feat: expose query operation timings by AlenaSviridenko · Pull Request #2491 · wundergraph/cosmo

AlenaSviridenko · 2026-02-05T13:34:12Z

Corresponding docs PR wundergraph/cosmo-docs#248

Why this change is needed

Our app uses a custom Go module to publish detailed per-request telemetry to our internal Hydro system (Kafka-based). We need GraphQL operation performance metrics (parse, normalize, validate, plan timing) for every request to analyze query performance and debug issues.

While we already export OTEL metrics to Datadog, we need the raw per-request timing data in our telemetry pipeline. Currently, these timings are only accessible by passing the X-WG-Trace header, which has several problems:

Can't control client behavior - We can't require all clients to pass a debugging header
Security risk - The trace response exposes internal subgraph implementation details to clients
Incomplete coverage - Only requests with the header get timing data, preventing comprehensive analysis
Performance overhead - Trace responses are verbose and add unnecessary payload size

This PR exposes operation timings via the OperationContext interface (similar to the existing QueryPlanStats() method), allowing custom modules to access this data programmatically without modifying responses or requiring client headers.

This enables us to:

Capture timing metrics for 100% of requests
Keep internal metrics separate from client-facing responses
Maintain security by not exposing implementation details
Avoid response payload overhead

Summary by CodeRabbit

New Features
- Added detailed operation timing metrics (parsing, validation, planning, normalization) for GraphQL requests.
- Added a middleware module to capture and asynchronously deliver operation timing data for custom integrations without impacting request flow.
Tests
- Added tests validating timing metrics for simple and complex queries to ensure non-negative and meaningful durations.

Checklist

I have discussed my proposed changes in an issue and have received approval to proceed.
I have followed the coding standards of the project.
Tests or benchmarks have been added or updated.
Documentation has been updated on https://github.com/wundergraph/cosmo-docs.
I have read the Contributors Guide.

coderabbitai · 2026-02-05T13:34:32Z

Walkthrough

Adds an OperationTimings struct and Timings() methods to expose parsing, validation, planning, and normalization durations; introduces a router middleware module that captures those timings and sends them over a channel; and adds tests that run queries and assert timing fields are non-negative and at least one is non-zero.

Changes

Cohort / File(s)	Summary
Core Timing Infrastructure `router/core/context.go`	Added exported `OperationTimings` (ParsingTime, ValidationTime, PlanningTime, NormalizationTime) and a `Timings()` method on `OperationContext`/`operationContext` to return current timing values.
Custom Operation Timings Module `router-tests/modules/custom-operation-timings/module.go`	New middleware `OperationTimingsModule` implementing `core.RouterMiddlewareHandler`; exposes `ResultsChan chan core.OperationTimings`, non-blockingly sends timings from `ctx.Operation().Timings()` in `Middleware`, and provides `Module()` metadata and factory.
Operation Timings Tests `router-tests/modules/operation_timings_test.go`	New test `TestCustomModuleOperationTimings` with subtests that register the custom module, execute simple and complex GraphQL requests, read timings from the module channel, and assert timing values are non-negative and at least one is non-zero.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'feat: expose query operation timings' directly and accurately summarizes the main change: exposing GraphQL operation timings through the OperationContext interface.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing touches

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coderabbitai

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@router-tests/modules/custom-operation-timings/module.go`:
- Around line 16-23: The middleware OperationTimingsModule.Middleware currently
does a blocking send m.ResultsChan <- timings which can hang when ResultsChan is
nil or unbuffered; update Middleware to first check if m.ResultsChan != nil and
then perform a non-blocking send using a select with a default case so the
request path never stalls (i.e., attempt to send timings on m.ResultsChan in one
select case and use default to skip sending if it would block), leaving the rest
of the handler flow (next.ServeHTTP(ctx.ResponseWriter(), ctx.Request()))
unchanged.

coderabbitai

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@router-tests/modules/custom-operation-timings/module.go`:
- Around line 31-41: The ResultsChan is created unbuffered in
OperationTimingsModule.Module() so non-blocking sends can drop timings; change
the New function to initialize ResultsChan as a buffered channel (e.g.,
make(chan core.OperationTimings, 1)) inside the New closure that returns
&OperationTimingsModule to preserve the latest timing without blocking callers.

SkArchon · 2026-02-09T17:51:05Z

Hi, thanks for your contribution. Could you also add a PR description with your use case. We usually have descriptions on the PRs in addition to what is generated by coderabbit.

AlenaSviridenko · 2026-02-10T09:52:53Z

@SkArchon Sorry I should have added it right away! Updated the description, please let me know what do you think?

codecov · 2026-02-11T08:18:00Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 56.05%. Comparing base (8546ee1) to head (f5bee3a).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2491      +/-   ##
==========================================
- Coverage   62.45%   56.05%   -6.41%     
==========================================
  Files         231      215      -16     
  Lines       24123    23548     -575     
==========================================
- Hits        15066    13199    -1867     
- Misses       7809     9107    +1298     
+ Partials     1248     1242       -6

Files with missing lines	Coverage Δ
router/core/context.go	`73.49% <100.00%> (+0.18%)`	⬆️

... and 103 files with indirect coverage changes

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
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StarpTech · 2026-02-11T09:10:26Z

HI @AlenaSviridenko, please also create PR to document that functionality https://github.com/wundergraph/cosmo-docs/blob/main/docs/router/custom-modules.mdx Thank you!

Co-authored-by: Alessandro Pagnin <ale@wundergraph.com>

Exposing operation timings

cbcb94f

AlenaSviridenko requested review from Noroth, StarpTech, devsergiy, endigma and jensneuse as code owners February 5, 2026 13:34

github-actions Bot added the router label Feb 5, 2026

coderabbitai Bot reviewed Feb 5, 2026

View reviewed changes

Comment thread router-tests/modules/custom-operation-timings/module.go

nil channel check in test module

934ff2e

coderabbitai Bot reviewed Feb 5, 2026

View reviewed changes

Comment thread router-tests/modules/custom-operation-timings/module.go

Added tiny buffer

46c0db1

Merge branch 'main' into asviridenko-expose-operation-timings

f5bee3a

Noroth approved these changes Feb 11, 2026

View reviewed changes

AlenaSviridenko mentioned this pull request Feb 11, 2026

Add docs for a the operation timings wundergraph/cosmo-docs#248

Merged

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StarpTech merged commit 010e8e2 into wundergraph:main Feb 11, 2026
30 checks passed

maxbol pushed a commit to maxbol/cosmo that referenced this pull request Feb 12, 2026

feat: expose query operation timings (wundergraph#2491)

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Co-authored-by: Alessandro Pagnin <ale@wundergraph.com>

coderabbitai Bot mentioned this pull request Mar 3, 2026

chore(router): gofmt #2576

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feat: expose query operation timings#2491

feat: expose query operation timings#2491
StarpTech merged 4 commits intowundergraph:mainfrom
AlenaSviridenko:asviridenko-expose-operation-timings

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Why this change is needed

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