scripts/style/json-fmt.py

#!/usr/bin/env fuchsia-vendored-python
# Copyright 2018 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Script to format JSON files.

This script accepts a list of files as arguments, and for each of them attempts
to parse it as JSON, and update it in-place with a pretty-printed version. Stops
on the first error.
"""

import argparse
import json


def main():
    parser = argparse.ArgumentParser()

    parser.add_argument(
        "file",
        type=argparse.FileType("r+"),
        nargs="+",
        help="JSON file to be pretty-printed.",
    )
    parser.add_argument(
        "--sort-keys",
        default=True,
        action=argparse.BooleanOptionalAction,
        dest="sort_keys",
        help="Indicates whether object keys should be sorted.",
    )
    parser.add_argument(
        "--ignore-errors",
        default=False,
        action=argparse.BooleanOptionalAction,
        dest="ignore_errors",
        help="Indicates whether invalid JSON should be ignored.",
    )
    parser.add_argument(
        "--quiet",
        default=False,
        action=argparse.BooleanOptionalAction,
        dest="quiet",
        help="Don't print any output.",
    )

    args = parser.parse_args()
    for json_file in args.file:
        try:
            with json_file:
                original = json_file.read()
                data = json.loads(original)
                formatted = json.dumps(
                    data,
                    indent=4,
                    sort_keys=args.sort_keys,
                    separators=(",", ": "),
                )
                if original != formatted:
                    json_file.seek(0)
                    json_file.truncate()
                    json_file.write(formatted + "\n")
        except json.JSONDecodeError:
            if not args.quiet:
                print(
                    f"Exception encountered while processing {json_file.name}"
                )
            if not args.ignore_errors:
                raise


if __name__ == "__main__":
    main()