Azure KeyVault Extensions for Azure Functions v2

• Azure KeyVault Extensions for Azure Functions v2
  • About
  • How to configure
  • Azure Deployment

About

This repo contains extensions for Azure KeyVault in Azure Function v2. It uses the Microsoft.Extensions.Configuration.AzureKeyVault library to include Azure KeyVault into the configuration of your Azure Functions. This lets you use Azure KeyVault with existing bindings on all AutoResolve properties, as well as properties that are filled from the configuration, e.g. connection strings. In addition you can use the AzureKeyVaultClient to get an IKeyVaultClient instance into your function.

Since this extensions uses the existing configuration provider, all requirements and restrictions are also valid for this extension.

Example usage:

[FunctionName("Function1")]
public static void Run(
    [BlobTrigger("%blobpath%", Connection = "storageconnection")]Stream myBlob,
    string name,
    ILogger log,
    [AzureKeyVaultClient]IKeyVaultClient client)
{
    log.LogInformation($"API Version: {client.ApiVersion}");
    log.LogInformation($"C# Blob trigger function Processed blob\n Name:{name} \n Size: {myBlob.Length} Bytes");
}

Values for blobpath and storageconnection are now also pulled from Azure KeyVault, if there are no values present in the normal config. The AzureKeyVaultClient Attributes binds an instance of an IKeyVaultClient into the function for advanced usage.

How to configure

The Azure KeyVault extensions are available as a nuget package. Once the package is added to function project, a WebJobsStartup is needed to register and configure the the extension.

This is an example WebJobsStartup class

using ExampleFunction;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Willezone.Azure.WebJobs.Extensions.AzureKeyVault;

[assembly: WebJobsStartup(typeof(Startup))]
namespace ExampleFunction
{
    public class Startup : IWebJobsStartup
    {
        public void Configure(IWebJobsBuilder builder)
        {
            // Create temporary service provider to access configuration.
            var tempProvider = builder.Services.BuildServiceProvider();
            var config = tempProvider.GetRequiredService<IConfiguration>();
            builder.AddAzureKeyVault(config["AzureKeyVault_Uri"]);
        }
    }
}

The nuget package contains two extension methods to register the extensions.

AddAzureKeyVault(this IWebJobsBuilder builder, string vault, string clientId, string clientSecret)

This configures the extension to use a client id and client secret to access the KeyVault.

AddAzureKeyVault(this IWebJobsBuilder builder, string vault)

This configures the extension to use managed service identity to access the KeyVault

Azure Deployment

Currently there is an issue when publishing your function application that the required extensions.json is not created correctly. The issue is discussed here. Luckily there is a workaround for this: Just copy the Directory.Build.targets file into your Azure Functions project, this will then create the correct extensions.json file.