Remove fallback for BooleanOptionalAction (obsolete in python>=3.9) (#…

…163)

src/pve_exporter/cli.py

@@ -2,62 +2,14 @@
 Proxmox VE exporter for the Prometheus monitoring system.
 """
 
-from argparse import ArgumentParser
-
+from argparse import ArgumentParser, BooleanOptionalAction
 import os
 import yaml
 from pve_exporter.http import start_http_server
 from pve_exporter.config import config_from_yaml
 from pve_exporter.config import config_from_env
 from pve_exporter.collector import CollectorsOptions
 
-try:
-    from argparse import BooleanOptionalAction
-except ImportError:
-    from argparse import Action
-    # https://github.com/python/cpython/blob/master/Lib/argparse.py#L856
-    # pylint: disable=all
-    class BooleanOptionalAction(Action):
-        def __init__(self,
-                     option_strings,
-                     dest,
-                     default=None,
-                     type=None,
-                     choices=None,
-                     required=False,
-                     help=None,
-                     metavar=None):
-
-            _option_strings = []
-            for option_string in option_strings:
-                _option_strings.append(option_string)
-
-                if option_string.startswith('--'):
-                    option_string = '--no-' + option_string[2:]
-                    _option_strings.append(option_string)
-
-            if help is not None and default is not None:
-                help += f" (default: {default})"
-
-            super().__init__(
-                option_strings=_option_strings,
-                dest=dest,
-                nargs=0,
-                default=default,
-                type=type,
-                choices=choices,
-                required=required,
-                help=help,
-                metavar=metavar)
-
-        def __call__(self, parser, namespace, values, option_string=None):
-            if option_string in self.option_strings:
-                setattr(namespace, self.dest, not option_string.startswith('--no-'))
-
-        def format_usage(self):
-            return ' | '.join(self.option_strings)
-
-
 def main():
     """
     Main entry point.
@@ -88,8 +40,10 @@ def main():
                         help='Port on which the exporter is listening (9221)')
     parser.add_argument('address', nargs='?', default='',
                         help='Address to which the exporter will bind')
-    parser.add_argument('--server.keyfile', dest='server_keyfile', help='SSL key for server')
-    parser.add_argument('--server.certfile', dest='server_certfile', help='SSL certificate for server')
+    parser.add_argument('--server.keyfile', dest='server_keyfile',
+                        help='SSL key for server')
+    parser.add_argument('--server.certfile', dest='server_certfile',
+                        help='SSL certificate for server')
 
     params = parser.parse_args()
 
@@ -106,7 +60,7 @@ def main():
     if 'PVE_USER' in os.environ:
         config = config_from_env(os.environ)
     else:
-        with open(params.config) as handle:
+        with open(params.config, encoding='utf-8') as handle:
             config = config_from_yaml(yaml.safe_load(handle))
 
     gunicorn_options = {