[release/13.4] Fix DistributedApplicationTestingBuilder dashboard with dynamic ports

src/Aspire.Hosting.Testing/DistributedApplicationFactory.cs

@@ -206,6 +206,12 @@ private static void PreConfigureBuilderOptions(
         SetDefault(KnownConfigNames.AspNetCoreUrls, "http://localhost:8080");
         SetDefaultFallback(KnownConfigNames.DashboardOtlpGrpcEndpointUrl, KnownConfigNames.Legacy.DashboardOtlpGrpcEndpointUrl, "http://localhost:4317");
 
+        // Since the testing builder defaults all dashboard/OTLP URLs to HTTP, also allow
+        // unsecured transport by default. This prevents OptionsValidationException when the
+        // user enables the dashboard (DisableDashboard = false) without explicitly setting
+        // ASPIRE_ALLOW_UNSECURED_TRANSPORT. See https://github.com/microsoft/aspire/issues/17622
+        SetDefault(KnownConfigNames.AllowUnsecuredTransport, "true");
+
         var appHostProjectPath = ResolveProjectPath(entryPointAssembly);
         if (!string.IsNullOrEmpty(appHostProjectPath) && Directory.Exists(appHostProjectPath))
         {

src/Aspire.Hosting/Dashboard/DashboardServiceHost.cs

@@ -138,9 +138,15 @@ void ConfigureKestrel(KestrelServerOptions kestrelOptions)
                 kestrelOptions.Listen(IPAddress.Loopback, port: 0, ConfigureListen);
                 _logger.LogDebug("Resource service endpoint not configured. Listening on {Scheme}://127.0.0.1:<random>.", scheme);
             }
-            else if (IsLocalResourceServiceEndpoint(uri))
+            else if (IPAddress.TryParse(uri.Host, out var ip) && IPAddress.IsLoopback(ip))
             {
-                // Listen on the requested localhost port.
+                // Bind to the exact loopback address specified (e.g. 127.0.0.1 or [::1]).
+                kestrelOptions.Listen(ip, uri.Port, ConfigureListen);
+                _logger.LogDebug("Resource service endpoint configured: {Uri}", uri);
+            }
+            else if (uri.IsLoopback || IsLocalhostOrLocalhostTld(uri))
+            {
+                // For "localhost" or *.localhost hosts, bind to both IPv4 and IPv6 loopback.
                 kestrelOptions.ListenLocalhost(uri.Port, ConfigureListen);
                 _logger.LogDebug("Resource service endpoint configured: {Uri}", uri);
             }
@@ -178,16 +184,8 @@ internal static string ResolveScheme(Uri? configuredUri, bool allowUnsecuredTran
         return allowUnsecuredTransport ? "http" : "https";
     }
 
-    /// <summary>
-    /// Determines whether the resource service endpoint is scoped to the local machine.
-    /// </summary>
-    internal static bool IsLocalResourceServiceEndpoint(Uri uri)
+    private static bool IsLocalhostOrLocalhostTld(Uri uri)
     {
-        if (uri.IsLoopback)
-        {
-            return true;
-        }
-
         var host = uri.Host.EndsWith(".", StringComparison.Ordinal)
             ? uri.Host[..^1]
             : uri.Host;

tests/Aspire.Hosting.Testing.Tests/Aspire.Hosting.Testing.Tests.csproj

@@ -24,6 +24,7 @@
     <Compile Include="$(TestsSharedDir)Logging\*.cs" LinkBase="shared\Logging" />
     <Compile Include="$(TestsSharedDir)ConsoleLogging\*.cs" LinkBase="shared" />
     <Compile Include="$(TestsSharedDir)DistributedApplicationTestingBuilderExtensions.cs" Link="shared/DistributedApplicationTestingBuilderExtensions.cs" />
+    <Compile Include="$(TestsSharedDir)AsyncTestHelpers.cs" Link="shared/AsyncTestHelpers.cs" />
   </ItemGroup>
 
   <ItemGroup>

tests/Aspire.Hosting.Testing.Tests/TestingBuilderTests.cs

@@ -8,6 +8,7 @@
 using Aspire.Hosting.Utils;
 using Aspire.TestProject;
 using Aspire.TestUtilities;
+using Microsoft.AspNetCore.InternalTesting;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
@@ -568,6 +569,69 @@ public async Task StartAsyncAbandonedAfterHang()
         }
     }
 
+    [Fact]
+    [RequiresFeature(TestFeature.Docker)]
+    public async Task DashboardEnabledInTestingBuilderShouldWorkWithDynamicPorts()
+    {
+        var builder = DistributedApplicationTestingBuilder.Create([], (options, _) =>
+        {
+            options.DisableDashboard = false;
+        });
+        builder.WithTestAndResourceLogging(output);
+
+        await using var app = await builder.BuildAsync();
+
+        await app.StartAsync().DefaultTimeout(TestConstants.LongTimeoutTimeSpan);
+
+        // Wait for the dashboard to become healthy, confirming it is actually running.
+        await app.ResourceNotifications.WaitForResourceHealthyAsync(
+            "aspire-dashboard",
+            CancellationToken.None).DefaultTimeout(TestConstants.LongTimeoutTimeSpan);
+    }
+
+    [Theory]
+    [RequiresFeature(TestFeature.Docker)]
+    [InlineData("https://127.0.0.1:0")]
+    [InlineData("https://[::1]:0")]
+    public async Task LoopbackWithDynamicPorts(string endpointUrl)
+    {
+        var builder = DistributedApplicationTestingBuilder.Create([], (opt, _) =>
+        {
+            opt.DisableDashboard = false;
+        });
+        builder.WithTestAndResourceLogging(output);
+
+        builder.Configuration["ASPNETCORE_URLS"] = endpointUrl;
+        builder.Configuration["ASPIRE_DASHBOARD_OTLP_ENDPOINT_URL"] = endpointUrl;
+        builder.Configuration["ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL"] = endpointUrl;
+
+        await using var app = await builder.BuildAsync();
+        await app.StartAsync().DefaultTimeout(TestConstants.LongTimeoutTimeSpan);
+
+        // Wait for the dashboard to become healthy, confirming it is actually running.
+        await app.ResourceNotifications.WaitForResourceHealthyAsync(
+            "aspire-dashboard",
+            CancellationToken.None).DefaultTimeout(TestConstants.LongTimeoutTimeSpan);
+    }
+
+    [Fact]
+    [RequiresFeature(TestFeature.Docker)]
+    public async Task NonLocalResourceServiceEndpointThrows()
+    {
+        var builder = DistributedApplicationTestingBuilder.Create([], (opt, _) =>
+        {
+            opt.DisableDashboard = false;
+        });
+        builder.WithTestAndResourceLogging(output);
+
+        builder.Configuration["ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL"] = "https://example.com:5001";
+
+        await using var app = await builder.BuildAsync();
+
+        var ex = await Assert.ThrowsAsync<ArgumentException>(() => app.StartAsync());
+        Assert.Equal("ASPIRE_RESOURCE_SERVICE_ENDPOINT_URL must contain a local loopback address.", ex.Message);
+    }
+
     private sealed record WeatherForecast(DateOnly Date, int TemperatureC, string? Summary)
     {
         public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);

tests/Aspire.Hosting.Tests/Dashboard/DashboardServiceHostTests.cs

@@ -22,21 +22,4 @@ public void ResolveScheme_ReturnsExpectedScheme(string? uriString, bool allowUns
 
         Assert.Equal(expectedScheme, scheme);
     }
-
-    [Theory]
-    [InlineData("https://localhost:5001", true)]
-    [InlineData("https://localhost.:5001", true)]
-    [InlineData("https://127.0.0.1:5001", true)]
-    [InlineData("https://[::1]:5001", true)]
-    [InlineData("https://myapp.dev.localhost:5001", true)]
-    [InlineData("https://myapp.dev.localhost.:5001", true)]
-    [InlineData("https://example.com:5001", false)]
-    [InlineData("https://localhost.example.com:5001", false)]
-    [InlineData("https://example-localhost:5001", false)]
-    public void IsLocalResourceServiceEndpoint_ReturnsExpectedResult(string uriString, bool expectedResult)
-    {
-        var result = DashboardServiceHost.IsLocalResourceServiceEndpoint(new Uri(uriString));
-
-        Assert.Equal(expectedResult, result);
-    }
 }