Add dump to config loader

common_utility/configLoader.py

@@ -6,7 +6,7 @@
 from argparse import ArgumentParser, Action, Namespace
 from configparser import ConfigParser
 from pathlib import Path
-from typing import Any, cast
+from typing import Any, cast, TextIO
 
 from context_logger import get_logger
 
@@ -16,6 +16,9 @@ class IConfigLoader(object):
     def load(self, argument_parser: ArgumentParser) -> Namespace:
         raise NotImplementedError()
 
+    def dump(self, argument_parser: ArgumentParser, config: Namespace, file: TextIO = sys.stdout) -> None:
+        raise NotImplementedError()
+
 
 class ConfigLoader(IConfigLoader):
 
@@ -57,6 +60,24 @@ def load(self, argument_parser: ArgumentParser) -> Namespace:
 
         return Namespace(**configuration)
 
+    def dump(self, argument_parser: ArgumentParser, config: Namespace, file: TextIO = sys.stdout) -> None:
+        for group in argument_parser._action_groups:
+            section = group.title if group.title else 'DEFAULT'
+            values = {}
+
+            for action in group._group_actions:
+                if not action.dest or action.dest == "help":
+                    continue
+                value = getattr(config, action.dest, None)
+                if value is None:
+                    continue
+                values[action.dest] = str(value)
+
+            if values:
+                self._config_parser[section] = values
+
+        self._config_parser.write(file)
+
     def _get_cli_overrides(self, parser: ArgumentParser, arguments: Namespace) -> dict[str, Any]:
         cli_overrides: dict[str, Any] = {}
         argv_tokens = set(sys.argv[1:])

tests/configLoaderTest.py

@@ -1,6 +1,8 @@
 import sys
 import unittest
-from argparse import ArgumentParser
+from argparse import ArgumentParser, Namespace
+from configparser import ConfigParser
+from io import StringIO
 from pathlib import Path
 from unittest import TestCase
 from unittest.mock import patch
@@ -211,6 +213,86 @@ def test_load_config_when_invalid_numeric_values_present_then_keep_original(self
         self.assertEqual('invalid', result.retry_count)
         self.assertEqual('invalid', result.timeout)
 
+    def test_dump_when_values_present_then_write_config_sections(self):
+        # Given
+        config_loader = ConfigLoader(Path(DEFAULT_CONFIG_FILE))
+        argument_parser = ArgumentParser()
+        network_group = argument_parser.add_argument_group('network')
+        network_group.add_argument('--host')
+        network_group.add_argument('--port')
+        runtime_group = argument_parser.add_argument_group('runtime')
+        runtime_group.add_argument('--debug')
+        config = Namespace(host='localhost', port=8080, debug=True)
+        output = StringIO()
+
+        # When
+        config_loader.dump(argument_parser, config, output)
+
+        # Then
+        parser = ConfigParser(interpolation=None)
+        parser.read_string(output.getvalue())
+        self.assertEqual('localhost', parser['network']['host'])
+        self.assertEqual('8080', parser['network']['port'])
+        self.assertEqual('True', parser['runtime']['debug'])
+
+    def test_dump_when_value_is_none_then_skip_value(self):
+        # Given
+        config_loader = ConfigLoader(Path(DEFAULT_CONFIG_FILE))
+        argument_parser = ArgumentParser()
+        runtime_group = argument_parser.add_argument_group('runtime')
+        runtime_group.add_argument('--timeout')
+        runtime_group.add_argument('--retries')
+        config = Namespace(timeout=None, retries=3)
+        output = StringIO()
+
+        # When
+        config_loader.dump(argument_parser, config, output)
+
+        # Then
+        parser = ConfigParser(interpolation=None)
+        parser.read_string(output.getvalue())
+        self.assertEqual('3', parser['runtime']['retries'])
+        self.assertNotIn('timeout', parser['runtime'])
+        self.assertNotIn('help', output.getvalue())
+
+    def test_dump_when_all_values_in_group_are_none_then_omit_section(self):
+        # Given
+        config_loader = ConfigLoader(Path(DEFAULT_CONFIG_FILE))
+        argument_parser = ArgumentParser()
+        secret_group = argument_parser.add_argument_group('secret')
+        secret_group.add_argument('--token')
+        config = Namespace(token=None)
+        output = StringIO()
+
+        # When
+        config_loader.dump(argument_parser, config, output)
+
+        # Then
+        self.assertNotIn('[secret]', output.getvalue())
+
+    def test_dump_when_group_has_no_title_then_uses_default_section(self):
+        # Given
+        config_loader = ConfigLoader(Path(DEFAULT_CONFIG_FILE))
+        argument_parser = ArgumentParser(add_help=False)
+        region_action = argument_parser.add_argument('--region')
+
+        class DummyGroup(object):
+            def __init__(self):
+                self.title = None
+                self._group_actions = [region_action]
+
+        argument_parser._action_groups = [DummyGroup()]
+        config = Namespace(region='eu-central')
+        output = StringIO()
+
+        # When
+        config_loader.dump(argument_parser, config, output)
+
+        # Then
+        parser = ConfigParser(interpolation=None)
+        parser.read_string(output.getvalue())
+        self.assertEqual('eu-central', parser.defaults()['region'])
+
 
 if __name__ == '__main__':
     unittest.main()