create an intel hex file from IDF build directory

makehex.py

#!/usr/bin/env python

import intelhex
import json
from pathlib import Path

def main():
    build_dir = Path('build')
    if not build_dir.exists() or not build_dir.is_dir():
        print('build directory doesn\'t exist')
        raise SystemExit(1)
    
    flasher_args_file = build_dir / 'flasher_args.json'
    if not flasher_args_file.exists():
        print('build/flasher_args.json doesn\'t exist')
        raise SystemExit(1)

    flasher_args = json.loads(flasher_args_file.read_text(encoding='utf-8'))
    flash_files = flasher_args['flash_files']
    output_file_name = flasher_args['app']['file'].replace('.bin', '.hex')

    hexfile = intelhex.IntelHex()
    for offset, filename in flash_files.items():
        file = build_dir / filename
        hexfile.loadbin(file, offset=int(offset, 0))

    hexfile.write_hex_file(build_dir / output_file_name)


if __name__ == "__main__":
    main()