feat(dashboard): AlarmsPage reads provider status from IGatewayAlarmService in-process

src/ZB.MOM.WW.MxGateway.Server/Dashboard/Components/Pages/AlarmsPage.razor

@@ -1,10 +1,9 @@
 @page "/alarms"
 @implements IAsyncDisposable
-@using Microsoft.AspNetCore.SignalR.Client
-@using ZB.MOM.WW.MxGateway.Server.Dashboard.Hubs
+@using ZB.MOM.WW.MxGateway.Server.Alarms
 @inject IDashboardLiveDataService LiveData
 @inject IOptions<GatewayOptions> GatewayOptions
-@inject DashboardHubConnectionFactory HubFactory
+@inject IGatewayAlarmService AlarmService
 
 <PageTitle>Dashboard Alarms</PageTitle>
 
@@ -173,13 +172,13 @@
     private Task? _pollTask;
 
     private DashboardAlarmProviderStatus _providerStatus = DashboardAlarmProviderStatus.Healthy;
-    private HubConnection? _alarmsHub;
+    private Task? _providerStatusTask;
 
     /// <inheritdoc />
     protected override void OnInitialized()
     {
         _pollTask = PollLoopAsync();
-        _ = AttachAlarmsHubAsync();
+        _providerStatusTask = ProviderStatusLoopAsync();
     }
 
     private string? ProviderStatusTitle()
@@ -189,26 +188,48 @@
             : null;
     }
 
-    private async Task AttachAlarmsHubAsync()
+    // The badge tracks the central monitor directly rather than looping back through
+    // /hubs/alarms: the alarm service is an in-process multi-subscriber fan-out, so a
+    // server-rendered page needs no SignalR client, no loopback socket and no auth token.
+    // Alarm rows still come from the 3-second poll below — this loop only feeds the badge.
+    private async Task ProviderStatusLoopAsync()
     {
-        _alarmsHub = HubFactory.Create("/hubs/alarms");
-        _alarmsHub.On<AlarmFeedMessage>(AlarmsHub.AlarmMessage, async message =>
+        while (!_cts.IsCancellationRequested)
         {
-            if (message.PayloadCase == AlarmFeedMessage.PayloadOneofCase.ProviderStatus)
+            try
             {
+                await foreach (AlarmFeedMessage message in AlarmService
+                    .StreamAsync(alarmFilterPrefix: null, _cts.Token)
+                    .ConfigureAwait(false))
+                {
+                    if (message.PayloadCase != AlarmFeedMessage.PayloadOneofCase.ProviderStatus)
+                    {
+                        continue;
+                    }
+
                     _providerStatus = DashboardAlarmProviderStatus.FromFeed(message);
                     await InvokeAsync(StateHasChanged).ConfigureAwait(false);
                 }
-        });
-
-        try
+            }
+            catch (OperationCanceledException)
             {
-            await _alarmsHub.StartAsync(_cts.Token).ConfigureAwait(false);
+                return;
             }
             catch
             {
-            // The badge is best-effort; it stays at the healthy default until
-            // the hub reconnects and delivers a fresh provider-status message.
+                // The monitor completes a subscriber's stream when it falls behind, and
+                // again when the monitor restarts. Both are recoverable by resubscribing;
+                // the badge holds its last value in the meantime.
+            }
+
+            try
+            {
+                await Task.Delay(TimeSpan.FromSeconds(1), _cts.Token).ConfigureAwait(false);
+            }
+            catch (OperationCanceledException)
+            {
+                return;
+            }
         }
     }
 
@@ -312,18 +333,6 @@
     {
         await _cts.CancelAsync();
 
-        if (_alarmsHub is not null)
-        {
-            try
-            {
-                await _alarmsHub.DisposeAsync();
-            }
-            catch
-            {
-                // Disposal-time errors are best-effort.
-            }
-        }
-
         if (_pollTask is not null)
         {
             try
@@ -335,6 +344,17 @@
             }
         }
 
+        if (_providerStatusTask is not null)
+        {
+            try
+            {
+                await _providerStatusTask;
+            }
+            catch (OperationCanceledException)
+            {
+            }
+        }
+
         _cts.Dispose();
         GC.SuppressFinalize(this);
     }