fix(parameters): AppConfigProvider when retrieving multiple unique configuration names (#2378)

Co-authored-by: heitorlessa <[email protected]>

Author: 2 people

aws_lambda_powertools/utilities/parameters/appconfig.py

@@ -94,7 +94,7 @@ def __init__(
         self.environment = environment
         self.current_version = ""
 
-        self._next_token = ""  # nosec - token for get_latest_configuration executions
+        self._next_token: Dict[str, str] = {}  # nosec - token for get_latest_configuration executions
         self.last_returned_value = ""
 
     def _get(self, name: str, **sdk_options) -> str:
@@ -108,19 +108,19 @@ def _get(self, name: str, **sdk_options) -> str:
         sdk_options: dict, optional
             SDK options to propagate to `start_configuration_session` API call
         """
-        if not self._next_token:
+        if name not in self._next_token:
             sdk_options["ConfigurationProfileIdentifier"] = name
             sdk_options["ApplicationIdentifier"] = self.application
             sdk_options["EnvironmentIdentifier"] = self.environment
             response_configuration = self.client.start_configuration_session(**sdk_options)
-            self._next_token = response_configuration["InitialConfigurationToken"]
+            self._next_token[name] = response_configuration["InitialConfigurationToken"]
 
         # The new AppConfig APIs require two API calls to return the configuration
         # First we start the session and after that we retrieve the configuration
         # We need to store the token to use in the next execution
-        response = self.client.get_latest_configuration(ConfigurationToken=self._next_token)
+        response = self.client.get_latest_configuration(ConfigurationToken=self._next_token[name])
         return_value = response["Configuration"].read()
-        self._next_token = response["NextPollConfigurationToken"]
+        self._next_token[name] = response["NextPollConfigurationToken"]
 
         if return_value:
             self.last_returned_value = return_value

docs/utilities/parameters.md

@@ -91,6 +91,9 @@ You can fetch application configurations in AWS AppConfig using `get_app_config`
 
 The following will retrieve the latest version and store it in the cache.
 
+???+ warning
+	We make two API calls to fetch each unique configuration name during the first time. This is by design in AppConfig. Please consider adjusting `max_age` parameter to enhance performance.
+
 === "getting_started_appconfig.py"
     ```python hl_lines="5 12"
     --8<-- "examples/parameters/src/getting_started_appconfig.py"

tests/functional/test_utilities_parameters.py

@@ -2171,14 +2171,68 @@ def test_appconf_provider_get_configuration_no_transform(mock_name, config):
     stubber.activate()
 
     try:
-        value: str = provider.get(mock_name)
+        value: bytes = provider.get(mock_name)
         str_value = value.decode("utf-8")
         assert str_value == json.dumps(mock_body_json)
         stubber.assert_no_pending_responses()
     finally:
         stubber.deactivate()
 
 
+def test_appconf_provider_multiple_unique_config_names(mock_name, config):
+    """
+    Test appconfig_provider.get with multiple config names
+    """
+
+    # GIVEN a provider instance, we should be able to retrieve multiple appconfig profiles.
+    environment = "dev"
+    application = "myapp"
+    provider = parameters.AppConfigProvider(environment=environment, application=application, config=config)
+
+    mock_body_json_first_call = {"myenvvar1": "Black Panther", "myenvvar2": 3}
+    encoded_message_first_call = json.dumps(mock_body_json_first_call).encode("utf-8")
+    mock_value_first_call = StreamingBody(BytesIO(encoded_message_first_call), len(encoded_message_first_call))
+
+    mock_body_json_second_call = {"myenvvar1": "Thor", "myenvvar2": 5}
+    encoded_message_second_call = json.dumps(mock_body_json_second_call).encode("utf-8")
+    mock_value_second_call = StreamingBody(BytesIO(encoded_message_second_call), len(encoded_message_second_call))
+
+    # WHEN making two API calls using the same provider instance.
+    stubber = stub.Stubber(provider.client)
+
+    response_get_latest_config_first_call = {
+        "Configuration": mock_value_first_call,
+        "NextPollConfigurationToken": "initial_token",
+        "ContentType": "application/json",
+    }
+
+    response_start_config_session = {"InitialConfigurationToken": "initial_token"}
+    stubber.add_response("start_configuration_session", response_start_config_session)
+    stubber.add_response("get_latest_configuration", response_get_latest_config_first_call)
+
+    response_get_latest_config_second_call = {
+        "Configuration": mock_value_second_call,
+        "NextPollConfigurationToken": "initial_token",
+        "ContentType": "application/json",
+    }
+    response_start_config_session = {"InitialConfigurationToken": "initial_token"}
+    stubber.add_response("start_configuration_session", response_start_config_session)
+    stubber.add_response("get_latest_configuration", response_get_latest_config_second_call)
+
+    stubber.activate()
+
+    try:
+        # THEN we should expect different return values.
+        value_first_call: bytes = provider.get(mock_name)
+        value_second_call: bytes = provider.get(f"{mock_name}_ second_config")
+
+        assert value_first_call != value_second_call
+        stubber.assert_no_pending_responses()
+
+    finally:
+        stubber.deactivate()
+
+
 def test_appconf_get_app_config_no_transform(monkeypatch, mock_name):
     """
     Test get_app_config()