---

This section details on the original issue you should resolve

<issue_title>Hang when trying to deploy a single comptue resource to app service</issue_title>
<issue_description>App

#:package Aspire.Hosting.Python@13.1.0-pr.12787.g68c1262c
#:package Aspire.Hosting.OpenAI@13.1.0-pr.12787.g68c1262c
#:package Aspire.Hosting.Docker@13.1.0-pr.12787.g68c1262c
#:package Aspire.Hosting.Azure.AppService@13.1.0-pr.12787.g68c1262c
#:package Aspire.Hosting.Azure.KeyVault@13.1.0-pr.12787.g68c1262c
#:sdk Aspire.AppHost.Sdk@13.1.0-pr.12787.g68c1262c

var builder = DistributedApplication.CreateBuilder(args);

builder.AddAzureAppServiceEnvironment("env");

var model = builder.AddOpenAI("openai");

var oaiKey = builder.AddAzureKeyVault("kv")
               .AddSecret("oaikey", model.Resource.Key);

builder.AddPythonApp("ai-agent", "./agent", "main.py")
    .WithHttpEndpoint(env: "PORT")
    .WithExternalHttpEndpoints()
    .WithEnvironment("HOST", "0.0.0.0")
    .WithEnvironment("LOG_LEVEL", "INFO")
    .WaitForStart(model)
    .WithEnvironment("OPENAI_API_KEY", oaiKey.Resource);

builder.Build().Run();

Log

<snip>
23:35:51 (provision-ai-agent-website) → Starting provision-ai-agent-website...
23:35:51 (provision-ai-agent-website) → Deploying ai-agent-website
^C23:39:38 (provision-ai-agent-website) i [DBG] Checksum mismatch for resource ai-agent-website. Expected: (null), Actual: 214fd003

PS: aspire deploy works, aspire do deploy-ai-agent hangs</issue_description>

<agent_instructions>We need to setup dependencies between azure resources. We do this by looking at parameters and finding azure resource references, then depending on their provision steps. This will happen in

aspire/src/Aspire.Hosting.Azure/AzureBicepResource.cs

Line 44 in 04b98f1

Annotations.Add(new PipelineStepAnnotation((factoryContext) =>

via a PipelineConfigurationAnnotation.

There are some examples of visiting parameters here

aspire/src/Aspire.Hosting.Azure/AzurePublishingContext.cs

Lines 418 to 458 in 04b98f1

	private static void Visit(object? value, Action<object> visitor) =>
	Visit(value, visitor, []);
	private static void Visit(object? value, Action<object> visitor, HashSet<object> visited)
	{
	if (value is null || !visited.Add(value))
	{
	return;
	}
	visitor(value);
	if (value is IValueWithReferences vwr)
	{
	foreach (var reference in vwr.References)
	{
	Visit(reference, visitor, visited);
	}
	}
	}
	private static Task VisitAsync(object? value, Func<object, CancellationToken, Task> visitor, CancellationToken cancellationToken = default) =>
	VisitAsync(value, visitor, [], cancellationToken);
	private static async Task VisitAsync(object? value, Func<object, CancellationToken, Task> visitor, HashSet<object> visited, CancellationToken cancellationToken = default)
	{
	if (value is null || !visited.Add(value))
	{
	return;
	}
	await visitor(value, cancellationToken).ConfigureAwait(false);
	if (value is IValueWithReferences vwr)
	{
	foreach (var reference in vwr.References)
	{
	await VisitAsync(reference, visitor, visited, cancellationToken).ConfigureAwait(false);
	}
	}
	}

.

Here

aspire/src/Aspire.Hosting.Azure/AzurePublishingContext.cs

Lines 286 to 300 in 04b98f1

	void CaptureBicepOutputs(object value)
	{
	if (value is BicepOutputReference bo)
	{
	outputs[bo.ValueExpression] = bo;
	}
	}
	void CaptureBicepOutputsFromParameters(IResourceWithParameters resource)
	{
	foreach (var parameter in resource.Parameters)
	{
	Visit(parameter.Value, CaptureBicepOutputs);
	}
	}

Another example of walking the graph to find azure references

aspire/src/Aspire.Hosting.Azure/AzureResourcePreparer.cs

Line 400 in ba4b4ec

private static void ProcessAzureReferences(HashSet<IAzureResource> azureReferences, object? value)

.

So the steps are:

1. In the pipeline step annoation call resource.GetBicepTemplateString() to Force evaluation of the Bicep template to ensure parameters are expanded.
2. Walk the parameters, find IAzureResourceReferences
3. Call GetSteps(resource, WellKnownPipelineTags.ProvisionInfrastructure) and depend on those steps from the azure resources own provision infrastructure steps.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

@davidfowl OK figured it out, this is a sneaky one. We don't express the dependencies between bicep resources today. This works well when all run concurrently and dependent resources unblock each other.

Where it DOES NOT WORK is when you run subsets of the graph as we need to know what dependees to run first.</comment_new>