tools/bazel/generate_samples_tests_build_files.py

# Copyright 2026 The Pigweed Authors
#
# 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
#
#     https://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.

import argparse
import os
from pathlib import Path


def create_build_files(zephyr_root, output_root):
    """Finds all subdirectories under zephyr_root/samples/ containing a
    sample.yaml file, and all subdirectories under zephyr_root/tests/
    containing a testcase.yaml file, and generates a BUILD.bazel file
    in the corresponding directory in output_root.
    """
    zephyr_root = Path(zephyr_root).resolve()
    output_root = Path(output_root).resolve()

    def process_dir(sub_dir_name, marker_file):
        target_root = zephyr_root / sub_dir_name
        if not target_root.exists():
            print(f'Warning: {target_root} does not exist.')
            return

        for root, _, files in os.walk(target_root):
            if marker_file in files:
                current_path = Path(root)
                relative_path = current_path.relative_to(zephyr_root)
                output_dir = output_root / relative_path
                output_dir.mkdir(parents=True, exist_ok=True)
                output_file = output_dir / 'BUILD.bazel'

                try:
                    with open(output_file, 'w') as f:
                        f.write("""# SPDX-License-Identifier: Apache-2.0

# Auto-generated from corresponding CMakeLists.txt in Zephyr using scripts
# in zephyr-bazel.

load("//:cc.bzl", "zephyr_app", "zephyr_cc_library")

package(default_visibility = ["//visibility:public"])

zephyr_app(
    name = package_name().split("/")[-1],
    deps = [":main"],
)

zephyr_cc_library(
    name = "main",
    visibility = ["//visibility:private"],
    srcs = glob(["**/*.c"]) + glob(["**/*.h"], allow_empty=True),
)
""")
                    print(f'Wrote {output_file}')
                except IOError as e:
                    print(f'Error: Could not write to {output_file}. {e}')

    process_dir('samples', 'sample.yaml')
    process_dir('tests', 'testcase.yaml')


def main():
    parser = argparse.ArgumentParser(
        description='Generate BUILD.bazel files for samples and tests directories.'
    )
    parser.add_argument(
        '--zephyr_root', required=True, help='The root directory of the Zephyr tree.'
    )
    parser.add_argument(
        '--output_root',
        help='The root directory for the generated BUILD.bazel files.',
    )
    args = parser.parse_args()
    create_build_files(args.zephyr_root, args.output_root)


if __name__ == '__main__':
    main()