feat: metadata support in the kubernetes_sync

[Nilushiya]

This PR

• Preserve FeatureFlag metadata when syncing from Kubernetes by marshalling spec.flagSpec directly from unstructured objects.
• Harden informer tombstone handling and watcher readiness for Kubernetes sync.
• Add unit tests covering metadata preservation and tombstone unwrap.

Related Issues

Fixes # #754 (CRD definition is not following the latest flagD specifications) - in the open-feature-operator
already rased the pr for open-feature-operator CRD support for metaData - (open-feature/open-feature-operator#808 that alone is not enough, so in Flagd also want to change. This PR refers to that.

Notes

• Architecture unchanged; only Kubernetes sync path touched.
• No dependency/version changes.

Follow-up Tasks

• None.
  This change keeps the Kubernetes sync path working with metadata by treating FeatureFlag resources as unstructured objects and marshaling spec.flagSpec directly. That avoids converting into typed CRDs (which can drop unknown fields like metadata) and ensures delete tombstones are handled safely, so the synced payload now preserves any metadata the CRD allows.

How to test

1. From repo root:
   • cd core && GOPATH=/tmp/go GOCACHE=/tmp/go-build go test ./pkg/sync/kubernetes
2. (Optional) Build and run your existing workflow to confirm metadata is present end-to-end.

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[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly enhances the Kubernetes synchronization mechanism by ensuring that FeatureFlag metadata is consistently preserved. It achieves this by directly processing spec.flagSpec from unstructured Kubernetes objects, which prevents the loss of unknown fields during conversion to typed CRDs. Additionally, the changes improve the robustness of informer tombstone handling and the readiness of the watcher, leading to a more reliable and complete synchronization of flag configurations.

Highlights

• Metadata Preservation: Preserved FeatureFlag metadata when syncing from Kubernetes by marshalling spec.flagSpec directly from unstructured objects, avoiding data loss from typed CRD conversions.
• Kubernetes Sync Hardening: Hardened informer tombstone handling and improved watcher readiness for the Kubernetes synchronization process.
• Unit Test Coverage: Added comprehensive unit tests covering metadata preservation and the unwrapping of tombstone objects.

Changelog

• core/pkg/sync/kubernetes/kubernetes_sync.go
  • Reordered import statements for consistency.
  • Modified the Sync function to buffer the notifies channel and reordered the startup of notify and watcher goroutines to improve readiness.
  • Updated the fetch function to utilize asUnstructured and marshalFlagSpec for processing Kubernetes objects.
  • Refactored commonHandler and updateFuncHandler to use asUnstructured and methods from unstructured.Unstructured for API version and name validation.
  • Renamed and refactored toFFCfg to asUnstructured, enhancing its capability to handle both unstructured.Unstructured and cache.DeletedFinalStateUnknown types.
  • Refactored marshallFeatureFlagSpec to marshalFlagSpec, which now directly extracts and marshals spec.flagSpec from an unstructured.Unstructured object.
• core/pkg/sync/kubernetes/kubernetes_sync_test.go
  • Added stdsync import for improved concurrency control in tests.
  • Renamed Test_toFFCfg to Test_asUnstructured and updated its logic to thoroughly test the new asUnstructured function, including scenarios for tombstone unwrapping.
  • Modified TestSync_ReSync to incorporate context.WithCancel and stdsync.WaitGroup for better management of asynchronous test execution and added a timeout for data channel reads.
  • Updated the getCFG helper function to include a default flagSpec structure in the generated configuration.
  • Modified the toUnstructured helper to return a *unstructured.Unstructured type.
  • Updated TestMeasure to use the new marshalFlagSpec with an unstructured.Unstructured input and require.JSONEq for more precise JSON comparison.

Activity

• No human activity (comments, reviews) has been recorded for this pull request yet.

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[gemini-code-assist]

Code Review

This pull request effectively adds metadata support for the Kubernetes sync provider by switching to unstructured objects, which prevents metadata from being dropped during marshalling. The changes also harden the sync logic by handling informer tombstones and improving watcher readiness with a buffered channel. The test suite has been significantly improved, with more robust asynchronous testing using proper context management. Overall, this is a solid enhancement. I have one suggestion to improve context handling in a test case for better consistency and correctness.

[Nilushiya]

Hi @toddbaert, @justinabrahms, @beeme1mr, @oxddr, @lukas-reining, @odubajDT, @thisthat, @bacherfl

This PR fixes #754 (CRD definition not following the latest flagD specifications).

As part of this fix, made the following changes:

• Updated the CRD definitions to align with the latest flagD specifications (feat: add flag metadata to FeatureFlag CRD open-feature-operator#808)
• I made this. I updated the flagd source code to support the metadata field that was missing

---

⚠️ FOSSA License Scan — 2 Flagged Issues

The automated FOSSA license scan on this PR is reporting 2 flagged license issues, but the details are behind a 🔒 Maintainer Access Required lock, so I'm unable to view or investigate them from my end.

Could a maintainer please:

1. Check the FOSSA scan report for this PR
2. Confirm whether the flagged issues are pre-existing or introduced by my changes
3. Let me know if any action is needed on my side

Note: My changes in this PR do not introduce any new dependencies, so the flagged issues are likely pre-existing in the repo.

---

If the license scan looks good from your side, could you please go ahead and review this PR? I believe the changes are ready for review. Happy to make any adjustments based on your feedback!

Thanks.

[lukas-reining]

I added ignore rules for the license issues as CairoSVG is only used as dev tooling and not shipped.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[toddbaert]

Thanks @Nilushiya ! I'll give this a look in the next couple days!