microsoft/aspire · error · InvalidOperationException

Embedded resource ' ' not found.

Error message

Embedded resource '{name}' not found.

What it means

The Rust code generator loads its template/runtime support files from embedded resources in the Aspire.Hosting.CodeGeneration.Rust assembly, using the namespace `Aspire.Hosting.CodeGeneration.Rust.Resources.{name}`. `GetEmbeddedResource` throws this InvalidOperationException when the requested resource name does not match any manifest resource in the assembly. Like the other embedded-resource errors, it signals a packaging/build problem rather than user input error.

Solutions

  1. Rebuild from a clean state or reinstall the official Aspire.Hosting.CodeGeneration.Rust package so embedded resources are intact.
  2. Confirm the requested resource file exists under the Rust Resources directory and is listed as `<EmbeddedResource>` in the project file.
  3. Inspect the assembly's manifest resource names to find the actual name and fix a mismatch if building from source.
  4. File an issue with the missing resource name if this occurs on an official package build.
Defensive patterns

Strategy: try-catch

Validate before calling

var hasRustResources = typeof(AtsRustCodeGenerator).Assembly
  .GetManifestResourceNames()
  .Any(n => n.StartsWith("Aspire.Hosting.CodeGeneration.Rust.Resources."));

Try / catch

try {
  string template = GetEmbeddedResource(name);
} catch (InvalidOperationException ex) when (ex.Message.Contains("Embedded resource")) {
  // reinstall/rebuild before retrying generation
}

Prevention

When it happens

Trigger: Calling GenerateDistributedApplication in the Rust generator when a template resource it requests was not embedded (file missing/renamed, csproj EmbeddedResource entry removed, or assembly built without resources).

Common situations: Custom builds that exclude .rs template files; a renamed resource folder breaking the expected namespace; unofficial or corrupted package installs.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/ec58618ec60611dc. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting.CodeGeneration.Rust/AtsRustCodeGenerator.cs:73

                pub mod aspire;

                pub use transport::*;
                pub use base::*;
                pub use aspire::*;
                """,
            ["transport.rs"] = GetEmbeddedResource("transport.rs"),
            ["base.rs"] = GetEmbeddedResource("base.rs"),
            ["aspire.rs"] = GenerateAspireSdk(context)
        };
    }

    private static string GetEmbeddedResource(string name)
    {
        var assembly = Assembly.GetExecutingAssembly();
        var resourceName = $"Aspire.Hosting.CodeGeneration.Rust.Resources.{name}";

        using var stream = assembly.GetManifestResourceStream(resourceName)
            ?? throw new InvalidOperationException($"Embedded resource '{name}' not found.");
        using var reader = new StreamReader(stream);
        return reader.ReadToEnd();
    }

    private string GenerateAspireSdk(AtsContext context)
    {
        using var stringWriter = new StringWriter(CultureInfo.InvariantCulture);
        _writer = stringWriter;

        var capabilities = context.Capabilities;
        var dtoTypes = context.DtoTypes;
        var enumTypes = context.EnumTypes;

        _enumNames.Clear();
        foreach (var enumType in enumTypes)
        {
            _enumNames[enumType.TypeId] = SanitizeIdentifier(enumType.Name);
        }

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