#!/usr/bin/env python3
# Copyright 2020 Red Hat, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

#
# This script is intended to run on mirror-update.opendev.org
# periodically called from a cron job.
#

import argparse
import fcntl
import logging
import os
import re
import sys
import statsd
import subprocess

from contextlib import contextmanager
from datetime import datetime

VOLUMES = ['docs',
           'docs.dev',
           'project.airship',
           'project.governance',
           'project.opendev',
           'project.meetings',
           'project.releases',
           'project.security',
           'project.service-types',
           'project.specs',
           'project.starlingx',
           'project.tarballs',
           'project.zuul',
           ]

STATSD_PREFIX='afs.release'

UPDATE_RE = re.compile("^\s+Last Update (.*)$")

log = logging.getLogger("release")


def get_last_update(volume):
    ret = []
    out = subprocess.check_output(['vos', 'examine', volume],
                                  stderr=subprocess.STDOUT).decode('utf-8')
    state = 0
    for line in out.split('\n'):
        if state == 0 and line.startswith(volume):
            state = 1
            site = None
        elif state == 1:
            site = line.strip()
            state = 0
        m = UPDATE_RE.match(line)
        if m:
            ret.append(dict(site=site,
                            volume=volume,
                            updated=datetime.strptime(m.group(1),
                                                      '%a %b %d %H:%M:%S %Y')))
    return ret


def release(volume, host, user, key, stats):
    log.info("Releasing %s" % volume)

    vn = volume.replace('.','_')

    with stats.timer('%s.%s' % (STATSD_PREFIX, vn)):
        # NOTE(ianw) : clearly paramiko would be better, but bionic
        # version 2.0.0 can't read a ed25519 key which we used in the
        # all the other ansible setup.
        cmd = ('ssh', '-T', '-i', '%s' % key,
               '%s@%s' % (user, host), '--',
               'vos', 'release', volume)
        log.debug('Running: %s' % ' '.join(cmd))
        p = subprocess.Popen(cmd,
                             shell=False,
                             stdout=subprocess.PIPE,
                             stderr=subprocess.PIPE,
                             universal_newlines=True)
        output, error = p.communicate()
        for line in output.split('\n'):
            log.debug(line)
        if not error:
            log.info("Release of %s successful" % volume)
        else:
            log.error("Release of %s failed" % volume)


def check_release(volume):
    '''Check if a volume needs release.

    Return TRUE if it needs to be released, FALSE if not
    '''
    log.info("Checking %s" % volume)
    rw = get_last_update(volume)[0]
    log.debug("  %s %s %s" % (rw['site'], rw['updated'], rw['volume']))
    ros = get_last_update(volume + '.readonly')
    update = False
    for ro in ros:
        log.debug("  %s %s %s" % (ro['site'], ro['updated'], ro['volume']))
        if ro['updated'] < rw['updated']:
            update = True
    if update:
        return True
    else:
        log.info("... no release required")


@contextmanager
def get_lock(path):
    with open(path, 'w') as f:
        try:
            fcntl.flock(f, fcntl.LOCK_EX | fcntl.LOCK_NB)
        except IOError as e:
            print("Unable to get lockfile: %s" % e)
            sys.exit(1)
        f.write("%s\n" % os.getpid())
        f.flush()
        log.debug("Acquired release lock")
        yield
        log.debug("Release lock")
        fcntl.flock(f, fcntl.LOCK_UN)


def main():
    parser = argparse.ArgumentParser(
        description='Periodically release various OpenDev AFS volumes')
    parser.add_argument('-d', '--debug', action='store_true')
    parser.add_argument('--lockfile', action='store',
                        default='/var/run/release-volumes.lock',
                        help='volume release lockfile')
    parser.add_argument('--force-release', action='store_true',
                        help="Force vos release, even if not required")
    parser.add_argument('--skip-release', action='store_true',
                        help="Skip vos release, even if required")
    parser.add_argument('--ssh-user', action='store',
                        default='vos_release', help="SSH user on remote host")
    parser.add_argument('--ssh-identity', action='store',
                        default='/root/.ssh/id_vos_release',
                        help="SSH identify file for remote vos release")
    parser.add_argument('--ssh-server', action='store',
                        default='afs01.dfw.openstack.org',
                        help="Remote host to run vos release")
    parser.add_argument('--statsd-host', action='store',
                        default='graphite.opendev.org',
                        help='Remote host to send stats to')
    parser.add_argument('--statsd-port', action='store',
                        default=8125,
                        help='Remote port to send stats to')

    args = parser.parse_args()

    level = logging.DEBUG if args.debug else logging.INFO
    logging.basicConfig(level=level,
                        format='%(asctime)s %(name)s '
                        '%(levelname)-8s %(message)s')

    log.debug("--- Starting %s ---" % datetime.now())
    log.debug("Sending stats to %s:%s" % (args.statsd_host, args.statsd_port))
    if args.force_release:
        log.info("Forcing release of all volumes")

    stats = statsd.StatsClient(host=args.statsd_host,
                                port=args.statsd_port)

    with get_lock(args.lockfile):
        for volume in VOLUMES:
            if check_release(volume) or args.force_release:
                if args.skip_release:
                    log.info("Force skipping release")
                else:
                    release(volume, args.ssh_server, args.ssh_user,
                            args.ssh_identity, stats)

    log.debug("--- Complete %s ---" % datetime.now())

if __name__ == '__main__':
    main()