What is a feature flag?

Feature flag can be used to enable disable specific functionalities of our application by turning a feature toggle on or off, without deploying code. 

What is Microsoft App Configuration?

Azure App Configuration provides a service to centrally manage application settings and feature flags. Modern programs, especially programs running in a cloud, generally have many components that are distributed in nature. Spreading configuration settings across these components can lead to hard-to-troubleshoot errors during an application deployment 

There are many benefits when using feature flags. Below is a couple of them:

• Quickly hiding a badly developed functionality or a failure 
• Delivering a feature to a specific user group 
• Assist developers when doing trunk-based development 
• Quicker release cycles 
• Testing a new feature in a production environment

Please find the full code in github repository

How to setup App Configuration in Azure

STEP 01: Create a Free Trail account in the Azure portal Start Free 

STEP 02: Navigate to App Configuration -> Create App Configuration 

STEP 03: Fill in the resource information and click “Review & Create”, make sure to select the Pricing tier “Free” 

STEP 04: Add feature flag through feature manager -> Create 

STEP 05: Find the access keys to make a connection through the .net core application

Create Console Application

_Now let’s create a Console application where we will read this newly created feature flag and enable or disable a part of the code based on its value. _

Install the following NuGet Packages that our application will use:

Microsoft.Extensions.DependencyInjection
Microsoft.Azure.AppConfiguration.AspNetCore
Microsoft.FeatureManagement

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Configuration;
using Microsoft.FeatureManagement;


Console.WriteLine("Azure App Configuration Article Demo\n");


//Retrieve the Connection String from Azure App Configuration Resource
const string connectionString = "{Azure_App_ConnectionString}";


var configuration = new ConfigurationBuilder()
            .AddAzureAppConfiguration(options =>
            {
                options.Connect(connectionString).UseFeatureFlags();
            }).Build();


var services = new ServiceCollection();


services.AddSingleton<IConfiguration>(configuration).AddFeatureManagement();


using (var serviceProvider = services.BuildServiceProvider())
{
    var featureManager = serviceProvider.GetRequiredService<IFeatureManager>();


    //read great day feature
    if (await featureManager.IsEnabledAsync("TogglePreviewFeature"))
    {
        Console.WriteLine("Preview Feature Enabled!!!");
    }
    else
    {
        Console.WriteLine("Preview Feature Disabled!");
    }
};

The Last thing is to replace the {your_app_configuration_connection_string} with the connection string from the Azure App Configuration, which can be found under Settings -> Access keys. 

Please find the full code in github repository

Output

Thanks for reading!