Revert "Cache the custom secrets backend so the same instance gets re…

…-used (apache#25556)"

This reverts commit ed9bf28.

airflow/configuration.py

@@ -1513,23 +1513,18 @@ def ensure_secrets_loaded() -> List[BaseSecretsBackend]:
 def get_custom_secret_backend() -> Optional[BaseSecretsBackend]:
     """Get Secret Backend if defined in airflow.cfg"""
     secrets_backend_cls = conf.getimport(section='secrets', key='backend')
+
     if secrets_backend_cls:
         try:
             backends: Any = conf.get(section='secrets', key='backend_kwargs', fallback='{}')
             alternative_secrets_config_dict = json.loads(backends)
         except JSONDecodeError:
             alternative_secrets_config_dict = {}
 
-        return _custom_secrets_backend(secrets_backend_cls, **alternative_secrets_config_dict)
+        return secrets_backend_cls(**alternative_secrets_config_dict)
     return None
 
 
-@functools.lru_cache(maxsize=2)
-def _custom_secrets_backend(secrets_backend_cls, **alternative_secrets_config_dict):
-    """Separate function to create secrets backend instance to allow caching"""
-    return secrets_backend_cls(**alternative_secrets_config_dict)
-
-
 def initialize_secrets_backends() -> List[BaseSecretsBackend]:
     """
     * import secrets backend classes

tests/core/test_configuration.py

@@ -33,7 +33,6 @@
 from airflow.configuration import (
     AirflowConfigException,
     AirflowConfigParser,
-    _custom_secrets_backend,
     conf,
     expand_env_var,
     get_airflow_config,
@@ -272,7 +271,6 @@ def test_config_from_secret_backend(self, mock_hvac):
     def test_config_raise_exception_from_secret_backend_connection_error(self, mock_hvac):
         """Get Config Value from a Secret Backend"""
 
-        _custom_secrets_backend.cache_clear()
         mock_client = mock.MagicMock()
         # mock_client.side_effect = AirflowConfigException
         mock_hvac.Client.return_value = mock_client
@@ -299,7 +297,6 @@ def test_config_raise_exception_from_secret_backend_connection_error(self, mock_
             ),
         ):
             test_conf.get('test', 'sql_alchemy_conn')
-        _custom_secrets_backend.cache_clear()
 
     def test_getboolean(self):
         """Test AirflowConfigParser.getboolean"""
@@ -1264,81 +1261,3 @@ def test_conf_as_dict_when_deprecated_value_in_secrets_disabled_config(
                 conf.read_dict(dictionary=cfg_dict)
                 os.environ.clear()
                 assert conf.get('database', 'sql_alchemy_conn') == f'sqlite:///{HOME_DIR}/airflow/airflow.db'
-
-    @mock.patch("airflow.providers.hashicorp._internal_client.vault_client.hvac")
-    @conf_vars(
-        {
-            ("secrets", "backend"): "airflow.providers.hashicorp.secrets.vault.VaultBackend",
-            ("secrets", "backend_kwargs"): '{"url": "http://127.0.0.1:8200", "token": "token"}',
-        }
-    )
-    def test_config_from_secret_backend_caches_instance(self, mock_hvac):
-        """Get Config Value from a Secret Backend"""
-        _custom_secrets_backend.cache_clear()
-
-        test_config = '''[test]
-sql_alchemy_conn_secret = sql_alchemy_conn
-secret_key_secret = secret_key
-'''
-        test_config_default = '''[test]
-sql_alchemy_conn = airflow
-secret_key = airflow
-'''
-
-        mock_client = mock.MagicMock()
-        mock_hvac.Client.return_value = mock_client
-
-        def fake_read_secret(path, mount_point, version):
-            if path.endswith('sql_alchemy_conn'):
-                return {
-                    'request_id': '2d48a2ad-6bcb-e5b6-429d-da35fdf31f56',
-                    'lease_id': '',
-                    'renewable': False,
-                    'lease_duration': 0,
-                    'data': {
-                        'data': {'value': 'fake_conn'},
-                        'metadata': {
-                            'created_time': '2020-03-28T02:10:54.301784Z',
-                            'deletion_time': '',
-                            'destroyed': False,
-                            'version': 1,
-                        },
-                    },
-                    'wrap_info': None,
-                    'warnings': None,
-                    'auth': None,
-                }
-            if path.endswith('secret_key'):
-                return {
-                    'request_id': '2d48a2ad-6bcb-e5b6-429d-da35fdf31f56',
-                    'lease_id': '',
-                    'renewable': False,
-                    'lease_duration': 0,
-                    'data': {
-                        'data': {'value': 'fake_key'},
-                        'metadata': {
-                            'created_time': '2020-03-28T02:10:54.301784Z',
-                            'deletion_time': '',
-                            'destroyed': False,
-                            'version': 1,
-                        },
-                    },
-                    'wrap_info': None,
-                    'warnings': None,
-                    'auth': None,
-                }
-
-        mock_client.secrets.kv.v2.read_secret_version.side_effect = fake_read_secret
-
-        test_conf = AirflowConfigParser(default_config=parameterized_config(test_config_default))
-        test_conf.read_string(test_config)
-        test_conf.sensitive_config_values = test_conf.sensitive_config_values | {
-            ('test', 'sql_alchemy_conn'),
-            ('test', 'secret_key'),
-        }
-
-        assert 'fake_conn' == test_conf.get('test', 'sql_alchemy_conn')
-        mock_hvac.Client.assert_called_once()
-        assert 'fake_key' == test_conf.get('test', 'secret_key')
-        mock_hvac.Client.assert_called_once()
-        _custom_secrets_backend.cache_clear()