refactor: rename get_feature_toggle to evaluate

aws_lambda_powertools/utilities/feature_toggles/feature_flags.py

@@ -103,9 +103,7 @@ def get_configuration(self) -> Dict[str, Any]:
         self._schema_validator.validate_json_schema(config)
         return config
 
-    def get_feature_toggle(
-        self, *, feature_name: str, context: Optional[Dict[str, Any]] = None, value_if_missing: bool
-    ) -> bool:
+    def evaluate(self, *, feature_name: str, context: Optional[Dict[str, Any]] = None, default: bool) -> bool:
         """Get a feature toggle boolean value. Value is calculated according to a set of rules and conditions.
 
         See below for explanation.
@@ -117,10 +115,9 @@ def get_feature_toggle(
         context: Optional[Dict[str, Any]]
             dict of attributes that you would like to match the rules
             against, can be {'tenant_id: 'X', 'username':' 'Y', 'region': 'Z'} etc.
-        value_if_missing: bool
-            this will be the returned value in case the feature toggle doesn't exist in
-            the schema or there has been an error while fetching the
-            configuration from appconfig
+        default: bool
+            default value if feature flag doesn't exist in the schema,
+            or there has been an error while fetching the configuration from appconfig
 
         Returns
         ------
@@ -138,16 +135,16 @@ def get_feature_toggle(
         try:
             toggles_dict: Dict[str, Any] = self.get_configuration()
         except ConfigurationError:
-            logger.error("unable to get feature toggles JSON, returning provided value_if_missing value")
-            return value_if_missing
+            logger.error("unable to get feature toggles JSON, returning provided default value")
+            return default
 
         feature: Dict[str, Dict] = toggles_dict.get(schema.FEATURES_KEY, {}).get(feature_name, None)
         if feature is None:
             logger.warning(
-                f"feature does not appear in configuration, using provided value_if_missing, "
-                f"feature_name={feature_name}, value_if_missing={value_if_missing}"
+                f"feature does not appear in configuration, using provided default, "
+                f"feature_name={feature_name}, default={default}"
             )
-            return value_if_missing
+            return default
 
         rules_list = feature.get(schema.RULES_KEY)
         feature_default_value = feature.get(schema.FEATURE_DEFAULT_VAL_KEY)

docs/utilities/feature_flags.md

@@ -63,9 +63,11 @@ Potential changes to be validated when docs are in a better shape
 - [x] ~~`rules_context` to `context`~~
 - [x] `ConfigurationStore` to `FeatureFlags`
 - [x] `StoreProvider` to `StoreProvider`
-- [ ] Use `base.py` for interfaces for consistency (e.g. Metrics, Tracer, etc.)
+- [x] ~~Use `base.py` for interfaces for consistency (e.g. Metrics, Tracer, etc.)~~
+- [x] ~~AppConfig construct parameter names for consistency (e.g. `configuration_name` -> `name`, `service` -> `application`)~~
+- [x] ~~Rename `value_if_missing` param to `default` to match Python consistency (e.g. `os.getenv("VAR", default=False)`)~~
+- [x] ~~Review `get_feature` in favour of `evaluate`~~
 - [ ] Some docstrings and logger refer to AWS AppConfig only (outdated given StoreProvider)
 - [ ] Review why we're testing a private method(`is_rule_matched`)
-- [x] AppConfig construct parameter names for consistency (e.g. `configuration_name` -> `name`, `service` -> `application`)
 - [ ] Review `get_configuration`, `get_json_configuration`
-- [ ] Review `get_feature` in favour of `get_feature_toggle`
+- [ ] Review potentially redundant logging

tests/functional/feature_toggles/test_feature_toggles.py

@@ -68,18 +68,18 @@ def test_toggles_rule_does_not_match(mocker, config):
     }
 
     conf_store = init_configuration_store(mocker, mocked_app_config_schema, config)
-    toggle = conf_store.get_feature_toggle(feature_name="my_feature", context={}, value_if_missing=False)
+    toggle = conf_store.evaluate(feature_name="my_feature", context={}, default=False)
     assert toggle == expected_value
 
 
 # this test checks that if you try to get a feature that doesn't exist in the schema,
-# you get the default value of False that was sent to the get_feature_toggle API
+# you get the default value of False that was sent to the evaluate API
 def test_toggles_no_conditions_feature_does_not_exist(mocker, config):
     expected_value = False
     mocked_app_config_schema = {"features": {"my_fake_feature": {"feature_default_value": True}}}
 
     conf_store = init_configuration_store(mocker, mocked_app_config_schema, config)
-    toggle = conf_store.get_feature_toggle(feature_name="my_feature", context={}, value_if_missing=expected_value)
+    toggle = conf_store.evaluate(feature_name="my_feature", context={}, default=expected_value)
     assert toggle == expected_value
 
 
@@ -89,9 +89,7 @@ def test_toggles_no_rules(mocker, config):
     expected_value = True
     mocked_app_config_schema = {"features": {"my_feature": {"feature_default_value": expected_value}}}
     conf_store = init_configuration_store(mocker, mocked_app_config_schema, config)
-    toggle = conf_store.get_feature_toggle(
-        feature_name="my_feature", context={"tenant_id": "6", "username": "a"}, value_if_missing=False
-    )
+    toggle = conf_store.evaluate(feature_name="my_feature", context={"tenant_id": "6", "username": "a"}, default=False)
     assert toggle == expected_value
 
 
@@ -119,9 +117,7 @@ def test_toggles_conditions_no_match(mocker, config):
         },
     }
     conf_store = init_configuration_store(mocker, mocked_app_config_schema, config)
-    toggle = conf_store.get_feature_toggle(
-        feature_name="my_feature", context={"tenant_id": "6", "username": "a"}, value_if_missing=False
-    )
+    toggle = conf_store.evaluate(feature_name="my_feature", context={"tenant_id": "6", "username": "a"}, default=False)
     assert toggle == expected_value
 
 
@@ -156,13 +152,13 @@ def test_toggles_conditions_rule_match_equal_multiple_conditions(mocker, config)
         },
     }
     conf_store = init_configuration_store(mocker, mocked_app_config_schema, config)
-    toggle = conf_store.get_feature_toggle(
+    toggle = conf_store.evaluate(
         feature_name="my_feature",
         context={
             "tenant_id": tenant_id_val,
             "username": username_val,
         },
-        value_if_missing=True,
+        default=True,
     )
     assert toggle == expected_value
 
@@ -198,9 +194,7 @@ def test_toggles_conditions_no_rule_match_equal_multiple_conditions(mocker, conf
         },
     }
     conf_store = init_configuration_store(mocker, mocked_app_config_schema, config)
-    toggle = conf_store.get_feature_toggle(
-        feature_name="my_feature", context={"tenant_id": "6", "username": "a"}, value_if_missing=False
-    )
+    toggle = conf_store.evaluate(feature_name="my_feature", context={"tenant_id": "6", "username": "a"}, default=False)
     assert toggle == expected_val
 
 
@@ -259,25 +253,25 @@ def test_toggles_conditions_rule_match_multiple_actions_multiple_rules_multiple_
 
     conf_store = init_configuration_store(mocker, mocked_app_config_schema, config)
     # match first rule
-    toggle = conf_store.get_feature_toggle(
-        feature_name="my_feature", context={"tenant_id": "6", "username": "abcd"}, value_if_missing=False
+    toggle = conf_store.evaluate(
+        feature_name="my_feature", context={"tenant_id": "6", "username": "abcd"}, default=False
     )
     assert toggle == expected_value_first_check
     # match second rule
-    toggle = conf_store.get_feature_toggle(
-        feature_name="my_feature", context={"tenant_id": "4446", "username": "az"}, value_if_missing=False
+    toggle = conf_store.evaluate(
+        feature_name="my_feature", context={"tenant_id": "4446", "username": "az"}, default=False
     )
     assert toggle == expected_value_second_check
     # match no rule
-    toggle = conf_store.get_feature_toggle(
-        feature_name="my_feature", context={"tenant_id": "11114446", "username": "ab"}, value_if_missing=False
+    toggle = conf_store.evaluate(
+        feature_name="my_feature", context={"tenant_id": "11114446", "username": "ab"}, default=False
     )
     assert toggle == expected_value_third_check
     # feature doesn't exist
-    toggle = conf_store.get_feature_toggle(
+    toggle = conf_store.evaluate(
         feature_name="my_fake_feature",
         context={"tenant_id": "11114446", "username": "ab"},
-        value_if_missing=expected_value_fourth_case,
+        default=expected_value_fourth_case,
     )
     assert toggle == expected_value_fourth_case
 
@@ -306,9 +300,7 @@ def test_toggles_match_rule_with_contains_action(mocker, config):
         },
     }
     conf_store = init_configuration_store(mocker, mocked_app_config_schema, config)
-    toggle = conf_store.get_feature_toggle(
-        feature_name="my_feature", context={"tenant_id": "6", "username": "a"}, value_if_missing=False
-    )
+    toggle = conf_store.evaluate(feature_name="my_feature", context={"tenant_id": "6", "username": "a"}, default=False)
     assert toggle == expected_value
 
 
@@ -335,9 +327,7 @@ def test_toggles_no_match_rule_with_contains_action(mocker, config):
         },
     }
     conf_store = init_configuration_store(mocker, mocked_app_config_schema, config)
-    toggle = conf_store.get_feature_toggle(
-        feature_name="my_feature", context={"tenant_id": "6", "username": "a"}, value_if_missing=False
-    )
+    toggle = conf_store.evaluate(feature_name="my_feature", context={"tenant_id": "6", "username": "a"}, default=False)
     assert toggle == expected_value
 
 
@@ -425,10 +415,10 @@ def test_get_feature_toggle_handles_error(mocker, config):
     schema_fetcher = init_fetcher_side_effect(mocker, config, GetParameterError())
     conf_store = FeatureFlags(schema_fetcher)
 
-    # WHEN calling get_feature_toggle
-    toggle = conf_store.get_feature_toggle(feature_name="Foo", value_if_missing=False)
+    # WHEN calling evaluate
+    toggle = conf_store.evaluate(feature_name="Foo", default=False)
 
-    # THEN handle the error and return the value_if_missing
+    # THEN handle the error and return the default
     assert toggle is False