call rancher 1.6 api to upgrade service.

rancher-service-upgrade.py

#!/usr/bin/env python2
# encoding: utf-8

import urlparse
import argparse
import base64
import json
import time
import os
import sys
import ssl
import httplib
import collections


class Client(object):
    def __init__(self):
        args = self.parse_arg()
        self.url = urlparse.urlparse(args.url)
        self.image = args.image
        self.conn = httplib.HTTPSConnection(
            self.url.hostname,
            self.url.port,
            context=ssl._create_unverified_context()
        )

        token = base64.standard_b64encode('%s:%s' % (args.key, args.secret))
        self.headers = {
            'Content-Type': 'application/json',
            'Authorization': 'Basic %s' % (token)
        }

        self._info = {}

    def info(self):
        self.conn.request('GET', self.url.path, None, self.headers)
        self._info = self.__getresponse()
        return self._info

    def finish_upgrade(self):
        self.conn.request(
            'POST',
            '%s?action=finishupgrade' % (self.url.path),
            None,
            self.headers
        )
        return self.__getresponse()

    def upgrade(self):
        if not self._info['upgrade'] or not self._info['upgrade']['inServiceStrategy']:
            # upgrade in first time
            payload = {
                "inServiceStrategy": {
                    "type": "inServiceUpgradeStrategy",
                    "batchSize": 1,
                    "intervalMillis": 2000,
                    "previousSecondaryLaunchConfigs": [],
                    "secondaryLaunchConfigs": [],
                    "startFirst": False,
                    "launchConfig": self._info['launchConfig'],
                },
                "toServiceStrategy": None
            }
        else:
            payload = {
                "inServiceStrategy": self._info['upgrade']['inServiceStrategy'],
                "toServiceStrategy": None
            }
        payload['inServiceStrategy']['launchConfig']['imageUuid'] = 'docker:%s' % (self.image)

        self.conn.request(
            'POST',
            '%s?action=upgrade' % (self.url.path),
            json.dumps(payload),
            self.headers
        )
        return self.__getresponse()

    def __getresponse(self):
        res = self.conn.getresponse()
        if res.status >= 300:
            raise Exception('rancher server error: %s' % (res.status))
        return json.loads(res.read().decode('utf-8'), object_pairs_hook=collections.OrderedDict)

    def parse_arg(self):
        parser = argparse.ArgumentParser(description='Upgrade rancher service')
        parser.add_argument('--url', required=True, help='rancher service api url')
        parser.add_argument('--key', required=True, help='env name for api key')
        parser.add_argument('--secret', required=True, help='env name for api secret')
        parser.add_argument('--image', required=True, help='new docker image')
        args = parser.parse_args()
        key = os.environ.get(args.key)
        secret = os.environ.get(args.secret)

        if not key or not secret:
            print('missing api key or api secret')
            sys.exit(2)
        args.key = key
        args.secret = secret
        return args


def check_state(client):
    max_try = 40
    i = 0
    info = client.info()
    while 'ing' in info['state']:
        # this service is busy.
        info = client.info()
        i += 1
        if i >= max_try:
            break
        time.sleep(5)
    return info['state'] == 'active'


def finish_upgrade(client):
    info = client.info()
    if info['state'] == 'active':
        return True

    if info['state'] == 'upgraded':
        # there is a unfinished upgrade
        print('finish a old upgrade')
        client.finish_upgrade()

    return check_state(client)


def main():
    client = Client()

    if not finish_upgrade(client):
        raise Exception("this service is not active")

    print('start to upgrade')
    client.upgrade()
    if check_state(client) or client._info['state'] == 'upgraded':
        print('Current service upgrade finished')

    # auto finish upgrade
    if os.environ.get('AUTO_FINISH_UPGRADE', '1') == '1' and not finish_upgrade(client):
        print('Finish upgrade failed')

if __name__ == '__main__':
    main()