microsoft/aspire · error · InvalidOperationException

Resource ' ' cannot produce a " " launch configuration…

Error message

Resource '{resource.Name}' cannot produce a "{KnownLaunchConfigurationTypes.Project}" launch configuration because it has no project metadata. The "{KnownLaunchConfigurationTypes.Project}" launch configuration type is reserved for .NET project resources; use a resource that carries IProjectMetadata or a different launch configuration type.

What it means

ProjectLaunchConfigurationFactory.Create only produces a 'Project' launch configuration for resources that carry IProjectMetadata. Given any other resource type (container, executable, connection), it throws InvalidOperationException because the 'Project' configuration type is reserved for .NET project resources.

Solutions

1. Only request project launch configurations for resources where resource.TryGetProjectMetadata(out _) returns true
2. Use the launch configuration factory that matches the resource's actual kind (e.g. container/executable configuration types)
3. If the resource should be a project, add the project metadata annotation in the resource builder

Example fix

// before
var config = ProjectLaunchConfigurationFactory.Create(resource, mode);
// after
if (resource.TryGetProjectMetadata(out _))
{
    var config = ProjectLaunchConfigurationFactory.Create(resource, mode);
}

if (!resource.TryGetProjectMetadata(out _))
    throw new InvalidOperationException($"'{resource.Name}' is not a project resource.");

bool IsProjectResource(IResource r) => r.TryGetProjectMetadata(out _);

try { var cfg = ProjectLaunchConfigurationFactory.Create(resource, mode); } catch (InvalidOperationException) { /* use the resource's actual launch config type */ }

When it happens

Trigger: Requesting launch configurations for a resource whose annotation list lacks IProjectMetadata, e.g. resolving launch configurations for a container resource or a plain custom resource.

Common situations: Enumerating launch configurations over all resources in the app model where non-project resources are included; a custom resource builder forgot to add project metadata; dashboard/IDE tooling asking for a project config for a container.

Understand the failure class

Background: "not installed", "pip install", "required for": how missing-dependency errors surface across open-source libraries — this error's family across 34 libraries.

Related errors

• Launch arguments must contain at least one entry.
• Resource ' ' carries more than one IProjectMetadata…
• Resource ' ' does not carry an IProjectMetadata annotation.
• Resource ' ' project metadata was replaced after project…
• The leading resource argument to remove cannot be empty.

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/3efcaffecefeede3. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting/ApplicationModel/ProjectLaunchConfigurationFactory.cs:18

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

#pragma warning disable ASPIREEXTENSION001
#pragma warning disable ASPIREPROJECTS001

namespace Aspire.Hosting.ApplicationModel;

/// <summary>
/// Builds the <see cref="ProjectLaunchConfiguration"/> that Aspire hands to the IDE for a .NET resource.
/// </summary>
internal static class ProjectLaunchConfigurationFactory
{
    public static ProjectLaunchConfiguration Create(IResource resource, string mode)
    {
        if (!resource.TryGetProjectMetadata(out var projectMetadata))
        {
            throw new InvalidOperationException(
                $"Resource '{resource.Name}' cannot produce a \"{KnownLaunchConfigurationTypes.Project}\" launch configuration because it has no project metadata. " +
                $"The \"{KnownLaunchConfigurationTypes.Project}\" launch configuration type is reserved for .NET project resources; use a resource that carries {nameof(IProjectMetadata)} or a different launch configuration type.");
        }

        return Create(resource, projectMetadata, mode);
    }

    public static ProjectLaunchConfiguration Create(IResource resource, IProjectMetadata projectMetadata, string mode)
    {
        resource.TryGetLastAnnotation<ProjectLaunchDefaultsAnnotation>(out var launchDefaults);
        var projectLaunchConfiguration = new ProjectLaunchConfiguration
        {
            Type = GetLaunchConfigurationType(resource, projectMetadata),
            ProjectPath = projectMetadata.ProjectPath,
            Mode = mode,
            BuildConfiguration = launchDefaults?.BuildConfiguration,
            BuildEnvironment = projectMetadata.BuildEnvironment.Count == 0
                ? null

View on GitHub (pinned to 25830f84bd)