libdot/bin/npm

#!/usr/bin/env python3
# Copyright 2019 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Run npm with the right settings."""

import contextlib
import os
from pathlib import Path
import sys

import libdot


@contextlib.contextmanager
def temp_switch_path_owner(path: os.PathLike):
    """Change |path| owner to root temporarily.

    Starting with node-16, npm will automatically change uid/gid when the
    current user is root.  It determines that target uid/gid based on the
    owner of the cwd.  To defeat that logic, we have to temporarily change
    the cwd ownership to root.
    """
    switch = os.getuid() == 0
    if switch:
        st = path.stat()
        uid = st.st_uid
        gid = st.st_gid
        os.chown(path, 0, 0)
    try:
        yield
    finally:
        if switch:
            os.chown(path, uid, gid)


def run(cmd, **kwargs):
    """Run the npm |cmd|."""
    cwd = Path(kwargs.get("cwd", "."))
    with temp_switch_path_owner(cwd):
        return libdot.node.run(["npm"] + cmd, **kwargs)


def main(argv):
    """The main func!"""
    libdot.setup_logging()
    libdot.node_and_npm_setup()
    run(argv)


if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))