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
+}

server/backup/backup.go

@@ -20,6 +20,10 @@ const (
 	S3BackupAdapter    AdapterType = "s3"
 )
 
+// RestoreCallback is a generic restoration callback that exists for both local
+// and remote backups allowing the files to be restored.
+type RestoreCallback func(file string, r io.Reader) error
+
 type ArchiveDetails struct {
 	Checksum     string `json:"checksum"`
 	ChecksumType string `json:"checksum_type"`
@@ -51,35 +55,33 @@ type Backup struct {
 
 // noinspection GoNameStartsWithPackageName
 type BackupInterface interface {
-	// Returns the UUID of this backup as tracked by the panel instance.
+	// Identifier returns the UUID of this backup as tracked by the panel
+	// instance.
 	Identifier() string
-
-	// Attaches additional context to the log output for this backup.
+	// WithLogContext attaches additional context to the log output for this
+	// backup.
 	WithLogContext(map[string]interface{})
-
-	// Generates a backup in whatever the configured source for the specific
-	// implementation is.
+	// Generate creates a backup in whatever the configured source for the
+	// specific implementation is.
 	Generate(string, string) (*ArchiveDetails, error)
-
-	// Returns the ignored files for this backup instance.
+	// Ignored returns the ignored files for this backup instance.
 	Ignored() string
-
-	// Returns a SHA1 checksum for the generated backup.
+	// Checksum returns a SHA1 checksum for the generated backup.
 	Checksum() ([]byte, error)
-
-	// Returns the size of the generated backup.
+	// Size returns the size of the generated backup.
 	Size() (int64, error)
-
-	// Returns the path to the backup on the machine. This is not always the final
-	// storage location of the backup, simply the location we're using to store
-	// it until it is moved to the final spot.
+	// Path returns the path to the backup on the machine. This is not always
+	// the final storage location of the backup, simply the location we're using
+	// to store it until it is moved to the final spot.
 	Path() string
-
-	// Returns details about the archive.
+	// Details returns details about the archive.
 	Details() *ArchiveDetails
-
-	// Removes a backup file.
+	// Remove removes a backup file.
 	Remove() error
+	// Restore is called when a backup is ready to be restored to the disk from
+	// the given source. Not every backup implementation will support this nor
+	// will every implementation require a reader be provided.
+	Restore(reader io.Reader, callback RestoreCallback) error
 }
 
 func (b *Backup) Identifier() string {

server/backup/backup_local.go

@@ -2,7 +2,11 @@ package backup
 
 import (
 	"errors"
+	"io"
 	"os"
+
+	"github.com/mholt/archiver/v3"
+	"github.com/pterodactyl/wings/system"
 )
 
 type LocalBackup struct {
@@ -70,3 +74,17 @@ func (b *LocalBackup) Generate(basePath, ignore string) (*ArchiveDetails, error)
 	return b.Details(), nil
 }
 
+// Restore will walk over the archive and call the callback function for each
+// file encountered.
+func (b *LocalBackup) Restore(_ io.Reader, callback RestoreCallback) error {
+	return archiver.Walk(b.Path(), func(f archiver.File) error {
+		if f.IsDir() {
+			return nil
+		}
+		name, err := system.ExtractArchiveSourceName(f, "/")
+		if err != nil {
+			return err
+		}
+		return callback(name, f)
+	})
+}

server/backup/backup_s3.go

@@ -1,13 +1,17 @@
 package backup
 
 import (
+	"archive/tar"
+	"compress/gzip"
 	"fmt"
 	"io"
 	"net/http"
 	"os"
 	"strconv"
 
+	"github.com/juju/ratelimit"
 	"github.com/pterodactyl/wings/api"
+	"github.com/pterodactyl/wings/config"
 )
 
 type S3Backup struct {
@@ -149,3 +153,40 @@ func (s *S3Backup) generateRemoteRequest(rc io.ReadCloser) error {
 
 	return nil
 }
+
+// Restore will read from the provided reader assuming that it is a gzipped
+// tar reader. When a file is encountered in the archive the callback function
+// will be triggered. If the callback returns an error the entire process is
+// stopped, otherwise this function will run until all files have been written.
+//
+// This restoration uses a workerpool to use up to the number of CPUs available
+// on the machine when writing files to the disk.
+func (s *S3Backup) Restore(r io.Reader, callback RestoreCallback) error {
+	reader := r
+	// Steal the logic we use for making backups which will be applied when restoring
+	// this specific backup. This allows us to prevent overloading the disk unintentionally.
+	if writeLimit := int64(config.Get().System.Backups.WriteLimit * 1024 * 1024); writeLimit > 0 {
+		reader = ratelimit.Reader(r, ratelimit.NewBucketWithRate(float64(writeLimit), writeLimit))
+	}
+	gr, err := gzip.NewReader(reader)
+	if err != nil {
+		return err
+	}
+	defer gr.Close()
+	tr := tar.NewReader(gr)
+	for {
+		header, err := tr.Next()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+		if header.Typeflag == tar.TypeReg {
+			if err := callback(header.Name, tr); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}

server/filesystem/compress.go

@@ -115,12 +115,10 @@ func (fs *Filesystem) DecompressFile(dir string, file string) error {
 		return err
 	}
 
-	// Walk over all of the files spinning up an additional go-routine for each file we've encountered
-	// and then extract that file from the archive and write it to the disk. If any part of this process
-	// encounters an error the entire process will be stopped.
+	// Walk all of the files in the archiver file and write them to the disk. If any
+	// directory is encountered it will be skipped since we handle creating any missing
+	// directories automatically when writing files.
 	err = archiver.Walk(source, func(f archiver.File) error {
-		// Don't waste time with directories, we don't need to create them if they have no contents, and
-		// we will ensure the directory exists when opening the file for writing anyways.
 		if f.IsDir() {
 			return nil
 		}