add high priority queue

MareSynchronosServer/MareSynchronosStaticFilesServer/Services/RequestQueueService.cs

@@ -5,25 +5,34 @@ using Microsoft.AspNetCore.SignalR;
 using System.Collections.Concurrent;
 using System.Timers;
 using MareSynchronos.API.SignalR;
+using MareSynchronosShared.Data;
+using Microsoft.EntityFrameworkCore;
+using System.Linq;
 
 namespace MareSynchronosStaticFilesServer.Services;
 
 public class RequestQueueService : IHostedService
 {
+    private record PriorityEntry(bool IsHighPriority, DateTime LastChecked);
+
     private readonly IHubContext<MareSynchronosServer.Hubs.MareHub> _hubContext;
+    private readonly MareDbContext _mareDbContext;
     private readonly ILogger<RequestQueueService> _logger;
     private readonly MareMetrics _metrics;
     private readonly ConcurrentQueue<UserRequest> _queue = new();
+    private readonly ConcurrentQueue<UserRequest> _priorityQueue = new();
     private readonly int _queueExpirationSeconds;
     private readonly SemaphoreSlim _queueProcessingSemaphore = new(1);
     private readonly ConcurrentDictionary<Guid, string> _queueRemoval = new();
     private readonly SemaphoreSlim _queueSemaphore = new(1);
     private readonly UserQueueEntry[] _userQueueRequests;
+    private readonly ConcurrentDictionary<string, PriorityEntry> _priorityCache = new(StringComparer.Ordinal);
     private int _queueLimitForReset;
     private readonly int _queueReleaseSeconds;
     private System.Timers.Timer _queueTimer;
 
-    public RequestQueueService(MareMetrics metrics, IConfigurationService<StaticFilesServerConfiguration> configurationService, ILogger<RequestQueueService> logger, IHubContext<MareSynchronosServer.Hubs.MareHub> hubContext)
+    public RequestQueueService(MareMetrics metrics, IConfigurationService<StaticFilesServerConfiguration> configurationService,
+        ILogger<RequestQueueService> logger, IHubContext<MareSynchronosServer.Hubs.MareHub> hubContext, MareDbContext mareDbContext)
     {
         _userQueueRequests = new UserQueueEntry[configurationService.GetValueOrDefault(nameof(StaticFilesServerConfiguration.DownloadQueueSize), 50)];
         _queueExpirationSeconds = configurationService.GetValueOrDefault(nameof(StaticFilesServerConfiguration.DownloadTimeoutSeconds), 5);
@@ -32,6 +41,7 @@ public class RequestQueueService : IHostedService
         _metrics = metrics;
         _logger = logger;
         _hubContext = hubContext;
+        _mareDbContext = mareDbContext;
     }
 
     public void ActivateRequest(Guid request)
@@ -41,20 +51,36 @@ public class RequestQueueService : IHostedService
         req.MarkActive();
     }
 
+    private async Task<bool> IsHighPriority(string uid)
+    {
+        if (!_priorityCache.TryGetValue(uid, out PriorityEntry entry) || entry.LastChecked.Add(TimeSpan.FromHours(6)) < DateTime.UtcNow)
+        {
+            var user = await _mareDbContext.Users.FirstOrDefaultAsync(u => u.UID == uid).ConfigureAwait(false);
+            entry = new(user != null && !string.IsNullOrEmpty(user.Alias), DateTime.UtcNow);
+            _priorityCache[uid] = entry;
+        }
+
+        return entry.IsHighPriority;
+    }
+
     public async Task EnqueueUser(UserRequest request)
     {
         _logger.LogDebug("Enqueueing req {guid} from {user} for {file}", request.RequestId, request.User, string.Join(", ", request.FileIds));
 
+        bool isPriorityQueue = await IsHighPriority(request.User).ConfigureAwait(false);
+
         if (_queueProcessingSemaphore.CurrentCount == 0)
         {
-            _queue.Enqueue(request);
+            if (isPriorityQueue) _priorityQueue.Enqueue(request);
+            else _queue.Enqueue(request);
             return;
         }
 
         try
         {
             await _queueSemaphore.WaitAsync().ConfigureAwait(false);
-            _queue.Enqueue(request);
+            if (isPriorityQueue) _priorityQueue.Enqueue(request);
+            else _queue.Enqueue(request);
 
             return;
         }
@@ -120,8 +146,13 @@ public class RequestQueueService : IHostedService
         return Task.CompletedTask;
     }
 
-    public bool StillEnqueued(Guid request, string user)
+    public async Task<bool> StillEnqueued(Guid request, string user)
     {
+        bool isPriorityQueue = await IsHighPriority(user).ConfigureAwait(false);
+        if (isPriorityQueue)
+        {
+            return _priorityQueue.Any(c => c.RequestId == request && string.Equals(c.User, user, StringComparison.Ordinal));
+        }
         return _queue.Any(c => c.RequestId == request && string.Equals(c.User, user, StringComparison.Ordinal));
     }
 
@@ -179,6 +210,20 @@ public class RequestQueueService : IHostedService
                         bool enqueued = false;
                         while (!enqueued)
                         {
+                            if (_priorityQueue.TryDequeue(out var prioRequest))
+                            {
+                                if (_queueRemoval.TryGetValue(prioRequest.RequestId, out string user) && string.Equals(user, prioRequest.User, StringComparison.Ordinal))
+                                {
+                                    _logger.LogDebug("Request cancelled: {requestId} by {user}", prioRequest.RequestId, user);
+                                    _queueRemoval.Remove(prioRequest.RequestId, out _);
+                                    continue;
+                                }
+
+                                await DequeueIntoSlotAsync(prioRequest, i).ConfigureAwait(false);
+                                enqueued = true;
+                                break;
+                            }
+
                             if (_queue.TryDequeue(out var request))
                             {
                                 if (_queueRemoval.TryGetValue(request.RequestId, out string user) && string.Equals(user, request.User, StringComparison.Ordinal))