Quickstart: Create an Azure Functions app with Azure App Configuration

In this quickstart, you incorporate the Azure App Configuration service into an Azure Functions app to centralize storage and management of all your application settings separate from your code.

Prerequisites

Create an App Configuration store

  1. To create a new App Configuration store, sign in to the Azure portal. In the upper-left corner of the home page, select Create a resource. In the Search the Marketplace box, enter App Configuration and select Enter.

    Search for App Configuration

  2. Select App Configuration from the search results, and then select Create.

    Select Create

  3. On the Create App Configuration pane, enter the following settings:

    Setting Suggested value Description
    Subscription Your subscription Select the Azure subscription that you want to use to test App Configuration. If your account has only one subscription, it's automatically selected and the Subscription list isn't displayed.
    Resource group AppConfigTestResources Select or create a resource group for your App Configuration store resource. This group is useful for organizing multiple resources that you might want to delete at the same time by deleting the resource group. For more information, see Use resource groups to manage your Azure resources.
    Resource name Globally unique name Enter a unique resource name to use for the App Configuration store resource. The name must be a string between 5 and 50 characters and contain only numbers, letters, and the - character. The name can't start or end with the - character.
    Location Central US Use Location to specify the geographic location in which your app configuration store is hosted. For the best performance, create the resource in the same region as other components of your application.
    Pricing tier Free Select the desired pricing tier. For more information, see the App Configuration pricing page.
  4. Select Review + create to validate your settings.

  5. Select Create. The deployment might take a few minutes.

  6. After the deployment finishes, navigate to the App Configuration resource. Select Settings > Access keys. Make a note of the primary read-only key connection string. You'll use this connection string later to configure your application to communicate with the App Configuration store that you created.

  1. Select Configuration Explorer > + Create > Key-value to add the following key-value pairs:

    Key Value
    TestApp:Settings:Message Data from Azure App Configuration

    Leave Label and Content Type empty for now.

  2. Select Apply.

Create a Functions app

The Azure Functions project template in Visual Studio creates a C# class library project that you can publish to a function app in Azure. You can use a function app to group functions as a logical unit for easier management, deployment, scaling, and sharing of resources.

  1. From the Visual Studio menu, select File > New > Project.

  2. In Create a new project, enter functions in the search box, choose the Azure Functions template, and then select Next.

  3. In Configure your new project, enter a Project name for your project, and then select Create. The function app name must be valid as a C# namespace, so don't use underscores, hyphens, or any other nonalphanumeric characters.

  4. For the Create a new Azure Functions application settings, use the values in the following table:

    Setting Value Description
    .NET version .NET Core 3 (LTS) This value creates a function project that uses the version 3.x runtime of Azure Functions, which supports .NET Core 3.x. Azure Functions 1.x supports the .NET Framework. For more information, see Azure Functions runtime versions overview.
    Function template HTTP trigger This value creates a function triggered by an HTTP request.
    Storage account (AzureWebJobsStorage) Storage emulator Because a function app in Azure requires a storage account, one is assigned or created when you publish your project to Azure. An HTTP trigger doesn't use an Azure Storage account connection string; all other trigger types require a valid Azure Storage account connection string.
    Authorization level Anonymous The created function can be triggered by any client without providing a key. This authorization setting makes it easy to test your new function. For more information about keys and authorization, see Authorization keys and HTTP and webhook bindings.

    Azure Functions project settings

    Make sure you set the Authorization level to Anonymous. If you choose the default level of Function, you're required to present the function key in requests to access your function endpoint.

  5. Select Create to create the function project and HTTP trigger function.

Connect to an App Configuration store

This project will use dependency injection in .NET Azure Functions and add Azure App Configuration as an extra configuration source.

  1. Right-click your project, and select Manage NuGet Packages. On the Browse tab, search for and add following NuGet packages to your project.

  2. Add a new file, Startup.cs, with the following code. It defines a class named Startup that implements the FunctionsStartup abstract class. An assembly attribute is used to specify the type name used during Azure Functions startup.

    The ConfigureAppConfiguration method is overridden and Azure App Configuration provider is added as an extra configuration source by calling AddAzureAppConfiguration(). The Configure method is left empty as you don't need to register any services at this point.

    using System;
    using Microsoft.Azure.Functions.Extensions.DependencyInjection;
    using Microsoft.Extensions.Configuration;
    
    [assembly: FunctionsStartup(typeof(FunctionApp.Startup))]
    
    namespace FunctionApp
    {
        class Startup : FunctionsStartup
        {
            public override void ConfigureAppConfiguration(IFunctionsConfigurationBuilder builder)
            {
                string cs = Environment.GetEnvironmentVariable("ConnectionString");
                builder.ConfigurationBuilder.AddAzureAppConfiguration(cs);
            }
    
            public override void Configure(IFunctionsHostBuilder builder)
            {
            }
        }
    }
    
  3. Open Function1.cs, and add the following namespace.

    using Microsoft.Extensions.Configuration;
    

    Add a constructor used to obtain an instance of IConfiguration through dependency injection.

    private readonly IConfiguration _configuration;
    
    public Function1(IConfiguration configuration)
    {
        _configuration = configuration;
    }
    
  4. Update the Run method to read values from the configuration.

    public async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req, ILogger log)
    {
        log.LogInformation("C# HTTP trigger function processed a request.");
    
        string keyName = "TestApp:Settings:Message";
        string message = _configuration[keyName];
    
        return message != null
            ? (ActionResult)new OkObjectResult(message)
            : new BadRequestObjectResult($"Please create a key-value with the key '{keyName}' in App Configuration.");
    }
    

    Note

    The Function1 class and the Run method should not be static. Remove the static modifier if it was autogenerated.

Test the function locally

  1. Set an environment variable named ConnectionString, and set it to the access key to your App Configuration store. If you use the Windows command prompt, run the following command and restart the command prompt to allow the change to take effect:

        setx ConnectionString "connection-string-of-your-app-configuration-store"
    

    If you use Windows PowerShell, run the following command:

        $Env:ConnectionString = "connection-string-of-your-app-configuration-store"
    

    If you use macOS or Linux, run the following command:

        export ConnectionString='connection-string-of-your-app-configuration-store'
    
  2. Press F5 to test your function. If prompted, accept the request from Visual Studio to download and install Azure Functions Core (CLI) tools. You might also need to enable a firewall exception so that the tools can handle HTTP requests.

  3. Copy the URL of your function from the Azure Functions runtime output.

    Quickstart Function debugging in VS

  4. Paste the URL for the HTTP request into your browser's address bar. The following image shows the response in the browser to the local GET request returned by the function.

    Quickstart Function launch local

Clean up resources

If you do not want to continue using the resources created in this article, delete the resource group you created here to avoid charges.

Important

Deleting a resource group is irreversible. The resource group and all the resources in it are permanently deleted. Make sure that you don't accidentally delete the wrong resource group or resources. If you created the resources for this article inside a resource group that contains other resources you want to keep, delete each resource individually from its respective pane instead of deleting the resource group.

  1. Sign in to the Azure portal, and select Resource groups.
  2. In the Filter by name box, enter the name of your resource group.
  3. In the result list, select the resource group name to see an overview.
  4. Select Delete resource group.
  5. You're asked to confirm the deletion of the resource group. Enter the name of your resource group to confirm, and select Delete.

After a few moments, the resource group and all its resources are deleted.

Next steps

In this quickstart, you created a new App Configuration store and used it with an Azure Functions app via the App Configuration provider. To learn how to update your Azure Functions app to dynamically refresh configuration, continue to the next tutorial.