microsoft/aspire · error · FailedToApplyEnvironmentException

Failed to apply configuration to executable

Error message

Failed to apply configuration to executable {renderedResource.ModelResource.Name}

What it means

Before creating a DCP Executable, Aspire resolves the resource's configuration (environment variables, args, etc.). If the resolution result carries an exception in configuration.Configuration.Exception, the resolved configuration is invalid, so this FailedToApplyEnvironmentException is thrown wrapping the inner exception. It signals that the resource model could not be turned into a concrete process configuration.

Solutions

1. Inspect the InnerException (configuration.Configuration.Exception) for the real cause and fix that error first
2. Verify all referenced resources, endpoints, and parameters the failing executable depends on are valid and running
3. Check resource logs in the dashboard for the underlying configuration resolution error

Example fix

// before
var cs = builder.AddProject<Projects.Api>("api").GetEndpoint("https"); // endpoint that never exists
// after
var cs = builder.AddProject<Projects.Api>("api").WithEndpoint("https", e => e.Scheme = "https"); // ensure the endpoint is defined

try
{
    await creator.CreateObjectAsync(renderedResource, resourceLogger, ct);
}
catch (FailedToApplyEnvironmentException ex)
{
    // Inspect ex.InnerException — the real configuration-resolution failure is there.
    logger.LogError(ex.InnerException, "Config resolution failed for {Resource}.", resource.Name);
}

When it happens

Trigger: A resource's configuration producer threw during ResolveAsync: bad endpoint references, a connection string property that failed to resolve, a value callback (IValueProvider) throwing, or an environment variable producer failing.

Common situations: Referencing an endpoint or connection string of a resource that failed to start; a custom IValueProvider/AddEnvironment callback throwing; missing referenced secret/parameter values.

Related errors

• Failed to apply launch configuration for resource
• ASPIRE_REMOTE_APPHOST_TOKEN environment variable is not set.
• ASPIRE_REMOTE_APPHOST_TOKEN environment variable is not set
• Failed to apply configuration to container
• Failed to create executable launch plan for resource

AI-assisted analysis of microsoft/aspire@25830f84bd (2026-09-16). Data as JSON: /api/errors/11fdd397a60b4dc9. Report an issue: GitHub.

Appendix: source

Thrown at src/Aspire.Hosting/Dcp/ExecutableCreator.cs:63

        !DcpModelUtilities.ShouldDeferCreateForExplicitStart(
            resource.ModelResource,
            resource.DcpResource.Spec.Start);

    public async Task CreateObjectAsync(
        RenderedModelResource<Executable> renderedResource,
        EmptyCreationContext context,
        ILogger resourceLogger,
        IDcpObjectFactory factory,
        CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();

        var configuration = await _configurationResolver
            .ResolveAsync(renderedResource, resourceLogger, cancellationToken)
            .ConfigureAwait(false);
        if (configuration.Configuration.Exception is not null)
        {
            throw new FailedToApplyEnvironmentException(
                $"Failed to apply configuration to executable {renderedResource.ModelResource.Name}",
                configuration.Configuration.Exception);
        }

        ExecutableLaunchPlan plan;
        try
        {
            plan = await ResolveLaunchPlanAsync(
                renderedResource.ModelResource,
                configuration.Configuration,
                _configuration,
                _distributedApplicationOptions,
                _launchPolicy,
                resourceLogger,
                cancellationToken).ConfigureAwait(false);
        }
        catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
        {

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