With LocalStack 1.0 we have introduced LocalStack Extensions that allow developers to extend and customize LocalStack. Both the feature and the API are currently experimental and may be subject to change.
Extensions are a LocalStack Pro feature. To use and install extensions, use the CLI to first log in to your account
$ localstack login Please provide your login credentials below Username: ...
$ localstack extensions --help Usage: localstack extensions [OPTIONS] COMMAND [ARGS]... Manage LocalStack extensions (beta) Options: --help Show this message and exit. Commands: init Initialize the LocalStack extensions environment install Install a LocalStack extension uninstall Remove a LocalStack extension
To install an extension, specify the name of the pip dependency that contains the extension. For example, for the official Stripe extension, you can either use the package distributed on pypi:
$ localstack extensions install localstack-extensions-stripe
or you can install it directly from this git repository
$ localstack extensions install "git+https://github.com/localstack/localstack-extensions/#egg=localstack-extensions-stripe&subdirectory=stripe"
The extensions API
LocalStack exposes a Python API for building extensions that can be found in the core codebase in
The basic interface to implement is as follows:
class Extension(BaseExtension): """ An extension that is loaded into LocalStack dynamically. The method execution order of an extension is as follows: - on_extension_load - on_platform_start - update_gateway_routes - update_request_handlers - update_response_handlers - on_platform_ready """ namespace: str = "localstack.extensions" """The namespace of all basic localstack extensions.""" name: str """The unique name of the extension set by the implementing class.""" def on_extension_load(self): """ Called when LocalStack loads the extension. """ pass def on_platform_start(self): """ Called when LocalStack starts the main runtime. """ pass def update_gateway_routes(self, router: Router[RouteHandler]): """ Called with the Router attached to the LocalStack gateway. Overwrite this to add or update routes. :param router: the Router attached in the gateway """ pass def update_request_handlers(self, handlers: CompositeHandler): """ Called with the custom request handlers of the LocalStack gateway. Overwrite this to add or update handlers. :param handlers: custom request handlers of the gateway """ pass def update_response_handlers(self, handlers: CompositeResponseHandler): """ Called with the custom response handlers of the LocalStack gateway. Overwrite this to add or update handlers. :param handlers: custom response handlers of the gateway """ pass def on_platform_ready(self): """ Called when LocalStack is ready and the Ready marker has been printed. """ pass
A minimal example would look like this:
import logging from localstack.extensions.api import Extension LOG = logging.getLogger(__name__) class ReadyAnnoucerExtension(Extension): name = "my_ready_annoucer" def on_platform_ready(self): LOG.info("my plugin is laded and localstack is ready to roll!")
Package your Extension
You can either use Plux to discover the entrypoints from your code when building and publishing your distribution, or manually define them as in the example below.
setup.cfg for the extension above could look like this:
[metadata] name = localstack-extension-ready-announcer description = LocalStack extension that logs when LocalStack is ready to receive requests author = Your Name author_email = email@example.com url = https://link-to-your-project [options] zip_safe = False packages = find: install_requires = localstack>=1.0.0 [options.entry_points] localstack.extensions = my_ready_annoucer = localstack_annoucer.extension:ReadyAnnoucerExtension
The entry point group is the Plux namespace
locastack.extensions, and the entry point name is the plugin name
my_ready_announcer. The object reference points to the plugin class.