Support ASB Geo-Recovery alias for querying queue names

Author: DavidBoike

src/Directory.Packages.props

@@ -12,6 +12,7 @@
     <PackageVersion Include="Azure.ResourceManager.ServiceBus" Version="1.1.0" />
     <PackageVersion Include="ByteSize" Version="2.1.2" />
     <PackageVersion Include="Caliburn.Micro" Version="4.0.230" />
+    <PackageVersion Include="DnsClient" Version="1.8.0" />
     <PackageVersion Include="FluentValidation" Version="11.11.0" />
     <PackageVersion Include="Fody" Version="6.9.1" />
     <PackageVersion Include="GitHubActionsTestLogger" Version="2.4.1" />

src/ServiceControl.Transports.ASBS/AzureQuery.cs

@@ -18,6 +18,8 @@ namespace ServiceControl.Transports.ASBS;
 using Azure.ResourceManager.Resources;
 using Azure.ResourceManager.ServiceBus;
 using BrokerThroughput;
+using DnsClient;
+using DnsClient.Protocol;
 using Microsoft.Extensions.Logging;
 
 public class AzureQuery(ILogger<AzureQuery> logger, TimeProvider timeProvider, TransportSettings transportSettings)
@@ -263,14 +265,25 @@ async Task<IReadOnlyList<MetricValue>> GetMetrics(string queueName, DateOnly sta
     public override async IAsyncEnumerable<IBrokerQueue> GetQueueNames(
         [EnumeratorCancellation] CancellationToken cancellationToken = default)
     {
+        var validNamespaces = new HashSet<string>(StringComparer.OrdinalIgnoreCase) { serviceBusName };
+
+        var dnsLookup = new LookupClient();
+        var dnsResult = await dnsLookup.QueryAsync($"{serviceBusName}.servicebus.windows.net", QueryType.CNAME, cancellationToken: cancellationToken);
+        var domain = (dnsResult.Answers.FirstOrDefault() as CNameRecord)?.CanonicalName.Value;
+        if (domain is not null && domain.EndsWith(".servicebus.windows.net."))
+        {
+            var otherName = domain.Split('.').First();
+            validNamespaces.Add(otherName);
+        }
+
         SubscriptionResource? subscription = await armClient!.GetDefaultSubscriptionAsync(cancellationToken);
         var namespaces =
             subscription.GetServiceBusNamespacesAsync(cancellationToken);
 
         await foreach (var serviceBusNamespaceResource in namespaces.WithCancellation(
                            cancellationToken))
         {
-            if (serviceBusNamespaceResource.Data.Name == serviceBusName)
+            if (validNamespaces.Contains(serviceBusNamespaceResource.Data.Name))
             {
                 resourceId = serviceBusNamespaceResource.Id;
                 await foreach (var queue in serviceBusNamespaceResource.GetServiceBusQueues()

src/ServiceControl.Transports.ASBS/ServiceControl.Transports.ASBS.csproj

@@ -14,6 +14,7 @@
     <PackageReference Include="Azure.Identity" />
     <PackageReference Include="Azure.Monitor.Query" />
     <PackageReference Include="Azure.ResourceManager.ServiceBus" />
+    <PackageReference Include="DnsClient" />
     <PackageReference Include="NServiceBus.CustomChecks" />
     <PackageReference Include="NServiceBus.Transport.AzureServiceBus" />
   </ItemGroup>