Fix EventHubs GetNamespaceFromSettings (#7393)

We were calling RandomNumberGenerator.GetHexString and not using the result. The original intention was to use a random container name if we couldn't see ".servicebus" in the host name.

Instead of using a random name, just sanitize the host name and use it, so it is deterministc.

Fix #4886

Author: eerhardt

src/Components/Aspire.Azure.Messaging.EventHubs/EventHubsComponent.cs

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Security.Cryptography;
 using Aspire.Azure.Common;
 using Aspire.Azure.Messaging.EventHubs;
 using Azure.Core;
@@ -56,15 +55,15 @@ protected static string GetNamespaceFromSettings(AzureMessagingEventHubsSettings
                 : new Uri(settings.FullyQualifiedNamespace).Host;
 
             // This is likely to be similar to {yournamespace}.servicebus.windows.net or {yournamespace}.servicebus.chinacloudapi.cn
-            if (ns.Contains(".servicebus", StringComparison.OrdinalIgnoreCase))
+            var serviceBusIndex = ns.IndexOf(".servicebus", StringComparison.OrdinalIgnoreCase);
+            if (serviceBusIndex != -1)
             {
-                ns = ns[..ns.IndexOf(".servicebus")];
+                ns = ns[..serviceBusIndex];
             }
             else
             {
-                // Use a random prefix if no meaningful name is found e.g., "localhost", "127.0.0.1".
-                // This is used to create blob containers names that are unique in the referenced storage account.
-                RandomNumberGenerator.GetHexString(12, true);
+                // sanitize the namespace if it's not a servicebus namespace
+                ns = ns.Replace(".", "-");
             }
         }
         catch (Exception ex) when (ex is FormatException or IndexOutOfRangeException)

src/Components/Aspire.Azure.Messaging.EventHubs/EventProcessorClientComponent.cs

@@ -97,17 +97,14 @@ private static BlobContainerClient GetBlobContainerClient(
         // name specified in the settings.
         bool shouldTryCreateIfNotExists = false;
 
+        // Do we have a container name provided in the settings?
         if (string.IsNullOrWhiteSpace(settings.BlobContainerName))
         {
+            // If not, we'll create a container name based on the namespace, event hub name and consumer group
             var ns = GetNamespaceFromSettings(settings);
 
-            // Do we have a container name provided in the settings?
-            if (string.IsNullOrWhiteSpace(settings.BlobContainerName))
-            {
-                // If not, we'll create a container name based on the namespace, event hub name and consumer group
-                settings.BlobContainerName = $"{ns}-{settings.EventHubName}-{consumerGroup}";
-                shouldTryCreateIfNotExists = true;
-            }
+            settings.BlobContainerName = $"{ns}-{settings.EventHubName}-{consumerGroup}";
+            shouldTryCreateIfNotExists = true;
         }
 
         var containerClient = blobClient.GetBlobContainerClient(settings.BlobContainerName);

tests/Aspire.Azure.Messaging.EventHubs.Tests/Aspire.Azure.Messaging.EventHubs.Tests.csproj

@@ -11,6 +11,8 @@
 
     <ProjectReference Include="..\..\src\Components\Aspire.Azure.Storage.Blobs\Aspire.Azure.Storage.Blobs.csproj" />
     <ProjectReference Include="..\Aspire.Components.Common.Tests\Aspire.Components.Common.Tests.csproj" />
+
+    <Compile Include="..\Aspire.Azure.Security.KeyVault.Tests\MockTransport.cs" />
   </ItemGroup>
 
 </Project>

tests/Aspire.Azure.Messaging.EventHubs.Tests/AspireEventHubsExtensionsTests.cs

@@ -1,6 +1,8 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Text;
+using Azure.Core;
 using Azure.Identity;
 using Azure.Messaging.EventHubs;
 using Azure.Messaging.EventHubs.Consumer;
@@ -476,7 +478,7 @@ private static void AssertFullyQualifiedNamespace(string expectedNamespace, obje
             EventHubConsumerClient consumer => consumer.FullyQualifiedNamespace,
             EventProcessorClient processor => processor.FullyQualifiedNamespace,
             PartitionReceiver receiver => receiver.FullyQualifiedNamespace,
-            EventHubBufferedProducerClient  producer => producer.FullyQualifiedNamespace,
+            EventHubBufferedProducerClient producer => producer.FullyQualifiedNamespace,
             _ => throw new InvalidOperationException()
         });
     }
@@ -580,4 +582,48 @@ public void CanAddMultipleKeyedServices(int clientIndex)
 
     public static string CreateConfigKey(string prefix, string? key, string suffix)
         => string.IsNullOrEmpty(key) ? $"{prefix}:{suffix}" : $"{prefix}:{key}:{suffix}";
+
+    /// <summary>
+    /// Tests that the BlobContainerName defaults correctly when the connection string doesn't contain ".servicebus" and
+    /// contains invalid container name characters.
+    /// </summary>
+    [Fact]
+    public void ProcessorBlobContainerNameDefaultsCorrectly()
+    {
+        var builder = Host.CreateEmptyApplicationBuilder(null);
+        builder.Configuration.AddInMemoryCollection([
+            new KeyValuePair<string, string?>("ConnectionStrings:eh1", "Endpoint=sb://127.0.0.1:53589;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=SAS_KEY_VALUE;UseDevelopmentEmulator=true;"),
+            new KeyValuePair<string, string?>("Aspire:Azure:Messaging:EventHubs:EventProcessorClient:EventHubName", "MyHub"),
+        ]);
+
+        var mockTransport = new MockTransport(
+            CreateResponse("""{}"""));
+        var blobClient = new BlobServiceClient(new Uri(BlobsConnectionString), new BlobClientOptions() { Transport = mockTransport });
+        builder.Services.AddSingleton(blobClient);
+
+        builder.AddAzureEventProcessorClient("eh1");
+
+        using var host = builder.Build();
+
+        var client = host.Services.GetRequiredService<EventProcessorClient>();
+        Assert.NotNull(client);
+
+        Assert.Single(mockTransport.Requests);
+        // the container name should be based on the Endpoint, EventHubName, and ConsumerGroup
+        Assert.Equal("https://fake.blob.core.windows.net/127-0-0-1-MyHub-default?restype=container", mockTransport.Requests[0].Uri.ToString());
+    }
+
+    private static MockResponse CreateResponse(string content)
+    {
+        var buffer = Encoding.UTF8.GetBytes(content);
+        var response = new MockResponse(201)
+        {
+            ClientRequestId = Guid.NewGuid().ToString(),
+            ContentStream = new MemoryStream(buffer),
+        };
+
+        response.AddHeader(new HttpHeader("Content-Type", "application/json; charset=utf-8"));
+
+        return response;
+    }
 }