c# - 在订阅 Azure 应用程序配置中的更改的 Web API 中实现 Azure 事件网格事件处理程序

Question

我正在探索从 Azure 应用程序配置获取配置数据的各种方法，并且大多数方法都有效，但是我正在努力在 ASP.NET Core 3.1 上的 Web API 中实现 Azure 事件网格事件处理程序。我想知道是否可以通过事件网格通知 Web API 有关更改，而不是在为 Azure 应用程序配置设置的缓存过期时进行轮询。一旦收到通知，配置值应该更新，并且当有人向 Web API 发出请求时，新值应该提供给任何 Controller 。

我已将内容包含在我的 Program.cs、Startup.cs、服务总线使用者中，我在其中设置了事件网格订阅者和示例 Controller 。

根据我从 Microsoft 文档中读到的内容，我的理解是 IConfigurationRefresher.ProcessPushNotification 方法将缓存过期重置为短暂的随机延迟，而不是在 CreateHostedBuilder 方法中以及 IConfigurationRefresher.TryRefreshAsync() 时设置的缓存过期。称为更新配置值。

我遇到的问题是无法将 IConfigurationRefresher 的具体类的实例注入(inject) RegisterRefreshEventHandler 方法，然后调用 ProcessPushNotification 来重置过期时间。

我也可能会错误地处理这个问题，因为我假设在控制台应用程序中工作的 RegisterRefreshEventHandler 代码也适用于 Web API。请告诉我我的方法是否有效？

程序.cs

   public class Program
    {
        private static IConfiguration _configuration;

        private static IConfigurationRefresher _refresher;

        public static void Main(string[] args)
        {

            _configuration = new ConfigurationBuilder().AddJsonFile("appsettings.json", optional: false).Build();

            CreateHostBuilder(args).Build().Run();

        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            webBuilder.ConfigureAppConfiguration((hostingContext, config) =>
            {
                var settings = config.Build();
                config.AddAzureAppConfiguration(options =>
                    {
                        options
                            .Connect(_configuration["AppConfig"]).ConfigureRefresh(
                            refresh => refresh.Register(key: "Api:Sentinel", refreshAll: true).SetCacheExpiration(TimeSpan.FromDays(1))

                            ).Select(KeyFilter.Any, "ClientA");

                        _refresher = options.GetRefresher();
                    }
                );
            }).UseStartup<Startup>());
    }

启动.cs

   public class Startup
    {
        public Startup(IConfiguration configuration, IConfigurationRefresher configurationRefresher)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<TFASettings>(Configuration.GetSection("Api:TFA"));
            services.AddControllers();
            services.AddAzureAppConfiguration();
            services.AddSingleton<IServiceBusConsumer, ServiceBusConsumer>();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            var bus = app.ApplicationServices.GetRequiredService<IServiceBusConsumer>();
            bus.RegisterRefreshEventHandler();

            app.UseAzureAppConfiguration();

            app.UseHttpsRedirection();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }

ServiceBusConsumer.cs

    public class ServiceBusConsumer : IServiceBusConsumer
    {

        public IConfigurationRefresher configurationRefresher;

        public ServiceBusConsumer()
        {

        }

        public void RegisterRefreshEventHandler()
        {
            SubscriptionClient serviceBusClient = new SubscriptionClient("*****", "*****", "*****");

            serviceBusClient.RegisterMessageHandler(
                handler: (message, cancellationToken) =>
                {
                    // Build EventGridEvent from notification message
                    EventGridEvent eventGridEvent = EventGridEvent.Parse(BinaryData.FromBytes(message.Body));

                    // Create PushNotification from eventGridEvent
                    eventGridEvent.TryCreatePushNotification(out PushNotification pushNotification);

                    //// Prompt Configuration Refresh based on the PushNotification
                    //configurationRefresher.ProcessPushNotification(pushNotification);

                    return Task.CompletedTask;
                },
                exceptionReceivedHandler: (exceptionargs) =>
                {
                    Console.WriteLine($"{exceptionargs.Exception}");
                    return Task.CompletedTask;
                });
        }
    }

示例 Controller

    [ApiController]
    [Route("[controller]")]
    public class WeatherForecastController : ControllerBase
    {
        private readonly TFASettings _tfaSettings;

        public WeatherForecastController(IOptionsSnapshot<TFASettings> tfaSettings)
        {
            _tfaSettings = tfaSettings.Value;
        }

        [HttpGet]
        public WeatherForecast Get()
        {

            return new WeatherForecast
            {
                AuthenticationText = _tfaSettings.AuthenticationWording
            };
        }
    }

Answer 1

您可以通过依赖注入(inject)获取IConfigurationRefresher的具体实例。您甚至可以从构造函数中调用 RegisterRefreshEventHandler()。您的 ServiceBusConsumer.cs 可能如下所示。

private IConfigurationRefresher _configurationRefresher;

public ServiceBusConsumer(IConfigurationRefresherProvider refresherProvider)
{
    _configurationRefresher = refresherProvider.Refreshers.FirstOrDefault();
    RegisterRefreshEventHandler();
}