GET /api/vitals: slim scale + capacity endpoint

[nadaverell]

Summary

New endpoint returning per-cluster scale and capacity — node/pod phase counts, CPU/memory usage+requests vs allocatable, metrics-server availability — without the home-page payload. Purpose-built for Radar Cloud's fleet fan-out (which previously fetched the full /api/dashboard per cluster and discarded ~90% of it), equally usable by any consumer that wants vitals without the kitchen sink.

What changed

• GET /api/vitals (internal/server/vitals.go), mounted beside /api/dashboard in the authed API group. Pod counts are namespace-scoped to the caller's access; node counts gate on the caller's own node RBAC like the dashboard does.
• Typed completeness contract: completeness.{accessRestricted, pending[], restricted[], complete} — sentinel lists carry k8score ResourceType values filtered to vitals-relevant kinds, and complete is derived server-side. Includes a "nodes" restricted sentinel the dashboard never had (consumers previously had to infer node RBAC blindness from zero totals). Metrics availability is deliberately not part of completeness — it's a capability, reported separately.
• Metrics probe memoized 15s per RBAC scope: live usage hits metrics-server (8s timeout) — fine per page-load, wasteful for fleet polling. Requests/capacity stay informer-derived and fresh.
• Stable JSON shape: pod phase counts have no omitempty — fleet consumers get fixed fields, not fields that vanish at zero.

Testing

go test ./internal/server/ green, including two new tests: happy path against the smoke fixture (counts, completeness, no false metrics claim) and node-RBAC-denial surfacing restricted: ["nodes"] + complete: false through the real permission-cache gate.

Part of the endpoint rework for cloud; the hub-side switch of its vitals fan-out to this endpoint lands separately.

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Note

Medium Risk
New authenticated API surface with nuanced RBAC (pods vs namespace visibility, partial scopes) and cross-user metrics memoization; behavior is well-tested but wrong gates could leak aggregate cluster data.

Overview
Adds GET /api/vitals, a lightweight alternative to the full dashboard for fleet polling: node/pod phase counts, CPU/memory capacity vs requests vs live usage, and explicit completeness metadata (accessRestricted, pending, restricted, derived complete). Pod data is gated on pod list RBAC (not just namespace visibility); node metrics stay behind node list like the dashboard.

Shared metrics logic moves into node_metrics.go (fetchNodeUsage, listPodsScoped, computeCapacityRequests); dashboard metrics now call those helpers instead of inlining the same math.

For vitals, only the metrics-server usage probe is memoized 15s per kube-context + user (cleared on context switch); informer-derived capacity/requests stay fresh each request.

Tests cover namespace scoping sentinels, capacity math, vitals happy path, node RBAC denial, deployments-only users, and partial pod namespace access.

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[cursor]

Empty node cache probes metrics

Medium Severity

The vitals handler still calls the memoized metrics-server probe when the node lister returns zero nodes, unlike getDashboardMetrics, which returns before probing. That can set metricsServerAvailable true while node totals and CPU/memory summaries are absent, and mark completeness complete during informer catch-up when counts are still empty.

 

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[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

There are 3 total unresolved issues (including 2 from previous reviews).

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^{Reviewed by Cursor Bugbot for commit 197e6be. Configure here.}

[cursor]

Duplicate pods restricted entry

Low Severity

If the caller can list pods and pod scope is partial, but cache.Pods() is nil, vitals appends "pods" to completeness.restricted twice—once in the else branch and again for partial scope—yielding duplicate sentinel values in JSON.

 

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