Fix bug with queue names

Author: Unai Zorrilla Castro

src/BuildingBlocks/EventBus/EventBusRabbitMQ/EventBusRabbitMQ.cs

@@ -31,6 +31,7 @@ private readonly List<Type> _eventTypes
             = new List<Type>();
 
         private IModel _consumerChannel;
+        private string _queueName;
 
         public EventBusRabbitMQ(IRabbitMQPersisterConnection persisterConnection, ILogger<EventBusRabbitMQ> logger)
         {
@@ -93,7 +94,7 @@ public void Subscribe<T>(IIntegrationEventHandler<T> handler) where T : Integrat
 
                 using (var channel = _persisterConnection.CreateModel())
                 {
-                    channel.QueueBind(queue: channel.QueueDeclare().QueueName,
+                    channel.QueueBind(queue: _queueName,
                                       exchange: BROKER_NAME,
                                       routingKey: eventName);
 
@@ -131,9 +132,16 @@ public void Unsubscribe<T>(IIntegrationEventHandler<T> handler) where T : Integr
 
                         using (var channel = _persisterConnection.CreateModel())
                         {
-                            channel.QueueUnbind(queue: channel.QueueDeclare().QueueName,
+                            channel.QueueUnbind(queue: _queueName,
                                 exchange: BROKER_NAME,
                                 routingKey: eventName);
+
+                            if (_handlers.Keys.Count == 0)
+                            {
+                                _queueName = string.Empty;
+
+                                _consumerChannel.Close();
+                            }
                         }
                     }
                 }
@@ -142,7 +150,11 @@ public void Unsubscribe<T>(IIntegrationEventHandler<T> handler) where T : Integr
 
         public void Dispose()
         {
-            _consumerChannel.Dispose();
+            if (_consumerChannel != null)
+            {
+                _consumerChannel.Dispose();
+            }
+            
             _handlers.Clear();
         }
 
@@ -158,6 +170,8 @@ private IModel CreateConsumerChannel()
             channel.ExchangeDeclare(exchange: BROKER_NAME,
                                  type: "direct");
 
+            _queueName = channel.QueueDeclare().QueueName;
+
             var consumer = new EventingBasicConsumer(channel);
             consumer.Received += async (model, ea) =>
             {
@@ -167,16 +181,10 @@ private IModel CreateConsumerChannel()
                 await ProcessEvent(eventName, message);
             };
 
-            channel.BasicConsume(queue: channel.QueueDeclare().QueueName,
+            channel.BasicConsume(queue: _queueName,
                                  noAck: true,
                                  consumer: consumer);
 
-            channel.ModelShutdown += (sender, ea) =>
-            {
-                _consumerChannel.Dispose();
-                _consumerChannel = CreateConsumerChannel();
-            };
-
             channel.CallbackException += (sender, ea) =>
             {
                 _consumerChannel.Dispose();