Functions fails to enable Aspire Orchestration unless AppHost SDK is in local cache

[timheuer]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When creating a new Azure Functions project and using 'Enlist in Aspire Orchestration' -- it will fail if the AppHost SDK package has never been used before.

Expected Behavior

Creating an Azure Function project with orchestration should work.

Steps To Reproduce

Clear nuget cache (dotnet nuget locals all -c)
File...New Azure Function
Check "Enlist in orchestration" checkbox
Fail with (this shows preview 1, but could be rc1 depending on template versions installed):

[Workaround]
Create an Aspire app with the apphost sdk on the machine -- this will force a restore and cache the package
the above flow should now work

Exceptions (if any)

No response

.NET Version info

No response

Anything else?

No response

[joperezr]

Thanks for logging this, @timheuer. I don't think this is isolated to Functions projects, and should be able to be reproduced with any type of project when trying to add Aspire orchestration.

MSBuild SDKs are special type of NuGet packages, and are restored in a special way by both VS and the CLI, as they need to be restored very early in the project evaluation, even before the "real" NuGet package restore. My bet is that this special logic doesn't handle correctly the case where a project that is being dynamically being added to a solution depends on an MSBuild SDK NuGet package which is not in the cache yet. We should further investigate to confirm what the issue is and what the best course of action should be to address it.

cc: @phenning @DamianEdwards

[joperezr]

One potential workaround we can consider, is to make sure that every time we insert the Aspire templates into Visual Studio, we also insert the MSBuild SDK into VS's offline cache, so that this issue is less likely to be hit. It would still obviously be potentially hit if people reference a different SDK than the one we inserted in the offline cache.