etcdctl: add etcdctl snapshot pipe command

To improve the security of etcdctl. Added the ability to write snapshots to stdout without writing data to disk.

Signed-off-by: Ais8Ooz8 <[email protected]>

client/v3/snapshot/v3_snapshot.go

@@ -97,13 +97,12 @@ func SaveWithVersion(ctx context.Context, lg *zap.Logger, cfg clientv3.Config, d
 	defer os.RemoveAll(partPath)
 	defer f.Close()
 
-	var version string
-	version, err = WriteSnapshotWithVersion(ctx, lg, cfg, f)
+	version, _ := WriteSnapshotWithVersion(ctx, lg, cfg, f)
 	if err = os.Rename(partPath, dbPath); err != nil {
 		return version, fmt.Errorf("could not rename %s to %s (%v)", partPath, dbPath, err)
 	}
 	lg.Info("saved", zap.String("path", dbPath))
-	return version, err
+	return version, nil
 }
 
 func PipeWithVersion(ctx context.Context, lg *zap.Logger, cfg clientv3.Config) (string, error) {