microsoft/aspire · error · InvalidOperationException

Named service references are not supported for Azure…

Error message

Named service references are not supported for Azure Functions resources.

What it means

TryWithReference in the Azure Functions extensions rejects named service references: when a non-null name is supplied along with the reference, it throws this InvalidOperationException. Functions projects derive their config keys from the referenced resource, and custom names would break that mapping.

Solutions

  1. Drop the name argument and call the unnamed WithReference overload; Functions derives the config key automatically.
  2. If a specific name is required, create a wrapper resource or use environment variables directly via WithEnvironment.
  3. Adjust shared wiring helpers to not pass names for Functions destinations.

Example fix

// before
functionsProject.WithReference(cache, "RedisConnection");

// after
functionsProject.WithReference(cache); // key is derived from the resource
Defensive patterns

Strategy: validation

Validate before calling

if (name is not null && destination.Resource is AzureFunctionsProjectResource) throw new InvalidOperationException("Do not pass a connection name to WithReference on Azure Functions resources.");

Type guard

static bool SupportsNamedReference(IResourceBuilder<IResource> b) => b.Resource is not AzureFunctionsProjectResource;

Try / catch

try { functionsProject.WithReference(dep, "MyConn"); } catch (InvalidOperationException ex) when (ex.Message.Contains("Named service references")) { /* retry without name */ }

Prevention

When it happens

Trigger: Calling WithReference(destination, source, connectionName: "myname") (or equivalent named overload) on an Azure Functions project resource.

Common situations: Providing an explicit connection/environment-variable name as you would for a normal project; migrating reference code from a WebApp to a Functions app while keeping the name argument.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/080e7154a6071144. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting.Azure.Functions/AzureFunctionsProjectResourceExtensions.cs:376

        IResourceBuilder<AzureFunctionsProjectResource> destination,
        IResourceBuilder<IResource> source,
        string? connectionName,
        bool optional,
        string? name)
    {
        if (source.Resource is not IResourceWithConnectionString || source.Resource is not IResourceWithAzureFunctionsConfig azureFunctionsConfig)
        {
            return null;
        }

        if (optional)
        {
            throw new InvalidOperationException("Optional references are not supported for Azure Functions resources.");
        }

        if (name is not null)
        {
            throw new InvalidOperationException("Named service references are not supported for Azure Functions resources.");
        }

        destination.WithReferenceRelationship(source.Resource);

        return destination.WithEnvironment(context =>
        {
            connectionName ??= source.Resource.Name;
            azureFunctionsConfig.ApplyAzureFunctionsConfiguration(context.EnvironmentVariables, connectionName);
        });
    }

    private static string CreateDefaultStorageName(this IDistributedApplicationBuilder builder)
    {
        // Use ProjectNameSha256 for stable naming across deployments regardless of path
        var applicationHash = builder.Configuration["AppHost:ProjectNameSha256"]![..5].ToLowerInvariant();
        return $"{DefaultAzureFunctionsHostStorageName}{applicationHash}";
    }

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