Allow subnet addressprefix to be a parameter.

src/Aspire.Hosting.Azure.Network/AzureSubnetResource.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using Aspire.Hosting.ApplicationModel;
@@ -13,35 +14,68 @@ namespace Aspire.Hosting.Azure;
 /// <summary>
 /// Represents an Azure Subnet resource.
 /// </summary>
-/// <param name="name">The name of the resource.</param>
-/// <param name="subnetName">The subnet name.</param>
-/// <param name="addressPrefix">The address prefix for the subnet.</param>
-/// <param name="parent">The parent Virtual Network resource.</param>
 /// <remarks>
 /// Use <see cref="AzureProvisioningResourceExtensions.ConfigureInfrastructure{T}(ApplicationModel.IResourceBuilder{T}, Action{AzureResourceInfrastructure})"/> to configure specific <see cref="Azure.Provisioning"/> properties.
 /// </remarks>
-public class AzureSubnetResource(string name, string subnetName, string addressPrefix, AzureVirtualNetworkResource parent)
-    : Resource(name), IResourceWithParent<AzureVirtualNetworkResource>
+public class AzureSubnetResource : Resource, IResourceWithParent<AzureVirtualNetworkResource>
 {
+    // Backing field holds either string or ParameterResource
+    private readonly object _addressPrefix;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="AzureSubnetResource"/> class.
+    /// </summary>
+    /// <param name="name">The name of the resource.</param>
+    /// <param name="subnetName">The subnet name.</param>
+    /// <param name="addressPrefix">The address prefix for the subnet.</param>
+    /// <param name="parent">The parent Virtual Network resource.</param>
+    public AzureSubnetResource(string name, string subnetName, string addressPrefix, AzureVirtualNetworkResource parent)
+        : base(name)
+    {
+        SubnetName = ThrowIfNullOrEmpty(subnetName);
+        _addressPrefix = ThrowIfNullOrEmpty(addressPrefix);
+        Parent = parent ?? throw new ArgumentNullException(nameof(parent));
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="AzureSubnetResource"/> class with a parameterized address prefix.
+    /// </summary>
+    /// <param name="name">The name of the resource.</param>
+    /// <param name="subnetName">The subnet name.</param>
+    /// <param name="addressPrefix">The parameter resource containing the address prefix for the subnet.</param>
+    /// <param name="parent">The parent Virtual Network resource.</param>
+    public AzureSubnetResource(string name, string subnetName, ParameterResource addressPrefix, AzureVirtualNetworkResource parent)
+        : base(name)
+    {
+        SubnetName = ThrowIfNullOrEmpty(subnetName);
+        _addressPrefix = addressPrefix ?? throw new ArgumentNullException(nameof(addressPrefix));
+        Parent = parent ?? throw new ArgumentNullException(nameof(parent));
+    }
+
     /// <summary>
     /// Gets the subnet name.
     /// </summary>
-    public string SubnetName { get; } = ThrowIfNullOrEmpty(subnetName);
+    public string SubnetName { get; }
 
     /// <summary>
-    /// Gets the address prefix for the subnet (e.g., "10.0.1.0/24").
+    /// Gets the address prefix for the subnet (e.g., "10.0.1.0/24"), or <c>null</c> if the address prefix is provided via a <see cref="ParameterResource"/>.
     /// </summary>
-    public string AddressPrefix { get; } = ThrowIfNullOrEmpty(addressPrefix);
+    public string? AddressPrefix => _addressPrefix as string;
+
+    /// <summary>
+    /// Gets the parameter resource containing the address prefix for the subnet, or <c>null</c> if the address prefix is provided as a literal string.
+    /// </summary>
+    public ParameterResource? AddressPrefixParameter => _addressPrefix as ParameterResource;
 
     /// <summary>
     /// Gets the subnet Id output reference.
     /// </summary>
-    public BicepOutputReference Id => new($"{Infrastructure.NormalizeBicepIdentifier(Name)}_Id", parent);
+    public BicepOutputReference Id => new($"{Infrastructure.NormalizeBicepIdentifier(Name)}_Id", Parent);
 
     /// <summary>
     /// Gets the parent Azure Virtual Network resource.
     /// </summary>
-    public AzureVirtualNetworkResource Parent { get; } = parent ?? throw new ArgumentNullException(nameof(parent));
+    public AzureVirtualNetworkResource Parent { get; }
 
     private static string ThrowIfNullOrEmpty([NotNull] string? argument, [CallerArgumentExpression(nameof(argument))] string? paramName = null)
         => !string.IsNullOrEmpty(argument) ? argument : throw new ArgumentNullException(paramName);
@@ -54,9 +88,22 @@ internal SubnetResource ToProvisioningEntity(AzureResourceInfrastructure infra,
         var subnet = new SubnetResource(Infrastructure.NormalizeBicepIdentifier(Name))
         {
             Name = SubnetName,
-            AddressPrefix = AddressPrefix,
         };
 
+        // Set the address prefix from either the literal string or the parameter
+        if (_addressPrefix is string addressPrefix)
+        {
+            subnet.AddressPrefix = addressPrefix;
+        }
+        else if (_addressPrefix is ParameterResource addressPrefixParameter)
+        {
+            subnet.AddressPrefix = addressPrefixParameter.AsProvisioningParameter(infra);
+        }
+        else
+        {
+            throw new UnreachableException("AddressPrefix must be set either as a string or a ParameterResource.");
+        }
+
         if (dependsOn is not null)
         {
             subnet.DependsOn.Add(dependsOn);

src/Aspire.Hosting.Azure.Network/AzureVirtualNetworkExtensions.cs

@@ -38,66 +38,116 @@ public static IResourceBuilder<AzureVirtualNetworkResource> AddAzureVirtualNetwo
 
         builder.AddAzureProvisioning();
 
-        AzureVirtualNetworkResource resource = new(name, ConfigureVirtualNetwork);
+        AzureVirtualNetworkResource resource = new(name, ConfigureVirtualNetwork, addressPrefix);
 
+        return AddAzureVirtualNetworkCore(builder, resource);
+    }
+
+    /// <summary>
+    /// Adds an Azure Virtual Network resource to the application model with a parameterized address prefix.
+    /// </summary>
+    /// <param name="builder">The builder for the distributed application.</param>
+    /// <param name="name">The name of the Azure Virtual Network resource.</param>
+    /// <param name="addressPrefix">The parameter resource containing the address prefix for the virtual network (e.g., "10.0.0.0/16").</param>
+    /// <returns>A reference to the <see cref="IResourceBuilder{AzureVirtualNetworkResource}"/>.</returns>
+    /// <example>
+    /// This example creates a virtual network with a parameterized address prefix:
+    /// <code>
+    /// var vnetPrefix = builder.AddParameter("vnetPrefix");
+    /// var vnet = builder.AddAzureVirtualNetwork("vnet", vnetPrefix);
+    /// var subnet = vnet.AddSubnet("pe-subnet", "10.0.1.0/24");
+    /// </code>
+    /// </example>
+    public static IResourceBuilder<AzureVirtualNetworkResource> AddAzureVirtualNetwork(
+        this IDistributedApplicationBuilder builder,
+        [ResourceName] string name,
+        IResourceBuilder<ParameterResource> addressPrefix)
+    {
+        ArgumentNullException.ThrowIfNull(builder);
+        ArgumentException.ThrowIfNullOrEmpty(name);
+        ArgumentNullException.ThrowIfNull(addressPrefix);
+
+        builder.AddAzureProvisioning();
+
+        AzureVirtualNetworkResource resource = new(name, ConfigureVirtualNetwork, addressPrefix.Resource);
+
+        return AddAzureVirtualNetworkCore(builder, resource);
+    }
+
+    private static IResourceBuilder<AzureVirtualNetworkResource> AddAzureVirtualNetworkCore(
+        IDistributedApplicationBuilder builder,
+        AzureVirtualNetworkResource resource)
+    {
         if (builder.ExecutionContext.IsRunMode)
         {
             // In run mode, we don't want to add the resource to the builder.
             return builder.CreateResourceBuilder(resource);
         }
 
         return builder.AddResource(resource);
+    }
 
-        void ConfigureVirtualNetwork(AzureResourceInfrastructure infra)
-        {
-            var vnet = AzureProvisioningResource.CreateExistingOrNewProvisionableResource(infra,
-                (identifier, name) =>
+    private static void ConfigureVirtualNetwork(AzureResourceInfrastructure infra)
+    {
+        var azureResource = (AzureVirtualNetworkResource)infra.AspireResource;
+
+        var vnet = AzureProvisioningResource.CreateExistingOrNewProvisionableResource(infra,
+            (identifier, name) =>
+            {
+                var resource = VirtualNetwork.FromExisting(identifier);
+                resource.Name = name;
+                return resource;
+            },
+            (infrastructure) =>
+            {
+                var vnet = new VirtualNetwork(infrastructure.AspireResource.GetBicepIdentifier())
                 {
-                    var resource = VirtualNetwork.FromExisting(identifier);
-                    resource.Name = name;
-                    return resource;
-                },
-                (infrastructure) =>
+                    Tags = { { "aspire-resource-name", infrastructure.AspireResource.Name } }
+                };
+
+                // Set the address prefix from either the literal string or the parameter
+                if (azureResource.AddressPrefix is { } addressPrefix)
                 {
-                    var vnet = new VirtualNetwork(infrastructure.AspireResource.GetBicepIdentifier())
+                    vnet.AddressSpace = new VirtualNetworkAddressSpace()
                     {
-                        AddressSpace = new VirtualNetworkAddressSpace()
-                        {
-                            AddressPrefixes = { addressPrefix ?? "10.0.0.0/16" }
-                        },
-                        Tags = { { "aspire-resource-name", infrastructure.AspireResource.Name } }
+                        AddressPrefixes = { addressPrefix }
                     };
+                }
+                else if (azureResource.AddressPrefixParameter is { } addressPrefixParameter)
+                {
+                    vnet.AddressSpace = new VirtualNetworkAddressSpace()
+                    {
+                        AddressPrefixes = { addressPrefixParameter.AsProvisioningParameter(infrastructure) }
+                    };
+                }
 
-                    return vnet;
-                });
-
-            var azureResource = (AzureVirtualNetworkResource)infra.AspireResource;
+                return vnet;
+            });
 
-            // Add subnets
-            if (azureResource.Subnets.Count > 0)
+        // Add subnets
+        if (azureResource.Subnets.Count > 0)
+        {
+            // Chain subnet provisioning to ensure deployment doesn't fail
+            // due to parallel creation of subnets within the VNet.
+            ProvisionableResource? dependsOn = null;
+            foreach (var subnet in azureResource.Subnets)
             {
-                // Chain subnet provisioning to ensure deployment doesn't fail
-                // due to parallel creation of subnets within the VNet.
-                ProvisionableResource? dependsOn = null;
-                foreach (var subnet in azureResource.Subnets)
-                {
-                    var cdkSubnet = subnet.ToProvisioningEntity(infra, dependsOn);
-                    cdkSubnet.Parent = vnet;
-                    infra.Add(cdkSubnet);
+                var cdkSubnet = subnet.ToProvisioningEntity(infra, dependsOn);
+                cdkSubnet.Parent = vnet;
+                infra.Add(cdkSubnet);
 
-                    dependsOn = cdkSubnet;
-                }
+                dependsOn = cdkSubnet;
             }
+        }
 
-            // Output the VNet ID for references
-            infra.Add(new ProvisioningOutput("id", typeof(string))
-            {
-                Value = vnet.Id
-            });
+        // Output the VNet ID for references
+        infra.Add(new ProvisioningOutput("id", typeof(string))
+        {
+            Value = vnet.Id
+        });
 
-            // We need to output name so it can be referenced by others.
-            infra.Add(new ProvisioningOutput("name", typeof(string)) { Value = vnet.Name });
-        }
+        // We need to output name so it can be referenced by others.
+        infra.Add(new ProvisioningOutput("name", typeof(string)) { Value = vnet.Name });
     }
 
     /// <summary>
@@ -129,6 +179,46 @@ public static IResourceBuilder<AzureSubnetResource> AddSubnet(
 
         var subnet = new AzureSubnetResource(name, subnetName, addressPrefix, builder.Resource);
 
+        return AddSubnetCore(builder, subnet);
+    }
+
+    /// <summary>
+    /// Adds an Azure Subnet to the Virtual Network with a parameterized address prefix.
+    /// </summary>
+    /// <param name="builder">The Virtual Network resource builder.</param>
+    /// <param name="name">The name of the subnet resource.</param>
+    /// <param name="addressPrefix">The parameter resource containing the address prefix for the subnet (e.g., "10.0.1.0/24").</param>
+    /// <param name="subnetName">The subnet name in Azure. If null, the resource name is used.</param>
+    /// <returns>A reference to the <see cref="IResourceBuilder{AzureSubnetResource}"/>.</returns>
+    /// <example>
+    /// This example adds a subnet with a parameterized address prefix:
+    /// <code>
+    /// var subnetPrefix = builder.AddParameter("subnetPrefix");
+    /// var vnet = builder.AddAzureVirtualNetwork("vnet");
+    /// var subnet = vnet.AddSubnet("my-subnet", subnetPrefix);
+    /// </code>
+    /// </example>
+    public static IResourceBuilder<AzureSubnetResource> AddSubnet(
+        this IResourceBuilder<AzureVirtualNetworkResource> builder,
+        [ResourceName] string name,
+        IResourceBuilder<ParameterResource> addressPrefix,
+        string? subnetName = null)
+    {
+        ArgumentNullException.ThrowIfNull(builder);
+        ArgumentException.ThrowIfNullOrEmpty(name);
+        ArgumentNullException.ThrowIfNull(addressPrefix);
+
+        subnetName ??= name;
+
+        var subnet = new AzureSubnetResource(name, subnetName, addressPrefix.Resource, builder.Resource);
+
+        return AddSubnetCore(builder, subnet);
+    }
+
+    private static IResourceBuilder<AzureSubnetResource> AddSubnetCore(
+        IResourceBuilder<AzureVirtualNetworkResource> builder,
+        AzureSubnetResource subnet)
+    {
         builder.Resource.Subnets.Add(subnet);
 
         if (builder.ApplicationBuilder.ExecutionContext.IsRunMode)

src/Aspire.Hosting.Azure.Network/AzureVirtualNetworkResource.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using Aspire.Hosting.ApplicationModel;
 using Azure.Provisioning.Network;
 using Azure.Provisioning.Primitives;
 
@@ -14,8 +15,23 @@ namespace Aspire.Hosting.Azure;
 public class AzureVirtualNetworkResource(string name, Action<AzureResourceInfrastructure> configureInfrastructure)
     : AzureProvisioningResource(name, configureInfrastructure)
 {
+    private const string DefaultAddressPrefix = "10.0.0.0/16";
+
+    // Backing field holds either string or ParameterResource
+    private readonly object _addressPrefix = DefaultAddressPrefix;
+
     internal List<AzureSubnetResource> Subnets { get; } = [];
 
+    /// <summary>
+    /// Gets the address prefix for the virtual network (e.g., "10.0.0.0/16"), or <c>null</c> if the address prefix is provided via a <see cref="ParameterResource"/>.
+    /// </summary>
+    public string? AddressPrefix => _addressPrefix as string;
+
+    /// <summary>
+    /// Gets the parameter resource containing the address prefix for the virtual network, or <c>null</c> if the address prefix is provided as a literal string.
+    /// </summary>
+    public ParameterResource? AddressPrefixParameter => _addressPrefix as ParameterResource;
+
     /// <summary>
     /// Gets the "id" output reference from the Azure Virtual Network resource.
     /// </summary>
@@ -26,6 +42,31 @@ public class AzureVirtualNetworkResource(string name, Action<AzureResourceInfras
     /// </summary>
     public BicepOutputReference NameOutput => new("name", this);
 
+    /// <summary>
+    /// Initializes a new instance of the <see cref="AzureVirtualNetworkResource"/> class with a string address prefix.
+    /// </summary>
+    /// <param name="name">The name of the resource.</param>
+    /// <param name="configureInfrastructure">Callback to configure the Azure Virtual Network resource.</param>
+    /// <param name="addressPrefix">The address prefix for the virtual network (e.g., "10.0.0.0/16").</param>
+    public AzureVirtualNetworkResource(string name, Action<AzureResourceInfrastructure> configureInfrastructure, string? addressPrefix)
+        : this(name, configureInfrastructure)
+    {
+        _addressPrefix = addressPrefix ?? DefaultAddressPrefix;
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="AzureVirtualNetworkResource"/> class with a parameterized address prefix.
+    /// </summary>
+    /// <param name="name">The name of the resource.</param>
+    /// <param name="configureInfrastructure">Callback to configure the Azure Virtual Network resource.</param>
+    /// <param name="addressPrefix">The parameter resource containing the address prefix for the virtual network.</param>
+    public AzureVirtualNetworkResource(string name, Action<AzureResourceInfrastructure> configureInfrastructure, ParameterResource addressPrefix)
+        : this(name, configureInfrastructure)
+    {
+        ArgumentNullException.ThrowIfNull(addressPrefix);
+        _addressPrefix = addressPrefix;
+    }
+
     /// <inheritdoc/>
     public override ProvisionableResource AddAsExistingResource(AzureResourceInfrastructure infra)
     {