[rabbitmq-discuss] .Net Client locks trying to create a channel on a blocked connection

Thu Aug 23 15:45:45 BST 2012

I'm using the RabbitMQ .Net client in C# and have noticed that if I try to create a channel (IModel) on a connection that is already established but in a blocking state then the code will just sit and wait.

Here is the C# code, nothing special:

        IModel channel = connection.CreateModel();

I've taken a look at the source of the RabbitMQ .Net Client and have traced it down to this:

Calling CreateModel() does the following:

        public IModel CreateModel()
        {
            ISession session = CreateSession();
            IFullModel model = (IFullModel)Protocol.CreateModel(session);
            model._Private_ChannelOpen("");
            return model;
        }

When model._Private_ChannelOpen(""); is called it ends up in this block of code:

SimpleBlockingRpcContinuation k = new SimpleBlockingRpcContinuation();
TransmitAndEnqueue(new Command(method, header, body), k);
return k.GetReply().Method;

The problem appears to be with the last line, which ends up trying to get the Value of a BlockingCell object, which is basically a while(true) loop like this:

get {
        lock (this) {
        while (!m_valueSet) {
        Monitor.Wait(this);
        }
       	return m_value;
        }
}

And because the m_valueSet is never true this code never returns :-( and the call to CreateModel stays in a blocked condition - presumably until the connection is unblocked.

Does anyone have any advice on how best to handle this situation?

Many thanks!