Add some basic variable validation

Validate the `name`, `python_package` and `pypi_package_name`.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

cookiecutter/hooks/pre_gen_project.py

@@ -0,0 +1,80 @@
+# License: MIT
+# Copyright © 2023 Frequenz Energy-as-a-Service GmbH
+
+"""Cookiecutter pre-generation hooks.
+
+This module contains the pre-generation hooks for the cookiecutter template. It
+validates the cookiecutter variables and prints an error message and exits with a
+non-zero exit code if any of them are invalid.
+"""
+
+import collections
+import json
+import re
+import sys
+from typing import Any
+
+NAME_REGEX = re.compile(r"^[a-zA-Z][_a-zA-Z0-9]+(-[_a-zA-Z][_a-zA-Z0-9]+)*$")
+PYTHON_PACKAGE_REGEX = re.compile(r"^[a-zA-Z][_a-zA-Z0-9]+(\.[_a-zA-Z][_a-zA-Z0-9]+)*$")
+PYPI_PACKAGE_REGEX = NAME_REGEX
+
+
+def to_named_tuple(dictionary: dict[Any, Any], /) -> Any:
+    """Convert a dictionary to a named tuple.
+
+    Args:
+        dictionary: The dictionary to convert.
+
+    Returns:
+        The named tuple with the same keys and values as the dictionary.
+    """
+    filtered = {k: v for k, v in dictionary.items() if not k.startswith("_")}
+    return collections.namedtuple("Cookiecutter", filtered.keys())(*filtered.values())
+
+
+cookiecutter = to_named_tuple(json.loads(r"""{{cookiecutter | tojson}}"""))
+
+
+def main() -> None:
+    """Validate the cookiecutter variables.
+
+    This function validates the cookiecutter variables and prints an error message and
+    exits with a non-zero exit code if any of them are invalid.
+    """
+    errors: dict[str, list[str]] = {}
+
+    def add_error(key: str, message: str) -> None:
+        """Add an error to the error dictionary.
+
+        Args:
+            key: The key of the error.
+            message: The error message.
+        """
+        errors.setdefault(key, []).append(message)
+
+    if not NAME_REGEX.match(cookiecutter.name):
+        add_error("name", f"Invalid project name (must match {NAME_REGEX.pattern})")
+
+    if not PYTHON_PACKAGE_REGEX.match(cookiecutter.python_package):
+        add_error(
+            "python_package",
+            f"Invalid package name (must match {PYTHON_PACKAGE_REGEX.pattern})",
+        )
+
+    if not PYPI_PACKAGE_REGEX.match(cookiecutter.pypi_package_name):
+        add_error(
+            "pypi_package_name",
+            f"Invalid package name (must match {PYPI_PACKAGE_REGEX.pattern})",
+        )
+
+    if errors:
+        print("The following errors were found:", file=sys.stderr)
+        for key, messages in errors.items():
+            print(f"  {key}:", file=sys.stderr)
+            for message in messages:
+                print(f"    - {message}", file=sys.stderr)
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()