Mini Shell

#!/usr/libexec/platform-python

import sys
import optparse
import json
import time
from pyexpat import ExpatError

sys.path.append("/usr/share/rhn/")

from up2date_client import rhnserver
from up2date_client import up2dateAuth
from up2date_client import up2dateErrors
from up2date_client import up2dateUtils
from up2date_client import rhnreg
from up2date_client import config

up2date_path = '/etc/sysconfig/rhn/up2date'
valid_channels = ['7', '8']


def print_message(message):
    print(
        json.dumps({'result': message, 'timestamp': time.time()})
    )


def print_error_and_exit(error, retcode=1):
    print_message(error)
    sys.exit(retcode)


def sanity_check():
    """
    Check CloudLinux OS
    Check CL7
    """
    version = up2dateUtils.getVersion()
    release = up2dateUtils.getOSRelease()
    if version not in valid_channels or release != 'cloudlinux-release':
        valid_version_string = '/'.join(valid_channels)
        print_error_and_exit('Version upgrade is available for CloudLinux OS {} only'.format(valid_version_string), 10)


def set_version_override(value):
    up2date_conf = config.Config(up2date_path)
    up2date_conf.set('versionOverride', value)
    up2date_conf.save()


def main():
    """
    Return codes:
        1: Generic errors; with details printed
        2: Unable to read system id
        3: Switch channel error
        10: Sanity check failed
    """
    retcode = 0
    parser = optparse.OptionParser()
    parser.add_option('-t', '--target-channel', dest='channel',
                      help='Channel to switch to')
    parser.add_option('-f', '--force', action='store_true', default=False, dest='force',
                      help='Run command without additional checks')
    parser.add_option('-o', '--override', action='store_true', default=False, dest='override',
                      help='Set versionOverride config value')

    options, args = parser.parse_args()

    if not options.force:
        sanity_check()

    if not options.channel or options.channel not in valid_channels:
        print_error_and_exit("Invalid usage, please provide [-t|--target-channel] argument;"
                             " valid values are: %s" % valid_channels)

    system_id_xml = up2dateAuth.getSystemId()
    if not system_id_xml:
        print_error_and_exit('Unable to read system id, please make sure that your server is registered in CLN', 2)

    if options.channel in valid_channels:
        if options.override:
            set_version_override(options.channel)
        retcode = switch_channel(system_id_xml, options.channel)
    return retcode


def switch_channel(system_id, channel):
    """
    :param system_id: str, XML
    :param channel: str, intable
    """
    retcode = 3
    try:
        rhn_server = rhnserver.RhnServer()
        ret = rhn_server.registration.upgrade_version(system_id, channel)
        if '<?xml version="1.0"?>' in ret:  # XML returned on success, the same as `system_id`
            write_status = rhnreg.writeSystemId(ret)
            if write_status:
                print_message('Channel updated to %s' % channel)
                retcode = 0
    except ExpatError as _e:
        # CLN returns empty response when success
        if 'no element found' not in _e.message:
            raise
    return retcode


if __name__ == "__main__":
    try:
        _rc = main()
        sys.exit(_rc)
    except up2dateErrors.UnknownMethodException as e:
        print_error_and_exit('Unsupported CLN method. %s \n'
                             'Contact CloudLinux support if you require further assistance: '
                             'https://cloudlinux.zendesk.com/' % str(e))
    except up2dateErrors.RhnServerException as e:
        print_error_and_exit('Server exception, reason: %s \n'
                             'Contact CloudLinux support if you require further assistance: '
                             'https://cloudlinux.zendesk.com/' % str(e))
    except Exception as e:
        print_error_and_exit('Failed with common exception: %s \n'
                             'Contact CloudLinux support if you require further assistance: '
                             'https://cloudlinux.zendesk.com/' % str(e))