.NET Core 3.0 使用 IHostApplicationLifetime 處理應用啟動和停止事件

IHostedService

該接口中有兩個方法：

StartAsync：當應用程序主機准備啟動服務時觸發

StopAsync：當應用程序主機准備停止服務時觸發

//
// 摘要:
//     /// Defines methods for objects that are managed by the host. ///
public interface IHostedService
{
    //
    // 摘要:
    //     /// Triggered when the application host is ready to start the service. ///
    //
    // 參數:
    //   cancellationToken:
    //     Indicates that the start process has been aborted.
    Task StartAsync(CancellationToken cancellationToken);

    //
    // 摘要:
    //     /// Triggered when the application host is performing a graceful shutdown. ///
    //
    // 參數:
    //   cancellationToken:
    //     Indicates that the shutdown process should no longer be graceful.
    Task StopAsync(CancellationToken cancellationToken);
}

IHostApplicationLifetime

該接口中包含三個屬性：Host程序的啟動、正在停止、已停止，一個方法StopApplication，該方法用於主動停止程序。

//
// 摘要:
//     /// Allows consumers to be notified of application lifetime events. ///
public interface IHostApplicationLifetime
{
    //
    // 摘要:
    //     /// Triggered when the application host has fully started. ///
    CancellationToken ApplicationStarted
    {
        get;
    }

    //
    // 摘要:
    //     /// Triggered when the application host is performing a graceful shutdown. ///
    //     Shutdown will block until this event completes. ///
    CancellationToken ApplicationStopped
    {
        get;
    }

    //
    // 摘要:
    //     /// Triggered when the application host is performing a graceful shutdown. ///
    //     Shutdown will block until this event completes. ///
    CancellationToken ApplicationStopping
    {
        get;
    }

    //
    // 摘要:
    //     /// Requests termination of the current application. ///
    void StopApplication();
}

這里實現IHostedService接口，然后使用IHostApplicationLifetime（該接口由框架自動實現注入），在IHostedService的StartAsync方法中注冊IHostApplicationLifetime中的三個程序運行事件，可以做一些自定義的操作，我這里只是記錄了日志。

internal class LifetimeEventsHostedService : IHostedService
{
    private readonly string appCode = ConfigurationManager.GetAppSetting("AppCode");
    private readonly string appName = ConfigurationManager.GetAppSetting("AppName");
    private readonly IHostApplicationLifetime _appLifetime;

    public LifetimeEventsHostedService(IHostApplicationLifetime appLifetime)
    {
        _appLifetime = appLifetime;
    }

    public Task StartAsync(CancellationToken cancellationToken)
    {
        _appLifetime.ApplicationStarted.Register(OnStarted);
        _appLifetime.ApplicationStopping.Register(OnStopping);
        _appLifetime.ApplicationStopped.Register(OnStopped);

        return Task.CompletedTask;
    }

    public Task StopAsync(CancellationToken cancellationToken)
    {
        return Task.CompletedTask;
    }

    private void OnStarted()
    {
        var interNetworkV6 = System.Net.Sockets.AddressFamily.InterNetworkV6;
        var interNetwork = System.Net.Sockets.AddressFamily.InterNetwork;
        var ipList = System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces()
          .Select(p => p.GetIPProperties())
          .SelectMany(p => p.UnicastAddresses)
          .Where(p => (p.Address.AddressFamily == interNetwork || p.Address.AddressFamily == interNetworkV6) && !System.Net.IPAddress.IsLoopback(p.Address)).ToList();

        Console.WriteLine($"OnStarted has been called：【{appCode}】【{appName}】【{DateTime.Now}】 【{ipList[1].Address}】 【{ipList[0].Address}】");
        Logger.Info($"OnStarted has been called：【{appCode}】【{appName}】【{DateTime.Now}】 【{ipList[1].Address}】 【{ipList[0].Address}】");
    }

    private void OnStopping()
    {
        Console.WriteLine($"OnStopping has been called：【{appCode}】【{appName}】【{DateTime.Now}】");
        Logger.Info($"OnStopping has been called：【{appCode}】【{appName}】【{DateTime.Now}】");
    }

    private void OnStopped()
    {
        Console.WriteLine($"OnStopped has been called：【{appCode}】【{appName}】【{DateTime.Now}】");
        Logger.Info($"OnStopped has been called：【{appCode}】【{appName}】【{DateTime.Now}】");
    }
}

最后在服務中注入

.ConfigureServices(a =>
{
    a.AddSingleton<IHostedService, LifetimeEventsHostedService>();
});

也可以不使用IHostedService進行承載，直接使用IHostApplicationLifetime進行注冊

internal static class RegisterLifetimeEvents
    {
        private static readonly string appCode = ConfigurationManager.GetAppSetting("AppCode");
        private static readonly string appName = ConfigurationManager.GetAppSetting("AppName");
        private static readonly string iPV4Address;
        private static readonly string iPV6Address;

        static RegisterLifetimeEvents()
        {
            var interNetworkV6 = AddressFamily.InterNetworkV6;
            var interNetwork = AddressFamily.InterNetwork;
            var ipList = NetworkInterface.GetAllNetworkInterfaces()
                .Select(p => p.GetIPProperties())
                .SelectMany(p => p.UnicastAddresses)
                .Where(p => (p.Address.AddressFamily == interNetwork || p.Address.AddressFamily == interNetworkV6) && !System.Net.IPAddress.IsLoopback(p.Address)).ToList();

            iPV4Address = ipList[1]?.Address.ToString();
            iPV6Address = ipList[0]?.Address.ToString();
        }

        /// <summary>
        /// 注冊應用程序生命周期事件
        /// </summary>
        public static void RegisterApplicationLifetimeEvents(this IHost host)
        {
            var hostApplicationLifetime = host.Services.GetService<IHostApplicationLifetime>();
            hostApplicationLifetime.ApplicationStarted.Register(OnStarted);
            hostApplicationLifetime.ApplicationStopping.Register(OnStopping);
            hostApplicationLifetime.ApplicationStopped.Register(OnStopped);
        }

        private static void OnStarted()
        {
            Console.WriteLine($"OnStarted has been called：{appCode} {appName} {DateTime.Now} {iPV4Address} {iPV6Address}");
            Logger.Info($"OnStarted has been called：{appCode} {appName} {DateTime.Now} {iPV4Address} {iPV6Address}");
        }

        private static void OnStopping()
        {
            Console.WriteLine($"OnStopping has been called：{appCode} {appName} {DateTime.Now} {iPV4Address} {iPV6Address}");
            Logger.Info($"OnStopping has been called：{appCode} {appName} {DateTime.Now} {iPV4Address} {iPV6Address}");
        }

        private static void OnStopped()
        {
            Console.WriteLine($"OnStopped has been called：{appCode} {appName} {DateTime.Now} {iPV4Address} {iPV6Address}");
            Logger.Info($"OnStopped has been called：{appCode} {appName} {DateTime.Now} {iPV4Address} {iPV6Address}");
        }
    }

在Main函數中注冊一下即可

public static void Main(string[] args)
{
    var host = CreateHostBuilder(args).Build();
    host.RegisterApplicationLifetimeEvents();
    host.Run();
}