feat: rest of impact metrics definitions for dotnet (#76)

sighphyre · daveleek · web-flow · commit 28b7bdbbb202 · 2026-02-16T09:16:03.000+02:00
Co-authored-by: David Leek &lt;david@getunleash.io&gt;
diff --git a/dotnet-engine/Yggdrasil.Engine.Tests/YggdrasilImpactMetricsTest.cs b/dotnet-engine/Yggdrasil.Engine.Tests/YggdrasilImpactMetricsTest.cs
@@ -1,16 +1,9 @@
-using System;
-using System.Text.Json;
+using System.Collections.Generic;
 using NUnit.Framework;
 using Yggdrasil;
-using Yggdrasil.Test;
 
 public class YggdrasilImpactMetricsTest
 {
-    private JsonSerializerOptions options = new JsonSerializerOptions
-    {
-        PropertyNamingPolicy = JsonNamingPolicy.CamelCase
-    };
-
     [Test]
     public void DefineCounter_Throws_Only_When_Invalid()
     {
@@ -20,4 +13,77 @@ public void DefineCounter_Throws_Only_When_Invalid()
         Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.DefineCounter(null!, "Measures time spent on server doing things"));
         Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.DefineCounter(null!, null!));
     }
+
+    [Test]
+    public void IncCounter_Throws_Only_When_Invalid()
+    {
+        var yggdrasilEngine = new YggdrasilEngine();
+        yggdrasilEngine.DefineCounter("requests_total", "Total requests");
+
+        Assert.DoesNotThrow(() => yggdrasilEngine.IncCounter("requests_total"));
+        Assert.DoesNotThrow(() => yggdrasilEngine.IncCounter("requests_total", 5));
+        Assert.DoesNotThrow(() => yggdrasilEngine.IncCounter("requests_total", 3, new Dictionary<string, string> { { "env", "test" } }));
+
+        Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.IncCounter(null!));
+    }
+
+    [Test]
+    public void DefineGauge_Throws_Only_When_Invalid()
+    {
+        var yggdrasilEngine = new YggdrasilEngine();
+        Assert.DoesNotThrow(() => yggdrasilEngine.DefineGauge("cpu_usage", "CPU usage"));
+        Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.DefineGauge("cpu_usage", null!));
+        Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.DefineGauge(null!, "CPU usage"));
+        Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.DefineGauge(null!, null!));
+    }
+
+    [Test]
+    public void SetGauge_Throws_Only_When_Invalid()
+    {
+        var yggdrasilEngine = new YggdrasilEngine();
+        yggdrasilEngine.DefineGauge("queue_depth", "Queue depth");
+
+        Assert.DoesNotThrow(() => yggdrasilEngine.SetGauge("queue_depth", 10.5));
+        Assert.DoesNotThrow(() => yggdrasilEngine.SetGauge("queue_depth", 5.25, new Dictionary<string, string> { { "env", "prod" } }));
+        Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.SetGauge(null!, 1.0));
+    }
+
+    [Test]
+    public void DefineHistogram_Throws_Only_When_Invalid()
+    {
+        var yggdrasilEngine = new YggdrasilEngine();
+        Assert.DoesNotThrow(() => yggdrasilEngine.DefineHistogram("request_duration", "Request duration"));
+        Assert.DoesNotThrow(() => yggdrasilEngine.DefineHistogram("request_duration_custom", "Request duration custom", new[] { 0.1, 0.5, 1.0, 5.0 }));
+
+        Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.DefineHistogram("request_duration", null!));
+        Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.DefineHistogram(null!, "Request duration"));
+        Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.DefineHistogram(null!, null!));
+    }
+
+    [Test]
+    public void ObserveHistogram_Throws_Only_When_Invalid()
+    {
+        var yggdrasilEngine = new YggdrasilEngine();
+        yggdrasilEngine.DefineHistogram("request_duration", "Request duration", new[] { 0.1, 0.5, 1.0, 5.0 });
+
+        Assert.DoesNotThrow(() => yggdrasilEngine.ObserveHistogram("request_duration", 0.05));
+        Assert.DoesNotThrow(() => yggdrasilEngine.ObserveHistogram("request_duration", 0.75, new Dictionary<string, string> { { "env", "test" } }));
+        Assert.Throws<YggdrasilEngineException>(() => yggdrasilEngine.ObserveHistogram(null!, 1.0));
+    }
+
+    [Test]
+    public void ImpactMetrics_Methods_Can_Be_Used_Together()
+    {
+        var yggdrasilEngine = new YggdrasilEngine();
+
+        Assert.DoesNotThrow(() =>
+        {
+            yggdrasilEngine.DefineCounter("test_counter", "Test counter");
+            yggdrasilEngine.IncCounter("test_counter", 10);
+            yggdrasilEngine.DefineGauge("test_gauge", "Test gauge");
+            yggdrasilEngine.SetGauge("test_gauge", 42);
+            yggdrasilEngine.DefineHistogram("test_histogram", "Test histogram", new[] { 0.1, 0.5, 1.0 });
+            yggdrasilEngine.ObserveHistogram("test_histogram", 0.25);
+        });
+    }
 }
diff --git a/dotnet-engine/Yggdrasil.Engine/Flat.cs b/dotnet-engine/Yggdrasil.Engine/Flat.cs
@@ -17,6 +17,11 @@ static Flat()
         built_in_strategies = Marshal.GetDelegateForFunctionPointer<BuiltInStrategiesDelegate>(NativeLibLoader.LoadFunctionPointer(_libHandle, "flat_built_in_strategies"));
         get_metrics = Marshal.GetDelegateForFunctionPointer<GetMetricsDelegate>(NativeLibLoader.LoadFunctionPointer(_libHandle, "flat_get_metrics"));
         define_counter = Marshal.GetDelegateForFunctionPointer<DefineCounterDelegate>(NativeLibLoader.LoadFunctionPointer(_libHandle, "flat_define_counter"));
+        inc_counter = Marshal.GetDelegateForFunctionPointer<IncCounterDelegate>(NativeLibLoader.LoadFunctionPointer(_libHandle, "flat_inc_counter"));
+        define_gauge = Marshal.GetDelegateForFunctionPointer<DefineGaugeDelegate>(NativeLibLoader.LoadFunctionPointer(_libHandle, "flat_define_gauge"));
+        set_gauge = Marshal.GetDelegateForFunctionPointer<SetGaugeDelegate>(NativeLibLoader.LoadFunctionPointer(_libHandle, "flat_set_gauge"));
+        define_histogram = Marshal.GetDelegateForFunctionPointer<DefineHistogramDelegate>(NativeLibLoader.LoadFunctionPointer(_libHandle, "flat_define_histogram"));
+        observe_histogram = Marshal.GetDelegateForFunctionPointer<ObserveHistogramDelegate>(NativeLibLoader.LoadFunctionPointer(_libHandle, "flat_observe_histogram"));
     }
 
     [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
@@ -41,6 +46,16 @@ static Flat()
 
     [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
     public delegate Buf DefineCounterDelegate(IntPtr enginePtr, IntPtr messagePtr, nuint messageLen);
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    public delegate Buf IncCounterDelegate(IntPtr enginePtr, IntPtr messagePtr, nuint messageLen);
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    public delegate Buf DefineGaugeDelegate(IntPtr enginePtr, IntPtr messagePtr, nuint messageLen);
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    public delegate Buf SetGaugeDelegate(IntPtr enginePtr, IntPtr messagePtr, nuint messageLen);
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    public delegate Buf DefineHistogramDelegate(IntPtr enginePtr, IntPtr messagePtr, nuint messageLen);
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    public delegate Buf ObserveHistogramDelegate(IntPtr enginePtr, IntPtr messagePtr, nuint messageLen);
 
     private static readonly TakeStateDelegate take_state;
     private static readonly FreeBufferDelegate free_buffer;
@@ -51,6 +66,11 @@ static Flat()
     private static readonly GetMetricsDelegate get_metrics;
 
     private static readonly DefineCounterDelegate define_counter;
+    private static readonly IncCounterDelegate inc_counter;
+    private static readonly DefineGaugeDelegate define_gauge;
+    private static readonly SetGaugeDelegate set_gauge;
+    private static readonly DefineHistogramDelegate define_histogram;
+    private static readonly ObserveHistogramDelegate observe_histogram;
 
     public static Buf TakeState(IntPtr ptr, string json)
     {
@@ -86,6 +106,7 @@ public static Buf CheckVariant(IntPtr ptr, byte[] message)
             handle.Free();
         }
     }
+
     public static Buf ListKnownToggles(IntPtr ptr)
     {
         return list_known_toggles(ptr);
@@ -116,6 +137,81 @@ public static Buf DefineCounter(IntPtr ptr, byte[] message)
         }
     }
 
+    public static Buf IncCounter(IntPtr ptr, byte[] message)
+    {
+        nuint len = (nuint)message.Length;
+        GCHandle handle = GCHandle.Alloc(message, GCHandleType.Pinned);
+        try
+        {
+            IntPtr msgPtr = handle.AddrOfPinnedObject();
+            return inc_counter(ptr, msgPtr, len);
+        }
+        finally
+        {
+            handle.Free();
+        }
+    }
+
+    public static Buf DefineGauge(IntPtr ptr, byte[] message)
+    {
+        nuint len = (nuint)message.Length;
+        GCHandle handle = GCHandle.Alloc(message, GCHandleType.Pinned);
+        try
+        {
+            IntPtr msgPtr = handle.AddrOfPinnedObject();
+            return define_gauge(ptr, msgPtr, len);
+        }
+        finally
+        {
+            handle.Free();
+        }
+    }
+
+    public static Buf SetGauge(IntPtr ptr, byte[] message)
+    {
+        nuint len = (nuint)message.Length;
+        GCHandle handle = GCHandle.Alloc(message, GCHandleType.Pinned);
+        try
+        {
+            IntPtr msgPtr = handle.AddrOfPinnedObject();
+            return set_gauge(ptr, msgPtr, len);
+        }
+        finally
+        {
+            handle.Free();
+        }
+    }
+
+    public static Buf DefineHistogram(IntPtr ptr, byte[] message)
+    {
+        nuint len = (nuint)message.Length;
+        GCHandle handle = GCHandle.Alloc(message, GCHandleType.Pinned);
+        try
+        {
+            IntPtr msgPtr = handle.AddrOfPinnedObject();
+            return define_histogram(ptr, msgPtr, len);
+        }
+        finally
+        {
+            handle.Free();
+        }
+    }
+
+    public static Buf ObserveHistogram(IntPtr ptr, byte[] message)
+    {
+        nuint len = (nuint)message.Length;
+        GCHandle handle = GCHandle.Alloc(message, GCHandleType.Pinned);
+        try
+        {
+            IntPtr msgPtr = handle.AddrOfPinnedObject();
+            return observe_histogram(ptr, msgPtr, len);
+        }
+        finally
+        {
+            handle.Free();
+        }
+    }
+
     public static void FreeBuf(Buf buf)
     {
         free_buffer(buf);
diff --git a/dotnet-engine/Yggdrasil.Engine/Flatbuffers.cs b/dotnet-engine/Yggdrasil.Engine/Flatbuffers.cs
@@ -64,6 +64,118 @@ public static byte[] CreateDefineCounterBuffer(FlatBufferBuilder builder, string
         return builder.SizedByteArray();
     }
 
+    public static byte[] CreateIncCounterBuffer(FlatBufferBuilder builder, string name, long value, IDictionary<string, string>? labels = null)
+    {
+        var nameOffset = builder.CreateString(name);
+        var labelsOffset = CreateSampleLabelsVector(builder, labels);
+
+        IncCounter.StartIncCounter(builder);
+        IncCounter.AddName(builder, nameOffset);
+        IncCounter.AddValue(builder, value);
+        if (labelsOffset.HasValue)
+        {
+            IncCounter.AddLabels(builder, labelsOffset.Value);
+        }
+
+        var incCounterMessage = IncCounter.EndIncCounter(builder);
+        builder.Finish(incCounterMessage.Value);
+        return builder.SizedByteArray();
+    }
+
+    public static byte[] CreateDefineGaugeBuffer(FlatBufferBuilder builder, string name, string help)
+    {
+        var nameOffset = builder.CreateString(name);
+        var helpOffset = builder.CreateString(help);
+
+        DefineGauge.StartDefineGauge(builder);
+        DefineGauge.AddName(builder, nameOffset);
+        DefineGauge.AddHelp(builder, helpOffset);
+
+        var defineGaugeMessage = DefineGauge.EndDefineGauge(builder);
+        builder.Finish(defineGaugeMessage.Value);
+        return builder.SizedByteArray();
+    }
+
+    public static byte[] CreateSetGaugeBuffer(FlatBufferBuilder builder, string name, double value, IDictionary<string, string>? labels = null)
+    {
+        var nameOffset = builder.CreateString(name);
+        var labelsOffset = CreateSampleLabelsVector(builder, labels);
+
+        SetGauge.StartSetGauge(builder);
+        SetGauge.AddName(builder, nameOffset);
+        SetGauge.AddValue(builder, value);
+        if (labelsOffset.HasValue)
+        {
+            SetGauge.AddLabels(builder, labelsOffset.Value);
+        }
+
+        var setGaugeMessage = SetGauge.EndSetGauge(builder);
+        builder.Finish(setGaugeMessage.Value);
+        return builder.SizedByteArray();
+    }
+
+    public static byte[] CreateDefineHistogramBuffer(FlatBufferBuilder builder, string name, string help, IEnumerable<double>? buckets = null)
+    {
+        var nameOffset = builder.CreateString(name);
+        var helpOffset = builder.CreateString(help);
+        var bucketArray = (buckets ?? Enumerable.Empty<double>()).ToArray();
+        var bucketsOffset = bucketArray.Length > 0
+            ? DefineHistogram.CreateBucketsVector(builder, bucketArray)
+            : default(VectorOffset);
+
+        DefineHistogram.StartDefineHistogram(builder);
+        DefineHistogram.AddName(builder, nameOffset);
+        DefineHistogram.AddHelp(builder, helpOffset);
+        if (bucketArray.Length > 0)
+        {
+            DefineHistogram.AddBuckets(builder, bucketsOffset);
+        }
+
+        var defineHistogramMessage = DefineHistogram.EndDefineHistogram(builder);
+        builder.Finish(defineHistogramMessage.Value);
+        return builder.SizedByteArray();
+    }
+
+    public static byte[] CreateObserveHistogramBuffer(FlatBufferBuilder builder, string name, double value, IDictionary<string, string>? labels = null)
+    {
+        var nameOffset = builder.CreateString(name);
+        var labelsOffset = CreateSampleLabelsVector(builder, labels);
+
+        ObserveHistogram.StartObserveHistogram(builder);
+        ObserveHistogram.AddName(builder, nameOffset);
+        ObserveHistogram.AddValue(builder, value);
+        if (labelsOffset.HasValue)
+        {
+            ObserveHistogram.AddLabels(builder, labelsOffset.Value);
+        }
+
+        var observeHistogramMessage = ObserveHistogram.EndObserveHistogram(builder);
+        builder.Finish(observeHistogramMessage.Value);
+        return builder.SizedByteArray();
+    }
+
+    private static VectorOffset? CreateSampleLabelsVector(FlatBufferBuilder builder, IDictionary<string, string>? labels)
+    {
+        if (labels == null || labels.Count == 0)
+        {
+            return null;
+        }
+
+        var labelEntries = new Offset<SampleLabelEntry>[labels.Count];
+        var index = 0;
+        foreach (var kvp in labels)
+        {
+            labelEntries[index] = SampleLabelEntry.CreateSampleLabelEntry(
+                builder,
+                builder.CreateString(kvp.Key),
+                builder.CreateString(kvp.Value)
+            );
+            index++;
+        }
+
+        return IncCounter.CreateLabelsVector(builder, labelEntries);
+    }
+
     internal static VectorOffset CreatePropertiesVector(FlatBufferBuilder builder, Context context)
     {
         var propertyEntries = new Offset<PropertyEntry>[context.Properties?.Count ?? 0];
@@ -238,4 +350,4 @@ private static Dictionary<string, long> GetVariantCounts(ToggleStats stats)
             .ToDictionary(x => x.Key, v => v.Value);
     }
 
-}
+}
diff --git a/dotnet-engine/Yggdrasil.Engine/YggdrasilEngine.cs b/dotnet-engine/Yggdrasil.Engine/YggdrasilEngine.cs
@@ -90,6 +90,46 @@ public void DefineCounter(string name, string help)
         finally { Flat.FreeBuf(buf); }
     }
 
+    public void IncCounter(string name, long value = 1, IDictionary<string, string>? labels = null)
+    {
+        var messageBuffer = Flatbuffers.CreateIncCounterBuffer(new FlatBufferBuilder(128), name, value, labels);
+        var buf = Flat.IncCounter(state, messageBuffer);
+        try { Flatbuffers.ParseVoidAndThrow(buf); }
+        finally { Flat.FreeBuf(buf); }
+    }
+
+    public void DefineGauge(string name, string help)
+    {
+        var messageBuffer = Flatbuffers.CreateDefineGaugeBuffer(new FlatBufferBuilder(128), name, help);
+        var buf = Flat.DefineGauge(state, messageBuffer);
+        try { Flatbuffers.ParseVoidAndThrow(buf); }
+        finally { Flat.FreeBuf(buf); }
+    }
+
+    public void SetGauge(string name, double value, IDictionary<string, string>? labels = null)
+    {
+        var messageBuffer = Flatbuffers.CreateSetGaugeBuffer(new FlatBufferBuilder(128), name, value, labels);
+        var buf = Flat.SetGauge(state, messageBuffer);
+        try { Flatbuffers.ParseVoidAndThrow(buf); }
+        finally { Flat.FreeBuf(buf); }
+    }
+
+    public void DefineHistogram(string name, string help, IEnumerable<double>? buckets = null)
+    {
+        var messageBuffer = Flatbuffers.CreateDefineHistogramBuffer(new FlatBufferBuilder(128), name, help, buckets);
+        var buf = Flat.DefineHistogram(state, messageBuffer);
+        try { Flatbuffers.ParseVoidAndThrow(buf); }
+        finally { Flat.FreeBuf(buf); }
+    }
+
+    public void ObserveHistogram(string name, double value, IDictionary<string, string>? labels = null)
+    {
+        var messageBuffer = Flatbuffers.CreateObserveHistogramBuffer(new FlatBufferBuilder(128), name, value, labels);
+        var buf = Flat.ObserveHistogram(state, messageBuffer);
+        try { Flatbuffers.ParseVoidAndThrow(buf); }
+        finally { Flat.FreeBuf(buf); }
+    }
+
     public ICollection<FeatureDefinition> ListKnownToggles()
     {
         var buf = Flat.ListKnownToggles(state);
diff --git a/yggdrasilffi/src/flat/mod.rs b/yggdrasilffi/src/flat/mod.rs
