fix: backups get gzip, absolute paths, single archive file

cli/app/backup.go

@@ -1,9 +1,11 @@
 package app
 
 import (
+	"archive/tar"
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
+	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -19,6 +21,9 @@ import (
 	"github.com/docker/cli/cli/command"
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/pkg/archive"
+	"github.com/docker/docker/pkg/system"
+	"github.com/klauspost/pgzip"
 	"github.com/sirupsen/logrus"
 	"github.com/urfave/cli"
 )
@@ -150,34 +155,56 @@ func runBackup(app config.App, serviceName string, bkConfig backupConfig) error
 		}
 
 		if err := container.RunExec(dcli, cl, targetContainer.ID, &preHookExecOpts); err != nil {
-			return err
+			return fmt.Errorf("failed to run %s on %s: %s", bkConfig.preHookCmd, targetContainer.ID, err.Error())
 		}
 
 		logrus.Infof("succesfully ran %s pre-hook command: %s", fullServiceName, bkConfig.preHookCmd)
 	}
 
+	var tempBackupPaths []string
 	for _, remoteBackupPath := range bkConfig.backupPaths {
 		timestamp := strconv.Itoa(time.Now().Nanosecond())
 		sanitisedPath := strings.ReplaceAll(remoteBackupPath, "/", "_")
 		localBackupPath := filepath.Join(config.BACKUP_DIR, fmt.Sprintf("%s%s_%s.tar.gz", fullServiceName, sanitisedPath, timestamp))
-		logrus.Debugf("backing up %s:%s to %s", fullServiceName, remoteBackupPath, localBackupPath)
+		logrus.Debugf("temporarily backing up %s:%s to %s", fullServiceName, remoteBackupPath, localBackupPath)
+
+		logrus.Infof("backing up %s:%s", fullServiceName, remoteBackupPath)
 
 		content, _, err := cl.CopyFromContainer(context.Background(), targetContainer.ID, remoteBackupPath)
 		if err != nil {
-			return err
+			logrus.Debugf("failed to copy %s from container: %s", remoteBackupPath, err.Error())
+			if err := cleanupTempArchives(tempBackupPaths); err != nil {
+				return fmt.Errorf("failed to clean up temporary archives: %s", err.Error())
+			}
+			return fmt.Errorf("failed to copy %s from container: %s", remoteBackupPath, err.Error())
 		}
 		defer content.Close()
 
-		body, err := ioutil.ReadAll(content)
-		if err != nil {
-			return err
+		_, srcBase := archive.SplitPathDirEntry(remoteBackupPath)
+		preArchive := archive.RebaseArchiveEntries(content, srcBase, remoteBackupPath)
+		if err := copyToFile(localBackupPath, preArchive); err != nil {
+			logrus.Debugf("failed to create tar archive (%s): %s", localBackupPath, err.Error())
+			if err := cleanupTempArchives(tempBackupPaths); err != nil {
+				return fmt.Errorf("failed to clean up temporary archives: %s", err.Error())
+			}
+			return fmt.Errorf("failed to create tar archive (%s): %s", localBackupPath, err.Error())
 		}
 
-		if err := ioutil.WriteFile(localBackupPath, body, 0644); err != nil {
-			return err
-		}
+		tempBackupPaths = append(tempBackupPaths, localBackupPath)
+	}
 
-		logrus.Infof("backed up %s:%s to %s", fullServiceName, remoteBackupPath, localBackupPath)
+	logrus.Infof("compressing and merging archives...")
+
+	if err := mergeArchives(tempBackupPaths, fullServiceName); err != nil {
+		logrus.Debugf("failed to merge archive files: %s", err.Error())
+		if err := cleanupTempArchives(tempBackupPaths); err != nil {
+			return fmt.Errorf("failed to clean up temporary archives: %s", err.Error())
+		}
+		return fmt.Errorf("failed to merge archive files: %s", err.Error())
+	}
+
+	if err := cleanupTempArchives(tempBackupPaths); err != nil {
+		return fmt.Errorf("failed to clean up temporary archives: %s", err.Error())
 	}
 
 	if bkConfig.postHookCmd != "" {
@@ -203,3 +230,141 @@ func runBackup(app config.App, serviceName string, bkConfig backupConfig) error
 
 	return nil
 }
+
+func copyToFile(outfile string, r io.Reader) error {
+	tmpFile, err := system.TempFileSequential(filepath.Dir(outfile), ".tar_temp")
+	if err != nil {
+		return err
+	}
+
+	tmpPath := tmpFile.Name()
+
+	_, err = io.Copy(tmpFile, r)
+	tmpFile.Close()
+
+	if err != nil {
+		os.Remove(tmpPath)
+		return err
+	}
+
+	if err = os.Rename(tmpPath, outfile); err != nil {
+		os.Remove(tmpPath)
+		return err
+	}
+
+	return nil
+}
+
+func cleanupTempArchives(tarPaths []string) error {
+	for _, tarPath := range tarPaths {
+		if err := os.RemoveAll(tarPath); err != nil {
+			return err
+		}
+
+		logrus.Debugf("remove temporary archive file %s", tarPath)
+	}
+
+	return nil
+}
+
+func mergeArchives(tarPaths []string, serviceName string) error {
+	var out io.Writer
+	var cout *pgzip.Writer
+
+	timestamp := strconv.Itoa(time.Now().Nanosecond())
+	localBackupPath := filepath.Join(config.BACKUP_DIR, fmt.Sprintf("%s_%s.tar.gz", serviceName, timestamp))
+
+	fout, err := os.Create(localBackupPath)
+	if err != nil {
+		return fmt.Errorf("Failed to open %s: %s", localBackupPath, err)
+	}
+
+	defer fout.Close()
+	out = fout
+
+	cout = pgzip.NewWriter(out)
+	out = cout
+
+	tw := tar.NewWriter(out)
+
+	for _, tarPath := range tarPaths {
+		if err := addTar(tw, tarPath); err != nil {
+			return fmt.Errorf("failed to merge %s: %v", tarPath, err)
+		}
+	}
+
+	if err := tw.Close(); err != nil {
+		return fmt.Errorf("failed to close tar writer %v", err)
+	}
+
+	if cout != nil {
+		if err := cout.Flush(); err != nil {
+			return fmt.Errorf("failed to flush: %s", err)
+		} else if err = cout.Close(); err != nil {
+			return fmt.Errorf("failed to close compressed writer: %s", err)
+		}
+	}
+
+	logrus.Infof("backed up %s to %s", serviceName, localBackupPath)
+
+	return nil
+}
+
+func addTar(tw *tar.Writer, pth string) (err error) {
+	var tr *tar.Reader
+	var rc io.ReadCloser
+	var hdr *tar.Header
+
+	if tr, rc, err = openTarFile(pth); err != nil {
+		return
+	}
+
+	for {
+		if hdr, err = tr.Next(); err != nil {
+			if err == io.EOF {
+				err = nil
+			}
+			break
+		}
+		if err = tw.WriteHeader(hdr); err != nil {
+			break
+		} else if _, err = io.Copy(tw, tr); err != nil {
+			break
+		}
+	}
+	if err == nil {
+		err = rc.Close()
+	} else {
+		rc.Close()
+	}
+	return
+}
+
+func openTarFile(pth string) (tr *tar.Reader, rc io.ReadCloser, err error) {
+	var fin *os.File
+	var n int
+	buff := make([]byte, 1024)
+
+	if fin, err = os.Open(pth); err != nil {
+		return
+	}
+
+	if n, err = fin.Read(buff); err != nil {
+		fin.Close()
+		return
+	} else if n == 0 {
+		fin.Close()
+		err = fmt.Errorf("%s is empty", pth)
+		return
+	}
+
+	if _, err = fin.Seek(0, 0); err != nil {
+		fin.Close()
+		return
+	}
+
+	rc = fin
+	tr = tar.NewReader(rc)
+
+	return tr, rc, nil
+}

go.mod

@@ -38,6 +38,7 @@ require (
 	github.com/gorilla/mux v1.8.0 // indirect
 	github.com/hashicorp/go-retryablehttp v0.7.1
 	github.com/kevinburke/ssh_config v1.2.0
+	github.com/klauspost/pgzip v1.2.5
 	github.com/libdns/gandi v1.0.2
 	github.com/libdns/libdns v0.2.1
 	github.com/moby/sys/mount v0.2.0 // indirect

go.sum

@@ -656,7 +656,9 @@ github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/klauspost/compress v1.11.3/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
 github.com/klauspost/compress v1.11.13/go.mod h1:aoV0uJVorq1K+umq18yTdKaF57EivdYsUV+/s2qKfXs=
+github.com/klauspost/compress v1.14.2 h1:S0OHlFk/Gbon/yauFJ4FfJJF5V0fc5HbBTJazi28pRw=
 github.com/klauspost/compress v1.14.2/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
+github.com/klauspost/pgzip v1.2.5 h1:qnWYvvKqedOF2ulHpMG72XQol4ILEJ8k2wwRl/Km8oE=
 github.com/klauspost/pgzip v1.2.5/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQKQE9RUs=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/konsorten/go-windows-terminal-sequences v1.0.2/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=