Golang : Archive directory with tar and gzip

In the previous tutorial, we learn how to extract files from tar ball and deal with gzipped tar ball in Golang. However, the tar ball created in the previous tutorial example is created with the tar command in Unix/Linux OS. In this tutorial, we will learn how to create tar archive and gzip the archive in Golang.

The codes below will create a tar archive from the given source direcotry and compressed the tar if the filename ends with .gz

 package main

 import (
 "archive/tar"
 "compress/gzip"
 "flag"
 "fmt"
 "io"
 "os"
 "strings"
 "path/filepath"
 )

 func checkerror(err error) {

 if err != nil {
 fmt.Println(err)
 os.Exit(1)
 }
 }

 func main() {

 flag.Parse() // get the arguments from command line

 destinationfile := flag.Arg(0)

 if destinationfile == "" {
 fmt.Println("Usage : gotar destinationfile.tar.gz source")
 os.Exit(1)
 }

 sourcedir := flag.Arg(1)

 if sourcedir == "" {
 fmt.Println("Usage : gotar destinationfile.tar.gz source-directory")
 os.Exit(1)
 }

 dir, err := os.Open(sourcedir)

 checkerror(err)

 defer dir.Close()

 files, err := dir.Readdir(0) // grab the files list

 checkerror(err)

 tarfile, err := os.Create(destinationfile)

 checkerror(err)

 defer tarfile.Close()
 var fileWriter io.WriteCloser = tarfile

 if strings.HasSuffix(destinationfile, ".gz") {
 fileWriter = gzip.NewWriter(tarfile) // add a gzip filter
 defer fileWriter.Close() // if user add .gz in the destination filename
 }

 tarfileWriter := tar.NewWriter(fileWriter)
 defer tarfileWriter.Close()

 for _, fileInfo := range files {

 if fileInfo.IsDir() {
 continue
 }

 // see https://www.socketloop.com/tutorials/go-file-path-independent-of-operating-system

 file, err := os.Open(dir.Name() + string(filepath.Separator) + fileInfo.Name())

 checkerror(err)

 defer file.Close()


 // prepare the tar header

 header := new(tar.Header)
 header.Name = file.Name()
 header.Size = fileInfo.Size()
 header.Mode = int64(fileInfo.Mode())
 header.ModTime = fileInfo.ModTime()


 err = tarfileWriter.WriteHeader(header)

 checkerror(err)

 _, err = io.Copy(tarfileWriter, file)

 checkerror(err)
 }

 }

Sample tests :

> ./gotar testdir.tar.gz ./testdir1

> ./gotar testdir.tar ./testdir1

ls -la testdir

-rw-r--r-- 1 root root 3072 Dec 16 22:54 testdir.tar

-rw-r--r-- 1 root root 148 Dec 16 22:54 testdir.tar.gz

That's it. Creating tar balls and compressed them with gzip is simple in Golang. Hope this tutorial can be useful to you.