TokenRateLimitPolicy View: Metrics Tab with Perses Panels

[R-Lawton]

Context

Add a Metrics tab to the TokenRateLimitPolicy details page showing token-based rate limiting metrics using embedded Perses panels. This answers: "Are consumers hitting token limits? How many tokens are being consumed?"

Depends on the shared Perses infrastructure established in #220.

Requirements

New Metrics tab

Add a console.tab/horizontalNav on TokenRateLimitPolicy (kuadrant.io/v1alpha1):

• Tab name: "Metrics"
• Tab href: metrics

Panels:

Panel	Metric	Panel Type
Token Consumption Over Time	sum(rate(authorized_hits{limitador_namespace="<ns>/<route>"}[5m]))	TimeSeriesChart
Requests vs Tokens	sum(rate(authorized_calls{limitador_namespace="<ns>/<route>"}[5m])) and sum(rate(authorized_hits{limitador_namespace="<ns>/<route>"}[5m]))	TimeSeriesChart (2 series: requests, tokens)
Rejected Requests	sum(rate(limited_calls{limitador_namespace="<ns>/<route>"}[5m]))	TimeSeriesChart
Token Reports	sum(rate(report_calls{limitador_namespace="<ns>/<route>"}[5m]))	StatChart (reports/s)
Rejection Rate	sum(rate(limited_calls[5m])) / (sum(rate(authorized_calls[5m])) + sum(rate(limited_calls[5m]))) * 100 scoped to this policy	GaugeChart

Controls:

• Time range selector: 15m, 1h, 6h, 24h, 7d (default: 1h)

Token vs counter rate limiting

TokenRateLimitPolicy uses Limitador's report RPC instead of check_rate_limit. Key differences from RateLimitPolicy (#639):

• authorized_hits reflects actual token counts (e.g. LLM usage.total_tokens) — much larger than authorized_calls
• report_calls tracks token reporting operations (unique to token-based limiting)
• The report endpoint always returns OK — enforcement happens at the prior check_rate_limit call

Limitador namespace scoping

The limitador_namespace label format is "{k8s_namespace}/{route_name}". To scope to a specific TokenRateLimitPolicy, the target HTTPRoute's namespace and name must be resolved from the policy's targetRef.

With telemetry: exhaustive on the Limitador CR, limited_calls includes a limit_name label for per-limit breakdown.

Empty states

• No token data: "No token rate limiting metrics available. Metrics will appear once requests are evaluated against this policy."
• Prometheus unavailable: shared EmptyMetricsState component from Overview Page: Migrate to Perses Metrics Panels and Add Observability Tab #220

Notes

• Requires React 18 upgrade (OCP 4.22+ only)