rename app folder to internal.

internal/cache/cache.go

@@ -0,0 +1,31 @@
+package cache
+
+import (
+	"context"
+	"time"
+)
+
+type Cache struct {
+	store  Store
+	prefix string
+}
+
+// Create a new cache
+func NewCache(prefix string, store Store) *Cache {
+	return &Cache{
+		store:  store,
+		prefix: prefix,
+	}
+}
+
+func (cache *Cache) Get(ctx context.Context, key string, value any) error {
+	return cache.store.Get(ctx, cache.key(key), value)
+}
+
+func (cache *Cache) Set(ctx context.Context, key string, value any, ttl time.Duration) error {
+	return cache.store.Set(ctx, cache.key(key), value, ttl)
+}
+
+func (cache *Cache) key(key string) string {
+	return cache.prefix + "::" + key
+}