added abstract schema fetcher class

Author: Ran Isenberg

aws_lambda_powertools/utilities/feature_toggles/__init__.py

@@ -1,12 +1,16 @@
 """Advanced feature toggles utility
 """
+from .appconfig_fetcher import AppConfigFetcher
 from .configuration_store import ConfigurationStore
 from .exceptions import ConfigurationException
 from .schema import ACTION, SchemaValidator
+from .schema_fetcher import SchemaFetcher
 
 __all__ = [
     "ConfigurationException",
     "ConfigurationStore",
     "ACTION",
     "SchemaValidator",
+    "AppConfigFetcher",
+    "SchemaFetcher",
 ]

aws_lambda_powertools/utilities/feature_toggles/appconfig_fetcher.py

@@ -0,0 +1,57 @@
+import logging
+from typing import Any, Dict, Optional
+
+from botocore.config import Config
+
+from aws_lambda_powertools.utilities.parameters import AppConfigProvider, GetParameterError, TransformParameterError
+
+from .exceptions import ConfigurationException
+from .schema_fetcher import SchemaFetcher
+
+logger = logging.getLogger(__name__)
+
+
+TRANSFORM_TYPE = "json"
+
+
+class AppConfigFetcher(SchemaFetcher):
+    def __init__(
+        self,
+        environment: str,
+        service: str,
+        configuration_name: str,
+        cache_seconds: int,
+        config: Optional[Config] = None,
+    ):
+        """This class fetches JSON schemas from AWS AppConfig
+
+        Args:
+            environment (str): what appconfig environment to use 'dev/test' etc.
+            service (str): what service name to use from the supplied environment
+            configuration_name (str): what configuration to take from the environment & service combination
+            cache_seconds (int): cache expiration time, how often to call AppConfig to fetch latest configuration
+            config (Optional[Config]): boto3 client configuration
+        """
+        super().__init__(configuration_name, cache_seconds)
+        self._logger = logger
+        self._conf_store = AppConfigProvider(environment=environment, application=service, config=config)
+
+    def get_json_configuration(self) -> Dict[str, Any]:
+        """Get configuration string from AWs AppConfig and return the parsed JSON dictionary
+
+        Raises:
+            ConfigurationException: Any validation error or appconfig error that can occur
+
+        Returns:
+            Dict[str, Any]: parsed JSON dictionary
+        """
+        try:
+            return self._conf_store.get(
+                name=self.configuration_name,
+                transform=TRANSFORM_TYPE,
+                max_age=self._cache_seconds,
+            )  # parse result conf as JSON, keep in cache for self.max_age seconds
+        except (GetParameterError, TransformParameterError) as exc:
+            error_str = f"unable to get AWS AppConfig configuration file, exception={str(exc)}"
+            self._logger.error(error_str)
+            raise ConfigurationException(error_str)

aws_lambda_powertools/utilities/feature_toggles/configuration_store.py

@@ -1,36 +1,23 @@
-# pylint: disable=no-name-in-module,line-too-long
 import logging
 from typing import Any, Dict, List, Optional
 
-from botocore.config import Config
-
-from aws_lambda_powertools.utilities.parameters import AppConfigProvider, GetParameterError, TransformParameterError
-
 from . import schema
 from .exceptions import ConfigurationException
-
-TRANSFORM_TYPE = "json"
+from .schema_fetcher import SchemaFetcher
 
 logger = logging.getLogger(__name__)
 
 
 class ConfigurationStore:
-    def __init__(
-        self, environment: str, service: str, conf_name: str, cache_seconds: int, config: Optional[Config] = None
-    ):
+    def __init__(self, schema_fetcher: SchemaFetcher):
         """constructor
 
         Args:
-            environment (str): what appconfig environment to use 'dev/test' etc.
-            service (str): what service name to use from the supplied environment
-            conf_name (str): what configuration to take from the environment & service combination
-            cache_seconds (int): cache expiration time, how often to call AppConfig to fetch latest configuration
+            schema_fetcher (SchemaFetcher): A schema JSON fetcher, can be AWS AppConfig, Hashicorp Consul etc.
         """
-        self._cache_seconds = cache_seconds
         self._logger = logger
-        self._conf_name = conf_name
+        self._schema_fetcher = schema_fetcher
         self._schema_validator = schema.SchemaValidator(self._logger)
-        self._conf_store = AppConfigProvider(environment=environment, application=service, config=config)
 
     def _match_by_action(self, action: str, condition_value: Any, context_value: Any) -> bool:
         if not context_value:
@@ -99,17 +86,11 @@ def get_configuration(self) -> Dict[str, Any]:
         Returns:
             Dict[str, Any]: parsed JSON dictionary
         """
-        try:
-            schema = self._conf_store.get(
-                name=self._conf_name,
-                transform=TRANSFORM_TYPE,
-                max_age=self._cache_seconds,
-            )  # parse result conf as JSON, keep in cache for self.max_age seconds
-        except (GetParameterError, TransformParameterError) as exc:
-            error_str = f"unable to get AWS AppConfig configuration file, exception={str(exc)}"
-            self._logger.error(error_str)
-            raise ConfigurationException(error_str)
-
+        schema: Dict[
+            str, Any
+        ] = (
+            self._schema_fetcher.get_json_configuration()
+        )  # parse result conf as JSON, keep in cache for self.max_age seconds
         # validate schema
         self._schema_validator.validate_json_schema(schema)
         return schema

aws_lambda_powertools/utilities/feature_toggles/exceptions.py

@@ -1,2 +1,2 @@
 class ConfigurationException(Exception):
-    """When a a configuration store raises an exception on schema retrieval or parsing"""
+    """When a a configuration store raises an exception on config retrieval or parsing"""

aws_lambda_powertools/utilities/feature_toggles/schema_fetcher.py

@@ -0,0 +1,20 @@
+from abc import ABC, abstractclassmethod
+from typing import Any, Dict
+
+
+class SchemaFetcher(ABC):
+    def __init__(self, configuration_name: str, cache_seconds: int):
+        self.configuration_name = configuration_name
+        self._cache_seconds = cache_seconds
+
+    @abstractclassmethod
+    def get_json_configuration(self) -> Dict[str, Any]:
+        """Get configuration string from any configuration storing service and return the parsed JSON dictionary
+
+        Raises:
+            ConfigurationException: Any error that can occur during schema fetch or JSON parse
+
+        Returns:
+            Dict[str, Any]: parsed JSON dictionary
+        """
+        return None

tests/functional/feature_toggles/test_feature_toggles.py

@@ -3,6 +3,7 @@
 import pytest  # noqa: F401
 from botocore.config import Config
 
+from aws_lambda_powertools.utilities.feature_toggles.appconfig_fetcher import AppConfigFetcher
 from aws_lambda_powertools.utilities.feature_toggles.configuration_store import ConfigurationStore
 from aws_lambda_powertools.utilities.feature_toggles.schema import ACTION
 
@@ -15,13 +16,15 @@ def config():
 def init_configuration_store(mocker, mock_schema: Dict, config: Config) -> ConfigurationStore:
     mocked_get_conf = mocker.patch("aws_lambda_powertools.utilities.parameters.AppConfigProvider.get")
     mocked_get_conf.return_value = mock_schema
-    conf_store: ConfigurationStore = ConfigurationStore(
+
+    app_conf_fetcher = AppConfigFetcher(
         environment="test_env",
         service="test_app",
-        conf_name="test_conf_name",
+        configuration_name="test_conf_name",
         cache_seconds=600,
         config=config,
     )
+    conf_store: ConfigurationStore = ConfigurationStore(schema_fetcher=app_conf_fetcher)
     return conf_store
 
 

tests/functional/feature_toggles/test_schema_validation.py

@@ -5,12 +5,12 @@
 from aws_lambda_powertools.utilities.feature_toggles.exceptions import ConfigurationException
 from aws_lambda_powertools.utilities.feature_toggles.schema import (
     ACTION,
-    FEATURE_DEFAULT_VAL_KEY,
-    FEATURES_KEY,
     CONDITION_ACTION,
     CONDITION_KEY,
     CONDITION_VALUE,
     CONDITIONS_KEY,
+    FEATURE_DEFAULT_VAL_KEY,
+    FEATURES_KEY,
     RULE_DEFAULT_VALUE,
     RULE_NAME_KEY,
     RULES_KEY,