Do not skip directories when creating tar archive (#72)

* Update targz library to include potential ownership fix

* Move archive logic to main repo

* Remove assertions for debugging

* Use relative path in assertion

* Strip local part from archive location

* Log when extracting in tests

* Fix trimming of prfix

* Add license info to archive.go file

* Undo change in test assertion

* Add test checking for preserved file ownership

* use same postgres version in tests

* Wrap errors when archiving, handle deletion at script layer

cmd/backup/archive.go

@@ -0,0 +1,142 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+// Portions of this file are taken from package `targz`, Copyright (c) 2014 Fredrik Wallgren
+// Licensed under the MIT License: https://github.com/walle/targz/blob/57fe4206da5abf7dd3901b4af3891ec2f08c7b08/LICENSE
+
+package main
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+func createArchive(inputFilePath, outputFilePath string) error {
+	inputFilePath = stripTrailingSlashes(inputFilePath)
+	inputFilePath, outputFilePath, err := makeAbsolute(inputFilePath, outputFilePath)
+	if err != nil {
+		return fmt.Errorf("createArchive: error transposing given file paths: %w", err)
+	}
+	if err := os.MkdirAll(filepath.Dir(outputFilePath), 0755); err != nil {
+		return fmt.Errorf("createArchive: error creating output file path: %w", err)
+	}
+
+	if err := compress(inputFilePath, outputFilePath, filepath.Dir(inputFilePath)); err != nil {
+		return fmt.Errorf("createArchive: error creating archive: %w", err)
+	}
+
+	return nil
+}
+
+func stripTrailingSlashes(path string) string {
+	if len(path) > 0 && path[len(path)-1] == '/' {
+		path = path[0 : len(path)-1]
+	}
+
+	return path
+}
+
+func makeAbsolute(inputFilePath, outputFilePath string) (string, string, error) {
+	inputFilePath, err := filepath.Abs(inputFilePath)
+	if err == nil {
+		outputFilePath, err = filepath.Abs(outputFilePath)
+	}
+
+	return inputFilePath, outputFilePath, err
+}
+
+func compress(inPath, outFilePath, subPath string) error {
+	file, err := os.Create(outFilePath)
+	if err != nil {
+		return fmt.Errorf("compress: error creating out file: %w", err)
+	}
+
+	prefix := path.Dir(outFilePath)
+	gzipWriter := gzip.NewWriter(file)
+	tarWriter := tar.NewWriter(gzipWriter)
+
+	var paths []string
+	if err := filepath.WalkDir(inPath, func(path string, di fs.DirEntry, err error) error {
+		paths = append(paths, path)
+		return err
+	}); err != nil {
+		return fmt.Errorf("compress: error walking filesystem tree: %w", err)
+	}
+
+	for _, p := range paths {
+		if err := writeTarGz(p, tarWriter, prefix); err != nil {
+			return fmt.Errorf("compress error writing %s to archive: %w", p, err)
+		}
+	}
+
+	err = tarWriter.Close()
+	if err != nil {
+		return fmt.Errorf("compress: error closing tar writer: %w", err)
+	}
+
+	err = gzipWriter.Close()
+	if err != nil {
+		return fmt.Errorf("compress: error closing gzip writer: %w", err)
+	}
+
+	err = file.Close()
+	if err != nil {
+		return fmt.Errorf("compress: error closing file: %w", err)
+	}
+
+	return nil
+}
+
+func writeTarGz(path string, tarWriter *tar.Writer, prefix string) error {
+	fileInfo, err := os.Lstat(path)
+	if err != nil {
+		return fmt.Errorf("writeTarGz: error getting file infor for %s: %w", path, err)
+	}
+
+	if fileInfo.Mode()&os.ModeSocket == os.ModeSocket {
+		return nil
+	}
+
+	var link string
+	if fileInfo.Mode()&os.ModeSymlink == os.ModeSymlink {
+		var err error
+		if link, err = os.Readlink(path); err != nil {
+			return fmt.Errorf("writeTarGz: error resolving symlink %s: %w", path, err)
+		}
+	}
+
+	header, err := tar.FileInfoHeader(fileInfo, link)
+	if err != nil {
+		return fmt.Errorf("writeTarGz: error getting file info header: %w", err)
+	}
+	header.Name = strings.TrimPrefix(path, prefix)
+
+	err = tarWriter.WriteHeader(header)
+	if err != nil {
+		return fmt.Errorf("writeTarGz: error writing file info header: %w", err)
+	}
+
+	if !fileInfo.Mode().IsRegular() {
+		return nil
+	}
+
+	file, err := os.Open(path)
+	if err != nil {
+		return fmt.Errorf("writeTarGz: error opening %s: %w", path, err)
+	}
+	defer file.Close()
+
+	_, err = io.Copy(tarWriter, file)
+	if err != nil {
+		return fmt.Errorf("writeTarGz: error copying %s to tar writer: %w", path, err)
+	}
+
+	return nil
+}

cmd/backup/script.go

@@ -23,7 +23,6 @@ import (
 	"github.com/docker/docker/client"
 	"github.com/kelseyhightower/envconfig"
 	"github.com/leekchan/timeutil"
-	"github.com/m90/targz"
 	"github.com/minio/minio-go/v7"
 	"github.com/minio/minio-go/v7/pkg/credentials"
 	"github.com/otiai10/copy"
@@ -364,7 +363,7 @@ func (s *script) takeBackup() error {
 		s.logger.Infof("Removed tar file `%s`.", tarFile)
 		return nil
 	})
-	if err := targz.Compress(backupSources, tarFile); err != nil {
+	if err := createArchive(backupSources, tarFile); err != nil {
 		return fmt.Errorf("takeBackup: error compressing backup folder: %w", err)
 	}