feat: 🎉 Vectors na Vectors, the begining

Translate 1536 <-> 768 , 3072 <-> 2048

pkg/metrics/metrics.go

@@ -0,0 +1,112 @@
+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// Registry holds all vecna Prometheus metrics on a dedicated (non-global) registry.
+type Registry struct {
+	reg *prometheus.Registry
+
+	RequestsTotal       *prometheus.CounterVec
+	RequestDuration     *prometheus.HistogramVec
+	ForwardDuration     *prometheus.HistogramVec
+	TranslateDuration   *prometheus.HistogramVec
+	EndpointPriority    *prometheus.GaugeVec
+	EndpointInflight    *prometheus.GaugeVec
+	EndpointErrorsTotal *prometheus.CounterVec
+	TokensTotal         *prometheus.CounterVec
+}
+
+// New creates and registers all metrics on a fresh Prometheus registry.
+func New() *Registry {
+	reg := prometheus.NewRegistry()
+
+	r := &Registry{
+		reg: reg,
+
+		RequestsTotal: prometheus.NewCounterVec(prometheus.CounterOpts{
+			Name: "vecna_requests_total",
+			Help: "Total number of requests served by vecna.",
+		}, []string{"endpoint", "status"}),
+
+		RequestDuration: prometheus.NewHistogramVec(prometheus.HistogramOpts{
+			Name:    "vecna_request_duration_seconds",
+			Help:    "Total request wall-clock time.",
+			Buckets: prometheus.DefBuckets,
+		}, []string{"endpoint"}),
+
+		ForwardDuration: prometheus.NewHistogramVec(prometheus.HistogramOpts{
+			Name:    "vecna_forward_duration_seconds",
+			Help:    "Time spent waiting on the backing embedding model.",
+			Buckets: prometheus.DefBuckets,
+		}, []string{"target", "url"}),
+
+		TranslateDuration: prometheus.NewHistogramVec(prometheus.HistogramOpts{
+			Name:    "vecna_translate_duration_seconds",
+			Help:    "Time spent in the dimension adapter.",
+			Buckets: []float64{0.0001, 0.0005, 0.001, 0.005, 0.01, 0.05},
+		}, []string{"adapter_type"}),
+
+		EndpointPriority: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Name: "vecna_endpoint_priority",
+			Help: "Current dynamic routing priority for a forwarding endpoint.",
+		}, []string{"target", "url"}),
+
+		EndpointInflight: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Name: "vecna_endpoint_inflight",
+			Help: "Number of active in-flight requests per forwarding endpoint.",
+		}, []string{"target", "url"}),
+
+		EndpointErrorsTotal: prometheus.NewCounterVec(prometheus.CounterOpts{
+			Name: "vecna_endpoint_errors_total",
+			Help: "Total forwarding errors per endpoint, labelled by error type.",
+		}, []string{"target", "url", "error"}),
+
+		TokensTotal: prometheus.NewCounterVec(prometheus.CounterOpts{
+			Name: "vecna_tokens_total",
+			Help: "Tokens consumed by the backing embedding model, by target, model, and token type.",
+		}, []string{"target", "model", "token_type"}),
+	}
+
+	reg.MustRegister(
+		r.RequestsTotal,
+		r.RequestDuration,
+		r.ForwardDuration,
+		r.TranslateDuration,
+		r.EndpointPriority,
+		r.EndpointInflight,
+		r.EndpointErrorsTotal,
+		r.TokensTotal,
+	)
+
+	return r
+}
+
+// Prometheus returns the underlying registry for use with promhttp.HandlerFor.
+func (r *Registry) Prometheus() *prometheus.Registry {
+	return r.reg
+}
+
+// Convenience setters used by the router.
+
+func (r *Registry) SetEndpointPriority(target, url string, v float64) {
+	r.EndpointPriority.WithLabelValues(target, url).Set(v)
+}
+
+func (r *Registry) SetEndpointInflight(target, url string, v float64) {
+	r.EndpointInflight.WithLabelValues(target, url).Set(v)
+}
+
+func (r *Registry) IncEndpointErrors(target, url, errType string) {
+	r.EndpointErrorsTotal.WithLabelValues(target, url, errType).Inc()
+}
+
+func (r *Registry) AddTokens(target, model string, promptTokens, totalTokens int) {
+	if promptTokens > 0 {
+		r.TokensTotal.WithLabelValues(target, model, "prompt").Add(float64(promptTokens))
+	}
+	if totalTokens > 0 {
+		r.TokensTotal.WithLabelValues(target, model, "total").Add(float64(totalTokens))
+	}
+}