tar.go

package util

import (
	"archive/tar"
	"bytes"
	"compress/gzip"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"

	"github.com/mholt/archiver/v3"
	"github.com/pkg/errors"
)

func TGZArchive(dir string) ([]byte, error) {
	tempDir, err := ioutil.TempDir("", "kots")
	if err != nil {
		return nil, errors.Wrap(err, "failed to create temp dir")
	}
	defer os.RemoveAll(tempDir)

	tarGz := archiver.TarGz{
		Tar: &archiver.Tar{
			ImplicitTopLevelFolder: true,
		},
	}
	if err := tarGz.Archive([]string{dir}, filepath.Join(tempDir, "tmp.tar.gz")); err != nil {
		return nil, errors.Wrap(err, "failed to create tar gz")
	}

	archive, err := ioutil.ReadFile(filepath.Join(tempDir, "tmp.tar.gz"))
	if err != nil {
		return nil, errors.Wrap(err, "failed to read tar.gz file")
	}

	return archive, nil
}

func ExtractTGZArchive(tgzFile string, destDir string) error {
	fileReader, err := os.Open(tgzFile)
	if err != nil {
		return errors.Wrap(err, "failed to open tgz file")
	}

	gzReader, err := gzip.NewReader(fileReader)
	if err != nil {
		return errors.Wrap(err, "failed to create gzip reader")
	}

	tarReader := tar.NewReader(gzReader)
	for {
		hdr, err := tarReader.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			return errors.Wrap(err, "failed to read tar data")
		}

		if hdr.Typeflag != tar.TypeReg {
			continue
		}

		err = func() error {
			fileName := filepath.Join(destDir, hdr.Name)

			filePath, _ := filepath.Split(fileName)
			err := os.MkdirAll(filePath, 0755)
			if err != nil {
				return errors.Wrapf(err, "failed to create directory %q", filePath)
			}

			fileWriter, err := os.Create(fileName)
			if err != nil {
				return errors.Wrapf(err, "failed to create file %q", hdr.Name)
			}

			defer fileWriter.Close()

			_, err = io.Copy(fileWriter, tarReader)
			if err != nil {
				return errors.Wrapf(err, "failed to write file %q", hdr.Name)
			}

			return nil
		}()
		if err != nil {
			return err
		}
	}

	return nil
}

func GetFileFromTGZArchive(archive *bytes.Buffer, fileName string) (*bytes.Buffer, error) {
	gzReader, err := gzip.NewReader(archive)
	if err != nil {
		return nil, errors.Wrap(err, "failed to create gzip reader")
	}

	tarReader := tar.NewReader(gzReader)
	for {
		hdr, err := tarReader.Next()
		if err == io.EOF {
			break
		}
		if err != nil {
			return nil, errors.Wrap(err, "failed to read tar data")
		}

		if hdr.Typeflag != tar.TypeReg {
			continue
		}

		match, err := filepath.Match(fileName, hdr.Name)
		if err != nil {
			return nil, errors.Wrap(err, "failed to check filename match")
		}

		if !match {
			_, err = io.Copy(io.Discard, tarReader)
			if err != nil {
				return nil, errors.Wrapf(err, "failed to discard file %q", hdr.Name)
			}
		} else {
			buf := bytes.NewBuffer(nil)
			_, err = io.Copy(buf, tarReader)
			if err != nil {
				return nil, errors.Wrapf(err, "failed to copy file %q", hdr.Name)
			}
			return bytes.NewBuffer(buf.Bytes()), nil
		}
	}

	return nil, errors.Errorf("file %s not found in archive", fileName)
}