Pnpframework: Azure Functions: [A]PnPManifest cannot be cast to [B]PnPManifest

[YannickRe]

I load my PnP Template from a .pnp file, and this works without a problem when executing locally. If I deploy my Azure Function, I get the following error:

[Error] Error Message: [A]PnP.Framework.Provisioning.Connectors.OpenXML.Model.PnPManifest cannot be cast to [B]PnP.Framework.Provisioning.Connectors.OpenXML.Model.PnPManifest. Type A originates from 'PnP.Framework, Version=0.1.109.0, Culture=neutral, PublicKeyToken=null' in the context 'Default' at location 'C:\home\site\wwwroot\bin\PnP.Framework.dll'. Type B originates from 'PnP.Framework, Version=0.1.109.0, Culture=neutral, PublicKeyToken=null' in the context 'Default' at location 'C:\home\site\wwwroot\bin\PnP.Framework.dll'.
[Error] Error while processing dossier: [A]PnP.Framework.Provisioning.Connectors.OpenXML.Model.PnPManifest cannot be cast to [B]PnP.Framework.Provisioning.Connectors.OpenXML.Model.PnPManifest. Type A originates from 'PnP.Framework, Version=0.1.109.0, Culture=neutral, PublicKeyToken=null' in the context 'Default' at location 'C:\home\site\wwwroot\bin\PnP.Framework.dll'. Type B originates from 'PnP.Framework, Version=0.1.109.0, Culture=neutral, PublicKeyToken=null' in the context 'Default' at location 'C:\home\site\wwwroot\bin\PnP.Framework.dll'.
at PnP.Framework.Provisioning.Connectors.OpenXML.PnPPackage.GetXamlSerializedPackagePartValue[T](PackagePart part)
at PnP.Framework.Provisioning.Connectors.OpenXML.PnPPackage.get_Manifest()
at PnP.Framework.Provisioning.Connectors.OpenXML.PnPPackageExtensions.LoadPnPPackage(PnPPackage package)
at PnP.Framework.Provisioning.Connectors.OpenXML.PnPPackageExtensions.UnpackTemplate(MemoryStream stream)
at PnP.Framework.Provisioning.Connectors.OpenXMLConnector..ctor(String packageFileName, FileConnectorBase persistenceConnector, String author, X509Certificate2 signingCertificate, String templateFileName)
at ...

If I switch my code to run from .xml, it works in Azure Functions. Problem seems to happen in this method, but I don't see why. There are two casts happening...
https://github.com/pnp/pnpframework/blob/6b7b45166cf4fd17412fe3dff9ef14a6a1def35d/src/lib/PnP.Framework/Provisioning/Connectors/OpenXML/PnPPackage.cs#L315-L350

[erwinvanhunen]

Hi Yannick,

Can you share the contents of the manifest.xml file with us? It's located in the .pnp file (which is just a zip file) in the root folder.

Thanks!

[YannickRe]

Sure, this is it:

<PnPManifest Type="Full" xmlns="clr-namespace:PnP.Framework.Provisioning.Connectors.OpenXML.Model;assembly=PnP.Framework" />

[jansenbe]

@YannickRe : I think this is due to some conflict with already loaded assemblies (I will be really happy when the azure function team fixes this ~ https://techcommunity.microsoft.com/t5/apps-on-azure/net-5-support-on-azure-functions/ba-p/1973055).

Can you try to help the resolving continue with something like this: https://www.techmikael.com/2017/09/resolving-assemblies-when-using-pnp.html

[YannickRe]

I will try that, but I am not sure this is the same issue. I currently use Azure Functions v3, and that fix from Mikael was necessary in v1. The Functions team supposedly fixed that problem in v3.
The error I'm now getting (see first post) is nothing similar to what I used to get in Functions v1. The weird part is that it says that it can't cast type A to type B, but references the same appdomain AND the exact same DLL on the same location.

I'll report back when I had a chance to test that assembly redirect.

[YannickRe]

The assembly redirect doesn't fix this issue...

[jansenbe]

This is the thread I found that made me recommend the assembly load override: https://github.com/pnp/PnP-Sites-Core/issues/1474. Do you have a simple repro to share?

[jansenbe]

https://stackoverflow.com/questions/48901752/net-core-2-0-azure-function-exception-during-runtime-resolution-of-assembly might also be helpful

[YannickRe]

I'll try and get a repro Azure Function v3 over the weekend! Biggest issue is that this only occurs in Azure, not when running the function locally. Otherwise I'd be able to easier debug.

[erwinvanhunen]

The Azure function is C# function or are you using a PowerShell function, as in PowerShell the solution is relatively simple: https://pnp.github.io/powershell/articles/azurefunctions.html

[YannickRe]

It is a C# function, so no luck...

[jansenbe]

@YannickRe : did you manage to build a repro function?

[YannickRe]

Not yet, I made a bit too many commitments. I'm sorry, but I'll get this asap!

[jansenbe]

No rush...

[YannickRe]

@jansenbe I have a repro on https://github.com/YannickRe/PnPFrameworkIssue91

• Adjust FunctionApp/Function1.cs, and provide values for siteUrl, userName and password
• Deploy the Function App to Azure, on a v3 Function App Consumption Plan
• Trigger the function from the Azure Portal while watching the real time log stream

It might require multiple executions in a short timespan to get to the error message. As you can see in the screenshot my first execution worked but the second failed.

[YannickRe]

Not sure if this can be fixed here, or is an Azure Functions issue since I just found this issue report too: https://github.com/Azure/azure-functions-host/issues/7028

[github-actions[bot]]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days

[YannickRe]

Don’t feel like we should let this close automatically... 🙂

[jansenbe]

Too many things on the todo list, but indeed let's not close this one

[czullu]

Hi, you might try to change your csproj of the Azure Function and add this Line
"<_FunctionsSkipCleanOutput>true"

in here like this:

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <AzureFunctionsVersion>v3</AzureFunctionsVersion>
    <_FunctionsSkipCleanOutput>true</_FunctionsSkipCleanOutput>
  </PropertyGroup>

This usually helps to resolve conflicts with classes which the Azure Function Framework uses as well.

[YannickRe]

@czullu Thanks for chiming in! Unfortunately, I already have that line in my csproj file and that doesn't resolve this issue (it did resolve some other problems tho).

[github-actions[bot]]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days

[YannickRe]

@jansenbe Can we keep this alive?

[github-actions[bot]]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 5 days

[YannickRe]

bump

[jansenbe]

@YannickRe : been way too busy...so did not have time for this. Feel free to keep bumping it

[YannickRe]

No worries, I have a workaround now but it feels important enough to not let go stale.