feat: metrics test.

Game/Game/GameServiceSource.cs

@@ -1,10 +1,12 @@
 using Godot;
 using GodotHostTest.AetherBind;
 using GodotHostTest.Game.Level;
+using GodotHostTest.Game.Metrics;
 using GodotHostTest.Game.Score;
 using GodotHostTest.Game.Target;
 using GodotHostTest.Interfaces;
 using Microsoft.Extensions.DependencyInjection;
+using OwofGames.GodotHost;
 using OwofGames.GodotHost.Observability;
 using OwofGames.GodotLume;
 
@@ -23,12 +25,16 @@ public partial class GameServiceSource : RootServiceSource
             // current level / level data management
             .AddInstance<ILevelDataProvider, LevelsData>(_levelsData)
             .AddSingleton<ICurrentLevel, CurrentLevel>()
+            // metrics
+            .AddSingleton<IHostLifetime, MetricsHandler>()
             // level scope services
             .AddLevelServices();
     }
 
     protected override void ConfigureServices(IServiceCollection serviceCollection)
     {
-        serviceCollection.AddObservability(builder => builder.AddGrpcExporter("http://localhost:4317"));
+        serviceCollection.AddObservability(builder => builder
+            .AddGrpcExporter("http://localhost:4317")
+            .AddMeterName(MetricsHandler.MeterName));
     }
 }

Game/Metrics/MetricsHandler.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Diagnostics.Metrics;
+using System.Reflection;
+using GodotHostTest.Interfaces;
+using OwofGames.GodotHost;
+using R3;
+
+namespace GodotHostTest.Game.Metrics;
+
+public class MetricsHandler(IMeterFactory meterFactory, ITargetEventBus targetEventBus) : IHostLifetime
+{
+    public static readonly string MeterName;
+    private static readonly string? MeterVersion;
+    private IDisposable? _disposables;
+
+    static MetricsHandler()
+    {
+        var assemblyName = Assembly.GetExecutingAssembly().GetName();
+        MeterName = assemblyName.Name!;
+        MeterVersion = assemblyName.Version?.ToString();
+    }
+
+    public void Startup()
+    {
+        // create meter
+        var assemblyName = Assembly.GetExecutingAssembly().GetName();
+        var meterName = assemblyName.Name!;
+        var meterVersion = assemblyName.Version?.ToString();
+        var meter = meterFactory.Create(meterName, meterVersion);
+
+        // create instruments
+        var hitTargetsCounter =
+            meter.CreateCounter<int>("targets.hit", description: "number of targets hit");
+        var missedTargetsCounter =
+            meter.CreateCounter<int>("targets.missed", description: "number of targets missed");
+
+        // feed instruments data, and contextually create the disposable to clean up at shutdown time
+        _disposables = Disposable.Combine(
+            targetEventBus.Hit.Subscribe(_ => hitTargetsCounter.Add(1)),
+            targetEventBus.TimedOut.Subscribe(_ => missedTargetsCounter.Add(1)),
+            meter
+        );
+    }
+
+    public void Shutdown()
+    {
+        _disposables?.Dispose();
+        meterFactory.Create("godot-host-test")?.Dispose();
+    }
+}

Game/Metrics/MetricsHandler.cs.uid

@@ -0,0 +1 @@
+uid://5ramu7es1104

godot-host-test.csproj

@@ -17,6 +17,9 @@
         <Reference Include="OwofGames.GodotHost">
             <HintPath>..\OwofGames.Godot\OwofGames.GodotHost\bin\Debug\net8.0\OwofGames.GodotHost.dll</HintPath>
         </Reference>
+        <Reference Include="OwofGames.GodotHost.Abstractions">
+            <HintPath>..\OwofGames.Godot\OwofGames.GodotHost.Abstractions\bin\Debug\net8.0\OwofGames.GodotHost.Abstractions.dll</HintPath>
+        </Reference>
         <Reference Include="OwofGames.GodotHost.Observability">
             <HintPath>..\OwofGames.Godot\OwofGames.GodotHost.Observability\bin\Debug\net8.0\OwofGames.GodotHost.Observability.dll</HintPath>
         </Reference>

godot-host-test.sln.DotSettings.user

@@ -2,6 +2,7 @@
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 	<s:Boolean x:Key="/Default/AddReferences/RecentPaths/=_002Fhome_002Fredglow_002Fsources_002FOwofGames_002EGodot_002FOwofGames_002EAetherBind_002ESourceGenerators_002Fbin_002FDebug_002Fnetstandard2_002E0_002FOwofGames_002EAetherBind_002ESourceGenerators_002Edll/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/AddReferences/RecentPaths/=_002Fhome_002Fredglow_002Fsources_002FOwofGames_002EGodot_002FOwofGames_002EAetherBind_002Fbin_002FDebug_002Fnet8_002E0_002FOwofGames_002EAetherBind_002Edll/@EntryIndexedValue">True</s:Boolean>
+	<s:Boolean x:Key="/Default/AddReferences/RecentPaths/=_002Fhome_002Fredglow_002Fsources_002FOwofGames_002EGodot_002FOwofGames_002EGodotHost_002EAbstractions_002Fbin_002FDebug_002Fnet8_002E0_002FOwofGames_002EGodotHost_002EAbstractions_002Edll/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/AddReferences/RecentPaths/=_002Fhome_002Fredglow_002Fsources_002FOwofGames_002EGodot_002FOwofGames_002EGodotHost_002EObservability_002Fbin_002FDebug_002Fnet8_002E0_002FOwofGames_002EGodotHost_002EObservability_002Edll/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/AddReferences/RecentPaths/=_002Fhome_002Fredglow_002Fsources_002FOwofGames_002EGodot_002FOwofGames_002EGodotHost_002Fbin_002FDebug_002Fnet8_002E0_002FOwofGames_002EGodotHost_002Edll/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/AddReferences/RecentPaths/=_002Fhome_002Fredglow_002Fsources_002FOwofGames_002EGodot_002FOwofGames_002EGodotHost_002Fbin_002FDebug_002Fnet8_002E0_002FOwofGames_002EGodotLogger_002Edll/@EntryIndexedValue">True</s:Boolean>
@@ -20,6 +21,7 @@
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 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003ALoggerInformation_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2026_002E2_003Fresharper_002Dhost_003FSourcesCache_003F58a2e8187d354ab2e42d1cca1ce63b1edb0381e3ac126b055eb2481382014_003FLoggerInformation_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003ALogger_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2026_002E2_003Fresharper_002Dhost_003FSourcesCache_003F342e7081b95d68bdbbd320f210c35f9376e2b2b914a05d1cfef054c46bee58_003FLogger_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
+	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003AMeter_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2026_002E2_003Fresharper_002Dhost_003FDecompilerCache_003Fdecompiler_003Ffe1d9b60c4be4b2dad7000c1d31f96862ef10_003F62_003F109f0e8c_003FMeter_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003AMethodBaseInvoker_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2026_002E2_003Fresharper_002Dhost_003FDecompilerCache_003Fdecompiler_003F6cc9b871557b441baa469ce23b255f41dbb200_003F7b_003Fb6307b47_003FMethodBaseInvoker_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003ANode_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2026_002E2_003Fresharper_002Dhost_003FSourcesCache_003Fcd2081581a57397285b1beba7fc14bdbc61c89e3ac09a962676d880d9dd3c_003FNode_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=7020124F_002D9FFC_002D4AC3_002D8F3D_002DAAB8E0240759_002Ff_003AOtlpHttpExportClient_002Ecs_002Fl_003A_002E_002E_003F_002E_002E_003F_002Econfig_003FJetBrains_003FRider2026_002E2_003Fresharper_002Dhost_003FSourcesCache_003F4033dea463e391648d47bc0d947734cc9785594d32f2e63e7fdaa66dc6f69_003FOtlpHttpExportClient_002Ecs/@EntryIndexedValue">ForceIncluded</s:String>
@@ -32,7 +34,7 @@
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 	<s:String x:Key="/Default/Environment/AssemblyExplorer/XmlDocument/@EntryValue">&lt;AssemblyExplorer&gt;
-  &lt;Assembly Path="/home/redglow/sources/OwofGames.Godot/OwofGames.AetherBind.Observability/bin/Debug/net8.0/OwofGames.AetherBind.Observability.dll" /&gt;
+  &lt;Assembly Path="/home/redglow/sources/OwofGames.Godot/OwofGames.GodotHost/bin/Debug/net8.0/OwofGames.GodotHost.dll" /&gt;
 &lt;/AssemblyExplorer&gt;</s:String>
 	<s:String x:Key="/Default/Environment/Hierarchy/Build/BuildTool/DotNetCliExePath/@EntryValue">/usr/lib/dotnet/dotnet</s:String>
 	<s:String x:Key="/Default/Environment/Hierarchy/Build/BuildTool/CustomBuildToolPath/@EntryValue">/usr/lib/dotnet/sdk/10.0.109/MSBuild.dll</s:String>