cache

type Backend interface {
	// Get retrieves v from Backend. The returned v is a deepcopy of the original msg
	// if the key is stored in the cache. Otherwise, v is nil.
	// If allowExpired, v might be expired as long as the key is in the cache.
	// Note: The caller should change the TTLs and id of v.
	Get(ctx context.Context, key string, allowExpired bool) (v *dns.Msg, storedTime, expirationTime time.Time, err error)

	// Store stores a deepcopy of v into Backend. v cannot be nil.
	// If expirationTime is already passed, Store is a noop.
	Store(ctx context.Context, key string, v *dns.Msg, storedTime, expirationTime time.Time) (err error)

	// Closer closes the cache backend.
	io.Closer
}