microsoft/aspire · error · InvalidOperationException

The Container Registry associated with resource

Error message

The Container Registry associated with resource '{builder.Resource.Name}' is not an AzureContainerRegistryResource.

What it means

GetAzureContainerRegistry casts the associated ContainerRegistry to AzureContainerRegistryResource and throws InvalidOperationException when the object is an IContainerRegistry implementation of a different type (e.g. an existing/Bring-Your-Own registry resource rather than an Aspire-provisioned one).

Solutions

  1. Provision the registry via AddAzureContainerRegistry so the associated type is AzureContainerRegistryResource
  2. Use the existing-registry API appropriate for BYO registries instead of this getter
  3. Cast/check ContainerRegistry type before calling and handle the alternate type

Example fix

// before
var env = builder.AddAzureContainerAppEnvironment("env").WithExistingRegistry(existing);
var registry = env.GetAzureContainerRegistry();
// after
var env = builder.AddAzureContainerAppEnvironment("env");
env.AddAzureContainerRegistry("myregistry");
var registry = env.GetAzureContainerRegistry();
Defensive patterns

Strategy: type-guard

Validate before calling

if (env.Resource.ContainerRegistry is not AzureContainerRegistryResource)
    throw new InvalidOperationException("Environment is associated with a non-Aspire registry.");

Type guard

var registry = env.Resource.ContainerRegistry as AzureContainerRegistryResource;
if (registry is null) { /* use existing-registry APIs instead */ }

Try / catch

try { var registry = env.GetAzureContainerRegistry(); }
catch (InvalidOperationException ex) when (ex.Message.Contains("is not an Azure Container Registry")) { log.LogError(ex, "Registry type mismatch on {Env}", env.Resource.Name); }

Prevention

When it happens

Trigger: Calling GetAzureContainerRegistry on a compute environment whose ContainerRegistry property is set to a non-AzureContainerRegistryResource implementation of IContainerRegistry.

Common situations: Wiring the environment to an existing registry by name/connection string instead of an Aspire-provisioned AzureContainerRegistryResource; mixing registry types from different hosting integrations.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/641212e1acfe7b9b. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting.Azure.ContainerRegistry/AzureContainerRegistryExtensions.cs:119

    /// <summary>
    /// Gets the <see cref="AzureContainerRegistryResource"/> associated with the specified Azure compute environment resource.
    /// </summary>
    /// <ats-summary>Gets the Azure Container Registry associated with a compute environment resource.</ats-summary>
    /// <typeparam name="T">The resource type that implements <see cref="IAzureComputeEnvironmentResource"/>.</typeparam>
    /// <param name="builder">The resource builder for the compute environment resource.</param>
    /// <returns>A reference to the <see cref="IResourceBuilder{AzureContainerRegistryResource}"/> for the associated registry.</returns>
    /// <ats-returns>The resource builder.</ats-returns>
    /// <exception cref="ArgumentNullException">Thrown when <paramref name="builder"/> is <see langword="null"/>.</exception>
    /// <exception cref="InvalidOperationException">Thrown when the resource does not have an associated Azure Container Registry,
    /// or when the associated container registry is not an <see cref="AzureContainerRegistryResource"/>.</exception>
    [AspireExport]
    public static IResourceBuilder<AzureContainerRegistryResource> GetAzureContainerRegistry<T>(this IResourceBuilder<T> builder)
        where T : IResource, IAzureComputeEnvironmentResource
    {
        ArgumentNullException.ThrowIfNull(builder);

        var containerRegistry = builder.Resource.ContainerRegistry ?? throw new InvalidOperationException($"The resource '{builder.Resource.Name}' does not have an associated Azure Container Registry.");
        var registry = containerRegistry as AzureContainerRegistryResource ?? throw new InvalidOperationException($"The Container Registry associated with resource '{builder.Resource.Name}' is not an Azure Container Registry.");

        return builder.ApplicationBuilder.CreateResourceBuilder(registry);
    }

    /// <summary>
    /// Adds a scheduled ACR purge task to remove old or unused container images from the registry.
    /// </summary>
    /// <param name="builder">The resource builder for the <see cref="AzureContainerRegistryResource"/>.</param>
    /// <param name="schedule">The cron schedule for the purge task timer trigger. Must be a five-part cron expression
    /// (<c>minute hour day-of-month month day-of-week</c>); seconds are not supported.</param>
    /// <param name="filter">An optional filter for the <c>acr purge --filter</c> parameter. Only repositories matching this
    /// filter will be purged. Defaults to <c>".*:.*"</c> (all repositories and tags) when <see langword="null"/>.</param>
    /// <param name="ago">The age threshold for <c>acr purge --ago</c>. Images older than this duration will be considered
    /// for removal. Uses Go-style duration format (e.g., <c>2d3h6m</c>). Defaults to <c>0d</c> when <see langword="null"/>.</param>
    /// <param name="keep">The number of most recent images to keep per repository, regardless of age.
    /// Must be greater than zero. Defaults to 3.</param>
    /// <param name="taskName">An optional name for the ACR task resource. If not provided, a name is auto-generated
    /// based on existing purge tasks to avoid conflicts. If a task with the specified name already exists,

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