为什么在Program.cs中推荐的netcore 2.0中播种初始数据

Question

我正在使用Azure KeyVault来获取Program.cs中的秘密：

public static IWebHost BuildWebHost(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .ConfigureAppConfiguration((context, config) =>
                {
                    config.SetBasePath(Directory.GetCurrentDirectory())
                        .AddJsonFile("appsettings.json", optional: false)
                        .AddEnvironmentVariables();

                    var builtConfig = config.Build();

                    config.AddAzureKeyVault(
                        $"https://{builtConfig["KeyVault:Name"]}.vault.azure.net/",
                        builtConfig["KeyVault:ClientId"],
                        builtConfig["KeyVault:ClientSecret"]);
                })
                .UseStartup<Startup>()
                .UseApplicationInsights()
                .Build();

我有以下代码在ConfigureServices内的Startup.cs中播种数据，因此我可以获得Azure KeyVault值：

    Task.Run(async () =>
    {
            try
            {
                var context = services.BuildServiceProvider().GetRequiredService<ApplicationDbContext>();
                var userManager = services.BuildServiceProvider().GetRequiredService<UserManager<ApplicationUser>>();

                await SeedData.Initialize(context, userManager, Configuration);
            }
            catch (Exception ex)
            {
                var logger = services.BuildServiceProvider().GetRequiredService<ILogger<Program>>();
                logger.LogError(ex, "An error occurred seeding the DB.");
            }
    });

方法：

public class SeedData
    {
        public static async Task Initialize(ApplicationDbContext context, UserManager<ApplicationUser> userManager, IConfiguration configuration)
        {
            // Look for any users.
            if (context.Users.Any())
            {
                return; // DB has been seeded
            }

            var user = new ApplicationUser
            {
                Email = configuration["SeedData:InitialAdminUser"],
                UserName = configuration["SeedData:InitialAdminUser"]
            };

            var password = configuration["SeedData:InitialAdminPassword"];
            await userManager.CreateAsync(user, password);
            await userManager.AddClaimAsync(user, new Claim(ClaimTypes.Role, "admin"));
        }
    }

要播种数据，建议在Program.cs中使用它而不是Startup。那是为什么？

我在Program.cs中有这个，但我无法从AzureKeyVault获取配置值，因为AzureKeyVault是在（我在此阶段无法获得azure密钥库隐私值）之后配置的：< / p>

public class Program
    {
        public static void Main(string[] args)
        {
            var host = BuildWebHost(args);

            Task.Run(async () =>
            {
                // seeding initial admin user
                using (var scope = host.Services.CreateScope())
                {
                    var services = scope.ServiceProvider;
                    try
                    {
                        var context = services.GetRequiredService<ApplicationDbContext>();
                        var userManager = services.GetRequiredService<UserManager<ApplicationUser>>();

                        var builder = services.GetRequiredService<IConfigurationRoot>();

                        await SeedData.Initialize(context, userManager, builder);
                    }
                    catch (Exception ex)
                    {
                        var logger = services.GetRequiredService<ILogger<Program>>();
                        logger.LogError(ex, "An error occurred seeding the DB.");
                    }
                }
            });

            host.Run();
        }

        public static IWebHost BuildWebHost(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .ConfigureAppConfiguration((context, config) =>
                {
                    config.SetBasePath(Directory.GetCurrentDirectory())
                        .AddJsonFile("appsettings.json", optional: false)
                        .AddEnvironmentVariables();

                    var builtConfig = config.Build();

                    config.AddAzureKeyVault(
                        $"https://{builtConfig["KeyVault:Name"]}.vault.azure.net/",
                        builtConfig["KeyVault:ClientId"],
                        builtConfig["KeyVault:ClientSecret"]);
                })
                .UseStartup<Startup>()
                .UseApplicationInsights()
                .Build();
    }

要在Program.cs中实现这一点，我认为一种方法是在Task.Run之前将azurekeyvault移动到main？

你在想什么？