Rely on umask for default directory permissions

notebook/nbextensions.py

@@ -24,7 +24,7 @@
     jupyter_data_dir, jupyter_config_path, jupyter_path,
     SYSTEM_JUPYTER_PATH, ENV_JUPYTER_PATH,
 )
-from ipython_genutils.path import ensure_dir_exists
+from notebook.utils import ensure_dir_exists
 from ipython_genutils.py3compat import string_types, cast_unicode_py2
 from ipython_genutils.tempdir import TemporaryDirectory
 from ._version import __version__

notebook/services/contents/filecheckpoints.py

@@ -12,7 +12,7 @@
 )
 from .fileio import FileManagerMixin
 
-from ipython_genutils.path import ensure_dir_exists
+from notebook.utils import ensure_dir_exists
 from ipython_genutils.py3compat import getcwd
 from traitlets import Unicode
 

notebook/utils.py

@@ -305,3 +305,20 @@ def _check_pid_posix(pid):
     check_pid = _check_pid_win32
 else:
     check_pid = _check_pid_posix
+
+
+def ensure_dir_exists(path, mode=0o777):
+    """ensure that a directory exists
+
+    If it doesn't exist, try to create it and protect against a race condition
+    if another process is doing the same.
+
+    The default permissions are determined by the current umask.
+    """
+    try:
+        os.makedirs(path, mode=mode)
+    except OSError as e:
+        if e.errno != errno.EEXIST:
+            raise
+    if not os.path.isdir(path):
+        raise IOError("%r exists but is not a directory" % path)