server/generator/BackgroundService.cs

@@ -0,0 +1,69 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Hosting;
+
+
+
+namespace Sockeye.Generator
+{
+
+
+
+    // Copyright (c) .NET Foundation. Licensed under the Apache License, Version 2.0. 
+    /// <summary>
+    /// Base class for implementing a long running <see cref="IHostedService"/>.
+    /// </summary>
+    public abstract class BackgroundService : IHostedService, IDisposable
+    {
+        private Task _executingTask;
+        private readonly CancellationTokenSource _stoppingCts =
+                                                       new CancellationTokenSource();
+
+        protected abstract Task ExecuteAsync(CancellationToken stoppingToken);
+
+        public virtual Task StartAsync(CancellationToken cancellationToken)
+        {
+            // Store the task we're executing
+            _executingTask = ExecuteAsync(_stoppingCts.Token);
+
+            // If the task is completed then return it, 
+            // this will bubble cancellation and failure to the caller
+            if (_executingTask.IsCompleted)
+            {
+                return _executingTask;
+            }
+
+            // Otherwise it's running
+            return Task.CompletedTask;
+        }
+
+        public virtual async Task StopAsync(CancellationToken cancellationToken)
+        {
+            // Stop called without start
+            if (_executingTask == null)
+            {
+                return;
+            }
+
+            try
+            {
+                // Signal cancellation to the executing method
+                _stoppingCts.Cancel();
+            }
+            finally
+            {
+                // Wait until the task completes or the stop token triggers
+                await Task.WhenAny(_executingTask, Task.Delay(Timeout.Infinite,
+                                                              cancellationToken));
+            }
+
+        }
+
+        public virtual void Dispose()
+        {
+            _stoppingCts.Cancel();
+        }
+    }
+    
+}