[PHASE-8] Define metrics

internal/metrics/metrics.go

@@ -0,0 +1,33 @@
+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	ActiveConnections = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "wisdom_active_connections",
+		Help: "Number of currently active TCP connections",
+	})
+
+	RequestsTotal = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "wisdom_requests_total",
+		Help: "Total number of requests processed",
+	})
+
+	RequestErrors = promauto.NewCounterVec(prometheus.CounterOpts{
+		Name: "wisdom_request_errors_total",
+		Help: "Total number of request errors by type",
+	}, []string{"error_type"})
+
+	RequestDuration = promauto.NewHistogram(prometheus.HistogramOpts{
+		Name: "wisdom_request_duration_seconds",
+		Help: "Time taken to process requests",
+	})
+
+	QuotesServed = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "wisdom_quotes_served_total",
+		Help: "Total number of quotes successfully served to clients",
+	})
+)