Using existing Azure Functions project

[dochoss]

Hey team, I'd like to be able to use an existing Azure Functions project with my Aspire deployment to take advantage of Flex Consumption, but I'm getting compile errors when trying to use the **AsExisting() methods. I'm using VS Code with the latest package versions. I've searched the docs for examples of using AsExisting with Functions projects but can't seem to find clear guidance on how to do this (if it's possible).

AppHost.cs

var existingFuncName = builder.AddParameter("existingFuncName", value: "my-funcs");
var existingFuncResourceGroup = builder.AddParameter("existingFuncResourceGroup", value: "my-rg");

var funcs = builder.AddAzureFunctionsProject<Projects.MyProject_Functions>("functions")
    .RunAsExisting(existingFuncName, existingFuncResourceGroup);  // ERROR ON THIS LINE, red squiggles under "RunAsExisting"

Error text

The type 'Aspire.Hosting.Azure.AzureFunctionsProjectResource' cannot be used as type parameter 'T' in the generic type or method 'ExistingAzureResourceExtensions.RunAsExisting<T>(IResourceBuilder<T>, IResourceBuilder<ParameterResource>, IResourceBuilder<ParameterResource>?)'. There is no implicit reference conversion from 'Aspire.Hosting.Azure.AzureFunctionsProjectResource' to 'Aspire.Hosting.ApplicationModel.IAzureResource'.[CS0311](https://msdn.microsoft.com/query/roslyn.query?appId=roslyn&k=k(CS0311))

AppHost.csproj

<Project Sdk="Aspire.AppHost.Sdk/13.1.0">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net10.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <UserSecretsId><REDACTED></UserSecretsId>
  </PropertyGroup>

  <ItemGroup>
    <ProjectReference Include="..\MyProject.ApiService\MyProject.ApiService.csproj" />
    <ProjectReference Include="..\MyProject.Functions\MyProject.Functions.csproj" />
  </ItemGroup>

  <ItemGroup>
      <PackageReference Include="Aspire.Hosting.Azure.Sql" Version="13.1.0" />
      <PackageReference Include="Aspire.Hosting.Azure.Functions" Version="13.1.0" />
      <PackageReference Include="Aspire.Hosting.Azure.Storage" Version="13.1.0" />
      <PackageReference Include="Aspire.Hosting.JavaScript" Version="13.1.0" />
      <PackageReference Include="Aspire.Hosting.OpenAI" Version="13.1.0" />
      <PackageReference Include="Scalar.Aspire" Version="0.7.3" />
    </ItemGroup>

</Project>

User Secrets snippet

{
  "Azure:SubscriptionId": "<my subscription id>",
  "Azure:ResourceGroup": "my-rg",
  "Azure:Location": "eastus2"
}

[IEvangelist]

I just looked through the docs: https://aspire.dev/integrations/cloud/azure/azure-functions/

This isn't documented as being supported, but we do have some language here that implied all Azure resource types support this: https://aspire.dev/integrations/cloud/azure/overview/#use-existing-azure-resources

However, Azure Function project resources are a bit different. I think this is more or less a feature request, and we'd have to get @captainsafia thoughts on this.