Add AddHelmChart for installing external Helm charts

src/Aspire.Hosting.Azure.Kubernetes/AzureKubernetesIngressExtensions.cs

@@ -78,4 +78,58 @@ public static IResourceBuilder<KubernetesGatewayResource> AddGateway(
         var k8sEnvBuilder = builder.ApplicationBuilder.CreateResourceBuilder(builder.Resource.KubernetesEnvironment);
         return k8sEnvBuilder.AddGateway(name);
     }
+
+    /// <summary>
+    /// Adds an external Helm chart to be installed in the AKS environment's inner Kubernetes
+    /// environment. The chart is installed via <c>helm upgrade --install</c> as a pipeline step
+    /// after the main application Helm chart is deployed.
+    /// </summary>
+    /// <param name="builder">The AKS environment resource builder.</param>
+    /// <param name="name">The name of the Helm chart resource.</param>
+    /// <param name="chartReference">
+    /// The Helm chart reference. Can be an OCI registry URL (e.g., <c>oci://quay.io/jetstack/charts/cert-manager</c>)
+    /// or a chart name from an added repository.
+    /// </param>
+    /// <param name="chartVersion">The chart version to install.</param>
+    /// <returns>A resource builder for the Helm chart resource.</returns>
+    /// <remarks>
+    /// <para>
+    /// This method delegates to the inner <see cref="KubernetesEnvironmentResource"/> of the AKS
+    /// environment, so the returned <see cref="KubernetesHelmChartResource"/> can be configured
+    /// with the same <see cref="KubernetesHelmChartExtensions.WithHelmValue"/>,
+    /// <see cref="KubernetesHelmChartExtensions.WithNamespace"/>,
+    /// <see cref="KubernetesHelmChartExtensions.WithReleaseName"/>, and
+    /// <see cref="KubernetesHelmChartExtensions.WithDestroy"/> extensions used with
+    /// non-AKS Kubernetes environments.
+    /// </para>
+    /// <para>
+    /// External Helm charts are <em>not</em> uninstalled by <c>aspire destroy</c> by default,
+    /// because they may be shared with workloads outside the Aspire app. Opt in by chaining
+    /// <see cref="KubernetesHelmChartExtensions.WithDestroy"/>.
+    /// </para>
+    /// </remarks>
+    /// <example>
+    /// <code>
+    /// var aks = builder.AddAzureKubernetesEnvironment("aks");
+    ///
+    /// // Install cert-manager
+    /// aks.AddHelmChart("cert-manager", "oci://quay.io/jetstack/charts/cert-manager", "1.17.0")
+    ///     .WithHelmValue("crds.enabled", "true");
+    /// </code>
+    /// </example>
+    [AspireExport(Description = "Adds an external Helm chart to an AKS environment")]
+    public static IResourceBuilder<KubernetesHelmChartResource> AddHelmChart(
+        this IResourceBuilder<AzureKubernetesEnvironmentResource> builder,
+        [ResourceName] string name,
+        string chartReference,
+        string chartVersion)
+    {
+        ArgumentNullException.ThrowIfNull(builder);
+        ArgumentException.ThrowIfNullOrEmpty(name);
+        ArgumentException.ThrowIfNullOrEmpty(chartReference);
+        ArgumentException.ThrowIfNullOrEmpty(chartVersion);
+
+        var k8sEnvBuilder = builder.ApplicationBuilder.CreateResourceBuilder(builder.Resource.KubernetesEnvironment);
+        return k8sEnvBuilder.AddHelmChart(name, chartReference, chartVersion);
+    }
 }

src/Aspire.Hosting.Kubernetes/HelmChartOptions.cs

@@ -18,8 +18,8 @@ namespace Aspire.Hosting.Kubernetes;
 [AspireExport(ExposeMethods = true)]
 public sealed partial class HelmChartOptions
 {
-    private const int KubernetesNamespaceMaxLength = 63;
-    private const int HelmReleaseNameMaxLength = 53;
+    internal const int KubernetesNamespaceMaxLength = 63;
+    internal const int HelmReleaseNameMaxLength = 53;
     private const int HelmChartNameMaxLength = 250;
     private const int HelmChartDescriptionMaxLength = 1024;
 
@@ -39,7 +39,7 @@ internal HelmChartOptions(IResourceBuilder<KubernetesEnvironmentResource> enviro
     public HelmChartOptions WithNamespace(string @namespace)
     {
         ArgumentException.ThrowIfNullOrWhiteSpace(@namespace);
-        ValidateDnsLabel(@namespace, "Kubernetes namespace", KubernetesNamespaceMaxLength, nameof(@namespace));
+        ValidateNamespace(@namespace, nameof(@namespace));
 
         var expression = ReferenceExpression.Create($"{@namespace}");
         EnvironmentBuilder.WithAnnotation(new KubernetesNamespaceAnnotation(expression), ResourceAnnotationMutationBehavior.Replace);
@@ -83,7 +83,7 @@ internal HelmChartOptions WithNamespace([AspireUnion(typeof(string), typeof(IRes
     public HelmChartOptions WithReleaseName(string releaseName)
     {
         ArgumentException.ThrowIfNullOrWhiteSpace(releaseName);
-        ValidateDnsLabel(releaseName, "Helm release name", HelmReleaseNameMaxLength, nameof(releaseName));
+        ValidateReleaseName(releaseName, nameof(releaseName));
 
         var expression = ReferenceExpression.Create($"{releaseName}");
         EnvironmentBuilder.WithAnnotation(new HelmReleaseNameAnnotation(expression), ResourceAnnotationMutationBehavior.Replace);
@@ -255,7 +255,7 @@ internal HelmChartOptions WithChartDescription([AspireUnion(typeof(string), type
         };
     }
 
-    private static void ValidateDnsLabel(string value, string target, int maxLength, string paramName)
+    internal static void ValidateDnsLabel(string value, string target, int maxLength, string paramName)
     {
         if (value.Length > maxLength)
         {
@@ -268,6 +268,12 @@ private static void ValidateDnsLabel(string value, string target, int maxLength,
         }
     }
 
+    internal static void ValidateNamespace(string @namespace, string paramName)
+        => ValidateDnsLabel(@namespace, "Kubernetes namespace", KubernetesNamespaceMaxLength, paramName);
+
+    internal static void ValidateReleaseName(string releaseName, string paramName)
+        => ValidateDnsLabel(releaseName, "Helm release name", HelmReleaseNameMaxLength, paramName);
+
     // Matches Helm's own chart-version validation, which uses the lenient SemVer parser
     // (Masterminds/semver/v3 NewVersion) — see helm/helm pkg/chart/v2/metadata.go isValidSemver.
     // Helm accepts a leading "v" and partial versions (e.g. "v1", "1", "1.2"), coercing them