#!/usr/bin/env python3
#
# Copyright (C) 2022 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# 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/>.

# T4870: change underlaying container filesystem from vfs to overlay

import os
import shutil
import sys

from vyos.configtree import ConfigTree
from vyos.utils.process import call

if len(sys.argv) < 2:
    print("Must specify file name!")
    sys.exit(1)

file_name = sys.argv[1]

with open(file_name, 'r') as f:
    config_file = f.read()

base = ['container', 'name']
config = ConfigTree(config_file)

# Check if containers exist and we need to perform image manipulation
if config.exists(base):
    for container in config.list_nodes(base):
        # Stop any given container first
        call(f'sudo systemctl stop vyos-container-{container}.service')
        # Export container image for later re-import to new filesystem. We store
        # the backup on a real disk as a tmpfs (like /tmp) could probably lack
        # memory if a host has too many containers stored.
        image_name = config.return_value(base + [container, 'image'])
        call(f'sudo podman image save --quiet --output /root/{container}.tar --format oci-archive {image_name}')

# No need to adjust the strage driver online (this is only used for testing and
# debugging on a live system) - it is already overlay2 when the migration script
# is run during system update. But the specified driver in the image is actually
# overwritten by the still present VFS filesystem on disk. Thus podman still
# thinks it uses VFS until we delete the libpod directory under:
# /usr/lib/live/mount/persistence/container/storage
#call('sed -i "s/vfs/overlay2/g" /etc/containers/storage.conf /usr/share/vyos/templates/container/storage.conf.j2')

base_path = '/usr/lib/live/mount/persistence/container/storage'
for dir in ['libpod', 'vfs', 'vfs-containers', 'vfs-images', 'vfs-layers']:
    if os.path.exists(f'{base_path}/{dir}'):
        shutil.rmtree(f'{base_path}/{dir}')

# Now all remaining information about VFS is gone and we operate in overlayfs2
# filesystem mode. Time to re-import the images.
if config.exists(base):
    for container in config.list_nodes(base):
        # Export container image for later re-import to new filesystem
        image_name = config.return_value(base + [container, 'image'])
        image_path = f'/root/{container}.tar'
        call(f'sudo podman image load --quiet --input {image_path}')

        # Start any given container first
        call(f'sudo systemctl start vyos-container-{container}.service')

        # Delete temporary container image
        if os.path.exists(image_path):
            os.unlink(image_path)