Cara menulis daemon linux dengan .Net Core

Yang terbaik yang bisa saya dapatkan didasarkan pada jawaban atas dua pertanyaan lain:Membunuh dengan anggun daemon .NET Core yang berjalan di Linux dan Apakah mungkin menunggu acara alih-alih metode async lainnya?

using System;
using System.Runtime.Loader;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    public class Program
    {
        private static TaskCompletionSource<object> taskToWait;

        public static void Main(string[] args)
        {
            taskToWait = new TaskCompletionSource<object>();

            AssemblyLoadContext.Default.Unloading += SigTermEventHandler;
            Console.CancelKeyPress += new ConsoleCancelEventHandler(CancelHandler);

            //eventSource.Subscribe(eventSink) or something...

            taskToWait.Task.Wait();

            AssemblyLoadContext.Default.Unloading -= SigTermEventHandler;
            Console.CancelKeyPress -= new ConsoleCancelEventHandler(CancelHandler);

        }


        private static void SigTermEventHandler(AssemblyLoadContext obj)
        {
            System.Console.WriteLine("Unloading...");
            taskToWait.TrySetResult(null);
        }

        private static void CancelHandler(object sender, ConsoleCancelEventArgs e)
        {
            System.Console.WriteLine("Exiting...");
            taskToWait.TrySetResult(null);
        }

    }
}

Saya bermain-main dengan ide yang mirip dengan bagaimana .net core web host menunggu shutdown di aplikasi konsol. Saya sedang meninjaunya di GitHub dan dapat mengekstraksi inti dari bagaimana mereka melakukan Run

https://github.com/aspnet/Hosting/blob/15008b0b7fcb54235a9de3ab844c066aaf42ea44/src/Microsoft.AspNetCore.Hosting/WebHostExtensions.cs#L86

public static class ConsoleHost {
    /// <summary>
    /// Block the calling thread until shutdown is triggered via Ctrl+C or SIGTERM.
    /// </summary>
    public static void WaitForShutdown() {
        WaitForShutdownAsync().GetAwaiter().GetResult();
    }


    /// <summary>
    /// Runs an application and block the calling thread until host shutdown.
    /// </summary>
    /// <param name="host">The <see cref="IWebHost"/> to run.</param>
    public static void Wait() {
        WaitAsync().GetAwaiter().GetResult();
    }

    /// <summary>
    /// Runs an application and returns a Task that only completes when the token is triggered or shutdown is triggered.
    /// </summary>
    /// <param name="host">The <see cref="IConsoleHost"/> to run.</param>
    /// <param name="token">The token to trigger shutdown.</param>
    public static async Task WaitAsync(CancellationToken token = default(CancellationToken)) {
        //Wait for the token shutdown if it can be cancelled
        if (token.CanBeCanceled) {
            await WaitAsync(token, shutdownMessage: null);
            return;
        }
        //If token cannot be cancelled, attach Ctrl+C and SIGTERN shutdown
        var done = new ManualResetEventSlim(false);
        using (var cts = new CancellationTokenSource()) {
            AttachCtrlcSigtermShutdown(cts, done, shutdownMessage: "Application is shutting down...");
            await WaitAsync(cts.Token, "Application running. Press Ctrl+C to shut down.");
            done.Set();
        }
    }

    /// <summary>
    /// Returns a Task that completes when shutdown is triggered via the given token, Ctrl+C or SIGTERM.
    /// </summary>
    /// <param name="token">The token to trigger shutdown.</param>
    public static async Task WaitForShutdownAsync(CancellationToken token = default (CancellationToken)) {
        var done = new ManualResetEventSlim(false);
        using (var cts = CancellationTokenSource.CreateLinkedTokenSource(token)) {
            AttachCtrlcSigtermShutdown(cts, done, shutdownMessage: string.Empty);
            await WaitForTokenShutdownAsync(cts.Token);
            done.Set();
        }
    }

    private static async Task WaitAsync(CancellationToken token, string shutdownMessage) {
        if (!string.IsNullOrEmpty(shutdownMessage)) {
            Console.WriteLine(shutdownMessage);
        }
        await WaitForTokenShutdownAsync(token);
    }


    private static void AttachCtrlcSigtermShutdown(CancellationTokenSource cts, ManualResetEventSlim resetEvent, string shutdownMessage) {
        Action ShutDown = () => {
            if (!cts.IsCancellationRequested) {
                if (!string.IsNullOrWhiteSpace(shutdownMessage)) {
                    Console.WriteLine(shutdownMessage);
                }
                try {
                    cts.Cancel();
                } catch (ObjectDisposedException) { }
            }
            //Wait on the given reset event
            resetEvent.Wait();
        };

        AppDomain.CurrentDomain.ProcessExit += delegate { ShutDown(); };
        Console.CancelKeyPress += (sender, eventArgs) => {
            ShutDown();
            //Don't terminate the process immediately, wait for the Main thread to exit gracefully.
            eventArgs.Cancel = true;
        };
    }

    private static async Task WaitForTokenShutdownAsync(CancellationToken token) {
        var waitForStop = new TaskCompletionSource<object>();
        token.Register(obj => {
            var tcs = (TaskCompletionSource<object>)obj;
            tcs.TrySetResult(null);
        }, waitForStop);
        await waitForStop.Task;
    }
}

Saya mencoba mengadaptasi sesuatu seperti IConsoleHost tetapi dengan cepat menyadari bahwa saya terlalu merekayasanya. Mengekstrak bagian utama menjadi sesuatu seperti await ConsoleUtil.WaitForShutdownAsync(); yang beroperasi seperti Console.ReadLine

Ini kemudian memungkinkan utilitas untuk digunakan seperti ini

public class Program {

    public static async Task Main(string[] args) {
        //relevant code goes here
        //...

        //wait for application shutdown
        await ConsoleUtil.WaitForShutdownAsync();
    }
}

dari sana membuat systemd seperti pada tautan berikut akan membantu Anda

Menulis daemon Linux di C#