Add NB_UMASK flag to modify default umask

base-notebook/jupyter_notebook_config.py

@@ -37,3 +37,10 @@ if 'GEN_CERT' in os.environ:
     # Restrict access to the file
     os.chmod(pem_file, stat.S_IRUSR | stat.S_IWUSR)
     c.NotebookApp.certfile = pem_file
+
+# Change default umask if set using flag
+if 'NB_UMASK' in os.environ:
+    try:
+        os.umask(int(os.environ['NB_UMASK'], 8))
+    except:
+        raise