run-with-env.py

#!/usr/bin/env python3

import os
import re
import subprocess
from argparse import ArgumentParser, Namespace
from dataclasses import dataclass, field


def build_parser() -> ArgumentParser:
    parser: ArgumentParser = ArgumentParser(add_help=False, usage='%(prog)s {program} --env:{key} {val} {arg}')
    parser.add_argument('program', type=str)
    return parser

@dataclass
class Process:
    program: str
    args: list[str] = field(default_factory=list)
    environment: dict[str, str] = field(default_factory=dict)

    @classmethod
    def from_parser(cls, namespace: Namespace, args: list[str]) -> 'Process':
        process = Process(program=namespace.program)
        patterns = {'env': re.compile(r'^--env:(?P<key>\w+)$')}
        i: int = 0
        while i < len(args):
            arg = args[i]
            if match_object := patterns['env'].match(arg):
                process.environment[match_object.group('key')] = args[i+1]
                i += 1
            else:
                process.args.append(arg)
            i += 1
        return process

    def run(self) -> int:
        parent_envs: dict[str, str] = dict(os.environ)
        pid: object = subprocess.run(
            args=[self.program]+self.args,
            env={**parent_envs, **self.environment},
            check=False
        )
        return pid.returncode

if __name__ == '__main__':
    parser: ArgumentParser = build_parser()
    namespace, args = parser.parse_known_args()
    process: Process = Process.from_parser(namespace, args)
    print(process)
    return_code = process.run()
    exit(return_code)