GetConnectionStringAsync fails for AddConnectionString

[RicardoNiepel]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Adding a connection string in the AppHost doesn't allow to retrieve it in integration tests.

Sample:

• Using an existing connection string or creating the resource in AppHost
• In both ways a IResourceBuilder<IResourceWithConnectionString> is returned
• Calling GetConnectionStringAsync inside tests throws exception, don't find it anymore
  if builder.AddConnectionString was used for adding IResourceWithConnectionString>

Code:

// AppHost
var exisitingOpenAi = !builder.Configuration.GetSection("ConnectionStrings")["openAi"].IsNullOrEmpty();
var openAi = !builder.ExecutionContext.IsPublishMode && exisitingOpenAi
    ? builder.AddConnectionString("openAi")
    : builder.AddAzureOpenAI("openAi")
        .AddDeployment(new AzureOpenAIDeployment(azureDeployment, "gpt-4o", "2024-05-13", "Standard", 10));

var backend = builder.AddProject<Projects.ChatApp_Backend>("backend")
    .WithReference(openAi)

// Integration Tests
var appHost = await DistributedApplicationTestingBuilder.CreateAsync<Projects.ChatApp_AppHost>();
_app = await appHost.BuildAsync();
await _app.StartAsync();

// Throws 'System.ArgumentException' with "Resource 'openAi' does not expose a connection string." if `builder.AddConnectionString("openAi")` was executed
var openAi = await _app.GetConnectionStringAsync("openAi");

Insights:
Looking into DistributedApplicationModel.Resources of the app, there is no IResourceWithConnectionString, only a ParameterResource is now in the list:

Expected Behavior

GetConnectionStringAsync returns a connection string in both situations

• builder.AddConnectionString("openAi") was called
• builder.AddAzureOpenAI("openAi") was called

Steps To Reproduce

No response

Exceptions (if any)

System.ArgumentException : Resource 'openAi' does not expose a connection string. (Parameter 'resourceName')
   at Aspire.Hosting.Testing.DistributedApplicationHostingTestingExtensions.GetConnectionStringAsync(DistributedApplication app, String resourceName, CancellationToken cancellationToken) in /_/src/Aspire.Hosting.Testing/DistributedApplicationHostingTestingExtensions.cs:line 46

.NET Version info

.NET SDK:
Version: 9.0.102
Commit: cb83cd4923
Workload version: 9.0.100-manifests.d67a1f3e
MSBuild version: 17.12.18+ed8c6aec5

OS Name: Windows
OS Version: 10.0.26100
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\9.0.102\

Anything else?

<PackageReference Include="Aspire.Hosting.AppHost" Version="9.0.0" />
<PackageReference Include="Aspire.Hosting.Azure" Version="9.0.0" />

<PackageReference Include="Aspire.Hosting.Testing" Version="9.0.0" />

[davidfowl]

This is a valid bug but it has to do with how we implemented AddConnectionString