python-novaclient/novaclient/shell.py

# Copyright 2010 Jacob Kaplan-Moss

# Copyright 2011 OpenStack LLC.
# All Rights Reserved.
#
#    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.

"""
Command-line interface to the OpenStack Nova API.
"""

import argparse
import novaclient
import getpass
import httplib2
import os
import prettytable
import sys
import textwrap
import uuid

# Choices for flags.
DAY_CHOICES = [getattr(novaclient, i).lower()
               for i in dir(novaclient)
               if i.startswith('BACKUP_WEEKLY_')]
HOUR_CHOICES = [getattr(novaclient, i).lower()
                for i in dir(novaclient)
                if i.startswith('BACKUP_DAILY_')]


def pretty_choice_list(l):
    return ', '.join("'%s'" % i for i in l)

# Sentinal for boot --key
AUTO_KEY = object()


# Decorator for args
def arg(*args, **kwargs):
    def _decorator(func):
        # Because of the sematics of decorator composition if we just append
        # to the options list positional options will appear to be backwards.
        func.__dict__.setdefault('arguments', []).insert(0, (args, kwargs))
        return func
    return _decorator


class CommandError(Exception):
    pass


def env(e):
    return os.environ.get(e, '')


class OpenStackShell(object):

    # Hook for the test suite to inject a fake server.
    _api_class = novaclient.OpenStack

    def __init__(self):
        self.parser = argparse.ArgumentParser(
            prog='nova',
            description=__doc__.strip(),
            epilog='See "nova help COMMAND" '\
                   'for help on a specific command.',
            add_help=False,
            formatter_class=OpenStackHelpFormatter,
        )

        # Global arguments
        self.parser.add_argument('-h', '--help',
            action='help',
            help=argparse.SUPPRESS,
        )

        self.parser.add_argument('--debug',
            default=False,
            action='store_true',
            help=argparse.SUPPRESS)

        self.parser.add_argument('--username',
            default=env('NOVA_USERNAME'),
            help='Defaults to env[NOVA_USERNAME].')

        self.parser.add_argument('--apikey',
            default=env('NOVA_API_KEY'),
            help='Defaults to env[NOVA_API_KEY].')

        self.parser.add_argument('--projectid',
            default=env('NOVA_PROJECT_ID'),                                                       
            help='Defaults to env[NOVA_PROJECT_ID].')

        auth_url = env('NOVA_URL')
        if auth_url == '':
            auth_url = 'https://auth.api.rackspacecloud.com/v1.0'
        self.parser.add_argument('--url',
            default=auth_url,
            help='Defaults to env[NOVA_URL].')

        # Subcommands
        subparsers = self.parser.add_subparsers(metavar='<subcommand>')
        self.subcommands = {}

        # Everything that's do_* is a subcommand.
        for attr in (a for a in dir(self) if a.startswith('do_')):
            # I prefer to be hypen-separated instead of underscores.
            command = attr[3:].replace('_', '-')
            callback = getattr(self, attr)
            desc = callback.__doc__ or ''
            help = desc.strip().split('\n')[0]
            arguments = getattr(callback, 'arguments', [])

            subparser = subparsers.add_parser(command,
                help=help,
                description=desc,
                add_help=False,
                formatter_class=OpenStackHelpFormatter
            )
            subparser.add_argument('-h', '--help',
                action='help',
                help=argparse.SUPPRESS,
            )
            self.subcommands[command] = subparser
            for (args, kwargs) in arguments:
                subparser.add_argument(*args, **kwargs)
            subparser.set_defaults(func=callback)

    def main(self, argv):
        # Parse args and call whatever callback was selected
        args = self.parser.parse_args(argv)

        # Short-circuit and deal with help right away.
        if args.func == self.do_help:
            self.do_help(args)
            return 0

        # Deal with global arguments
        if args.debug:
            httplib2.debuglevel = 1

        user, apikey, projectid, url = args.username, args.apikey, \
                                       args.projectid, args.url

        #FIXME(usrleon): Here should be restrict for project id same as
        # for username or apikey but for compatibility it is not.

        if not user:
            raise CommandError("You must provide a username, either via "
                               "--username or via env[NOVA_USERNAME]")
        if not apikey:
            raise CommandError("You must provide an API key, either via "
                               "--apikey or via env[NOVA_API_KEY]")

        self.cs = self._api_class(user, apikey, projectid, url)
        try:
            self.cs.authenticate()
        except novaclient.Unauthorized:
            raise CommandError("Invalid OpenStack Nova credentials.")

        args.func(args)

    @arg('command', metavar='<subcommand>', nargs='?',
                    help='Display help for <subcommand>')
    def do_help(self, args):
        """
        Display help about this program or one of its subcommands.
        """
        if args.command:
            if args.command in self.subcommands:
                self.subcommands[args.command].print_help()
            else:
                raise CommandError("'%s' is not a valid subcommand." %
                                                         args.command)
        else:
            self.parser.print_help()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    @arg('--enable', dest='enabled', default=None, action='store_true',
                                                   help='Enable backups.')
    @arg('--disable', dest='enabled', action='store_false',
                                      help='Disable backups.')
    @arg('--weekly', metavar='<day>', choices=DAY_CHOICES,
         help='Schedule a weekly backup for <day> (one of: %s).' %
                                  pretty_choice_list(DAY_CHOICES))
    @arg('--daily', metavar='<time-window>', choices=HOUR_CHOICES,
         help='Schedule a daily backup during <time-window> (one of: %s).' %
                                           pretty_choice_list(HOUR_CHOICES))
    def do_backup_schedule(self, args):
        """
        Show or edit the backup schedule for a server.

        With no flags, the backup schedule will be shown. If flags are given,
        the backup schedule will be modified accordingly.
        """
        server = self._find_server(args.server)

        # If we have some flags, update the backup
        backup = {}
        if args.daily:
            backup['daily'] = getattr(novaclient, 'BACKUP_DAILY_%s' %
                                                    args.daily.upper())
        if args.weekly:
            backup['weekly'] = getattr(novaclient, 'BACKUP_WEEKLY_%s' %
                                                     args.weekly.upper())
        if args.enabled is not None:
            backup['enabled'] = args.enabled
        if backup:
            server.backup_schedule.update(**backup)
        else:
            print_dict(server.backup_schedule._info)

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_backup_schedule_delete(self, args):
        """
        Delete the backup schedule for a server.
        """
        server = self._find_server(args.server)
        server.backup_schedule.delete()

    def _boot(self, args, reservation_id=None, min_count=None, max_count=None):
        """Boot a new server."""
        if min_count is None:
            min_count = 1
        if max_count is None:
            max_count = min_count
        if min_count > max_count:
            raise CommandError("min_instances should be <= max_instances")
        if not min_count or not max_count:
            raise CommandError("min_instances nor max_instances should be 0")

        flavor = args.flavor or self.cs.flavors.find(ram=256)
        image = args.image or self.cs.images.find(name="Ubuntu 10.04 LTS "\
                                                       "(lucid)")

        # Map --ipgroup <name> to an ID.
        # XXX do this for flavor/image?
        if args.ipgroup:
            ipgroup = self._find_ipgroup(args.ipgroup)
        else:
            ipgroup = None

        metadata = dict(v.split('=') for v in args.meta)

        files = {}
        for f in args.files:
            dst, src = f.split('=', 1)
            try:
                files[dst] = open(src)
            except IOError, e:
                raise CommandError("Can't open '%s': %s" % (src, e))

        if args.key is AUTO_KEY:
            possible_keys = [os.path.join(os.path.expanduser('~'), '.ssh', k)
                             for k in ('id_dsa.pub', 'id_rsa.pub')]
            for k in possible_keys:
                if os.path.exists(k):
                    keyfile = k
                    break
            else:
                raise CommandError("Couldn't find a key file: tried "
                                   "~/.ssh/id_dsa.pub or ~/.ssh/id_rsa.pub")
        elif args.key:
            keyfile = args.key
        else:
            keyfile = None

        if keyfile:
            try:
                files['/root/.ssh/authorized_keys2'] = open(keyfile)
            except IOError, e:
                raise CommandError("Can't open '%s': %s" % (keyfile, e))

        return (args.name, image, flavor, ipgroup, metadata, files, 
                reservation_id, min_count, max_count)

    @arg('--flavor',
         default=None,
         metavar='<flavor>',
         help="Flavor ID (see 'novaclient flavors'). "\
              "Defaults to 256MB RAM instance.")
    @arg('--image',
         default=None,
         metavar='<image>',
         help="Image ID (see 'novaclient images'). "\
              "Defaults to Ubuntu 10.04 LTS.")
    @arg('--ipgroup',
         default=None,
         metavar='<group>',
         help="IP group name or ID (see 'novaclient ipgroup-list').")
    @arg('--meta',
         metavar="<key=value>",
         action='append',
         default=[],
         help="Record arbitrary key/value metadata. "\
              "May be give multiple times.")
    @arg('--file',
         metavar="<dst-path=src-path>",
         action='append',
         dest='files',
         default=[],
         help="Store arbitrary files from <src-path> locally to <dst-path> "\
              "on the new server. You may store up to 5 files.")
    @arg('--key',
         metavar='<path>',
         nargs='?',
         const=AUTO_KEY,
         help="Key the server with an SSH keypair. "\
              "Looks in ~/.ssh for a key, "\
              "or takes an explicit <path> to one.")
    @arg('name', metavar='<name>', help='Name for the new server')
    def do_boot(self, args):
        """Boot a new server."""
        name, image, flavor, ipgroup, metadata, files, reservation_id, \
                    min_count, max_count = self._boot(args)

        server = self.cs.servers.create(args.name, image, flavor,
                                        ipgroup=ipgroup,
                                        meta=metadata,
                                        files=files,
                                        min_count=min_count,
                                        max_count=max_count)
        print_dict(server._info)

    @arg('--flavor',
         default=None,
         metavar='<flavor>',
         help="Flavor ID (see 'novaclient flavors'). "\
              "Defaults to 256MB RAM instance.")
    @arg('--image',
         default=None,
         metavar='<image>',
         help="Image ID (see 'novaclient images'). "\
              "Defaults to Ubuntu 10.04 LTS.")
    @arg('--ipgroup',
         default=None,
         metavar='<group>',
         help="IP group name or ID (see 'novaclient ipgroup-list').")
    @arg('--meta',
         metavar="<key=value>",
         action='append',
         default=[],
         help="Record arbitrary key/value metadata. "\
              "May be give multiple times.")
    @arg('--file',
         metavar="<dst-path=src-path>",
         action='append',
         dest='files',
         default=[],
         help="Store arbitrary files from <src-path> locally to <dst-path> "\
              "on the new server. You may store up to 5 files.")
    @arg('--key',
         metavar='<path>',
         nargs='?',
         const=AUTO_KEY,
         help="Key the server with an SSH keypair. "\
              "Looks in ~/.ssh for a key, "\
              "or takes an explicit <path> to one.")
    @arg('account', metavar='<account>', help='Account to build this'\
         ' server for')
    @arg('name', metavar='<name>', help='Name for the new server')
    def do_boot_for_account(self, args):
        """Boot a new server in an account."""
        name, image, flavor, ipgroup, metadata, files, reservation_id, \
                min_count, max_count = self._boot(args)

        server = self.cs.accounts.create_instance_for(args.account, args.name,
                    image, flavor,
                    ipgroup=ipgroup,
                    meta=metadata,
                    files=files)
        print_dict(server._info)

    @arg('--flavor',
         default=None,
         metavar='<flavor>',
         help="Flavor ID (see 'novaclient flavors'). "\
              "Defaults to 256MB RAM instance.")
    @arg('--image',
         default=None,
         metavar='<image>',
         help="Image ID (see 'novaclient images'). "\
              "Defaults to Ubuntu 10.04 LTS.")
    @arg('--ipgroup',
         default=None,
         metavar='<group>',
         help="IP group name or ID (see 'novaclient ipgroup-list').")
    @arg('--meta',
         metavar="<key=value>",
         action='append',
         default=[],
         help="Record arbitrary key/value metadata. "\
              "May be give multiple times.")
    @arg('--file',
         metavar="<dst-path=src-path>",
         action='append',
         dest='files',
         default=[],
         help="Store arbitrary files from <src-path> locally to <dst-path> "\
              "on the new server. You may store up to 5 files.")
    @arg('--key',
         metavar='<path>',
         nargs='?',
         const=AUTO_KEY,
         help="Key the server with an SSH keypair. "\
              "Looks in ~/.ssh for a key, "\
              "or takes an explicit <path> to one.")
    @arg('--reservation_id',
         default=None,
         metavar='<reservation_id>',
         help="Reservation ID (a UUID). "\
              "If unspecified will be generated by the server.")
    @arg('--min_instances',
         default=None,
         type=int,
         metavar='<number>',
         help="The minimum number of instances to build. "\
                 "Defaults to 1.")
    @arg('--max_instances',
         default=None,
         type=int,
         metavar='<number>',
         help="The maximum number of instances to build. "\
                 "Defaults to 'min_instances' setting.")
    @arg('name', metavar='<name>', help='Name for the new server')
    def do_zone_boot(self, args):
        """Boot a new server, potentially across Zones."""
        reservation_id = args.reservation_id
        min_count = args.min_instances
        max_count = args.max_instances
        name, image, flavor, ipgroup, metadata, \
                files, reservation_id, min_count, max_count = \
                                 self._boot(args,
                                            reservation_id=reservation_id,
                                            min_count=min_count,
                                            max_count=max_count)

        reservation_id = self.cs.zones.boot(args.name, image, flavor,
                                            ipgroup=ipgroup,
                                            meta=metadata,
                                            files=files,
                                            reservation_id=reservation_id,
                                            min_count=min_count,
                                            max_count=max_count)
        print "Reservation ID=", reservation_id

    def _translate_flavor_keys(self, collection):
        convert = [('ram', 'memory_mb'), ('disk', 'local_gb')]
        for item in collection:
            keys = item.__dict__.keys()
            for from_key, to_key in convert:
                if from_key in keys and to_key not in keys:
                    setattr(item, to_key, item._info[from_key])
            
    def do_flavor_list(self, args):
        """Print a list of available 'flavors' (sizes of servers)."""
        flavors = self.cs.flavors.list()
        self._translate_flavor_keys(flavors)
        print_list(flavors, [
            'ID',
            'Name',
            'Memory_MB',
            'Swap',
            'Local_GB',
            'VCPUs',
            'RXTX_Quota',
            'RXTX_Cap'])

    def do_image_list(self, args):
        """Print a list of available images to boot from."""
        print_list(self.cs.images.list(), ['ID', 'Name', 'Status'])

    @arg('server', metavar='<server>', help='Name or ID of server.')
    @arg('name', metavar='<name>', help='Name of backup or snapshot.')
    @arg('--image-type',
         metavar='<backup|snapshot>',
         default='snapshot',
         help='type of image (default: snapshot)')
    @arg('--backup-type',
         metavar='<daily|weekly>',
         default=None,
         help='type of backup')
    @arg('--rotation',
         default=None,
         type=int,
         metavar='<rotation>',
         help="Number of backups to retain. Used for backup image_type.")
    def do_image_create(self, args):
        """Create a new image by taking a snapshot of a running server."""
        server = self._find_server(args.server)
        image = self.cs.images.create(server, args.name,
                                      image_type=args.image_type,
                                      backup_type=args.backup_type,
                                      rotation=args.rotation)
        print_dict(image._info)

    @arg('image', metavar='<image>', help='Name or ID of image.')
    def do_image_delete(self, args):
        """
        Delete an image.

        It should go without saying, but you can only delete images you
        created.
        """
        image = self._find_image(args.image)
        image.delete()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    @arg('group', metavar='<group>', help='Name or ID of group.')
    @arg('address', metavar='<address>', help='IP address to share.')
    def do_ip_share(self, args):
        """Share an IP address from the given IP group onto a server."""
        server = self._find_server(args.server)
        group = self._find_ipgroup(args.group)
        server.share_ip(group, args.address)

    @arg('server', metavar='<server>', help='Name or ID of server.')
    @arg('address', metavar='<address>',
                    help='Shared IP address to remove from the server.')
    def do_ip_unshare(self, args):
        """Stop sharing an given address with a server."""
        server = self._find_server(args.server)
        server.unshare_ip(args.address)

    def do_ipgroup_list(self, args):
        """Show IP groups."""
        def pretty_server_list(ipgroup):
            return ", ".join(self.cs.servers.get(id).name
                             for id in ipgroup.servers)

        print_list(self.cs.ipgroups.list(),
                   fields=['ID', 'Name', 'Server List'],
                   formatters={'Server List': pretty_server_list})

    @arg('group', metavar='<group>', help='Name or ID of group.')
    def do_ipgroup_show(self, args):
        """Show details about a particular IP group."""
        group = self._find_ipgroup(args.group)
        print_dict(group._info)

    @arg('name', metavar='<name>', help='What to name this new group.')
    @arg('server', metavar='<server>', nargs='?',
         help='Server (name or ID) to make a member of this new group.')
    def do_ipgroup_create(self, args):
        """Create a new IP group."""
        if args.server:
            server = self._find_server(args.server)
        else:
            server = None
        group = self.cs.ipgroups.create(args.name, server)
        print_dict(group._info)

    @arg('group', metavar='<group>', help='Name or ID of group.')
    def do_ipgroup_delete(self, args):
        """Delete an IP group."""
        self._find_ipgroup(args.group).delete()

    @arg('--fixed_ip',
        dest='fixed_ip',
        metavar='<fixed_ip>',
        default=None,
        help='Only match against fixed IP.')
    @arg('--reservation_id',
        dest='reservation_id',
        metavar='<reservation_id>',
        default=None,
        help='Only return instances that match reservation_id.')
    @arg('--recurse_zones',
        dest='recurse_zones',
        metavar='<0|1>',
        nargs='?',
        type=int,
        const=1,
        default=0,
        help='Recurse through all zones if set.')
    @arg('--ip',
        dest='ip',
        metavar='<ip_regexp>',
        default=None,
        help='Search with regular expression match by IP address')
    @arg('--ip6',
        dest='ip6',
        metavar='<ip6_regexp>',
        default=None,
        help='Search with regular expression match by IPv6 address')
    @arg('--server_name',
        dest='server_name',
        metavar='<name_regexp>',
        default=None,
        help='Search with regular expression match by server name')
    @arg('--name',
        dest='display_name',
        metavar='<name_regexp>',
        default=None,
        help='Search with regular expression match by display name')
    @arg('--instance_name',
        dest='name',
        metavar='<name_regexp>',
        default=None,
        help='Search with regular expression match by instance name')
    def do_list(self, args):
        """List active servers."""
        recurse_zones = args.recurse_zones
        search_opts = {
                'reservation_id': args.reservation_id,
                'fixed_ip': args.fixed_ip,
                'recurse_zones': recurse_zones,
                'ip': args.ip,
                'ip6': args.ip6,
                'name': args.name,
                'server_name': args.server_name,
                'display_name': args.display_name}
        if recurse_zones:
            to_print = ['UUID', 'Name', 'Status', 'Public IP', 'Private IP']
        else:
            to_print = ['ID', 'Name', 'Status', 'Public IP', 'Private IP']
        print_list(self.cs.servers.list(search_opts=search_opts),
                to_print)

    @arg('--hard',
        dest='reboot_type',
        action='store_const',
        const=novaclient.REBOOT_HARD,
        default=novaclient.REBOOT_SOFT,
        help='Perform a hard reboot (instead of a soft one).')
    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_reboot(self, args):
        """Reboot a server."""
        self._find_server(args.server).reboot(args.reboot_type)

    @arg('server', metavar='<server>', help='Name or ID of server.')
    @arg('image', metavar='<image>', help="Name or ID of new image.")
    def do_rebuild(self, args):
        """Shutdown, re-image, and re-boot a server."""
        server = self._find_server(args.server)
        image = self._find_image(args.image)
        server.rebuild(image)

    @arg('server', metavar='<server>', help='Name (old name) or ID of server.')
    @arg('name', metavar='<name>', help='New name for the server.')
    def do_rename(self, args):
        """Rename a server."""
        self._find_server(args.server).update(name=args.name)

    @arg('server', metavar='<server>', help='Name or ID of server.')
    @arg('flavor', metavar='<flavor>', help="Name or ID of new flavor.")
    def do_resize(self, args):
        """Resize a server."""
        server = self._find_server(args.server)
        flavor = self._find_flavor(args.flavor)
        server.resize(flavor)

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_migrate(self, args):
        """Migrate a server."""
        self._find_server(args.server).migrate()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_pause(self, args):
        """Pause a server."""
        self._find_server(args.server).pause()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_unpause(self, args):
        """Unpause a server."""
        self._find_server(args.server).unpause()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_suspend(self, args):
        """Suspend a server."""
        self._find_server(args.server).suspend()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_resume(self, args):
        """Resume a server."""
        self._find_server(args.server).resume()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_rescue(self, args):
        """Rescue a server."""
        self._find_server(args.server).rescue()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_unrescue(self, args):
        """Unrescue a server."""
        self._find_server(args.server).unrescue()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_diagnostics(self, args):
        """Retrieve server diagnostics."""
        print_dict(self.cs.servers.diagnostics(args.server)[1])

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_actions(self, args):
        """Retrieve server actions."""
        print_list(
            self.cs.servers.actions(args.server),
            ["Created_At", "Action", "Error"])

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_resize_confirm(self, args):
        """Confirm a previous resize."""
        self._find_server(args.server).confirm_resize()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_resize_revert(self, args):
        """Revert a previous resize (and return to the previous VM)."""
        self._find_server(args.server).revert_resize()

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_root_password(self, args):
        """
        Change the root password for a server.
        """
        server = self._find_server(args.server)
        p1 = getpass.getpass('New password: ')
        p2 = getpass.getpass('Again: ')
        if p1 != p2:
            raise CommandError("Passwords do not match.")
        server.update(password=p1)

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_show(self, args):
        """Show details about the given server."""
        s = self._find_server(args.server)

        info = s._info.copy()
        addresses = info.pop('addresses')
        for addrtype in addresses:
            info['%s ip' % addrtype] = ', '.join(addresses[addrtype])

        flavorId = info.get('flavorId', None)
        if flavorId:
            info['flavor'] = self._find_flavor(info.pop('flavorId')).name
        imageId = info.get('imageId', None)
        if imageId:
            info['image'] = self._find_image(info.pop('imageId')).name

        print_dict(info)

    @arg('server', metavar='<server>', help='Name or ID of server.')
    def do_delete(self, args):
        """Immediately shut down and delete a server."""
        self._find_server(args.server).delete()

    # --zone_username is required since --username is already used.
    @arg('zone', metavar='<zone_id>', help='ID of the zone', default=None)
    @arg('--api_url', dest='api_url', default=None, help='New URL.')
    @arg('--zone_username', dest='zone_username', default=None,
                            help='New zone username.')
    @arg('--password', dest='password', default=None, help='New password.')
    @arg('--weight_offset', dest='weight_offset', default=None,
                            help='Child Zone weight offset.')
    @arg('--weight_scale', dest='weight_scale', default=None,
                            help='Child Zone weight scale.')
    def do_zone(self, args):
        """Show or edit a child zone. No zone arg for this zone."""
        zone = self.cs.zones.get(args.zone)
 
        # If we have some flags, update the zone
        zone_delta = {}
        if args.api_url:
            zone_delta['api_url'] = args.api_url
        if args.zone_username:
            zone_delta['username'] = args.zone_username
        if args.password:
            zone_delta['password'] = args.password
        if args.weight_offset:
            zone_delta['weight_offset'] = args.weight_offset
        if args.weight_scale:
            zone_delta['weight_scale'] = args.weight_scale
        if zone_delta:
            zone.update(**zone_delta)
        else:
            print_dict(zone._info)

    def do_zone_info(self, args):
        """Get this zones name and capabilities."""
        zone = self.cs.zones.info()
        print_dict(zone._info)

    @arg('api_url', metavar='<api_url>', help="URL for the Zone's API")
    @arg('zone_username', metavar='<zone_username>', 
                          help='Authentication username.')
    @arg('password', metavar='<password>', help='Authentication password.')
    @arg('weight_offset', metavar='<weight_offset>',
                            help='Child Zone weight offset (typically 0.0).')
    @arg('weight_scale', metavar='<weight_scale>',
                            help='Child Zone weight scale (typically 1.0).')
    def do_zone_add(self, args):
        """Add a new child zone."""
        zone = self.cs.zones.create(args.api_url, args.zone_username, 
                                    args.password, args.weight_offset,
                                    args.weight_scale)
        print_dict(zone._info)

    @arg('zone', metavar='<zone>', help='Name or ID of the zone')
    def do_zone_delete(self, args):
        """Delete a zone."""
        self.cs.zones.delete(args.zone)

    def do_zone_list(self, args):
        """List the children of a zone."""
        print_list(self.cs.zones.list(), ['ID', 'Name', 'Is Active', \
                            'API URL', 'Weight Offset', 'Weight Scale'])

    @arg('server', metavar='<server>', help='Name or ID of server.')
    @arg('network_id', metavar='<network_id>', help='Network ID.')
    def do_add_fixed_ip(self, args):
        """Add new IP address to network."""
        server = self._find_server(args.server)
        server.add_fixed_ip(args.network_id)
    
    @arg('server', metavar='<server>', help='Name or ID of server.')
    @arg('address', metavar='<address>', help='IP Address.')
    def do_remove_fixed_ip(self, args):
        """Remove an IP address from a server."""
        server = self._find_server(args.server)
        server.remove_fixed_ip(args.address)

    def _find_server(self, server):
        """Get a server by name or ID."""
        return self._find_resource(self.cs.servers, server)

    def _find_ipgroup(self, group):
        """Get an IP group by name or ID."""
        return self._find_resource(self.cs.ipgroups, group)

    def _find_image(self, image):
        """Get an image by name or ID."""
        return self._find_resource(self.cs.images, image)

    def _find_flavor(self, flavor):
        """Get a flavor by name, ID, or RAM size."""
        try:
            return self._find_resource(self.cs.flavors, flavor)
        except novaclient.NotFound:
            return self.cs.flavors.find(ram=flavor)

    def _find_resource(self, manager, name_or_id):
        """Helper for the _find_* methods."""
        try:
            if isinstance(name_or_id, int) or name_or_id.isdigit():
                return manager.get(int(name_or_id))

            try:
                uuid.UUID(name_or_id)
                return manager.get(name_or_id)
            except ValueError:
                return manager.find(name=name_or_id)
        except novaclient.NotFound:
            raise CommandError("No %s with a name or ID of '%s' exists." %
                         (manager.resource_class.__name__.lower(), name_or_id))


# I'm picky about my shell help.
class OpenStackHelpFormatter(argparse.HelpFormatter):
    def start_section(self, heading):
        # Title-case the headings
        heading = '%s%s' % (heading[0].upper(), heading[1:])
        super(OpenStackHelpFormatter, self).start_section(heading)


# Helpers
def print_list(objs, fields, formatters={}):
    pt = prettytable.PrettyTable([f for f in fields], caching=False)
    pt.aligns = ['l' for f in fields]

    for o in objs:
        row = []
        for field in fields:
            if field in formatters:
                row.append(formatters[field](o))
            else:
                field_name = field.lower().replace(' ', '_')
                data = getattr(o, field_name, '')
                row.append(data)
        pt.add_row(row)

    pt.printt(sortby=fields[0])


def print_dict(d):
    pt = prettytable.PrettyTable(['Property', 'Value'], caching=False)
    pt.aligns = ['l', 'l']
    [pt.add_row(list(r)) for r in d.iteritems()]
    pt.printt(sortby='Property')


def main():
    try:
        OpenStackShell().main(sys.argv[1:])

    except Exception, e:
        if httplib2.debuglevel == 1:
            raise  # dump stack.
        else:
            print >> sys.stderr, e
        sys.exit(1)