Could not load file or assembly System.Fabric with Azure Functions

Question

Are there any restrictions with packages you can use with Azure Functions. I have researched as much as I can and it doesn't seem so, however when I try creating an Azure Function that references the package "Microsoft.ServiceFabric" I get the following error:

System.Private.CoreLib: Exception while executing function: ScaleDownServiceFabrics. FunctionApp2: Could not load file or assembly 'System.Fabric, Version=6.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. Could not find or load a specific file. (Exception from HRESULT: 0x80131621). System.Private.CoreLib: Could not load file or assembly 'System.Fabric, Version=6.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.

I have tried both Azure Func and.1 and 2, and .Net Framework and .Net Core with no luck.

using System;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Host;
using Microsoft.Extensions.Logging;
using System.Fabric;

namespace FunctionApp5
{
  public static class Function1
  {
    [FunctionName("Function1")]
    public static void Run([TimerTrigger("*/5 * * * * *")]TimerInfo myTimer, ILogger log)
    {
      log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");
      FabricClient client = new FabricClient();
    }
  }
}

Is this possible, or a limitation of Azure Functions in Visual Studio - if so, what packages are acceptable?

ServiceFabric packages are x64 bit, if your function target 32bit it will fail. Can you check that? Another point is, you have to add the dependencies as packages instead of reference the dll directly in the project, because of the dependencies on other libraries. — Diego Mendes
@tank: Diego has provided good checklist for the errors, also can you build the solution with the same and see if you get any errors on error list window, and also make sure to check the solution has all the packages(if using nuget just try to update the packages) and any other referencing dll's , and then test once. — Suraj Revankar
@diego - I tried changing to x64 (the default with new Azure Function in VS is Any CPU). But got this error: [13/11/2018 10:08:38 PM] A host error has occurred. [13/11/2018 10:08:38 PM] System.Private.CoreLib: Could not load file or assembly 'FunctionApp5, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.I don't think this is related. — tank104
@diego - I definitely referenced as a package not DLL. Package is "Microsoft.ServiceFabric". I updated the above code to the simplest possible way to replciate the issue. — tank104
@suraj - I am not sure what you mean by "build the solution with the same". Do you mean in x64? If so that causes issues above. All referencing DLLs are in the bin. Only thing I noticed was that System.Fabric.Dll has File Version 6.0.0.0 but product version 6.3.187.9494 - although I think this counts as 6.0.0.0 — tank104

Diego Mendes Diego Mendes · Accepted Answer · 2018-11-14T10:19:33

ServiceFabric packages are x64 bit, if your function target 32bit it will fail. Try the solution proposed by Jerry Liu
Service Fabric Packages have to be added as packages instead of reference the dll directly in the project, because of the dependencies on other libraries. You should add the NuGet package Microsoft.ServiceFabric.
Microsoft.ServiceFabric latest version 6.3.x targets .Net Standard 2.0 and .Net Framework from 4.5 to 4.7.1, make sure you are using any of these on your project.
Make sure the Microsoft.ServiceFabric DLLs are being copied to the bin folder when built\deployed.
When you use FabricClient outside the cluster, you have to specify the settings and credentials, otherwise you won't be able to connect to the cluster. See this example and this docs.
FabricClient uses Service Fabric API to interact with the cluster, if are having issues with the packages, another option is use HttpClient and make the requests to the API and avoid the packages conflicts

Could not load file or assembly System.Fabric with Azure Functions

3 Answers