feat: Add tar compression selection

src/lib/backup.sh

@@ -103,6 +103,7 @@ backup_files() {
     local dst_path
     local tar_opts
     local archive
+    local compression
     local file_ext
 
     uri="$1"
@@ -117,7 +118,8 @@ backup_files() {
         exit 1
     fi
 
-    is_installed tar # Exit if tar is not installed
+    # Exit if tar is not installed
+    is_installed tar
 
     # Overwrire __tar_options
     if [ -n "$tar_options" ]; then
@@ -126,9 +128,35 @@ backup_files() {
         tar_opts="$__tar_options"
     fi
 
-    # TODO выбор сжатия, можно в переменной __tar_options заменять букву z на
-    # другую для соответствующего сжатия
-    file_ext=.tar.gz
+    # Overwrite __tar_compression
+    if [ "$tar_compression" ]; then
+        compression="$tar_compression"
+    else
+        compression="$__tar_compression"
+    fi
+
+    # Select filename extension by compression type.
+    # Make sure for the `--auto-compress` is enabled in __tar_options
+    # Refference: https://www.gnu.org/software/tar/manual/html_node/gzip.html
+    case "$compression" in
+        gzip|gz)    file_ext='.tar.gz';;    # gzip
+        tgz)        file_ext='.tgz';;       # gzip
+        taz)        file_ext='.taz';;       # gzip
+        compress|Z) file_ext='.tar.Z';;     # compress
+        taZ)        file_ext='.taZ';;       # compress
+        bzip2|bz2)  file_ext='.tar.bz2';;   # bzip2
+        tz2)        file_ext='.tz2';;       # bzip2
+        tbz2)       file_ext='.tbz2';;      # bzip2
+        tbz)        file_ext='.tbz';;       # bzip2
+        lzip|lz)    file_ext='.tar.lz';;    # lzip
+        lzma)       file_ext='.tar.lzma';;  # lzma
+        tlz)        file_ext='.tlz';;       # lzma
+        lzop|lzo)   file_ext='.tar.lzo';;   # lzop
+        xz)         file_ext='.tar.xz';;    # xz
+        zstd|zst)   file_ext='.tar.zst';;   # zstd
+        tzst)       file_ext='.tzst';;      # zstd
+        *)          file_ext='.tar.gz';;    # Force gzip
+    esac
 
     archive="${dst_path}/$(gen_backup_name "$file_ext")"