.ToString(), new SmtpClientMxRecords());
SmtpClientQueue clientQueue = null;
lock (this._ClientPoolLock)
{
if (!mxConnections.TryGetValue(client.MXRecord.Host, out clientQueue))
{
clientQueue = new SmtpClientQueue();
if (!mxConnections.TryAdd(client.MXRecord.Host, clientQueue))
{
throw new Exception("Failed to add new SmtpClientQueue");
}
}
}
clientQueue.Enqueue(client);
try
{
clientQueue.InUseConnections.Remove(client);
}
catch (Exception)
{
// Already removed.
}
}
/// <summary>
/// Attempts to get a SmtpClient using the outbound IP address and the specified MX records collection.
///
/// WARNING: returned SmtpOutboundClient will have it's IsActive flag set to true make sure to set it to
/// false when done with it or it will never be removed by the idle timeout.
/// </summary>
/// <param name="ipAddress">The local outbound endpoint we wan't to use.</param>
/// <param name="mxs">The MX records for the domain we wan't a client to connect to.</param>
/// <returns>Tuple containing a DequeueAsyncResult and either an SmtpOutboundClient or Null if failed to dequeue.</returns>
public async Task <SmtpOutboundClientDequeueResponse> DequeueAsync(VirtualMTA ipAddress, MXRecord[] mxs)
{
// If there aren't any remote mx records then we can't send
if (mxs.Length < 1)
{
return(new SmtpOutboundClientDequeueResponse(SmtpOutboundClientDequeueAsyncResult.NoMxRecords));
}
SmtpClientMxRecords mxConnections = this._OutboundConnections.GetOrAdd(ipAddress.IPAddress.ToString(), new SmtpClientMxRecords());
SmtpOutboundClient smtpClient = null;
// Check that we aren't being throttled.
if (!ThrottleManager.Instance.TryGetSendAuth(ipAddress, mxs[0]))
{
return(new SmtpOutboundClientDequeueResponse(SmtpOutboundClientDequeueAsyncResult.Throttled));
}
// Loop through all the MX Records.
for (int i = 0; i < mxs.Length; i++)
{
try
{
// To prevent us bombarding a server that is blocking us we will check the service not available manager
// to see if we can send to this MX, Max 1 message/minute, if we can't we won't.
// At the moment we stop to all MXs for a domain if one of them responds with service unavailable.
// This could be improved to allow others to continue, we should however if blocked on all MX's with
// lowest preference not move on to the others.
if (ServiceNotAvailableManager.IsServiceUnavailable(ipAddress.IPAddress.ToString(), mxs[i].Host))
{
return(new SmtpOutboundClientDequeueResponse(SmtpOutboundClientDequeueAsyncResult.ServiceUnavalible));
}
SmtpClientQueue clientQueue = null;
lock (this._ClientPoolLock)
{
if (!mxConnections.TryGetValue(mxs[i].Host, out clientQueue))
{
clientQueue = new SmtpClientQueue();
if (!mxConnections.TryAdd(mxs[i].Host, clientQueue))
{
return(new SmtpOutboundClientDequeueResponse(SmtpOutboundClientDequeueAsyncResult.FailedToAddToSmtpClientQueue));
}
}
}
// Loop through the client queue and make sure we get one thats still connected.
// They may have idled out while waiting.
while (!clientQueue.IsEmpty)
{
if (clientQueue.TryDequeue(out smtpClient))
{
if (smtpClient.Connected)
{
clientQueue.InUseConnections.Add(smtpClient);
smtpClient.LastActive = DateTime.UtcNow;
smtpClient.IsActive = true;
return(new SmtpOutboundClientDequeueResponse(SmtpOutboundClientDequeueAsyncResult.Success, smtpClient));
}
}
}
// Nothing was in the queue or all queued items timed out.
CreateNewConnectionAsyncResult createNewConnectionResult = await clientQueue.CreateNewConnectionAsync(ipAddress, mxs[i]);
if (createNewConnectionResult.Exception == null)
{
return(new SmtpOutboundClientDequeueResponse(SmtpOutboundClientDequeueAsyncResult.Success, createNewConnectionResult.OutboundClient));
}
else if (createNewConnectionResult.Exception is MaxConnectionsException)
{
return(new SmtpOutboundClientDequeueResponse(SmtpOutboundClientDequeueAsyncResult.FailedMaxConnections));
}
else
{
throw createNewConnectionResult.Exception;
}
}
catch (SocketException ex)
{
// We have failed to connect to the remote host.
Logging.Warn("Failed to connect to " + mxs[i].Host, ex);
// If we fail to connect to an MX then don't try again for at least a minute.
ServiceNotAvailableManager.Add(ipAddress.IPAddress.ToString(), mxs[i].Host, DateTime.UtcNow);
// Failed to connect to MX
if (i == mxs.Length - 1)
{
return(new SmtpOutboundClientDequeueResponse(SmtpOutboundClientDequeueAsyncResult.FailedToConnect));
}
}
catch (Exception ex)
{
// Something unexpected and unhandled has happened, log it and return unknown.
Logging.Error("SmtpClientPool.DequeueAsync Unhandled Exception", ex);
return(new SmtpOutboundClientDequeueResponse(SmtpOutboundClientDequeueAsyncResult.Unknown));
}
}
// It we got here then we have failed to connect to the remote host.
return(new SmtpOutboundClientDequeueResponse(SmtpOutboundClientDequeueAsyncResult.FailedToConnect));
}
private SmtpClientPool()
{
new Thread(new ThreadStart(delegate
{
while (true)
{
try
{
IEnumerator <KeyValuePair <string, SmtpClientMxRecords> > enumMXs = this._OutboundConnections.GetEnumerator();
while (enumMXs.MoveNext())
{
int count = 0;
int removed = 0;
KeyValuePair <string, SmtpClientMxRecords> current = enumMXs.Current;
SmtpClientMxRecords mxRecords = current.Value;
IEnumerator <KeyValuePair <string, SmtpClientQueue> > enumClients = mxRecords.GetEnumerator();
while (enumClients.MoveNext())
{
count++;
KeyValuePair <string, SmtpClientQueue> current2 = enumClients.Current;
SmtpClientQueue clients = current2.Value;
if (clients.Count == 0 && clients.InUseConnections.Count == 0)
{
ConcurrentDictionary <string, SmtpClientQueue> arg_8B_0 = mxRecords;
current2 = enumClients.Current;
if (arg_8B_0.TryRemove(current2.Key, out clients))
{
//string arg_AF_0 = "Removed empty SMTP Clients Queue for ";
//current2 = enumClients.Current;
//Logging.Debug(arg_AF_0 + current2.Key);
removed++;
}
else
{
string arg_D6_0 = "Failed to remove empty SMTP Clients Queue for ";
current2 = enumClients.Current;
Logging.Debug(arg_D6_0 + current2.Key);
}
}
}
Logging.Debug(string.Concat(new string[]
{
"SmtpClientPool : Removed ",
removed.ToString("N0"),
" client queues. ",
(count - removed).ToString("N0"),
" remaining."
}));
}
}
catch (Exception ex)
{
Logging.Debug("SmtpClientPool: " + ex);
}
finally
{
Thread.Sleep(60000);
}
}
}))
{
IsBackground = true
}.Start();
}
