MqttHostedServer based on BackgroundService

Author: beppemarazzi

Source/MQTTnet.AspnetCore/MqttHostedServer.cs

@@ -7,61 +7,33 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Hosting;
-using Microsoft.Extensions.Logging;
-using Microsoft.Extensions.Logging.Abstractions;
 using MQTTnet.Diagnostics.Logger;
 using MQTTnet.Server;
 
 namespace MQTTnet.AspNetCore;
 
-public sealed class MqttHostedServer : MqttServer, IHostedService
+public sealed class MqttHostedServer : BackgroundService
 {
-    readonly IHostApplicationLifetime _hostApplicationLifetime;
     readonly MqttServerFactory _mqttFactory;
-    readonly ILogger _appLogger;
-
     public MqttHostedServer(
-        IHostApplicationLifetime hostApplicationLifetime,
         MqttServerFactory mqttFactory,
         MqttServerOptions options,
         IEnumerable<IMqttServerAdapter> adapters,
-        IMqttNetLogger logger,
-        ILogger<MqttHostedServer> appLogger = null
-        ) : base(options, adapters, logger)
+        IMqttNetLogger logger
+        )
     {
+        MqttServer = new(options, adapters, logger);
         _mqttFactory = mqttFactory ?? throw new ArgumentNullException(nameof(mqttFactory));
-        _hostApplicationLifetime = hostApplicationLifetime;
-        _appLogger = appLogger ?? NullLogger<MqttHostedServer>.Instance;
-    }
-
-    public async Task StartAsync(CancellationToken cancellationToken)
-    {
-        // The yield makes sure that the hosted service is considered up and running.
-        await Task.Yield();
-
-        _hostApplicationLifetime.ApplicationStarted.Register(OnStarted);
     }
 
-    public Task StopAsync(CancellationToken cancellationToken)
+    public MqttServer MqttServer { get; }
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
-        return StopAsync(_mqttFactory.CreateMqttServerStopOptionsBuilder().Build());
+        await MqttServer.StartAsync();
     }
-
-    void OnStarted()
+    public override async Task StopAsync(CancellationToken cancellationToken)
     {
-        async Task DoStart()
-        {
-            try
-            {
-                await StartAsync();
-            }
-            catch (Exception e)
-            {
-                _appLogger.LogError(e, "Stopping application: failed to start MqttServer: {Error}", e.Message);
-                _hostApplicationLifetime.StopApplication();
-                throw;
-            }
-        }
-        _ = DoStart();
+        await MqttServer.StopAsync(_mqttFactory.CreateMqttServerStopOptionsBuilder().Build());
+        await base.StopAsync(cancellationToken);
     }
-}
+}

Source/MQTTnet.AspnetCore/ServiceCollectionExtensions.cs

@@ -45,8 +45,8 @@ public static void AddHostedMqttServer(this IServiceCollection services)
         services.TryAddSingleton(new MqttServerFactory());
 
         services.AddSingleton<MqttHostedServer>();
-        services.AddSingleton<IHostedService>(s => s.GetService<MqttHostedServer>());
-        services.AddSingleton<MqttServer>(s => s.GetService<MqttHostedServer>());
+        services.AddHostedService(s => s.GetService<MqttHostedServer>());
+        services.AddSingleton<MqttServer>(s => s.GetService<MqttHostedServer>().MqttServer);
     }
 
     public static IServiceCollection AddHostedMqttServerWithServices(this IServiceCollection services, Action<AspNetMqttServerOptionsBuilder> configure)