Merge remote-tracking branch 'holahmeds/item-count-metric'

Emby.Server.Implementations/ApplicationHost.cs

@@ -31,6 +31,7 @@ using Emby.Server.Implementations.IO;
 using Emby.Server.Implementations.Library;
 using Emby.Server.Implementations.LiveTv;
 using Emby.Server.Implementations.Localization;
+using Emby.Server.Implementations.Metrics;
 using Emby.Server.Implementations.Net;
 using Emby.Server.Implementations.Playlists;
 using Emby.Server.Implementations.Plugins;
@@ -67,6 +68,7 @@ using MediaBrowser.Controller.Library;
 using MediaBrowser.Controller.LiveTv;
 using MediaBrowser.Controller.Lyrics;
 using MediaBrowser.Controller.MediaEncoding;
+using MediaBrowser.Controller.Metrics;
 using MediaBrowser.Controller.Net;
 using MediaBrowser.Controller.Persistence;
 using MediaBrowser.Controller.Playlists;
@@ -464,13 +466,7 @@ namespace Emby.Server.Implementations
 
             ConfigurationManager.AddParts(GetExports<IConfigurationFactory>());
 
-            NetManager = new NetworkManager(ConfigurationManager, LoggerFactory.CreateLogger<NetworkManager>());
-
-            // Initialize runtime stat collection
-            if (ConfigurationManager.Configuration.EnableMetrics)
-            {
-                DotNetRuntimeStatsBuilder.Default().StartCollecting();
-            }
+            NetManager = new NetworkManager(ConfigurationManager, LoggerFactory.CreateLogger<NetworkManager>()); 
 
             var networkConfiguration = ConfigurationManager.GetNetworkConfiguration();
             HttpPort = networkConfiguration.HttpServerPortNumber;
@@ -633,6 +629,12 @@ namespace Emby.Server.Implementations
             var userDataRepo = (SqliteUserDataRepository)Resolve<IUserDataRepository>();
             ((SqliteItemRepository)Resolve<IItemRepository>()).Initialize(userDataRepo, Resolve<IUserManager>());
 
+            // Initialize runtime stat collection
+            if (ConfigurationManager.Configuration.EnableMetrics)
+            {
+                Resolve<IMetricsCollector>().Initialize();
+            }
+
             FindParts();
         }
 

Emby.Server.Implementations/Metrics/PrometheusMetricsCollector.cs

@@ -0,0 +1,75 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using MediaBrowser.Controller.Entities;
+using MediaBrowser.Controller.Entities.Audio;
+using MediaBrowser.Controller.Entities.Movies;
+using MediaBrowser.Controller.Entities.TV;
+using MediaBrowser.Controller.Library;
+using MediaBrowser.Controller.Metrics;
+using Prometheus;
+using Prometheus.DotNetRuntime;
+
+namespace Emby.Server.Implementations.Metrics
+{
+    /// <summary>
+    /// Prometheus backend for metrics.
+    /// </summary>
+    public class PrometheusMetricsCollector : IMetricsCollector
+    {
+        private readonly ILibraryManager _libraryManager;
+
+        private static readonly Gauge _itemCountGauge = Prometheus.Metrics.CreateGauge("jellyfin_library_items_total", "The number of items in the library", new[] { "item_type" });
+        private static readonly string[] _metricTypes = new string[]
+        {
+            nameof(Movie),
+            nameof(Series), nameof(Season), nameof(Episode),
+            nameof(MusicArtist), nameof(MusicAlbum), nameof(MusicVideo), nameof(Audio),
+            nameof(Book),
+            nameof(PhotoAlbum), nameof(Photo)
+        };
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PrometheusMetricsCollector" /> class.
+        /// </summary>
+        /// <param name="libraryManager">The library manager</param>
+        public PrometheusMetricsCollector(ILibraryManager libraryManager)
+        {
+            _libraryManager = libraryManager;
+            _libraryManager.ItemAdded += IncrementItemCount;
+            _libraryManager.ItemRemoved += (s, e) => UpdateItemCount();
+        }
+
+        /// <inheritdoc />
+        public void Initialize()
+        {
+            DotNetRuntimeStatsBuilder.Default().StartCollecting();
+            UpdateItemCount();
+        }
+
+        private void UpdateItemCount()
+        {
+            foreach (var type in _metricTypes)
+            {
+                var query = new InternalItemsQuery
+                {
+                    IncludeItemTypes = new[] { type }
+                };
+                int count = _libraryManager.GetCount(query);
+                _itemCountGauge.WithLabels(type).Set(count);
+            }
+        }
+
+        private void IncrementItemCount(object? sender, ItemChangeEventArgs e)
+        {
+            var item = e.Item;
+            var typeName = item.GetType().Name;
+            if (_metricTypes.Contains(typeName))
+            {
+                _itemCountGauge.WithLabels(typeName).Inc();
+            }
+        }
+    }
+}

MediaBrowser.Controller/Metrics/IMetricsCollector.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace MediaBrowser.Controller.Metrics
+{
+    /// <summary>
+    /// Interface for metric backends.
+    /// </summary>
+    public interface IMetricsCollector
+    {
+        /// <summary>
+        /// Initializes metrics.
+        /// </summary>
+        public void Initialize();
+    }
+}