*: Fix tarballs and add compression

Signed-off-by: Thomas Hipp <thomas.hipp@canonical.com>

distrobuilder/main_lxd.go

@@ -83,7 +83,7 @@ func (c *cmdLXD) run(cmd *cobra.Command, args []string) error {
 		}
 	}
 
-	err := img.Build(c.flagType == "unified")
+	err := img.Build(c.flagType == "unified", c.flagCompression)
 	if err != nil {
 		return fmt.Errorf("Failed to create LXD image: %s", err)
 	}

image/lxc.go

@@ -73,7 +73,7 @@ func (l *LXCImage) Build() error {
 		return err
 	}
 
-	err = shared.Pack(filepath.Join(l.targetDir, "rootfs.tar.xz"), l.sourceDir,
+	err = shared.Pack(filepath.Join(l.targetDir, "rootfs.tar"), "xz", l.sourceDir,
 		"--transform", "s,^./,rootfs/,", ".")
 	if err != nil {
 		return err
@@ -143,7 +143,7 @@ func (l *LXCImage) packMetadata() error {
 		files = append(files, "templates")
 	}
 
-	err := shared.Pack(filepath.Join(l.targetDir, "meta.tar.xz"),
+	err := shared.Pack(filepath.Join(l.targetDir, "meta.tar"), "xz",
 		filepath.Join(l.cacheDir, "metadata"), files...)
 	if err != nil {
 		return fmt.Errorf("Failed to create metadata: %s", err)

image/lxd.go

@@ -41,7 +41,7 @@ func NewLXDImage(sourceDir, targetDir, cacheDir string,
 }
 
 // Build creates a LXD image.
-func (l *LXDImage) Build(unified bool) error {
+func (l *LXDImage) Build(unified bool, compression string) error {
 	err := l.createMetadata()
 	if err != nil {
 		return nil
@@ -86,12 +86,20 @@ func (l *LXDImage) Build(unified bool) error {
 			fname = "lxd"
 		}
 
-		paths = append(paths, "rootfs")
-		err = shared.Pack(filepath.Join(l.targetDir, fmt.Sprintf("%s.tar.xz", fname)),
-			l.sourceDir, paths...)
+		// Add the rootfs to the tarball, prefix all files with "rootfs"
+		err = shared.Pack(filepath.Join(l.targetDir, fmt.Sprintf("%s.tar", fname)),
+			"", l.sourceDir, "--transform", "s,^./,rootfs/,", ".")
 		if err != nil {
 			return err
 		}
+
+		// Add the metadata to the tarball which is located in the cache directory
+		err = shared.PackUpdate(filepath.Join(l.targetDir, fmt.Sprintf("%s.tar", fname)),
+			compression, l.cacheDir, paths...)
+		if err != nil {
+			return err
+		}
+
 	} else {
 		// Create rootfs as squashfs.
 		err = shared.RunCommand("mksquashfs", l.sourceDir,
@@ -101,7 +109,8 @@ func (l *LXDImage) Build(unified bool) error {
 		}
 
 		// Create metadata tarball.
-		err = shared.Pack(filepath.Join(l.targetDir, "lxd.tar.xz"), l.cacheDir, paths...)
+		err = shared.Pack(filepath.Join(l.targetDir, "lxd.tar"), compression,
+			l.cacheDir, paths...)
 		if err != nil {
 			return err
 		}

shared/util.go

@@ -120,9 +120,39 @@ func CreateGPGKeyring(keyserver string, keys []string) (string, error) {
 	return filepath.Join(gpgDir, "distrobuilder.gpg"), nil
 }
 
-// Pack creates an xz-compressed tarball.
-func Pack(filename, path string, args ...string) error {
-	return RunCommand("tar", append([]string{"-cJf", filename, "-C", path}, args...)...)
+// Pack creates an uncompressed tarball.
+func Pack(filename, compression, path string, args ...string) error {
+	err := RunCommand("tar", append([]string{"-cf", filename, "-C", path}, args...)...)
+	if err != nil {
+		return err
+	}
+
+	return compressTarball(filename, compression)
+}
+
+// PackUpdate updates an existing tarball.
+func PackUpdate(filename, compression, path string, args ...string) error {
+	err := RunCommand("tar", append([]string{"-uf", filename, "-C", path}, args...)...)
+	if err != nil {
+		return err
+	}
+
+	return compressTarball(filename, compression)
+}
+
+// compressTarball compresses a tarball, or not.
+func compressTarball(filename, compression string) error {
+	switch compression {
+	case "lzop":
+		// lzo does not remove the uncompressed file per default
+		defer os.Remove(filename)
+		fallthrough
+	case "bzip2", "xz", "lzip", "lzma", "gzip":
+		return RunCommand(compression, "-f", filename)
+	}
+
+	// Do not compress
+	return nil
 }
 
 //GetExpiryDate returns an expiry date based on the creationDate and format.