#!/usr/bin/env python
# Copyright 2015 OpenStack Foundation
#
# 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.

import argparse
import time

import jenkins


def delete_offline_nodes(server, timeout):
    start = time.time()
    end = start + timeout
    while True:
        nodes = server.get_nodes()
        offline_nodes = [node for node in nodes if node['offline']]
        if not offline_nodes:
            # We have converged to no offline nodes state
            break
        elif time.time() > end:
            raise Exception("Offline slave deletion timeout exceeded.")
        try:
            for n in offline_nodes:
                server.delete_node(n['name'])
        # This may have raced an external system deleting nodes
        # after jobs complete. Just retry as we should
        # converage on no jobs running and no deletions.
        except jenkins.NotFoundException:
            pass
        except jenkins.JenkinsException as e:
            if '[500]' in e.message:
                pass
            else:
                raise
        time.sleep(1)

def parse_args():
    parser = argparse.ArgumentParser(description='Safely stop Jenkins.')
    parser.add_argument('--url', default='http://localhost:8080',
                        help='Base url for Jenkins master.')
    parser.add_argument('--user', required=True,
                        help='Username to connect to Jenkins with.')
    parser.add_argument('--password', required=True,
                        help='Password to auth with.')
    parser.add_argument('--no-delete', dest='delete', action='store_false',
                        default=True, help="Don't delete offline slaves.")
    parser.add_argument('--delete-timeout', type=int, default=300,
                        help="Seconds to spend deleting offline slaves.")
    args = parser.parse_args()
    return args

def main():
    args = parse_args()
    server = jenkins.Jenkins(args.url,
                             username=args.user,
                             password=args.password)

    # Put in shutdown mode
    server.quiet_down()
    while True:
        try:
            if not server.get_running_builds():
                break
        # This may have raced an external system deleting executors
        # while listing the running jobs. Just retry as we should
        # converage on no jobs running and no deletions.
        except jenkins.NotFoundException:
            pass
        except jenkins.JenkinsException as e:
            if '[500]' in e.message:
                pass
            else:
                raise
        # Jobs are slow wait a minute between polls
        time.sleep(60)
    if args.delete:
        # Remove any offline nodes so they don't go online after restart.
        delete_offline_nodes(server, args.delete_timeout)

if __name__ == '__main__':
    main()