add Makefile and update README for utils package

- Add Makefile with build, publish, format, and lint targets
- Update README: rename Installation to Usage, show pyproject.toml dependency format

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: whummer

utils/Makefile

@@ -0,0 +1,40 @@
+VENV_BIN = python3 -m venv
+VENV_DIR ?= .venv
+VENV_ACTIVATE = $(VENV_DIR)/bin/activate
+VENV_RUN = . $(VENV_ACTIVATE)
+
+usage:          ## Show usage for this Makefile
+	@cat Makefile | grep -E '^[a-zA-Z_-]+:.*?## .*$$' | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-15s\033[0m %s\n", $$1, $$2}'
+
+venv: $(VENV_ACTIVATE)
+
+$(VENV_ACTIVATE): pyproject.toml
+	test -d .venv || $(VENV_BIN) .venv
+	$(VENV_RUN); pip install --upgrade pip setuptools wheel build
+	$(VENV_RUN); pip install -e .[dev]
+	touch $(VENV_DIR)/bin/activate
+
+clean:          ## Clean up build artifacts and virtual environment
+	rm -rf .venv/
+	rm -rf build/
+	rm -rf .eggs/
+	rm -rf *.egg-info/
+
+install: venv   ## Install the package in development mode
+
+dist: venv      ## Create distribution package
+	$(VENV_RUN); python -m build
+
+publish: clean-dist venv dist   ## Publish package to PyPI
+	$(VENV_RUN); pip install --upgrade twine; twine upload dist/*
+
+format: venv    ## Run ruff to format the code
+	$(VENV_RUN); python -m ruff format .; make lint
+
+lint: venv      ## Run ruff to lint the code
+	$(VENV_RUN); python -m ruff check --output-format=full .
+
+clean-dist: clean
+	rm -rf dist/
+
+.PHONY: clean clean-dist dist install publish usage venv format lint

utils/README.md

@@ -3,39 +3,32 @@ LocalStack Extensions Utils
 
 A utility library providing common functionality for building [LocalStack Extensions](https://github.com/localstack/localstack-extensions).
 
-## Installation
+## Usage
+
+To use this library in your LocalStack extension, add it to the `dependencies` in your extension's `pyproject.toml`:
 
-```bash
-pip install localstack-extensions-utils
+```toml
+[project]
+dependencies = [
+    "localstack-extensions-utils",
+]
 ```
 
-Or install directly from the GitHub repository:
+Or, to install directly from the GitHub repository:
 
-```bash
-pip install "git+https://github.com/localstack/localstack-extensions.git#egg=localstack-extensions-utils&subdirectory=utils"
+```toml
+[project]
+dependencies = [
+    "localstack-extensions-utils @ git+https://github.com/localstack/localstack-extensions.git#subdirectory=utils",
+]
 ```
 
-## Usage
-
-### Creating a Docker-based Extension
+Then import the utilities in your extension code, for example:
 
 ```python
 from localstack_extensions.utils import ProxiedDockerContainerExtension
-from werkzeug.datastructures import Headers
-
-class MyExtension(ProxiedDockerContainerExtension):
-    name = "my-extension"
-
-    def __init__(self):
-        super().__init__(
-            image_name="my-docker-image:latest",
-            container_ports=[8080],
-            host="myext.localhost.localstack.cloud",
-        )
 
-    def should_proxy_request(self, headers: Headers) -> bool:
-        # Define your routing logic
-        return "myext" in headers.get("Host", "")
+...
 ```
 
 ## Dependencies