signalr heartbeat

src/Notifications/HeartbeatHostedService.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Bit.Core;
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace Bit.Notifications
+{
+    public class HeartbeatHostedService : IHostedService, IDisposable
+    {
+        private readonly ILogger _logger;
+        private readonly IHubContext<NotificationsHub> _hubContext;
+        private readonly GlobalSettings _globalSettings;
+
+        private Task _executingTask;
+        private CancellationTokenSource _cts;
+
+        public HeartbeatHostedService(
+            ILogger<AzureQueueHostedService> logger,
+            IHubContext<NotificationsHub> hubContext,
+            GlobalSettings globalSettings)
+        {
+            _logger = logger;
+            _hubContext = hubContext;
+            _globalSettings = globalSettings;
+        }
+
+        public Task StartAsync(CancellationToken cancellationToken)
+        {
+            _cts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
+            _executingTask = ExecuteAsync(_cts.Token);
+            return _executingTask.IsCompleted ? _executingTask : Task.CompletedTask;
+        }
+
+        public async Task StopAsync(CancellationToken cancellationToken)
+        {
+            if(_executingTask == null)
+            {
+                return;
+            }
+            _logger.LogWarning("Stopping service.");
+            _cts.Cancel();
+            await Task.WhenAny(_executingTask, Task.Delay(-1, cancellationToken));
+            cancellationToken.ThrowIfCancellationRequested();
+        }
+
+        public void Dispose()
+        { }
+
+        private async Task ExecuteAsync(CancellationToken cancellationToken)
+        {
+            while(!cancellationToken.IsCancellationRequested)
+            {
+                await _hubContext.Clients.All.SendAsync("Heartbeat");
+                await Task.Delay(120000);
+            }
+            _logger.LogWarning("Done with heartbeat.");
+        }
+    }
+}

src/Notifications/Startup.cs

@@ -68,6 +68,7 @@ namespace Bit.Notifications
             // Mvc
             services.AddMvc();
 
+            services.AddHostedService<HeartbeatHostedService>();
             if(!globalSettings.SelfHosted)
             {
                 // Hosted Services