Allow only single AzureBlobStorageResource in AzureStorageResource

Resolves #6875

Author: RussKie

src/Aspire.Hosting.Azure.Storage/AzureStorageExtensions.cs

@@ -83,9 +83,9 @@ public static IResourceBuilder<AzureStorageResource> AddAzureStorage(this IDistr
 
             var azureResource = (AzureStorageResource)infrastructure.AspireResource;
 
-            foreach (var blobStorageResources in azureResource.Blobs)
+            if (azureResource.BlobsResource is not null)
             {
-                foreach (var blobContainer in blobStorageResources.BlobContainers)
+                foreach (var blobContainer in azureResource.BlobsResource.BlobContainers)
                 {
                     var cdkBlobContainer = blobContainer.ToProvisioningEntity();
                     cdkBlobContainer.Parent = blobs;
@@ -159,9 +159,9 @@ public static IResourceBuilder<AzureStorageResource> RunAsEmulator(this IResourc
                 throw new DistributedApplicationException($"ResourceReadyEvent was published for the '{builder.Resource.Name}' resource but the connection string was null.");
             }
 
-            foreach (var blobStorageResources in builder.Resource.Blobs)
+            if (builder.Resource.BlobsResource is not null)
             {
-                foreach (var blobContainer in blobStorageResources.BlobContainers)
+                foreach (var blobContainer in builder.Resource.BlobsResource.BlobContainers)
                 {
                     await blobServiceClient.GetBlobContainerClient(blobContainer.BlobContainerName).CreateIfNotExistsAsync(cancellationToken: ct).ConfigureAwait(false);
                 }
@@ -313,8 +313,13 @@ public static IResourceBuilder<AzureBlobStorageResource> AddBlobs(this IResource
         ArgumentNullException.ThrowIfNull(builder);
         ArgumentException.ThrowIfNullOrEmpty(name);
 
+        if (builder.Resource.BlobsResource is not null)
+        {
+            throw new InvalidOperationException("The Azure Storage resource already has a blob endpoint.");
+        }
+
         var resource = new AzureBlobStorageResource(name, builder.Resource);
-        builder.Resource.Blobs.Add(resource);
+        builder.Resource.BlobsResource = resource;
 
         return builder.ApplicationBuilder.AddResource(resource);
     }

src/Aspire.Hosting.Azure.Storage/AzureStorageResource.cs

@@ -23,7 +23,8 @@ public class AzureStorageResource(string name, Action<AzureResourceInfrastructur
     private EndpointReference EmulatorQueueEndpoint => new(this, "queue");
     private EndpointReference EmulatorTableEndpoint => new(this, "table");
 
-    internal List<AzureBlobStorageResource> Blobs { get; } = [];
+    // This is, essentially, a reference to the Azure "Blob containers" node, represented by BlobServiceClient.
+    internal AzureBlobStorageResource? BlobsResource { get; set; }
 
     /// <summary>
     /// Gets the "blobEndpoint" output reference from the bicep template for the Azure Storage resource.