Azure function V3 could not load file or assembly Microsoft.Extensions.DependencyInjection.Abstractions, Version=5.0.0.0 with EF core 5.0-rc1

Question

Case

We are creating azure function v3 with .netcore 3.1. Using EF core 5.0-rc1 and Depdency Injection

1) DependecyInjection

[assembly: FunctionsStartup(typeof(xxxxx.Startup))]
namespace xxxxx
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            var services = builder.Services;
            var configBuilder = new ConfigurationBuilder()
                .SetBasePath(Environment.CurrentDirectory)
                .AddJsonFile("local.settings.json", true, reloadOnChange: true)
                .AddEnvironmentVariables() ;
            ConfigureServices(services);
            ConfigureAppSettings(services, configBuilder.Build());
            ConfigureLogging(services, configBuilder.Build());
        }
    }
}

2) EF core 5.0 rc-1

https://devblogs.microsoft.com/dotnet/announcing-entity-framework-core-efcore-5-0-rc1/

Error

Could not load file or assembly 'Microsoft.Extensions.DependencyInjection.Abstractions, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'. The system cannot find the file specified.

Packages

Following are the packages referenced

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <AzureFunctionsVersion>v3</AzureFunctionsVersion>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.Azure.Functions.Extensions" Version="1.1.0" />
    <PackageReference Include="Microsoft.Azure.WebJobs.Extensions.ServiceBus" Version="4.1.0" />
    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="5.0.0-rc.1.20451.14" />
    <PackageReference Include="Microsoft.NET.Sdk.Functions" Version="3.0.7" />
    <PackageReference Include="Serilog.Extensions.Logging" Version="3.0.1" />
    <PackageReference Include="Serilog.Sinks.Console" Version="3.1.1" />
  </ItemGroup>
  <ItemGroup>
    <None Update="host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="local.settings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
    </None>
  </ItemGroup>
</Project>

Troubleshooting

commenting the following line in startup.cs (Dependency injection) solves the problem

[assembly: FunctionsStartup(typeof(xxxxx.Startup))]

Answer 1

The Microsoft.Azure.Functions.Extensions depends on .net standard 2.0.

While the Entity Framework Core 5.0 RC1 will not run on .Net standard 2.0 platforms, it requires .net standard 2.1. So it could not find the Microsoft.Azure.Functions.Extensions.

For more details, you could refer to this article.

Answer 2

If you are using .NET core 3.1 or below that. Downgrade the NuGet packages of Microsoft.Extensions.DependencyInjection and Microsoft.Extensions.DependencyInjection.Abstractions to 3.x.x.

Answer 3

It's not supported in Azure Function v3, yet. https://github.com/Azure/azure-functions-vs-build-sdk/issues/472

But, if you want to test it locally, I was able to run updating the DLL's in the Azure Function Core Tools directory: C:\Program Files\Microsoft\Azure Functions Core Tools

I needed to replace/update these Dll's to use EF5 with my functions: Dll's list

Microsoft.Extensions.DependencyInjection.Abstractions.dll
Microsoft.Extensions.Logging.Abstractions.dll
Microsoft.Extensions.Options.dll
Microsoft.Extensions.Primitives.dll