feat(exporter): add prometheus exporter for cache, database & webserver stats

internal/cache/cache.go

@@ -16,6 +16,15 @@ func NewCache(ttl time.Duration) *Cache {
 	}
 }
 
+func (c *Cache) Count() uint {
+	var counter uint
+	c.store.Range(func(_, _ any) bool {
+		counter++
+		return true
+	})
+	return counter
+}
+
 func (c *Cache) Set(key, value uint) {
 	c.store.Store(key, value)
 	time.AfterFunc(c.ttl, func() {