type Manager interface {
	// Save fetches snapshot from remote etcd server and saves data
	// to target path. If the context "ctx" is canceled or timed out,
	// snapshot save stream will error out (e.g. context.Canceled,
	// context.DeadlineExceeded). Make sure to specify only one endpoint
	// in client configuration. Snapshot API must be requested to a
	// selected node, and saved snapshot is the point-in-time state of
	// the selected node.
	Save(ctx context.Context, cfg clientv3.Config, dbPath string) error

	// Status returns the snapshot file information.
	Status(dbPath string) (Status, error)

	// Restore restores a new etcd data directory from given snapshot
	// file. It returns an error if specified data directory already
	// exists, to prevent unintended data directory overwrites.
	Restore(cfg RestoreConfig) error
}

type RestoreConfig struct {
	// SnapshotPath is the path of snapshot file to restore from.
	SnapshotPath string

	// Name is the human-readable name of this member.
	Name string

	// OutputDataDir is the target data directory to save restored data.
	// OutputDataDir should not conflict with existing etcd data directory.
	// If OutputDataDir already exists, it will return an error to prevent
	// unintended data directory overwrites.
	// If empty, defaults to "[Name].etcd" if not given.
	OutputDataDir string
	// OutputWALDir is the target WAL data directory.
	// If empty, defaults to "[OutputDataDir]/member/wal" if not given.
	OutputWALDir string

	// PeerURLs is a list of member's peer URLs to advertise to the rest of the cluster.
	PeerURLs []string

	// InitialCluster is the initial cluster configuration for restore bootstrap.
	InitialCluster string
	// InitialClusterToken is the initial cluster token for etcd cluster during restore bootstrap.
	InitialClusterToken string

	// SkipHashCheck is "true" to ignore snapshot integrity hash value
	// (required if copied from data directory).
	SkipHashCheck bool
}

type Status struct {
	Hash      uint32 `json:"hash"`
	Revision  int64  `json:"revision"`
	TotalKey  int    `json:"totalKey"`
	TotalSize int64  `json:"totalSize"`
}