#! /usr/bin/env python3
#
# SPDX-License-Identifier: GPL-2.0-or-later
#
# TASST - Test A Simple Socket Transport
#
# test/tasst/pasta.py - Helpers for seeting up pasta instances
#
# Copyright Red Hat
# Author: David Gibson <david@gibson.dropbear.id.au>

import contextlib
import os
from typing import Iterator

import tunbridge


@contextlib.contextmanager
def pasta(host: tunbridge.Site, guest: tunbridge.Site, *opts: str) \
        -> Iterator[tunbridge.site.SiteProcess]:
    if tunbridge.unshare.parent(guest) is not host:
        raise ValueError("pasta guest must be a namespace under host site")

    # This implies guest is a namespace site
    assert isinstance(guest, tunbridge.unshare.NsenterSite)

    exe = os.environ['PASTA']

    with host.tempdir() as piddir:
        pidfile = os.path.join(piddir, 'pasta.pid')
        cmd = [exe, '-f', '-P', pidfile] + list(opts) + [f'{guest.pid}']
        with host.bg(*cmd, stop=True) as pasta:
            # Wait for the PID file to be written
            pidstr = None
            while not pidstr:
                pidstr = host.readfile(pidfile, check=False)
            pid = int(pidstr)
            print(f'pasta started, host: {host}, guest: {guest}, pid: {pid}')
            yield pasta