Service Bus - Retrieve message from session by sequence number

Question

I am currently trying to retrieve a specific message from a session.

To do so I use want to use the .Receive(Int64) on the MessageSession where I pass in the sequence number of the message.

Here is my code -

long msgSequenceNr = 1337;

QueueClient queueClient = QueueClient.CreateFromConnectionString(Constants.ServiceBusConnectionString, Constants.TestQueueEntityName, ReceiveMode.PeekLock);
MessageSession msgSession = queueClient.AcceptMessageSession(Constants.TestSessionId);

var peekedMsg = msgSession.Peek(msgSequenceNr); // <-- Works fine!
var receivedMsg = msgSession.Receive(msgSequenceNr); // <-- MessageNotFoundException

Unfortunately the Receive will result in a MessageNotFoundException while the Peek works fine. Is this a limitation that I missed or is there another way to achieve this.

Note that it is possible that there are multiple messages in the session

Sandrino Di Mattia · Accepted Answer · 2014-10-23T14:57:19.267

Receive with the SequenceNumber can only be used in combination with the Defer method. This is how you would implement it:

Message received, but it can't be processed right now (maybe it's waiting for a different process to complete).
Persist the SequenceNumber in some persistent storage (Table Storage, SQL Database, ...)
When you know that processing can continue (eg: the dependent process is complete), load all SequenceNumbers from your persistent storage.
Use Receive(int sequenceNumber) or ReceiveBatch(int[] sequenceNumbers) to received and process your deferred messages.

Sample application: https://code.msdn.microsoft.com/windowsazure/Brokered-Messaging-ccc4f879#content

Update:

Form your comment I noticed that "undeferring" a deferred message could be a solution. Here's some sample code to undefer the message which copies the deferred message to a new message, Completes the deferred message and sends the new message back in the queue. This uses a TransactionScope to transactionally Complete and Resend the message to avoid the risk of losing the message:

    var messageId = "12434539828282";

    // Send.
    var msg = new BrokeredMessage {SessionId = "user1", MessageId = messageId };
    msg.Properties.Add("Language", "Dutch");
    queue.Send(msg);

    // Receive.
    var session = queue.AcceptMessageSession();
    msg = session.Receive();

    // Store the sequence number.
    var sequenceNumber = msg.SequenceNumber;

    // Defer.
    msg.Defer();

    // Change to true to test if the transaction worked.
    var shouldThrow = false;

    // Later processing of deferred message.
    msg = session.Receive(sequenceNumber);

    try
    {
        using (var ts = new TransactionScope())
        {
            // Create a new message.
            var undeferredMessage = new BrokeredMessage {SessionId = msg.SessionId, MessageId = msg.MessageId};
            foreach (var prop in msg.Properties)
                undeferredMessage.Properties.Add(prop);

            // Complete and send within the same transaction.
            msg.Complete();
            if (shouldThrow)
                throw new InvalidOperationException("Some error");
            queue.Send(undeferredMessage);

            // Complete the transaction.
            ts.Complete();
        }
    }
    catch (Exception ex)
    {
        msg.Abandon();
    }

    if (shouldThrow)
    {
        msg = session.Receive(sequenceNumber);
        Console.WriteLine(msg.MessageId + " should match: " + messageId);
    }
    else
    {
        try
        {
            msg = session.Receive(sequenceNumber);
        }
        catch (Exception ex)
        {
            Console.WriteLine("Message not found, transaction worked OK.");
        }
    }

Note: here I'm simply taking a copy of the Properties. Keep into account that you might want to copy the Body and any other additional information.

Problem with defering is that you are not able to "undefer" them, unfortunately this is also a requirement for us. Is this documented somewhere dat you need to defer in order to use Sequence Number receive? — Tom Kerkhove, Oct 23 '14 at 14:26
There's this post by Clemens Vasters: http://stackoverflow.com/questions/18211179/how-to-use-the-messagereceiver-receive-method-by-sequencenumber-on-servicebus so I assume there should be some info on MSDN. — Sandrino Di Mattia, Oct 23 '14 at 14:36
Thank you, then I'll have to find another way to retrieve a specific message from a session! — Tom Kerkhove, Oct 23 '14 at 14:43
@TomKerkhove could the "Undefer" code sample be an option for your scenario? — Sandrino Di Mattia, Oct 23 '14 at 15:06
That initial sample application must use an old version of the ServiceBus API/SDK bits, many of the methods and objects don't exist (CreateReceiver, MessageReceipt, etc) — JoeBrockhaus, Jun 02 '15 at 00:08
It's the code on the 'Description' tab of that blog post that is out of date. When you click the 'browse code' tab, you get updated code. https://code.msdn.microsoft.com/windowsazure/Brokered-Messaging-ccc4f879/view/SourceCode#content — JoeBrockhaus, Jun 02 '15 at 00:10

Service Bus - Retrieve message from session by sequence number

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