initiall commit

apps/backend/internal/middleware/metrics.go

@@ -0,0 +1,22 @@
+package middleware
+
+import (
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/tdvorak/primora/apps/backend/internal/observability"
+)
+
+func Metrics(metrics *observability.Metrics) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		start := time.Now()
+		metrics.IncrementActive()
+		defer metrics.DecrementActive()
+
+		c.Next()
+
+		duration := time.Since(start)
+		isError := c.Writer.Status() >= 400
+		metrics.RecordRequest(duration, isError)
+	}
+}