adds utils.py file

Author: chalmerlowe

scripts/microgenerator/utils.py

@@ -0,0 +1,120 @@
+# -*- coding: utf-8 -*-
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+"""Utility functions for the microgenerator."""
+
+import os
+import sys
+import yaml
+import jinja2
+from typing import Dict, Any, Iterator, Callable
+
+
+def _load_resource(
+    loader_func: Callable,
+    path: str,
+    not_found_exc: type,
+    parse_exc: type,
+    resource_type_name: str,
+) -> Any:
+    """
+    Generic resource loader with common error handling.
+
+    Args:
+        loader_func: A callable that performs the loading and returns the resource.
+                     It should raise appropriate exceptions on failure.
+        path: The path/name of the resource for use in error messages.
+        not_found_exc: The exception type to catch for a missing resource.
+        parse_exc: The exception type to catch for a malformed resource.
+        resource_type_name: A human-readable name for the resource type.
+    """
+    try:
+        return loader_func()
+    except not_found_exc:
+        print(f"Error: {resource_type_name} '{path}' not found.", file=sys.stderr)
+        sys.exit(1)
+    except parse_exc as e:
+        print(
+            f"Error: Could not load {resource_type_name.lower()} from '{path}': {e}",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+
+def load_template(template_path: str) -> jinja2.Template:
+    """
+    Loads a Jinja2 template from a given file path.
+    """
+    template_dir = os.path.dirname(template_path)
+    template_name = os.path.basename(template_path)
+
+    def _loader() -> jinja2.Template:
+        env = jinja2.Environment(
+            loader=jinja2.FileSystemLoader(template_dir or "."),
+            trim_blocks=True,
+            lstrip_blocks=True,
+        )
+        return env.get_template(template_name)
+
+    return _load_resource(
+        loader_func=_loader,
+        path=template_path,
+        not_found_exc=jinja2.exceptions.TemplateNotFound,
+        parse_exc=jinja2.exceptions.TemplateError,
+        resource_type_name="Template file",
+    )
+
+
+def load_config(config_path: str) -> Dict[str, Any]:
+    """Loads the generator's configuration from a YAML file."""
+
+    def _loader() -> Dict[str, Any]:
+        with open(config_path, "r", encoding="utf-8") as f:
+            return yaml.safe_load(f)
+
+    return _load_resource(
+        loader_func=_loader,
+        path=config_path,
+        not_found_exc=FileNotFoundError,
+        parse_exc=yaml.YAMLError,
+        resource_type_name="Configuration file",
+    )
+
+
+def walk_codebase(path: str) -> Iterator[str]:
+    """Yields all .py file paths in a directory."""
+    for root, _, files in os.walk(path):
+        for file in files:
+            if file.endswith(".py"):
+                yield os.path.join(root, file)
+
+
+def write_code_to_file(output_path: str, content: str):
+    """Ensures the output directory exists and writes content to the file."""
+    output_dir = os.path.dirname(output_path)
+
+    # An empty output_dir means the file is in the current directory.
+    if output_dir:
+        print(f"  Ensuring output directory exists: {os.path.abspath(output_dir)}")
+        os.makedirs(output_dir, exist_ok=True)
+        if not os.path.isdir(output_dir):
+            print(f"  Error: Output directory was not created.", file=sys.stderr)
+            sys.exit(1)
+
+    print(f"  Writing generated code to: {os.path.abspath(output_path)}")
+    with open(output_path, "w", encoding="utf-8") as f:
+        f.write(content)
+    print(f"Successfully generated {output_path}")