Allow users to opt into mtime preservation (#1489)

bazelbuild · May 6, 2020 · 972f3eb · 972f3eb
1 parent 734ed53
commit 972f3eb
Show file tree

Hide file tree

Showing 2 changed files with 12 additions and 3 deletions.
diff --git a/container/build_tar.py b/container/build_tar.py
@@ -47,6 +47,9 @@
         ' value "portable", to get the value 2000-01-01, which is'
         ' usable with non *nix OSes.')
 
+gflags.DEFINE_bool(
+    'enable_mtime_preservation', False, 'Preserve file mtimes from input tar file.')
+
 gflags.DEFINE_multistring(
     'empty_root_dir',
     [],
@@ -121,12 +124,14 @@ def parse_pkg_name(metadata, filename):
     else:
       return os.path.basename(os.path.splitext(filename)[0])
 
-  def __init__(self, output, directory, compression, root_directory, default_mtime):
+  def __init__(self, output, directory, compression, root_directory,
+               default_mtime, enable_mtime_preservation):
     self.directory = directory
     self.output = output
     self.compression = compression
     self.root_directory = root_directory
     self.default_mtime = default_mtime
+    self.enable_mtime_preservation = enable_mtime_preservation
 
   def __enter__(self):
     self.tarfile = archive.TarFileWriter(
@@ -406,7 +411,9 @@ def main(unused_argv):
       ids_map[f] = (int(user), int(group))
 
   # Add objects to the tar file
-  with TarFile(FLAGS.output, FLAGS.directory, FLAGS.compression, FLAGS.root_directory, FLAGS.mtime) as output:
+  with TarFile(FLAGS.output, FLAGS.directory, FLAGS.compression,
+               FLAGS.root_directory, FLAGS.mtime,
+               FLAGS.enable_mtime_preservation) as output:
     def file_attributes(filename):
       if filename.startswith('/'):
         filename = filename[1:]

diff --git a/container/layer.bzl b/container/layer.bzl
@@ -111,7 +111,8 @@ def build_layer(
         args.add(ctx.attr.mtime, format = "--mtime=%s")
     if ctx.attr.portable_mtime:
         args.add("--mtime=portable")
-
+    if ctx.attr.enable_mtime_preservation:
+        args.add("--enable_mtime_preservation=true")
     if toolchain_info.xz_path != "":
         args.add(toolchain_info.xz_path, format = "--xz_path=%s")
 
@@ -275,6 +276,7 @@ _layer_attrs = dicts.add({
     "empty_dirs": attr.string_list(),
     # Implicit/Undocumented dependencies.
     "empty_files": attr.string_list(),
+    "enable_mtime_preservation": attr.bool(default = False),
     "env": attr.string_dict(),
     "files": attr.label_list(allow_files = True),
     "mode": attr.string(default = "0o555"),  # 0o555 == a+rx