[Fusion] Add OpenTelemetry instrumentation#8909
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tobias-tengler merged 12 commits intomainfrom Feb 25, 2026
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Pull request overview
Adds OpenTelemetry-based activity instrumentation for HotChocolate Fusion (vnext), including a new diagnostics package and a dedicated test suite to validate emitted activities via snapshots.
Changes:
- Introduces
HotChocolate.Fusion.Diagnosticswith activity sources, enrichers, scopes, and diagnostic listeners for Fusion execution and ASP.NET request lifecycle. - Adds
Fusion.Diagnostics.Testswith snapshot-based assertions for activity names/tags/status across common request scenarios (success, validation errors, document capture, display-name formatting). - Wires required pooling/services and updates solution files to include the new projects.
Reviewed changes
Copilot reviewed 38 out of 38 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/HotChocolate.Fusion.Diagnostics.csproj | New Fusion diagnostics package project (OpenTelemetry API dependency). |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/HotChocolateFusionActivitySource.cs | Defines Fusion ActivitySource name/version. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/InstrumentationOptions.cs | Adds Fusion instrumentation configuration options. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/FusionActivityScopes.cs | Defines selectable Fusion activity scopes. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/RequestDetails.cs | Flags enum for request-detail inclusion. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/ContextKeys.cs | Context keys for storing activities. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/FusionActivityEnricher.cs | Adds tags/events/display-name logic for Fusion spans. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Listeners/ActivityFusionExecutionDiagnosticEventListener.cs | Emits activities for Fusion execution pipeline stages. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Listeners/ActivityServerDiagnosticListener.cs | Emits activities for HTTP request pipeline stages. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Scopes/RequestScopeBase.cs | Common scope disposal/enrichment base. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Scopes/ExecuteRequestScope.cs | ExecuteRequest scope enrichment/status logic. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Scopes/ParseDocumentScope.cs | ParseDocument scope enrichment/status logic. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Scopes/ValidateDocumentScope.cs | ValidateDocument scope enrichment/status logic. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Scopes/CoerceVariablesScope.cs | CoerceVariables scope enrichment/status logic. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Scopes/PlanOperationScope.cs | PlanOperation scope enrichment/status logic. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Scopes/ExecuteOperationScope.cs | ExecuteOperation scope enrichment/status logic. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Extensions/DiagnosticsFusionGatewayBuilderExtensions.cs | Adds AddInstrumentation to Fusion gateway builder. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Diagnostics/Extensions/TracerProviderBuilderExtensions.cs | Adds Fusion activity source to OTel TracerProviderBuilder. |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/HotChocolate.Fusion.Diagnostics.Tests.csproj | New test project for Fusion diagnostics. |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/ActivityTestHelper.cs | Captures and serializes activities for snapshot tests. |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/QueryInstrumentationTests.cs | New snapshot-based instrumentation tests. |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Track_Events_Of_A_Simple_Query_Default.snap | New snapshot baseline (default scopes). |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Track_Events_Of_A_Simple_Query_Detailed.snap | New snapshot baseline (all scopes). |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Ensure_Operation_Name_Is_Used_As_Request_Name.snap | New snapshot baseline (operation-name behavior). |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Allow_Document_To_Be_Captured.snap | New snapshot baseline (document body tagging). |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Ensure_That_The_Validation_Activity_Has_An_Error_Status.snap | New snapshot baseline (validation error status/event). |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Create_Operation_Display_Name_With_1_Field.snap | New snapshot baseline (display-name formatting). |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Create_Operation_Display_Name_With_1_Field_And_Op.snap | New snapshot baseline (display-name + op name). |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Create_Operation_Display_Name_With_3_Field.snap | New snapshot baseline (3-field formatting). |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Create_Operation_Display_Name_With_4_Field.snap | New snapshot baseline (4-field elision). |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Cause_A_Resolver_Error_That_Deletes_The_Whole_Result.snap | New snapshot baseline (execution error status). |
| src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/snapshots/QueryInstrumentationTests.Cause_A_Resolver_Error_That_Deletes_The_Whole_Result_Deep.snap | New snapshot baseline (nested error surface). |
| src/HotChocolate/Fusion-vnext/src/Fusion.Execution/Execution/FusionRequestExecutorManager.cs | Adds ObjectPoolProvider/StringBuilder pool registrations needed by instrumentation. |
| src/HotChocolate/Fusion-vnext/src/Fusion.Execution/DependencyInjection/HotChocolateFusionServiceCollectionExtensions.cs | Adds core DI registrations (options + object pools) for Fusion gateway. |
| src/HotChocolate/Fusion-vnext/HotChocolate.Fusion-vnext.slnx | Includes new Fusion diagnostics projects in Fusion-vnext solution. |
| src/All.slnx | Includes new Fusion diagnostics projects in global solution list. |
| src/HotChocolate/Diagnostics/src/Diagnostics/Extensions/DiagnosticsRequestExecutorBuilderExtensions.cs | Minor refactor to primary-constructor style for internal enricher. |
| src/HotChocolate/Diagnostics/src/Diagnostics/ActivityEnricher.cs | Adjusts how request variables are serialized into tags (and changes protected virtual signatures). |
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src/HotChocolate/Fusion-vnext/test/Fusion.Diagnostics.Tests/QueryInstrumentationTests.cs
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Fusion Gateway Performance ResultsSimple Composite Query
Response Times & Query
query TestQuery {
topProducts(first: 5) {
inStock
name
price
shippingEstimate
upc
weight
reviews {
id
body
author {
id
username
name
}
}
}
}Deep Recursion Query
Response Times & Query
query TestQuery {
users {
id
username
name
reviews {
id
body
product {
inStock
name
price
shippingEstimate
upc
weight
reviews {
id
body
author {
id
username
name
reviews {
id
body
product {
inStock
name
price
shippingEstimate
upc
weight
}
}
}
}
}
}
}
topProducts(first: 5) {
inStock
name
price
shippingEstimate
upc
weight
reviews {
id
body
author {
id
username
name
reviews {
id
body
product {
inStock
name
price
shippingEstimate
upc
weight
}
}
}
}
}
}Variable Batching Throughput
Response Times & Query
query TestQuery($upc: ID!, $price: Long!, $weight: Long!) {
productByUpc(upc: $upc) {
inStock
shippingEstimate(weight: $weight, price: $price)
}
}Variables (5 sets batched per request) [
{ "upc": "1", "price": 899, "weight": 100 },
{ "upc": "2", "price": 1299, "weight": 1000 },
{ "upc": "3", "price": 15, "weight": 20 },
{ "upc": "4", "price": 499, "weight": 100 },
{ "upc": "5", "price": 1299, "weight": 1000 }
]Run 22387847918 • Commit 1eade5c • Wed, 25 Feb 2026 08:43:48 GMT |
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