AppConfig Extension

AWS AppConfig configuration retrieval through the AWS AppConfig Agent Lambda extension

CLASS	DESCRIPTION
`AppConfigExtensionProvider`	AWS AppConfig provider backed by the AWS AppConfig Agent Lambda extension.

AppConfigExtensionProvider ¶

AppConfigExtensionProvider(environment: str, application: str | None = None, port: int | None = None, timeout: float = DEFAULT_EXTENSION_TIMEOUT_SECS)

Bases: BaseProvider

AWS AppConfig provider backed by the AWS AppConfig Agent Lambda extension.

The extension runs as a Lambda layer, keeps a local cache of configuration data, polls AWS AppConfig in the background, and serves configuration over HTTP on localhost. This provider reads from that local endpoint instead of calling the AppConfig APIs with boto3.

PARAMETER	DESCRIPTION
`environment`	Environment of the configuration TYPE: `str`
`application`	Application of the configuration, by default POWERTOOLS_SERVICE_NAME TYPE: `str \| None` DEFAULT: `None`
`port`	Port of the extension's local HTTP server, by default AWS_APPCONFIG_EXTENSION_HTTP_PORT or 2772 TYPE: `int \| None` DEFAULT: `None`
`timeout`	Seconds to wait for a response from the extension, by default 3 TYPE: `float` DEFAULT: `DEFAULT_EXTENSION_TIMEOUT_SECS`

Example

Retrieves a configuration from the AppConfig Agent Lambda extension

>>> from aws_lambda_powertools.utilities import parameters
>>>
>>> appconf_provider = parameters.AppConfigExtensionProvider(environment="my_env", application="my_app")
>>>
>>> value: dict = appconf_provider.get("my_conf", transform="json")

Retrieves selected feature flags only

>>> value: dict = appconf_provider.get("my_flags", transform="json", flag=["beta_ui", "new_checkout"])

Notes

Attach the AWS-AppConfig-Extension layer to the function and grant the execution role appconfig:StartConfigurationSession and appconfig:GetLatestConfiguration. The extension uses those permissions; this provider only talks to localhost.

Source code in aws_lambda_powertools/utilities/parameters/appconfig_extension.py

def __init__(
    self,
    environment: str,
    application: str | None = None,
    port: int | None = None,
    timeout: float = DEFAULT_EXTENSION_TIMEOUT_SECS,
):
    super().__init__()
    self.environment = environment
    self.application = resolve_env_var_choice(
        choice=application,
        env=os.getenv(constants.SERVICE_NAME_ENV, "service_undefined"),
    )
    self.port = (
        port if port is not None else int(os.getenv(constants.APPCONFIG_EXTENSION_PORT_ENV, DEFAULT_EXTENSION_PORT))
    )
    self.timeout = timeout