App Secrets Load at Start Up Time

app-secrets-loading-at-startup-time.cs

public static IHostBuilder CreateHostBuilder(string[] args) =>
          Host.CreateDefaultBuilder(args)
              .ConfigureWebHostDefaults(webBuilder =>
              {
                  webBuilder.UseStartup<Startup>();
              })
              .ConfigureAppConfiguration((context, config) =>
              {
                  if (context.HostingEnvironment.IsProduction())
                  {
                      var builtConfig = config.SetBasePath(Directory.GetCurrentDirectory())
                                  .AddJsonFile("appsettings.json", false)
                                  .AddJsonFile($"appsettings.Production.json", true)
                                  .AddEnvironmentVariables()
                                  .Build();
                      var settings = builtConfig.GetSection("AppSettings").Get<AppSettings>();
                      using (var store = new X509Store(StoreName.My, StoreLocation.CurrentUser))
                      {
                          store.Open(OpenFlags.ReadOnly);
                          var allCerts = store.Certificates;
                          var certs = allCerts
                              .Find(X509FindType.FindByThumbprint,
                                  settings.AzureKeyVaultSettings.AzureADCertThumbprint, false);
                          config.AddAzureKeyVault(new Uri($"https://{settings.AzureKeyVaultSettings.KeyVaultName}.vault.azure.net/"),
                                                  new ClientCertificateCredential(
                                                      settings.AzureKeyVaultSettings.AzureADDirectoryId,
                                                      settings.AzureKeyVaultSettings.AzureADApplicationId,
                                                      certs.OfType<X509Certificate2>().Single()));
                          store.Close();
                      }
                  }
              });