Using DefaultAzureCredential to run the application locally and in the Cloud

Program.cs

using Azure.Identity;
using Microsoft.Extensions.Configuration.AzureAppConfiguration;

namespace MusicStore.Web
{
    public class Program
    {
        ...

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder => {
                    webBuilder.UseStartup<Startup>();
                })
                .ConfigureAppConfiguration((context, config) => {
                    var settings = config.Build();
                    var appConfigEndpoint = settings["AppSettings:AppConfiguration:Endpoint"];
                    var userAssignedIdentityClientId = settings["AppSettings:Identity:ClientId"];

                    if (!string.IsNullOrEmpty(appConfigEndpoint))
                    {
                        var endpoint = new Uri(appConfigEndpoint);
                        
                        // Create the token credential instance with the client id of the Managed Identity
                        var credentialOptions = new DefaultAzureCredentialOptions {
                            ManagedIdentityClientId = userAssignedIdentityClientId
                        };

                        config.AddAzureAppConfiguration(options =>
                        {
                            options
                                // Use managed identity to access app configuration
                                .Connect(endpoint, new DefaultAzureCredential(credentialOptions))                                

                                ...
                                
                                // Configure Azure Key Vault with Managed Identity
                                .ConfigureKeyVault(vaultOpt =>
                                {
                                    vaultOpt.SetCredential(new DefaultAzureCredential(credentialOptions));
                                })
                                
                                ...
                        });
                    }

                });
    }
}