cache

type CacheData struct {
	ExpireAt int64  // ExpireAt is virtual expire time
	Data     string // Data is cache data
}

type Cacher interface {
	// GetData load data from cache
	// if cache not exist load data by LoadFunc
	// ttl is redis server ttl
	// virtualTTL is developer ttl
	GetData(ctx context.Context, key string, ttl time.Duration, virtualTTL time.Duration, f LoadFunc, data interface{}) (err error)

	// FlushCache flush cache
	// if cache not exist, load data and save cache
	FlushCache(ctx context.Context, key string, ttl time.Duration, virtualTTL time.Duration, f LoadFunc, data interface{}) (err error)
}

type LoadFunc func(ctx context.Context, target interface{}) (err error)