Enhance HostApplicationLifetime and add logging

- Added `using` directive for `TelegramBot.Services` in `BotApp.cs`.
- Retrieve `HostApplicationLifetime` using `GetRequiredService<HostApplicationLifetime>()`.
- Added logging for hosted services start and stop events.
- `ApplicationStopping` event now triggers logging and cancels `_cancellationTokenSource`.
- Added `NotifyStarted`, `NotifyStopping`, and `NotifyStopped` methods to manage lifecycle events.
- Implemented `IDisposable` in `HostApplicationLifetime` to manage three `CancellationTokenSource` instances.
- `StopApplication` method now cancels all three `CancellationTokenSource` instances.
- `Dispose` method now disposes of the three `CancellationTokenSource` instances.

Author: bvdcode

Sources/TelegramBot/BotApp.cs

@@ -15,6 +15,7 @@
 using Microsoft.Extensions.Hosting;
 using Newtonsoft.Json.Linq;
 using TelegramBot.Attributes;
+using TelegramBot.Services;
 
 namespace TelegramBot
 {
@@ -117,10 +118,23 @@ public async Task StartAsync(CancellationToken cancellationToken = default)
                 throw ex;
             }
             var hostedServices = _serviceProvider.GetServices<IHostedService>();
+            var hostApplicationLifetime = _serviceProvider.GetRequiredService<HostApplicationLifetime>();
             foreach (var hostedService in hostedServices)
             {
                 await hostedService.StartAsync(mergedToken);
+                _logger.LogInformation("Started '{hostedService}'.", hostedService.GetType().Name);
+                hostApplicationLifetime.ApplicationStopping.Register(() =>
+                {
+                    _logger.LogInformation("Stopping '{hostedService}'...", hostedService.GetType().Name);
+                    hostedService.StopAsync(mergedToken).Wait();
+                });
             }
+            hostApplicationLifetime.ApplicationStopping.Register(() =>
+            {
+                _logger.LogInformation("Application stopping event received.");
+                _cancellationTokenSource.Cancel();
+            });
+            hostApplicationLifetime.NotifyStarted();
         }
 
         private void OnProcessExit(object sender, EventArgs e)
@@ -138,8 +152,8 @@ public async Task StopAsync(CancellationToken cancellationToken = default)
         {
             CheckDisposed();
             _logger.LogInformation("Stopping hosted services...");
-            var hostApplicationLifetime = _serviceProvider.GetRequiredService<IHostApplicationLifetime>();
-            hostApplicationLifetime.StopApplication();
+            var hostApplicationLifetime = _serviceProvider.GetRequiredService<HostApplicationLifetime>();
+            hostApplicationLifetime.NotifyStopping();
             var hostedServices = _serviceProvider.GetServices<IHostedService>();
             List<Task> tasks = new List<Task>();
             foreach (var hostedService in hostedServices)
@@ -158,6 +172,8 @@ public async Task StopAsync(CancellationToken cancellationToken = default)
             _logger.LogInformation("Stopping bot updates...");
             _cancellationTokenSource.Cancel();
             await Task.WhenAll(tasks);
+            hostApplicationLifetime.NotifyStopped();
+            hostApplicationLifetime.StopApplication();
         }
 
         /// <summary>

Sources/TelegramBot/Services/HostApplicationLifetime.cs

@@ -1,26 +1,48 @@
-using System.Threading;
+using System;
+using System.Threading;
 using Microsoft.Extensions.Hosting;
 
 namespace TelegramBot.Services
 {
-    internal class HostApplicationLifetime : IHostApplicationLifetime
+    internal class HostApplicationLifetime : IHostApplicationLifetime, IDisposable
     {
-        private readonly CancellationTokenSource _cancellationTokenSource;
+        private readonly CancellationTokenSource stopTokenSource = new CancellationTokenSource();
+        private readonly CancellationTokenSource stoppingTokenSource = new CancellationTokenSource();
+        private readonly CancellationTokenSource startTokenSource = new CancellationTokenSource();
 
-        public HostApplicationLifetime(CancellationTokenSource cancellationTokenSource)
+        public CancellationToken ApplicationStarted => startTokenSource.Token;
+
+        public CancellationToken ApplicationStopping => stoppingTokenSource.Token;
+
+        public CancellationToken ApplicationStopped => stopTokenSource.Token;
+
+        public void StopApplication()
         {
-            _cancellationTokenSource = cancellationTokenSource ?? throw new System.ArgumentNullException(nameof(cancellationTokenSource));
+            stopTokenSource.Cancel();
+            stoppingTokenSource.Cancel();
+            startTokenSource.Cancel();
         }
 
-        public CancellationToken ApplicationStarted => _cancellationTokenSource.Token;
+        public void NotifyStarted()
+        {
+            startTokenSource.Cancel();
+        }
 
-        public CancellationToken ApplicationStopping => _cancellationTokenSource.Token;
+        public void NotifyStopped()
+        {
+            stopTokenSource.Cancel();
+        }
 
-        public CancellationToken ApplicationStopped => _cancellationTokenSource.Token;
+        public void NotifyStopping()
+        {
+            stoppingTokenSource.Cancel();
+        }
 
-        public void StopApplication()
+        public void Dispose()
         {
-            _cancellationTokenSource.Cancel();
+            stopTokenSource.Dispose();
+            stoppingTokenSource.Dispose();
+            startTokenSource.Dispose();
         }
     }
 }