feat: rest of impact metrics definitions for dotnet by sighphyre · Pull Request #76 · Unleash/yggdrasil-bindings

sighphyre · 2026-02-09T14:23:09Z

Implements counter, gauge and histogram types in the FFI layers

Copilot

Pull request overview

Adds the remaining impact-metrics FlatBuffers messages + FFI plumbing so the .NET engine can define and update counters, gauges, and histograms via the Rust FlatBuffer FFI layer.

Changes:

Added new Rust FlatBuffer FFI endpoints: inc counter, define/set gauge, define/observe histogram (with optional labels/buckets).
Extended the FlatBuffers schema and regenerated Rust/C# messaging types for the new metric messages.
Added .NET engine wrappers and tests for the new impact-metrics APIs.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
`yggdrasilffi/src/flat/mod.rs`	Adds FlatBuffer FFI handlers for counter/gauge/histogram metric operations and label parsing.
`yggdrasilffi/src/flat/enabled-message_generated.rs`	Regenerated Rust FlatBuffers types for new metric messages.
`flat-buffer-defs/enabled-message.fbs`	Extends schema with `IncCounter`, `DefineGauge`, `SetGauge`, `DefineHistogram`, `ObserveHistogram`.
`dotnet-engine/Yggdrasil.Engine/yggdrasil/messaging/*.cs`	New autogenerated C# FlatBuffers message types for the added schema tables.
`dotnet-engine/Yggdrasil.Engine/YggdrasilEngine.cs`	Public .NET API surface for the new impact-metrics operations.
`dotnet-engine/Yggdrasil.Engine/Flatbuffers.cs`	Builders for the new FlatBuffer request payloads (incl. labels/buckets).
`dotnet-engine/Yggdrasil.Engine/Flat.cs`	Loads new native symbols and exposes managed wrappers for them.
`dotnet-engine/Yggdrasil.Engine.Tests/YggdrasilImpactMetricsTest.cs`	Adds .NET tests covering the new metric methods and basic invalid-arg behavior.

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Copilot · 2026-02-09T14:28:24Z

dotnet-engine/Yggdrasil.Engine/Flatbuffers.cs

+    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];
+        for (var i = 0; i < labels.Count; i++)
+        {
+            var kvp = labels.ElementAt(i);
+            labelEntries[i] = SampleLabelEntry.CreateSampleLabelEntry(
+                builder,
+                builder.CreateString(kvp.Key),
+                builder.CreateString(kvp.Value)
+            );
+        }
+
+        return IncCounter.CreateLabelsVector(builder, labelEntries);


SampleLabelEntry.key is marked as a FlatBuffers (key) field (see enabled-message.fbs), which means vectors of SampleLabelEntry are expected to be sorted by key for generated LabelsByKey(...) / __lookup_by_key helpers to work correctly. CreateSampleLabelsVector currently preserves the IDictionary enumeration order, so any by-key lookups on these vectors may return incorrect results. Sort the label entries by key (or use the FlatBuffers helper for creating sorted vectors of tables) before creating the vector.

Copilot · 2026-02-09T14:28:24Z

dotnet-engine/Yggdrasil.Engine/Flatbuffers.cs

+            );
+        }
+
+        return IncCounter.CreateLabelsVector(builder, labelEntries);


CreateSampleLabelsVector returns IncCounter.CreateLabelsVector(...), which unnecessarily couples this generic label-builder to the IncCounter schema/type. This makes the code harder to maintain if IncCounter’s generated API changes, and it’s confusing when the same helper is used for SetGauge/ObserveHistogram labels. Prefer building the vector directly via the FlatBufferBuilder, or use the CreateLabelsVector method on the specific message type being built.

Suggested change

return IncCounter.CreateLabelsVector(builder, labelEntries);

return builder.CreateVectorOfTables(labelEntries);

Copilot · 2026-02-09T14:28:25Z

yggdrasilffi/src/flat/mod.rs

+pub unsafe extern "C" fn flat_inc_counter(
+    engine_ptr: *mut c_void,
+    message_ptr: u64,
+    message_len: u64,
+) -> Buf {


New FlatBuffer FFI endpoints for impact metrics (inc counter / gauge / histogram) are added here, but the existing test module in this file doesn’t exercise any of them. Adding a few Rust-side tests (similar to the existing flat_check_enabled / flat_take_state tests) would help catch schema/ABI mismatches early, especially around label parsing and optional bucket handling.

dotnet-engine/Yggdrasil.Engine/Flatbuffers.cs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.

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Copilot · 2026-02-10T06:34:54Z

dotnet-engine/Yggdrasil.Engine/Flatbuffers.cs

+    }
+
+    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++;
+        }
+


CreateSampleLabelsVector builds the [SampleLabelEntry] vector by calling IncCounter.CreateLabelsVector(...), which unnecessarily couples label serialization to the presence/name of the IncCounter table. Consider building the vector directly with FlatBufferBuilder.StartVector/AddOffset (or introducing a dedicated helper) so label encoding remains independent of any specific message type.

Copilot

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 1 comment.

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Copilot · 2026-02-13T07:53:56Z

dotnet-engine/Yggdrasil.Engine/Flatbuffers.cs

+            index++;
+        }
+
+        return IncCounter.CreateLabelsVector(builder, labelEntries);


The method uses IncCounter.CreateLabelsVector to create label vectors for all message types (IncCounter, SetGauge, ObserveHistogram). While this works because all generated FlatBuffer types have identical CreateLabelsVector methods, it's semantically confusing and reduces code clarity. Consider using a more neutral type like SetGauge.CreateLabelsVector or documenting why IncCounter is used here.

Suggested change

return IncCounter.CreateLabelsVector(builder, labelEntries);

return SetGauge.CreateLabelsVector(builder, labelEntries);

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

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sighphyre added 2 commits February 9, 2026 16:15

feat: implement counter, gauge and histogram

a6bac62

feat: wire up to public api and basic tests

6d27798

Copilot AI review requested due to automatic review settings February 9, 2026 14:23

thomasheartman added this to Issues and PRs Feb 9, 2026

github-project-automation bot moved this to New in Issues and PRs Feb 9, 2026

Copilot started reviewing on behalf of sighphyre February 9, 2026 14:23 View session

daveleek added the 🤖 all-ai Fully LLM generated (minor human check) label Feb 9, 2026

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Update dotnet-engine/Yggdrasil.Engine/Flatbuffers.cs

aca6916

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings February 10, 2026 06:29

Copilot started reviewing on behalf of sighphyre February 10, 2026 06:29 View session

fix: avoid nested serialisation in histogram

c31bfab

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This was referenced Feb 10, 2026

feat: rest of impact metrics implementation #78

Merged

feat: flatbuffers definitions for rest of impact metrics regular operations #77

Merged

chriswk assigned sighphyre Feb 11, 2026

chriswk moved this from New to In Progress in Issues and PRs Feb 11, 2026

sighphyre added 2 commits February 13, 2026 09:47

chore: clippy

0f4b925

chore: fmt

7fa3437

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Merge branch 'main' into feat/rest-of-impact-metrics

baa5c5b

daveleek approved these changes Feb 13, 2026

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github-project-automation bot moved this from In Progress to Approved PRs in Issues and PRs Feb 13, 2026

Merge branch 'main' into feat/rest-of-impact-metrics

8cc8b58

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sighphyre merged commit 28b7bdb into main Feb 16, 2026
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sighphyre deleted the feat/rest-of-impact-metrics branch February 16, 2026 07:16

github-project-automation bot moved this from Approved PRs to Done in Issues and PRs Feb 16, 2026

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feat: rest of impact metrics definitions for dotnet#76

feat: rest of impact metrics definitions for dotnet#76
sighphyre merged 8 commits intomainfrom
feat/rest-of-impact-metrics

sighphyre commented Feb 9, 2026 •

edited

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	return IncCounter.CreateLabelsVector(builder, labelEntries);
	return builder.CreateVectorOfTables(labelEntries);

	return IncCounter.CreateLabelsVector(builder, labelEntries);
	return SetGauge.CreateLabelsVector(builder, labelEntries);

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sighphyre commented Feb 9, 2026 •

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