Quickstart: Create an ASP.NET Core app with Azure App Configuration

• 02/19/2020
• 7 minutes to read
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In this quickstart, you will use Azure App Configuration to centralize storage and management of application settings for an ASP.NET Core application. ASP.NET Core builds a single key-value-based configuration object using settings from one or more data sources specified by an application. These data sources are known as configuration providers. Because App Configuration's .NET Core client is implemented as a configuration provider, the service appears like another data source.

Prerequisites

• Azure subscription - create one for free
• .NET Core SDK

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.

   

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

   

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

   Setting	Suggested value	Description
   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.
   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.
   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 details, please see the App Configuration pricing page.

   

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

5. After the deployment finishes, 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.

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

   Key	Value
   TestApp:Settings:BackgroundColor	White
   TestApp:Settings:FontSize	24
   TestApp:Settings:FontColor	Black
   TestApp:Settings:Message	Data from Azure App Configuration

   Leave Label and Content Type empty for now. Select Apply.

Create an ASP.NET Core web app

Use the .NET Core command-line interface (CLI) to create a new ASP.NET Core MVC web app project. The Azure Cloud Shell provides these tools for you. They are also available across the Windows, macOS, and Linux platforms.

1. Create a new folder for your project. For this quickstart, name it TestAppConfig.

2. In the new folder, run the following command to create a new ASP.NET Core MVC web app project:

dotnet new mvc --no-https

Add Secret Manager

To use Secret Manager, add a UserSecretsId element to your .csproj file.

1. Open the .csproj file.

2. Add a UserSecretsId element as shown here. You can use the same GUID, or you can replace this value with your own.

   Important

   CreateHostBuilder replaces CreateWebHostBuilder in .NET Core 3.0. Select the correct syntax based on your environment.

   • .NET Core 2.x
   • .NET Core 3.x

   <Project Sdk="Microsoft.NET.Sdk.Web">
   
       <PropertyGroup>
           <TargetFramework>netcoreapp2.1</TargetFramework>
           <UserSecretsId>79a3edd0-2092-40a2-a04d-dcb46d5ca9ed</UserSecretsId>
       </PropertyGroup>
   
       <ItemGroup>
           <PackageReference Include="Microsoft.AspNetCore.App" />
           <PackageReference Include="Microsoft.AspNetCore.Razor.Design" Version="2.1.2" PrivateAssets="All" />
       </ItemGroup>
   
   </Project>
   

3. Save the .csproj file.

The Secret Manager tool stores sensitive data for development work outside of your project tree. This approach helps prevent the accidental sharing of app secrets within source code.

Connect to an App Configuration store

1. Add a reference to the Microsoft.Azure.AppConfiguration.AspNetCore NuGet package by running the following command:

   dotnet add package Microsoft.Azure.AppConfiguration.AspNetCore
   

2. Run the following command to restore packages for your project:

   dotnet restore
   

3. Add a secret named ConnectionStrings:AppConfig to Secret Manager.

   This secret contains the connection string to access your App Configuration store. Replace the value in the following command with the connection string for your App Configuration store. You can find the connection string under Access Keys in the Azure portal.

   This command must be executed in the same directory as the .csproj file.

   dotnet user-secrets set ConnectionStrings:AppConfig <your_connection_string>
   

   Important

   Some shells will truncate the connection string unless it is enclosed in quotes. Ensure that the output of the dotnet user-secrets command shows the entire connection string. If it doesn't, rerun the command, enclosing the connection string in quotes.

   Secret Manager is used only to test the web app locally. When the app is deployed to Azure App Service, for example, you use the Connection Strings application setting in App Service instead of Secret Manager to store the connection string.

   Access this secret using the configuration API. A colon (:) works in the configuration name with the configuration API on all supported platforms. See Configuration by environment.

4. Open Program.cs, and add a reference to the .NET Core App Configuration provider.

   using Microsoft.Extensions.Configuration.AzureAppConfiguration;
   

5. Update the CreateWebHostBuilder method to use App Configuration by calling the config.AddAzureAppConfiguration() method.

   Important

   CreateHostBuilder replaces CreateWebHostBuilder in .NET Core 3.0. Select the correct syntax based on your environment.

   • .NET Core 2.x
   • .NET Core 3.x

   public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
       WebHost.CreateDefaultBuilder(args)
           .ConfigureAppConfiguration((hostingContext, config) =>
           {
               var settings = config.Build();
               config.AddAzureAppConfiguration(settings["ConnectionStrings:AppConfig"]);
           })
           .UseStartup<Startup>();
   

6. Navigate to /Views/Home and open Index.cshtml. Replace its content with the following code:

   @using Microsoft.Extensions.Configuration
   @inject IConfiguration Configuration
   
   <style>
       body {
           background-color: @Configuration["TestApp:Settings:BackgroundColor"]
       }
       h1 {
           color: @Configuration["TestApp:Settings:FontColor"];
           font-size: @Configuration["TestApp:Settings:FontSize"]px;
       }
   </style>
   
   <h1>@Configuration["TestApp:Settings:Message"]</h1>
   

7. Navigate to /Views/Shared and open _Layout.cshtml. Replace its content with the following code:

   <!DOCTYPE html>
   <html>
   <head>
       <meta charset="utf-8" />
       <meta name="viewport" content="width=device-width, initial-scale=1.0" />
       <title>@ViewData["Title"] - hello_world</title>
   
       <link rel="stylesheet" href="~/lib/bootstrap/dist/css/bootstrap.css" />
       <link rel="stylesheet" href="~/css/site.css" />
   </head>
   <body>
       <div class="container body-content">
           @RenderBody()
       </div>
   
       <script src="~/lib/jquery/dist/jquery.js"></script>
       <script src="~/lib/bootstrap/dist/js/bootstrap.js"></script>
       <script src="~/js/site.js" asp-append-version="true"></script>
   
       @RenderSection("Scripts", required: false)
   </body>
   </html>
   

Build and run the app locally

1. To build the app using the .NET Core CLI, navigate to the root directory of your application and run the following command in the command shell:

   dotnet build
   

2. After the build successfully completes, run the following command to run the web app locally:

   dotnet run
   

3. If you're working on your local machine, use a browser to navigate to http://localhost:5000. This is the default URL for the web app hosted locally.

If you're working in the Azure Cloud Shell, select the Web Preview button followed by Configure.

When prompted to configure the port for preview, enter '5000' and select Open and browse. The web page will read "Data from Azure App Configuration."

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.

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, and either right-click the row or use the ellipsis (...) button to open the context menu.
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 ASP.NET Core web app via the App Configuration provider. To learn how to configure your ASP.NET Core app to dynamically refresh configuration settings, continue to the next tutorial.