FreedomBox/actions/deluge

#!/usr/bin/python3
# SPDX-License-Identifier: AGPL-3.0-or-later
"""
Configuration helper for BitTorrent web client.
"""

import argparse
import json
import pathlib
import subprocess
import time

import augeas

from plinth import action_utils
from plinth.modules.deluge.utils import Config

DELUGED_DEFAULT_FILE = '/etc/default/deluged'
DELUGE_CONF_DIR = pathlib.Path('/var/lib/deluged/.config/deluge/')

DELUGE_WEB_SYSTEMD_SERVICE_PATH = '/etc/systemd/system/deluge-web.service'
DELUGE_WEB_SYSTEMD_SERVICE = '''
#
# This file is managed and overwritten by Plinth.  If you wish to edit
# it, disable Deluge in Plinth, remove this file and manage it manually.
#
[Unit]
Description=Deluge Web Interface
Documentation=man:deluge-web(1)
After=network.target

[Service]
ExecStart=bash -c "/usr/bin/deluge-web --base=deluge $(/usr/bin/deluge-web --version | grep deluge-web | cut -f2 -d' ' | grep -q '^1.' && echo '' || echo '--do-not-daemonize')"
Restart=on-failure
User=debian-deluged
Group=debian-deluged
LockPersonality=yes
NoNewPrivileges=yes
PrivateDevices=yes
PrivateTmp=yes
ProtectControlGroups=yes
ProtectKernelLogs=yes
ProtectKernelModules=yes
ProtectKernelTunables=yes
ProtectSystem=yes
RestrictAddressFamilies=AF_UNIX AF_INET AF_INET6
RestrictRealtime=yes
StateDirectory=deluged
SystemCallArchitectures=native

[Install]
WantedBy=multi-user.target
'''  # noqa: E501


def parse_arguments():
    """Return parsed command line arguments as dictionary."""
    parser = argparse.ArgumentParser()
    subparsers = parser.add_subparsers(dest='subcommand', help='Sub command')

    subparsers.add_parser('setup', help='Setup deluge')

    subparsers.add_parser('get-configuration',
                          help='Return the current configuration')

    subparser = subparsers.add_parser('set-configuration',
                                      help='Set the configuration parameter')
    subparser.add_argument('parameter',
                           help='Name of the configuration parameter')
    subparser.add_argument('value',
                           help='Value of the configuration parameter')

    subparsers.required = True
    return parser.parse_args()


def _set_configuration(filename, parameter, value):
    """Set the configuration parameter."""
    deluged_is_running = action_utils.service_is_running('deluged')
    if deluged_is_running:
        action_utils.service_stop('deluged')
    deluge_web_is_running = action_utils.service_is_running('deluge-web')
    if deluge_web_is_running:
        action_utils.service_stop('deluge-web')

    with Config(DELUGE_CONF_DIR / filename) as config:
        config.content[parameter] = value

    if deluged_is_running:
        action_utils.service_start('deluged')
    if deluge_web_is_running:
        action_utils.service_start('deluge-web')


def _get_host_id():
    """Get default host id."""
    try:
        with Config(DELUGE_CONF_DIR / 'hostlist.conf') as config:
            return config.content['hosts'][0][0]
    except FileNotFoundError:
        with Config(DELUGE_CONF_DIR / 'hostlist.conf.1.2') as config:
            return config.content['hosts'][0][0]


def _set_deluged_daemon_options():
    """Set deluged daemon options."""
    aug = augeas.Augeas(flags=augeas.Augeas.NO_LOAD +
                        augeas.Augeas.NO_MODL_AUTOLOAD)
    aug.set('/augeas/load/Shellvars/lens', 'Shellvars.lns')
    aug.set('/augeas/load/Shellvars/incl[last() + 1]', DELUGED_DEFAULT_FILE)
    aug.load()
    aug.set('/files' + DELUGED_DEFAULT_FILE + '/ENABLE_DELUGED', '1')
    # overwrite daemon args, use default config directory (same as deluge-web)
    aug.set('/files' + DELUGED_DEFAULT_FILE + '/DAEMON_ARGS',
            '"-d -l /var/log/deluged/daemon.log -L info"')
    aug.save()


def subcommand_get_configuration(_):
    """Return the current deluged configuration in JSON format."""
    with Config(DELUGE_CONF_DIR / 'core.conf') as config:
        download_location = config.content['download_location']

    print(json.dumps({'download_location': download_location}))


def subcommand_set_configuration(arguments):
    """Set the deluged configuration."""
    if arguments.parameter != 'download_location':
        return

    _set_configuration('core.conf', arguments.parameter, arguments.value)


def subcommand_setup(_):
    """Perform initial setup for deluge."""

    with open(DELUGE_WEB_SYSTEMD_SERVICE_PATH, 'w') as file_handle:
        file_handle.write(DELUGE_WEB_SYSTEMD_SERVICE)

    _set_deluged_daemon_options()

    subprocess.check_call(['systemctl', 'daemon-reload'])

    # Restarting an old deluge-web service stops also possible deluged process
    # that was started from the web interface.
    action_utils.service_try_restart('deluge-web')

    # Wait until core configuration is available so that status of the app can
    # be shown properly.
    _wait_for_configuration('deluged', 'core.conf')

    # Configure deluge-web to autoconnect to the default deluged daemon.
    _wait_for_configuration('deluge-web', 'web.conf')
    host_id = _get_host_id()
    _set_configuration('web.conf', 'default_daemon', host_id)


def _wait_for_configuration(service, file_name):
    """Wait until configuration file has been created."""
    conf_file = DELUGE_CONF_DIR / file_name
    if conf_file.exists():
        return

    # deluge-web creates files on first run. deluged on the other than differs
    # in version. Older version in Debian Buster creates the files after a
    # restart while newer versions create the files on first run. The following
    # approach is slightly better for create-on-exit case.
    is_running = action_utils.service_is_running(service)
    for interval in range(7):
        action_utils.service_restart(service)
        if conf_file.exists():
            break

        print('Waiting for {service} configuration')
        time.sleep(2**interval)  # Exponentially increase the time waited
    else:
        raise Exception(f'Unable to setup {service}.')

    if not is_running:
        action_utils.service_stop(service)


def main():
    """Parse arguments and perform all duties."""
    arguments = parse_arguments()

    subcommand = arguments.subcommand.replace('-', '_')
    subcommand_method = globals()['subcommand_' + subcommand]
    subcommand_method(arguments)


if __name__ == '__main__':
    main()