config: allow to customize default config file mode

mylib/config.py

@@ -6,7 +6,6 @@ import argparse
 import logging
 import os
 import re
-import stat
 import sys
 import textwrap
 import traceback
@@ -24,6 +23,7 @@ log = logging.getLogger(__name__)
 # Constants
 DEFAULT_ENCODING = "utf-8"
 DEFAULT_CONFIG_DIRPATH = os.path.expanduser("./")
+DEFAULT_CONFIG_FILE_MODE = 0o600
 DEFAULT_LOG_FORMAT = "%(asctime)s - %(module)s:%(lineno)d - %(levelname)s - %(message)s"
 DEFAULT_CONSOLE_LOG_FORMAT = DEFAULT_LOG_FORMAT
 DEFAULT_FILELOG_FORMAT = DEFAULT_LOG_FORMAT
@@ -679,6 +679,7 @@ class Config:  # pylint: disable=too-many-instance-attributes
         config_file_env_variable=None,
         default_config_dirpath=None,
         default_config_filename=None,
+        default_config_file_mode=None,
     ):
         self.appname = appname
         self.shortname = shortname
@@ -694,6 +695,7 @@ class Config:  # pylint: disable=too-many-instance-attributes
         self.config_file_env_variable = config_file_env_variable
         self.default_config_dirpath = default_config_dirpath
         self.default_config_filename = default_config_filename
+        self.default_config_file_mode = default_config_file_mode or DEFAULT_CONFIG_FILE_MODE
         self.add_logging_sections()
         self._init_config_parser()
 
@@ -894,7 +896,7 @@ class Config:  # pylint: disable=too-many-instance-attributes
                 fd.write("\n".join(lines).encode(self.encoding))
 
             # Privacy!
-            os.chmod(filepath, stat.S_IRUSR | stat.S_IWUSR)
+            os.chmod(filepath, self.default_config_file_mode)
         except Exception:  # pylint: disable=broad-except
             log.exception("Failed to write generated configuration file %s", filepath)
             return False