Preserve unmodeled fields when editing K8s endpoint aggregators

[ikhoon]

Motivation:

The xDS Kubernetes endpoint aggregator editor rebuilds the aggregator YAML from its form model on every save. Because the form modeled only a subset of the schema, saving from the console silently dropped every field the form has no editor for — distinctEndpoint, metadataMapping, and the aggregator-level policy today, and any field added to the schema later. An operator who edited an aggregator through the console would unknowingly discard them; losing distinctEndpoint, for example, re-introduces duplicate endpoints on the next rolling restart.

Modifications:

• Add distinctEndpoint to the watcher form as a checkbox next to "Trust certificates".
• On update, overlay the form's edits onto the document the form was loaded from instead of rebuilding it from scratch. Fields the form owns come from the form (an emptied optional field is dropped — an intentional clear), and any field the form does not model is preserved verbatim. This closes the whole class of silent drops: a field added to the proto later survives an edit with no change here.
• Carry the loaded document — per watcher and at the aggregator level — through the form so the overlay has the original to merge onto. A newly-added watcher or a new aggregator has none, so creation is unaffected.
• Show a read-only note with the number of configured metadata-mapping rules, since the form has no editor for them.

Result:

Editing a Kubernetes endpoint aggregator through the web console no longer drops fields the form has no editor for, including fields added to the schema later. distinctEndpoint is now viewable and editable in the form.

Testing:

• Component tests (jest + @testing-library/react) covering load → edit → save round-trips: distinctEndpoint on/off, a multi-watcher removal that keeps each mapping with its own watcher, that a field the form does not model survives an update, and that an emptied optional field is still cleared. The "unmodeled field survives" test was confirmed failing before this change and passing after.
• Verified live in the web console against a local test server, in light and dark mode: the "Distinct endpoint" checkbox reflects the stored value, and the read-only metadata-mapping note appears only when mappings exist.

Screenshots (web console, light / dark):

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📝 Walkthrough

Walkthrough

The Kubernetes aggregator editor preserves unmanaged watcher and aggregator YAML fields across load/save operations. It adds a distinct endpoint checkbox, displays preserved metadata mapping counts, and tests round-trip serialization, watcher isolation, and optional-field clearing.

Changes

xDS aggregator preservation

Layer / File(s)	Summary
Round-trip model and YAML handling webapp/src/dogma/features/xds/K8sAggregatorEditor.tsx	Form state and YAML serialization retain watcher distinctEndpoint, unmanaged watcher fields, and aggregator-level fields such as policy.
Watcher editor controls and indicators webapp/src/dogma/features/xds/K8sAggregatorEditor.tsx	The watcher editor adds a distinct endpoint checkbox and conditionally displays preserved metadata mapping counts.
Round-trip and watcher isolation tests webapp/tests/dogma/features/xds/K8sAggregatorEditor.test.tsx	Tests cover preservation, toggling, policy omission, per-watcher mappings, conditional UI messages, future fields, and optional-field clearing.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Sequence Diagram(s)

sequenceDiagram
  participant YAML
  participant K8sAggregatorEditor
  participant Form
  participant UpdateMutation
  YAML->>K8sAggregatorEditor: Load watcher and aggregator fields
  K8sAggregatorEditor->>Form: Populate managed values and original YAML entries
  Form->>K8sAggregatorEditor: Submit edited values
  K8sAggregatorEditor->>UpdateMutation: Send overlaid YAML
  UpdateMutation->>YAML: Persist updated and preserved fields

Loading

Possibly related PRs

• line/centraldogma#1326: Adds related backend support for watcher distinct_endpoint and metadata_mapping.
• line/centraldogma#1338: Modifies the same editor’s YAML serialization and parsing flows.

Suggested labels: new feature

Suggested reviewers: jrhee17, minwoox

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly and concisely describes the primary change: preserving fields not directly modeled by the Kubernetes endpoint aggregator editor.
Description check	✅ Passed	The description directly explains the motivation, implementation, behavior, and testing for preserving unmodeled aggregator and watcher fields.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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🧹 Nitpick comments (1)

webapp/src/dogma/features/xds/K8sAggregatorEditor.tsx (1)

83-117: 📐 Maintainability & Code Quality | 🔵 Trivial | 💤 Low value

Clarify the round-trip contract for MetadataMappingForm.

The fields are only passed through as watcher.metadataMapping on load/save, so this interface does not validate the persisted schema; if those shapes are a documented Central Dogma xDS convention, cite or move the contract to the backend/proto definition to prevent future UI changes from silently dropping or reformatting unsupported mappings.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@webapp/src/dogma/features/xds/K8sAggregatorEditor.tsx` around lines 83 - 117,
Clarify the round-trip contract represented by MetadataMappingForm: reference
the authoritative Central Dogma xDS backend or proto schema if one exists, or
move the mapping type definition there and reuse it in K8sAggregatorEditor.
Ensure parseToFormData and buildBody continue preserving all supported
metadataMapping fields without silently dropping or reformatting unknown values.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@webapp/src/dogma/features/xds/K8sAggregatorEditor.tsx`:
- Around line 83-117: Clarify the round-trip contract represented by
MetadataMappingForm: reference the authoritative Central Dogma xDS backend or
proto schema if one exists, or move the mapping type definition there and reuse
it in K8sAggregatorEditor. Ensure parseToFormData and buildBody continue
preserving all supported metadataMapping fields without silently dropping or
reformatting unknown values.

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ℹ️ Review info

⚙️ Run configuration

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Run ID: 061031ec-a7a2-46eb-9590-f40dbc9e5f0f

📥 Commits

Reviewing files that changed from the base of the PR and between 5afa110 and 33eb336.

📒 Files selected for processing (2)

• webapp/src/dogma/features/xds/K8sAggregatorEditor.tsx
• webapp/tests/dogma/features/xds/K8sAggregatorEditor.test.tsx