Get general concept for backup resotration using a unified interface implemented

server/backup.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"io"
 	"io/ioutil"
 	"os"
 
@@ -50,9 +51,9 @@ func (s *Server) getServerwideIgnoredFiles() (string, error) {
 	return string(b), nil
 }
 
-// Performs a server backup and then emits the event over the server websocket. We
-// let the actual backup system handle notifying the panel of the status, but that
-// won't emit a websocket event.
+// Backup performs a server backup and then emits the event over the server
+// websocket. We let the actual backup system handle notifying the panel of the
+// status, but that won't emit a websocket event.
 func (s *Server) Backup(b backup.BackupInterface) error {
 	ignored := b.Ignored()
 	if b.Ignored() == "" {
@@ -108,3 +109,43 @@ func (s *Server) Backup(b backup.BackupInterface) error {
 
 	return nil
 }
+
+// RestoreBackup calls the Restore function on the provided backup. Once this
+// restoration is completed an event is emitted to the websocket to notify the
+// Panel that is has been completed.
+//
+// In addition to the websocket event an API call is triggered to notify the
+// Panel of the new state.
+func (s *Server) RestoreBackup(b backup.BackupInterface, reader io.ReadCloser) (err error) {
+	s.Config().SetSuspended(true)
+	// Local backups will not pass a reader through to this function, so check first
+	// to make sure it is a valid reader before trying to close it.
+	defer func() {
+		s.Config().SetSuspended(false)
+		if reader != nil {
+			reader.Close()
+		}
+	}()
+	// Don't try to restore the server until we have completely stopped the running
+	// instance, otherwise you'll likely hit all types of write errors due to the
+	// server being suspended.
+	err = s.Environment.WaitForStop(120, false)
+	if err != nil {
+		return err
+	}
+	// Send an API call to the Panel as soon as this function is done running so that
+	// the Panel is informed of the restoration status of this backup.
+	defer func() {
+		if err := api.New().SendRestorationStatus(b.Identifier(), err == nil); err != nil {
+			s.Log().WithField("error", err).WithField("backup", b.Identifier()).Error("failed to notify Panel of backup restoration status")
+		}
+	}()
+
+	// Attempt to restore the backup to the server by running through each entry
+	// in the file one at a time and writing them to the disk.
+	err = b.Restore(reader, func(file string, r io.Reader) error {
+		return s.Filesystem().Writefile(file, r)
+	})
+
+	return err
+}