feat: Enhance queue creation with instance-specific settings. Now supports AutoDeleteOnIdle.

Author: warwickschroeder

src/Transport/Administration/QueueCreator.cs

@@ -11,7 +11,7 @@ class QueueCreator(AzureServiceBusTransport transportSettings)
 {
     static readonly ILog Logger = LogManager.GetLogger<QueueCreator>();
 
-    public async Task Create(ServiceBusAdministrationClient adminClient, string[] queues,
+    public async Task Create(ServiceBusAdministrationClient adminClient, string[] queues, string? instanceName = null,
         CancellationToken cancellationToken = default)
     {
         foreach (var address in queues)
@@ -25,6 +25,15 @@ public async Task Create(ServiceBusAdministrationClient adminClient, string[] qu
                 EnablePartitioning = transportSettings.EnablePartitioning
             };
 
+            // Only apply AutoDeleteOnIdle if an instance name is provided to avoid unintentional deletions
+            // of shared queues, e.g. error.
+            if (instanceName is not null
+               && string.Equals(instanceName, address, StringComparison.Ordinal)
+               && transportSettings.AutoDeleteOnIdle is not null)
+            {
+                queue.AutoDeleteOnIdle = transportSettings.AutoDeleteOnIdle.Value;
+            }
+
             try
             {
                 await adminClient.CreateQueueAsync(queue, cancellationToken).ConfigureAwait(false);

src/Transport/Administration/TopologyCreator.cs

@@ -6,13 +6,13 @@ namespace NServiceBus.Transport.AzureServiceBus;
 
 class TopologyCreator(AzureServiceBusTransport transportSettings)
 {
-    public async Task Create(ServiceBusAdministrationClient adminClient, string[] queues,
+    public async Task Create(ServiceBusAdministrationClient adminClient, string[] queues, string? instanceName = null,
         CancellationToken cancellationToken = default)
     {
         var topologyCreator = new MigrationTopologyCreator(transportSettings);
         await topologyCreator.Create(adminClient, cancellationToken).ConfigureAwait(false);
 
         var queueCreator = new QueueCreator(transportSettings);
-        await queueCreator.Create(adminClient, queues, cancellationToken).ConfigureAwait(false);
+        await queueCreator.Create(adminClient, queues, instanceName, cancellationToken).ConfigureAwait(false);
     }
 }

src/Transport/AzureServiceBusTransport.cs

@@ -118,7 +118,15 @@ await administrationClient.AssertNamespaceManageRightsAvailable(cancellationToke
                 .ToArray();
 
             var queueCreator = new TopologyCreator(this);
-            await queueCreator.Create(administrationClient, allQueues, cancellationToken).ConfigureAwait(false);
+
+            // Pass in the instance specific queue address (if it exists) so that the queue creator can set the 
+            // AutoDeleteOnIdle (if set) only on that queue and not on shared queues like error.
+            string? instanceReceiverAddress = null;
+            if (infrastructure.Receivers.TryGetValue("InstanceSpecific", out var instanceReceiver))
+            {
+                instanceReceiverAddress = instanceReceiver.ReceiveAddress;
+            }
+            await queueCreator.Create(administrationClient, allQueues, instanceReceiverAddress, cancellationToken).ConfigureAwait(false);
 
             foreach (IMessageReceiver messageReceiver in infrastructure.Receivers.Values)
             {
@@ -133,7 +141,6 @@ await subscriptionManager.SetupInfrastructureIfNecessary(cancellationToken)
         }
 
         return infrastructure;
-
     }
 
     void ApplyRetryPolicyOptionsIfNeeded(ServiceBusClientOptions options)
@@ -201,6 +208,36 @@ public int EntityMaximumSize
 
     internal int EntityMaximumSizeInMegabytes => EntityMaximumSize * 1024;
 
+    /// <summary>
+    /// Gets or sets the maximum time period that a queue can remain idle before Azure Service Bus automatically deletes it.
+    /// </summary>
+    /// <value>The idle timeout after which unused entities are automatically deleted. The minimum allowed value is 5 minutes.</value>    
+    /// <remarks>
+    /// <para>
+    /// This property controls the AutoDeleteOnIdle setting for queues created by the transport.
+    /// When an entity has no messages and no active connections for the specified duration,
+    /// Azure Service Bus will automatically delete it to help manage resource cleanup.
+    /// See <see href="https://learn.microsoft.com/en-us/azure/service-bus-messaging/advanced-features-overview#autodelete-on-idle"/>.
+    /// </para>
+    /// <para>
+    /// Setting this value can be useful for temporary queues (dynamically scaling endpoints that make use of 'MakeInstanceUniquelyAddressable') that should be cleaned up automatically
+    /// when they are no longer being used. However, be cautious when setting this for production endpoints as it may result in unexpected entity deletion during periods of low activity.
+    /// </para>
+    /// </remarks>
+    /// <exception cref="ArgumentOutOfRangeException">Thrown when the value is less than 5 minutes.</exception>
+    public TimeSpan? AutoDeleteOnIdle
+    {
+        get;
+        set
+        {
+            if (value.HasValue)
+            {
+                ArgumentOutOfRangeException.ThrowIfLessThan(value.Value, TimeSpan.FromMinutes(5), nameof(AutoDeleteOnIdle));
+            }
+            field = value;
+        }
+    }
+
     /// <summary>
     /// Enables entity partitioning when creating queues and topics.
     /// </summary>

src/Transport/AzureServiceBusTransportInfrastructure.cs

@@ -64,7 +64,8 @@ void WriteStartupDiagnostics(StartupDiagnosticEntries startupDiagnostic) =>
             UseWebSockets = transportSettings.UseWebSockets.ToString(),
             TimeToWaitBeforeTriggeringCircuitBreaker = transportSettings.TimeToWaitBeforeTriggeringCircuitBreaker.ToString(),
             CustomTokenProvider = transportSettings.TokenCredential?.ToString() ?? "default",
-            CustomRetryPolicy = transportSettings.RetryPolicyOptions?.ToString() ?? "default"
+            CustomRetryPolicy = transportSettings.RetryPolicyOptions?.ToString() ?? "default",
+            AutoDeleteOnIdle = transportSettings.AutoDeleteOnIdle?.ToString() ?? "default",
         });
 
     IMessageReceiver CreateMessagePump(ReceiveSettings receiveSettings, ServiceBusClient receiveClient)