Compressing archive to save storage costs

Enable compressing to save storage costs. Archive is compressed
by gzip. If in future zstd is supported natively by Go, we can
move to that.

internal/tar/file-utils.go

@@ -2,8 +2,11 @@ package tar
 
 import (
 	"archive/tar"
+	"bytes"
+	"compress/gzip"
 	"context"
 	"io"
+	"log"
 	"os"
 	"path/filepath"
 	"strings"
@@ -12,16 +15,19 @@ import (
 )
 
 func Tarit(source, target string) error {
+	var buf bytes.Buffer
+
+	// write the .tar.gzip
 	tarfile, err := os.Create(target)
 	if err != nil {
 		return err
 	}
 	defer tarfile.Close()
 
-	tarball := tar.NewWriter(tarfile)
-	defer tarball.Close()
+	gz := gzip.NewWriter(&buf)
+	tarball := tar.NewWriter(gz)
 
-	return filepath.Walk(source,
+	err = filepath.Walk(source,
 		func(path string, info os.FileInfo, err error) error {
 			if err != nil {
 				return err
@@ -49,6 +55,18 @@ func Tarit(source, target string) error {
 			_, err = io.Copy(tarball, file)
 			return err
 		})
+	if err != nil {
+		return err
+	}
+
+	gz.Close()
+	tarball.Close()
+
+	if _, err := io.Copy(tarfile, &buf); err != nil {
+		log.Println("error copying tarfile", err)
+		return err
+	}
+	return nil
 }
 
 func Untar(ctx context.Context, file *os.File, target string) error {
@@ -57,5 +75,5 @@ func Untar(ctx context.Context, file *os.File, target string) error {
 		return err
 	}
 	defer f.Close()
-	return extract.Archive(ctx, f, target, nil)
+	return extract.Gz(ctx, f, target, nil)
 }