tests/qemu-iotests/tests/nbd-reconnect-on-open

#!/usr/bin/env python3
#
# Test nbd reconnect on open
#
# Copyright (c) 2020 Virtuozzo International GmbH
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

import time

import iotests
from iotests import qemu_img_create, file_path, qemu_io_popen, qemu_nbd, \
    qemu_io_log, log

iotests.script_initialize(supported_fmts=['qcow2'])

disk, nbd_sock = file_path('disk', 'nbd-sock')


def create_args(open_timeout):
    return ['--image-opts', '-c', 'read 0 1M',
            f'driver=nbd,open-timeout={open_timeout},'
            f'server.type=unix,server.path={nbd_sock}']


def check_fail_to_connect(open_timeout):
    log(f'Check fail to connect with {open_timeout} seconds of timeout')

    start_t = time.time()
    qemu_io_log(*create_args(open_timeout), check=False)
    delta_t = time.time() - start_t

    max_delta = open_timeout + 0.2
    if open_timeout <= delta_t <= max_delta:
        log(f'qemu_io finished in {open_timeout}..{max_delta} seconds, OK')
    else:
        note = 'too early' if delta_t < open_timeout else 'too long'
        log(f'qemu_io finished in {delta_t:.1f} seconds, {note}')


qemu_img_create('-f', iotests.imgfmt, disk, '1M')

# Start NBD client when NBD server is not yet running. It should not fail, but
# wait for 5 seconds for the server to be available.
client = qemu_io_popen(*create_args(5))

time.sleep(1)
qemu_nbd('-k', nbd_sock, '-f', iotests.imgfmt, disk)

# client should succeed
log(client.communicate()[0], filters=[iotests.filter_qemu_io])

# Server was started without --persistent flag, so it should be off now. Let's
# check it and at the same time check that with open-timeout=0 client fails
# immediately.
check_fail_to_connect(0)

# Check that we will fail after non-zero timeout if server is still unavailable
check_fail_to_connect(1)