Make compresslevel configurable for .tar.gz

Author: gdh1995

pkg/private/tar/build_tar.py

@@ -42,7 +42,8 @@ class TarFile(object):
   class DebError(Exception):
     pass
 
-  def __init__(self, output, directory, compression, compressor, create_parents, allow_dups_from_deps, default_mtime):
+  def __init__(self, output, directory, compression, compressor, create_parents,
+               allow_dups_from_deps, default_mtime, compresslevel=None):
     # Directory prefix on all output paths
     d = directory.strip('/')
     self.directory = (d + '/') if d else None
@@ -52,6 +53,7 @@ def __init__(self, output, directory, compression, compressor, create_parents, a
     self.default_mtime = default_mtime
     self.create_parents = create_parents
     self.allow_dups_from_deps = allow_dups_from_deps
+    self.compresslevel = compresslevel
 
   def __enter__(self):
     self.tarfile = tar_writer.TarFileWriter(
@@ -60,7 +62,8 @@ def __enter__(self):
         self.compressor,
         self.create_parents,
         self.allow_dups_from_deps,
-        default_mtime=self.default_mtime)
+        default_mtime=self.default_mtime,
+        compresslevel=self.compresslevel)
     return self
 
   def __exit__(self, t, v, traceback):
@@ -397,6 +400,9 @@ def main():
   parser.add_argument('--allow_dups_from_deps',
                       action='store_true',
                       help='')
+  parser.add_argument(
+      '--compresslevel', default='',
+      help='Specify the numeric compress level in gzip mode; may be 0-9 or empty(6).')
   options = parser.parse_args()
 
   # Parse modes arguments
@@ -448,7 +454,8 @@ def main():
       compressor = options.compressor,
       default_mtime=default_mtime,
       create_parents=options.create_parents,
-      allow_dups_from_deps=options.allow_dups_from_deps) as output:
+      allow_dups_from_deps=options.allow_dups_from_deps,
+      compresslevel = options.compresslevel) as output:
 
     def file_attributes(filename):
       if filename.startswith('/'):

pkg/private/tar/tar.bzl

@@ -114,6 +114,8 @@ def _pkg_tar_impl(ctx):
                 "--owner_names",
                 "%s=%s" % (_quote(key), ctx.attr.ownernames[key]),
             )
+    if ctx.attr.compresslevel:
+        args.add("--compresslevel", ctx.attr.compresslevel)
 
     # Now we begin processing the files.
     path_mapper = None
@@ -272,6 +274,10 @@ pkg_tar_impl = rule(
         ),
         "create_parents": attr.bool(default = True),
         "allow_duplicates_from_deps": attr.bool(default = False),
+        "compresslevel": attr.string(
+            doc = """Specify the numeric compress level in gzip mode; may be 0-9 or empty (6).""",
+            default = "",
+        ),
 
         # Common attributes
         "out": attr.output(mandatory = True),

pkg/private/tar/tar_writer.py

@@ -49,7 +49,8 @@ def __init__(self,
                create_parents=False,
                allow_dups_from_deps=True,
                default_mtime=None,
-               preserve_tar_mtimes=True):
+               preserve_tar_mtimes=True,
+               compresslevel=None):
     """TarFileWriter wraps tarfile.open().
 
     Args:
@@ -86,10 +87,11 @@ def __init__(self,
     else:
       mode = 'w:'
       if compression in ['tgz', 'gz']:
+        compresslevel = int(compresslevel) if compresslevel or compresslevel == 0 else 6
         # The Tarfile class doesn't allow us to specify gzip's mtime attribute.
         # Instead, we manually reimplement gzopen from tarfile.py and set mtime.
         self.fileobj = gzip.GzipFile(
-            filename=name, mode='w', compresslevel=6, mtime=self.default_mtime)
+            filename=name, mode='w', compresslevel=compresslevel, mtime=self.default_mtime)
     self.compressor_proc = None
     if self.compressor_cmd:
       mode = 'w|'