Core.BluePrint.Packages/Core.Blueprint.KeyVault/Configuration/RegisterBlueprint.cs

using Azure.Identity;
using Azure.Security.KeyVault.Secrets;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace Core.Blueprint.KeyVault.Configuration
{
    /// <summary>
    /// Registers the SecretClient for Azure Key Vault as a singleton service.
    /// </summary>
    /// <param name="services">The IServiceCollection to add the services to.</param>
    /// <param name="configuration">The application's configuration.</param>
    /// <returns>The updated IServiceCollection.</returns>
    /// <exception cref="ArgumentNullException">Thrown when the KeyVault URI is missing in the configuration.</exception>
    public static class RegisterBlueprint
    {
        public static IServiceCollection AddKeyVault(this IServiceCollection services, IConfiguration configuration)
        {
            var keyVaultUriString = configuration["ConnectionStrings:KeyVaultDAL"];

            if (string.IsNullOrEmpty(keyVaultUriString))
            {
                throw new ArgumentNullException("ConnectionStrings:KeyVault", "KeyVault URI is missing in the configuration.");
            }

            var keyVaultUri = new Uri(keyVaultUriString);

            // Register SecretClient as a singleton
            services.AddSingleton(_ => new SecretClient(keyVaultUri, new DefaultAzureCredential()));

            services.AddSingleton<IKeyVaultProvider, KeyVaultProvider>();
            return services;
        }
    }
}