Merge pull request #205714 from zhenlan/af-iso

Add isolated process for Azure Functions

Author: JamesJBarnett

articles/azure-app-configuration/quickstart-azure-functions-csharp.md

@@ -2,13 +2,13 @@
 title: Quickstart for Azure App Configuration with Azure Functions | Microsoft Docs
 description: "In this quickstart, make an Azure Functions app with Azure App Configuration and C#. Create and connect to an App Configuration store. Test the function locally."
 services: azure-app-configuration
-author: AlexandraKemperMS
+author: zhenlan
 ms.service: azure-app-configuration
 ms.devlang: csharp
 ms.custom: devx-track-csharp, mode-other
 ms.topic: quickstart
 ms.date: 06/02/2021
-ms.author: alkemper
+ms.author: zhenlwa
 #Customer intent: As an Azure Functions developer, I want to manage all my app settings in one place using Azure App Configuration.
 ---
 # Quickstart: Create an Azure Functions app with Azure App Configuration
@@ -17,9 +17,9 @@ In this quickstart, you incorporate the Azure App Configuration service into an
 
 ## Prerequisites
 
-- Azure subscription - [create one for free](https://azure.microsoft.com/free/dotnet)
-- [Visual Studio 2019](https://visualstudio.microsoft.com/vs) with the **Azure development** workload.
-- [Azure Functions tools](../azure-functions/functions-develop-vs.md#check-your-tools-version)
+- Azure subscription - [create one for free](https://azure.microsoft.com/free/dotnet).
+- [Visual Studio](https://visualstudio.microsoft.com/vs) with the **Azure development** workload.
+- [Azure Functions tools](../azure-functions/functions-develop-vs.md), if you don't have it installed with Visual Studio already.
 
 ## Create an App Configuration store
 
@@ -40,13 +40,24 @@ In this quickstart, you incorporate the Azure App Configuration service into an
 [!INCLUDE [Create a project using the Azure Functions template](../../includes/functions-vstools-create.md)]
 
 ## Connect to an App Configuration store
-This project will use [dependency injection in .NET Azure Functions](../azure-functions/functions-dotnet-dependency-injection.md) and add Azure App Configuration as an extra configuration source.
+This project will use [dependency injection in .NET Azure Functions](/azure/azure-functions/functions-dotnet-dependency-injection) and add Azure App Configuration as an extra configuration source. Azure Functions support running [in-process](/azure/azure-functions/functions-dotnet-class-library) or [isolated-process](/azure/azure-functions/dotnet-isolated-process-guide). Pick the one that matches your requirements.
 
 1. Right-click your project, and select **Manage NuGet Packages**. On the **Browse** tab, search for and add following NuGet packages to your project.
-   - [Microsoft.Extensions.Configuration.AzureAppConfiguration](https://www.nuget.org/packages/Microsoft.Extensions.Configuration.AzureAppConfiguration/) version 4.1.0 or later
-   - [Microsoft.Azure.Functions.Extensions](https://www.nuget.org/packages/Microsoft.Azure.Functions.Extensions/) version 1.1.0 or later 
+    ### [In-process](#tab/in-process)
 
-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.
+    - [Microsoft.Extensions.Configuration.AzureAppConfiguration](https://www.nuget.org/packages/Microsoft.Extensions.Configuration.AzureAppConfiguration/) version 4.1.0 or later
+    - [Microsoft.Azure.Functions.Extensions](https://www.nuget.org/packages/Microsoft.Azure.Functions.Extensions/) version 1.1.0 or later 
+
+    ### [Isolated process](#tab/isolated-process)
+
+    - [Microsoft.Azure.AppConfiguration.Functions.Worker](https://www.nuget.org/packages/Microsoft.Azure.AppConfiguration.Functions.Worker)
+
+    ---
+
+2. Add code to connect to Azure App Configuration.
+    ### [In-process](#tab/in-process)
+
+    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.
 
@@ -74,13 +85,35 @@ This project will use [dependency injection in .NET Azure Functions](../azure-fu
     }
     ```
 
-3. Open *Function1.cs*, and add the following namespace.
+    ### [Isolated process](#tab/isolated-process)
+
+    Open *Program.cs* and update the `Main()` method as following. You add Azure App Configuration provider as an extra configuration source by calling `AddAzureAppConfiguration()`.
+
+    ```csharp
+    public static void Main()
+    {
+        var host = new HostBuilder()
+            .ConfigureAppConfiguration(builder =>
+            {
+                string cs = Environment.GetEnvironmentVariable("ConnectionString");
+                builder.AddAzureAppConfiguration(cs);
+            })
+            .ConfigureFunctionsWorkerDefaults()
+            .Build();
+
+        host.Run();
+    }
+    ```
+    ---
+
+3. Open *Function1.cs*, and add the following namespace if it's not present already.
 
     ```csharp
     using Microsoft.Extensions.Configuration;
     ```
 
-   Add a constructor used to obtain an instance of `IConfiguration` through dependency injection.
+   Add or update the constructor used to obtain an instance of `IConfiguration` through dependency injection.
+    ### [In-process](#tab/in-process)
 
     ```csharp
     private readonly IConfiguration _configuration;
@@ -91,14 +124,29 @@ This project will use [dependency injection in .NET Azure Functions](../azure-fu
     }
     ```
 
+    ### [Isolated process](#tab/isolated-process)
+    ```csharp
+    private readonly IConfiguration _configuration;
+
+    public Function1(ILoggerFactory loggerFactory, IConfiguration configuration)
+    {
+        _logger = loggerFactory.CreateLogger<Function1>();
+        _configuration = configuration;
+    }
+    ```
+    ---
+
 4. Update the `Run` method to read values from the configuration.
+    ### [In-process](#tab/in-process)
 
     ```csharp
+    [FunctionName("Function1")]
     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.");
 
+        // Read configuration data
         string keyName = "TestApp:Settings:Message";
         string message = _configuration[keyName];
 
@@ -111,6 +159,28 @@ This project will use [dependency injection in .NET Azure Functions](../azure-fu
     > [!NOTE]
     > The `Function1` class and the `Run` method should not be static. Remove the `static` modifier if it was autogenerated.
 
+    ### [Isolated process](#tab/isolated-process)
+
+    ```csharp
+    [Function("Function1")]
+    public HttpResponseData Run([HttpTrigger(AuthorizationLevel.Anonymous, "get", "post")] HttpRequestData req)
+    {
+        _logger.LogInformation("C# HTTP trigger function processed a request.");
+
+        var response = req.CreateResponse(HttpStatusCode.OK);
+        response.Headers.Add("Content-Type", "text/plain; charset=utf-8");
+
+        // Read configuration data
+        string keyName = "TestApp:Settings:Message";
+        string message = _configuration[keyName];
+
+        response.WriteString(message ?? $"Please create a key-value with the key '{keyName}' in Azure App Configuration.");
+
+        return response;
+    }
+    ```
+    ---
+
 ## 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:
@@ -151,3 +221,8 @@ In this quickstart, you created a new App Configuration store and used it with a
 
 > [!div class="nextstepaction"]
 > [Enable dynamic configuration in Azure Functions](./enable-dynamic-configuration-azure-functions-csharp.md)
+
+To learn how to use an Azure managed identity to streamline the access to App Configuration, continue to the next tutorial.
+
+> [!div class="nextstepaction"]
+> [Access App Configuration using managed identity](./howto-integrate-azure-managed-service-identity.md)