Add telemetry tracking for task factory names and runtime usage #12989

Copilot · 2026-01-08T14:09:58Z

Context

MSBuild needs visibility into TaskFactory usage patterns to inform deprecation decisions. This PR implements telemetry to track which task factories are being used for task execution, including custom factories and the deprecated CodeTaskFactory.

Changes Made

TaskExecutionStats.cs

Added TaskFactoryName property to track which factory created each task (AssemblyTaskFactory, CodeTaskFactory, RoslynCodeTaskFactory, XamlTaskFactory, or custom factory names)
Added TaskHostRuntime property to track out-of-process execution runtime ("CLR2", "CLR4", "NET", or null)
Updated Accumulate, Equals, and GetHashCode methods to include new properties

TelemetryDataUtils.cs

Enhanced to hash custom (non-MSBuild) task factory names for privacy
Known factories (AssemblyTaskFactory, CodeTaskFactory, RoslynCodeTaskFactory, XamlTaskFactory, IntrinsicTaskFactory) are not hashed
Hashing protects proprietary/internal factory names while still providing usage data

WorkerNodeTelemetryData.cs, WorkerNodeTelemetryEventArgs.cs

Updated to propagate factory name and runtime information through telemetry pipeline
Factory data is now included in task execution details sent to telemetry consumers

ProjectTelemetry.cs

Refactored for cleaner code structure with AddIfNotEmpty helper method
Maintains existing telemetry events (build/tasks/taskfactory, build/tasks, build/tasks/msbuild-subclassed)

Telemetry_Tests.cs

Added WorkerNodeTelemetryCollection_TaskFactoryName test to verify factory names are captured for both built-in and inline tasks
Added TelemetryDataUtils_HashesCustomFactoryName test to verify custom factory names are hashed while known factories are not
Enhanced existing tests to verify factory names and runtime information are populated

ProjectTelemetry_Tests.cs

Maintained existing tests for MSBuild task subclassing tracking

Testing

All ProjectTelemetry unit tests pass (6/6)
All Telemetry integration tests pass (including 2 new comprehensive tests)
Build succeeds with zero warnings
Verified factory names are captured for built-in tasks (AssemblyTaskFactory)
Verified factory names are captured for inline tasks (RoslynCodeTaskFactory)
Verified custom factory names are properly hashed for privacy
Verified task host runtime information is correctly tracked

Notes

This telemetry captures factory information for ALL tasks (not just custom ones) and associates it with individual task execution statistics. This approach provides comprehensive visibility into:

CodeTaskFactory usage to inform deprecation decisions (Deprecate and restrict non-MSBuild TaskFactory implementations #12347)
Custom task factory adoption and usage patterns
Task host runtime preferences across the ecosystem
Data to support TaskFactory support and deprecation decisions

Original prompt

This section details on the original issue you should resolve

<issue_title>Collect telemetry to see the features usage</issue_title>
<issue_description>Use existing telemetry infrastructure, collect telemetry to see the usage for:

Non-MSBuild TaskFactory implementations (so we can proceed with Deprecate and restrict non-MSBuild TaskFactory implementations #12347)

CodeTaskFactory</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes Collect telemetry to see the features usage #12988

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

dotnet-policy-service · 2026-01-08T14:10:21Z

Hello @@copilot, I noticed that you’re changing an .swr file or any file under src/Package/MSBuild.VSSetup.. Please make sure to validate this change by an experimental VS insertion. This is accomplished by pushing to an exp/* branch, which requires write permissions to this repo.

Co-authored-by: YuliiaKovalova <[email protected]>

…sanitization Co-authored-by: YuliiaKovalova <[email protected]>

Co-authored-by: YuliiaKovalova <[email protected]>

…ests Co-authored-by: YuliiaKovalova <[email protected]>

Co-authored-by: YuliiaKovalova <[email protected]>

YuliiaKovalova · 2026-01-09T15:38:01Z

@copilot update description according to the pushed changes

Copilot · 2026-01-09T15:42:43Z

@copilot update description according to the pushed changes

Updated the PR description to reflect the refactored implementation that tracks factory name and runtime in TaskExecutionStats rather than using a separate dictionary in ProjectTelemetry. The new approach captures this information for all tasks and includes it in the worker node telemetry data.

Copilot

Pull request overview

This pull request adds telemetry tracking for task factory usage patterns to inform deprecation decisions for custom TaskFactory implementations and CodeTaskFactory. The implementation extends the existing telemetry infrastructure to capture and report task factory names alongside task execution statistics.

Key Changes

Extended TaskExecutionStats to include TaskFactoryName and TaskHostRuntime fields
Updated telemetry serialization to transmit factory information across worker nodes
Added hashing logic for custom factory names while keeping built-in factory names readable
Modified telemetry collection points to capture and forward factory information

Reviewed changes

Copilot reviewed 13 out of 14 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/Framework/Telemetry/TaskExecutionStats.cs	Added TaskFactoryName and TaskHostRuntime properties to track factory metadata
src/Framework/Telemetry/WorkerNodeTelemetryData.cs	Updated AddTask method signature to accept factory parameters; modernized constructor with collection expressions
src/Framework/Telemetry/WorkerNodeTelemetryEventArgs.cs	Extended serialization to include factory name and runtime fields
src/Framework/Telemetry/TelemetryDataUtils.cs	Added KnownTaskFactoryNames list and hashing logic for custom factory names
src/Build/TelemetryInfra/ITelemetryForwarder.cs	Extended AddTask interface with factory parameters
src/Build/TelemetryInfra/TelemetryForwarderProvider.cs	Updated implementations to pass factory information through telemetry pipeline
src/Build/BackEnd/Components/RequestBuilder/RequestBuilder.cs	Modified task statistics collection to extract and forward factory metadata
src/Build/BackEnd/Components/Logging/ProjectTelemetry.cs	Refactored property building with AddIfNotEmpty helper; improved TryGetValue pattern usage
src/Build.UnitTests/Telemetry/Telemetry_Tests.cs	Added tests for factory name tracking and hashing behavior
src/Framework.UnitTests/WorkerNodeTelemetryEventArgs_Tests.cs	Updated serialization test with factory parameters
src/Build.UnitTests/BackEnd/ProjectTelemetry_Tests.cs	Formatting cleanup
src/Tasks.UnitTests/TelemetryTaskTests.cs	Removed empty comment lines
src/Framework/TelemetryEventArgs.cs	Minor formatting (blank line)
src/Build/TelemetryInfra/InternalTelemetryConsumingLogger.cs	Minor formatting (blank lines)

Copilot · 2026-01-09T15:45:30Z

src/Build/BackEnd/Components/Logging/ProjectTelemetry.cs

+        private static void AddIfNotEmpty(Dictionary<string, string> properties, string propertyName, int count)
+        {
+            if (count > 0)
+            {
+                properties[propertyName] = count.ToString(CultureInfo.InvariantCulture);
+            }
+        }


The AddIfNotEmpty helper method is only used for converting integer counts to strings for telemetry. Consider using a more descriptive name like AddCountIfNonZero to better communicate its specific purpose and constraints.

Copilot · 2026-01-09T15:45:31Z

src/Framework/Telemetry/WorkerNodeTelemetryData.cs

    }

-    public void AddTask(TaskOrTargetTelemetryKey task, TimeSpan cumulativeExectionTime, int executionsCount, long totalMemoryConsumption)
+    public void AddTask(TaskOrTargetTelemetryKey task, TimeSpan cumulativeExectionTime, int executionsCount, long totalMemoryConsumption, string? factoryName, string? taskHostRuntime)


The parameter name has a typo: cumulativeExectionTime should be cumulativeExecutionTime (missing 'u' in 'Execution').

Copilot · 2026-01-09T15:45:31Z

src/Framework/Telemetry/TelemetryDataUtils.cs

+            "TaskHostFactory",
+            "CodeTaskFactory",
+            "RoslynCodeTaskFactory",
+            "XamlTaskFactory",


The KnownTaskFactoryNames HashSet is missing "IntrinsicTaskFactory" which is listed as a built-in factory in ProjectTelemetry.cs. If IntrinsicTaskFactory is used, it will be incorrectly hashed as a custom factory name instead of being reported as-is. Consider adding "IntrinsicTaskFactory" to this HashSet to match the other built-in factories.

Suggested change

"XamlTaskFactory",

"XamlTaskFactory",

"IntrinsicTaskFactory",

Copilot · 2026-01-09T15:45:31Z

src/Framework/Telemetry/WorkerNodeTelemetryData.cs

-    public WorkerNodeTelemetryData()
-        : this(new Dictionary<TaskOrTargetTelemetryKey, TaskExecutionStats>(), new Dictionary<TaskOrTargetTelemetryKey, bool>())
-    { }
+    public WorkerNodeTelemetryData() : this([], new Dictionary<TaskOrTargetTelemetryKey, bool>()) { }


Inconsistent usage of collection expressions. The first parameter uses [] (collection expression) while the second uses new Dictionary<TaskOrTargetTelemetryKey, bool>(). For consistency with the coding guidelines that prefer collection expressions, consider using [] for both dictionaries.

Suggested change

public WorkerNodeTelemetryData() : this([], new Dictionary<TaskOrTargetTelemetryKey, bool>()) { }

public WorkerNodeTelemetryData() : this([], []) { }

Initial plan

e75e0e1

Copilot AI assigned Copilot and YuliiaKovalova Jan 8, 2026

Copilot started work on behalf of YuliiaKovalova January 8, 2026 14:10 View session

Copilot AI and others added 6 commits January 8, 2026 14:21

Add telemetry tracking for custom task factories and CodeTaskFactory

ebc3ce6

Co-authored-by: YuliiaKovalova <[email protected]>

Address code review feedback: optimize dictionary lookup and improve …

c87d27d

…sanitization Co-authored-by: YuliiaKovalova <[email protected]>

Add System.Text using statement and use StringBuilder directly

44c1aa3

Co-authored-by: YuliiaKovalova <[email protected]>

Improve consistency: use TryGetValue and SanitizePropertyName throughout

9a10f62

Co-authored-by: YuliiaKovalova <[email protected]>

Add null safety to SanitizePropertyName and comprehensive edge case t…

8a33e5b

…ests Co-authored-by: YuliiaKovalova <[email protected]>

Final polish: improve compatibility and add clarifying comments

3584c4c

Co-authored-by: YuliiaKovalova <[email protected]>

Copilot AI changed the title ~~[WIP] Collect telemetry for feature usage analysis~~ Add telemetry tracking for custom task factories and CodeTaskFactory usage Jan 8, 2026

Copilot AI requested a review from YuliiaKovalova January 8, 2026 14:49

Copilot finished work on behalf of YuliiaKovalova January 8, 2026 14:49

YuliiaKovalova added 2 commits January 9, 2026 16:36

add collection of factory name and runtime used in tasks

c824292

undo extra change

dfd217e

YuliiaKovalova marked this pull request as ready for review January 9, 2026 15:38

Copilot AI review requested due to automatic review settings January 9, 2026 15:38

Copilot started reviewing on behalf of YuliiaKovalova January 9, 2026 15:38 View session

YuliiaKovalova changed the title ~~Add telemetry tracking for custom task factories and CodeTaskFactory usage~~ Add telemetry tracking for custom task factories and CodeTaskFactory usage Jan 9, 2026

Copilot started work on behalf of YuliiaKovalova January 9, 2026 15:40 View session

Copilot AI changed the title ~~Add telemetry tracking for custom task factories and CodeTaskFactory usage~~ Add telemetry tracking for task factory names and runtime usage Jan 9, 2026

Copilot finished work on behalf of YuliiaKovalova January 9, 2026 15:44

Copilot AI reviewed Jan 9, 2026

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Add telemetry tracking for task factory names and runtime usage #12989

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	public WorkerNodeTelemetryData() : this([], new Dictionary<TaskOrTargetTelemetryKey, bool>()) { }
	public WorkerNodeTelemetryData() : this([], []) { }

Add telemetry tracking for task factory names and runtime usage #12989

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Add telemetry tracking for task factory names and runtime usage #12989

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Key Changes

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