#!/usr/bin/python -uO
# Copyright (c) 2010-2011 OpenStack, LLC.
#
# 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 cPickle as pickle
from errno import EEXIST
from gzip import GzipFile
from os import mkdir
from os.path import basename, dirname, exists, join as pathjoin
from sys import argv, exit
from textwrap import wrap
from time import time

from swift.common.ring import RingBuilder


MAJOR_VERSION = 1
MINOR_VERSION = 2
EXIT_RING_CHANGED = 0
EXIT_RING_UNCHANGED = 1
EXIT_ERROR = 2


def search_devs(builder, search_value):
    """
The <search-value> can be of the form:
    d<device_id>z<zone>-<ip>:<port>/<device_name>_<meta>
    Any part is optional, but you must include at least one part.
    Examples:
        d74              Matches the device id 74
        z1               Matches devices in zone 1
        z1-1.2.3.4       Matches devices in zone 1 with the ip 1.2.3.4
        1.2.3.4          Matches devices in any zone with the ip 1.2.3.4
        z1:5678          Matches devices in zone 1 using port 5678
        :5678            Matches devices that use port 5678
        /sdb1            Matches devices with the device name sdb1
        _shiny           Matches devices with shiny in the meta data
        _"snet: 5.6.7.8" Matches devices with snet: 5.6.7.8 in the meta data
    Most specific example:
        d74z1-1.2.3.4:5678/sdb1_"snet: 5.6.7.8"
    Nerd explanation:
        All items require their single character prefix except the ip, in which
        case the - is optional unless the device id or zone is also included.
    """
    orig_search_value = search_value
    match = []
    if search_value.startswith('d'):
        i = 1
        while i < len(search_value) and search_value[i].isdigit():
            i += 1
        match.append(('id', int(search_value[1:i])))
        search_value = search_value[i:]
    if search_value.startswith('z'):
        i = 1
        while i < len(search_value) and search_value[i].isdigit():
            i += 1
        match.append(('zone', int(search_value[1:i])))
        search_value = search_value[i:]
    if search_value.startswith('-'):
        search_value = search_value[1:]
    if len(search_value) and search_value[0].isdigit():
        i = 1
        while i < len(search_value) and search_value[i] in '0123456789.':
            i += 1
        match.append(('ip', search_value[:i]))
        search_value = search_value[i:]
    if search_value.startswith(':'):
        i = 1
        while i < len(search_value) and search_value[i].isdigit():
            i += 1
        match.append(('port', int(search_value[1:i])))
        search_value = search_value[i:]
    if search_value.startswith('/'):
        i = 1
        while i < len(search_value) and search_value[i] != '_':
            i += 1
        match.append(('device', search_value[1:i]))
        search_value = search_value[i:]
    if search_value.startswith('_'):
        match.append(('meta', search_value[1:]))
        search_value = ''
    if search_value:
        raise ValueError('Invalid <search-value>: %s' %
                         repr(orig_search_value))
    devs = []
    for dev in builder.devs:
        if not dev:
            continue
        matched = True
        for key, value in match:
            if key == 'meta':
                if value not in dev.get(key):
                    matched = False
            elif dev.get(key) != value:
                matched = False
        if matched:
            devs.append(dev)
    return devs


class Commands:

    def unknown():
        print 'Unknown command: %s' % argv[2]
        exit(EXIT_ERROR)

    def create():
        """
swift-ring-builder <builder_file> create <part_power> <replicas>
                                         <min_part_hours>
    Creates <builder_file> with 2^<part_power> partitions and <replicas>.
    <min_part_hours> is number of hours to restrict moving a partition more
    than once.
        """
        if len(argv) < 6:
            print Commands.create.__doc__.strip()
            exit(EXIT_RING_UNCHANGED)
        builder = RingBuilder(int(argv[3]), int(argv[4]), int(argv[5]))
        backup_dir = pathjoin(dirname(argv[1]), 'backups')
        try:
            mkdir(backup_dir)
        except OSError, err:
            if err.errno != EEXIST:
                raise
        pickle.dump(builder, open(pathjoin(backup_dir,
            '%d.' % time() + basename(argv[1])), 'wb'), protocol=2)
        pickle.dump(builder, open(argv[1], 'wb'), protocol=2)
        exit(EXIT_RING_CHANGED)

    def default():
        """
swift-ring-builder <builder_file>
    Shows information about the ring and the devices within.
        """
        print '%s, build version %d' % (argv[1], builder.version)
        zones = 0
        balance = 0
        if builder.devs:
            zones = len(set(d['zone'] for d in builder.devs if d is not None))
            balance = builder.get_balance()
        print '%d partitions, %d replicas, %d zones, %d devices, %.02f ' \
              'balance' % (builder.parts, builder.replicas, zones,
                           len([d for d in builder.devs if d]), balance)
        print 'The minimum number of hours before a partition can be ' \
              'reassigned is %s' % builder.min_part_hours
        if builder.devs:
            print 'Devices:    id  zone      ip address  port      name ' \
                  'weight partitions balance meta'
            weighted_parts = builder.parts * builder.replicas / \
                sum(d['weight'] for d in builder.devs if d is not None)
            for dev in builder.devs:
                if dev is None:
                    continue
                if not dev['weight']:
                    if dev['parts']:
                        balance = 999.99
                    else:
                        balance = 0
                else:
                    balance = 100.0 * dev['parts'] / \
                              (dev['weight'] * weighted_parts) - 100.0
                print '         %5d %5d %15s %5d %9s %6.02f %10s %7.02f %s' % \
                    (dev['id'], dev['zone'], dev['ip'], dev['port'],
                     dev['device'], dev['weight'], dev['parts'], balance,
                     dev['meta'])
        exit(EXIT_RING_UNCHANGED)

    def search():
        """
swift-ring-builder <builder_file> search <search-value>
    Shows information about matching devices.
        """
        if len(argv) < 4:
            print Commands.search.__doc__.strip()
            print
            print search_devs.__doc__.strip()
            exit(EXIT_RING_UNCHANGED)
        devs = search_devs(builder, argv[3])
        if not devs:
            print 'No matching devices found'
            exit(EXIT_ERROR)
        print 'Devices:    id  zone      ip address  port      name ' \
              'weight partitions balance meta'
        weighted_parts = builder.parts * builder.replicas / \
            sum(d['weight'] for d in builder.devs if d is not None)
        for dev in devs:
            if not dev['weight']:
                if dev['parts']:
                    balance = 999.99
                else:
                    balance = 0
            else:
                balance = 100.0 * dev['parts'] / \
                          (dev['weight'] * weighted_parts) - 100.0
            print '         %5d %5d %15s %5d %9s %6.02f %10s %7.02f %s' % \
                (dev['id'], dev['zone'], dev['ip'], dev['port'],
                 dev['device'], dev['weight'], dev['parts'], balance,
                 dev['meta'])
        exit(EXIT_RING_UNCHANGED)

    def add():
        """
swift-ring-builder <builder_file> add z<zone>-<ip>:<port>/<device_name>_<meta>
                                      <wght>
    Adds a device to the ring with the given information. No partitions will be
    assigned to the new device until after running 'rebalance'. This is so you
    can make multiple device changes and rebalance them all just once.
        """
        if len(argv) < 5:
            print Commands.add.__doc__.strip()
            exit(EXIT_RING_UNCHANGED)

        if not argv[3].startswith('z'):
            print 'Invalid add value: %s' % argv[3]
            exit(EXIT_ERROR)
        i = 1
        while i < len(argv[3]) and argv[3][i].isdigit():
            i += 1
        zone = int(argv[3][1:i])
        rest = argv[3][i:]

        if not rest.startswith('-'):
            print 'Invalid add value: %s' % argv[3]
            exit(EXIT_ERROR)
        i = 1
        while i < len(rest) and rest[i] in '0123456789.':
            i += 1
        ip = rest[1:i]
        rest = rest[i:]

        if not rest.startswith(':'):
            print 'Invalid add value: %s' % argv[3]
            exit(EXIT_ERROR)
        i = 1
        while i < len(rest) and rest[i].isdigit():
            i += 1
        port = int(rest[1:i])
        rest = rest[i:]

        if not rest.startswith('/'):
            print 'Invalid add value: %s' % argv[3]
            exit(EXIT_ERROR)
        i = 1
        while i < len(rest) and rest[i] != '_':
            i += 1
        device_name = rest[1:i]
        rest = rest[i:]

        meta = ''
        if rest.startswith('_'):
            meta = rest[1:]

        weight = float(argv[4])

        for dev in builder.devs:
            if dev is None:
                continue
            if dev['ip'] == ip and dev['port'] == port and \
                    dev['device'] == device_name:
                print 'Device %d already uses %s:%d/%s.' % \
                      (dev['id'], dev['ip'], dev['port'], dev['device'])
                exit(EXIT_ERROR)

        next_dev_id = 0
        if builder.devs:
            next_dev_id = max(d['id'] for d in builder.devs if d) + 1
        builder.add_dev({'id': next_dev_id, 'zone': zone, 'ip': ip,
                         'port': port, 'device': device_name, 'weight': weight,
                         'meta': meta})
        print 'Device z%s-%s:%s/%s_"%s" with %s weight got id %s' % \
              (zone, ip, port, device_name, meta, weight, next_dev_id)
        pickle.dump(builder, open(argv[1], 'wb'), protocol=2)
        exit(EXIT_RING_UNCHANGED)

    def set_weight():
        """
swift-ring-builder <builder_file> set_weight <search-value> <weight>
    Resets the device's weight. No partitions will be reassigned to or from the
    device until after running 'rebalance'. This is so you can make multiple
    device changes and rebalance them all just once.
        """
        if len(argv) != 5:
            print Commands.set_weight.__doc__.strip()
            print
            print search_devs.__doc__.strip()
            exit(EXIT_RING_UNCHANGED)
        devs = search_devs(builder, argv[3])
        weight = float(argv[4])
        if not devs:
            print 'No matching devices found'
            exit(EXIT_ERROR)
        if len(devs) > 1:
            print 'Matched more than one device:'
            for dev in devs:
                print '    d%(id)sz%(zone)s-%(ip)s:%(port)s/%(device)s_' \
                      '"%(meta)s"' % dev
            if raw_input('Are you sure you want to update the weight for '
                         'these %s devices? (y/N) ' % len(devs)) != 'y':
                print 'Aborting device modifications'
                exit(EXIT_ERROR)
        for dev in devs:
            builder.set_dev_weight(dev['id'], weight)
            print 'd%(id)sz%(zone)s-%(ip)s:%(port)s/%(device)s_"%(meta)s" ' \
                  'weight set to %(weight)s' % dev
        pickle.dump(builder, open(argv[1], 'wb'), protocol=2)
        exit(EXIT_RING_UNCHANGED)

    def set_info():
        """
swift-ring-builder <builder_file> set_info <search-value>
                                           <ip>:<port>/<device_name>_<meta>
    Resets the device's information. This information isn't used to assign
    partitions, so you can use 'write_ring' afterward to rewrite the current
    ring with the newer device information. Any of the parts are optional
    in the final <ip>:<port>/<device_name>_<meta> parameter; just give what you
    want to change. For instance set_info d74 _"snet: 5.6.7.8" would just
    update the meta data for device id 74.
        """
        if len(argv) != 5:
            print Commands.set_info.__doc__.strip()
            print
            print search_devs.__doc__.strip()
            exit(EXIT_RING_UNCHANGED)
        devs = search_devs(builder, argv[3])
        change_value = argv[4]
        change = []
        if len(change_value) and change_value[0].isdigit():
            i = 1
            while i < len(change_value) and change_value[i] in '0123456789.':
                i += 1
            change.append(('ip', change_value[:i]))
            change_value = change_value[i:]
        if change_value.startswith(':'):
            i = 1
            while i < len(change_value) and change_value[i].isdigit():
                i += 1
            change.append(('port', int(change_value[1:i])))
            change_value = change_value[i:]
        if change_value.startswith('/'):
            i = 1
            while i < len(change_value) and change_value[i] != '_':
                i += 1
            change.append(('device', change_value[1:i]))
            change_value = change_value[i:]
        if change_value.startswith('_'):
            change.append(('meta', change_value[1:]))
            change_value = ''
        if change_value or not change:
            raise ValueError('Invalid set info change value: %s' %
                             repr(argv[4]))
        if not devs:
            print 'No matching devices found'
            exit(EXIT_ERROR)
        if len(devs) > 1:
            print 'Matched more than one device:'
            for dev in devs:
                print '    d%(id)sz%(zone)s-%(ip)s:%(port)s/%(device)s_' \
                      '"%(meta)s"' % dev
            if raw_input('Are you sure you want to update the info for '
                         'these %s devices? (y/N) ' % len(devs)) != 'y':
                print 'Aborting device modifications'
                exit(EXIT_ERROR)
        for dev in devs:
            orig_dev_string = \
                'd%(id)sz%(zone)s-%(ip)s:%(port)s/%(device)s_"%(meta)s"' % dev
            test_dev = dict(dev)
            for key, value in change:
                test_dev[key] = value
            for check_dev in builder.devs:
                if not check_dev or check_dev['id'] == test_dev['id']:
                    continue
                if check_dev['ip'] == test_dev['ip'] and \
                        check_dev['port'] == test_dev['port'] and \
                        check_dev['device'] == test_dev['device']:
                    print 'Device %d already uses %s:%d/%s.' % \
                          (check_dev['id'], check_dev['ip'], check_dev['port'],
                           check_dev['device'])
                    exit(EXIT_ERROR)
            for key, value in change:
                dev[key] = value
            new_dev_string = \
                'd%(id)sz%(zone)s-%(ip)s:%(port)s/%(device)s_"%(meta)s"' % dev
            print 'Device %s is now %s' % (orig_dev_string, new_dev_string)
        pickle.dump(builder, open(argv[1], 'wb'), protocol=2)
        exit(EXIT_RING_UNCHANGED)

    def remove():
        """
swift-ring-builder <builder_file> remove <search-value>
    Removes the device(s) from the ring. This should normally just be used for
    a device that has failed. For a device you wish to decommission, it's best
    to set its weight to 0, wait for it to drain all its data, then use this
    remove command. This will not take effect until after running 'rebalance'.
    This is so you can make multiple device changes and rebalance them all just
    once.
        """
        if len(argv) < 4:
            print Commands.remove.__doc__.strip()
            print
            print search_devs.__doc__.strip()
            exit(EXIT_RING_UNCHANGED)
        devs = search_devs(builder, argv[3])
        if not devs:
            print 'No matching devices found'
            exit(EXIT_ERROR)
        if len(devs) > 1:
            print 'Matched more than one device:'
            for dev in devs:
                print '    d%(id)sz%(zone)s-%(ip)s:%(port)s/%(device)s_' \
                      '"%(meta)s"' % dev
            if raw_input('Are you sure you want to remove these %s devices? '
                         '(y/N) ' % len(devs)) != 'y':
                print 'Aborting device removals'
                exit(EXIT_ERROR)
        for dev in devs:
            builder.remove_dev(dev['id'])
            print 'd%(id)sz%(zone)s-%(ip)s:%(port)s/%(device)s_"%(meta)s" ' \
                  'marked for removal and will be removed next rebalance.' \
                  % dev
        pickle.dump(builder, open(argv[1], 'wb'), protocol=2)
        exit(EXIT_RING_UNCHANGED)

    def rebalance():
        """
swift-ring-builder <builder_file> rebalance
    Attempts to rebalance the ring by reassigning partitions that haven't been
    recently reassigned.
        """
        devs_changed = builder.devs_changed
        last_balance = builder.get_balance()
        parts, balance = builder.rebalance()
        if not parts:
            print 'No partitions could be reassigned.'
            print 'Either none need to be or none can be due to ' \
                  'min_part_hours [%s].' % builder.min_part_hours
            exit(EXIT_RING_UNCHANGED)
        if not devs_changed and abs(last_balance - balance) < 1:
            print 'Cowardly refusing to save rebalance as it did not change ' \
                  'at least 1%.'
            exit(EXIT_RING_UNCHANGED)
        builder.validate()
        print 'Reassigned %d (%.02f%%) partitions. Balance is now %.02f.' % \
              (parts, 100.0 * parts / builder.parts, balance)
        if balance > 5:
            print '-' * 79
            print 'NOTE: Balance of %.02f indicates you should push this ' % \
                  balance
            print '      ring, wait at least %d hours, and rebalance/repush.' \
                  % builder.min_part_hours
            print '-' * 79
        ts = time()
        pickle.dump(builder.get_ring(),
                    GzipFile(pathjoin(backup_dir, '%d.' % ts +
                        basename(ring_file)), 'wb'), protocol=2)
        pickle.dump(builder, open(pathjoin(backup_dir,
            '%d.' % ts + basename(argv[1])), 'wb'), protocol=2)
        pickle.dump(builder.get_ring(), GzipFile(ring_file, 'wb'), protocol=2)
        pickle.dump(builder, open(argv[1], 'wb'), protocol=2)
        exit(EXIT_RING_CHANGED)

    def validate():
        """
swift-ring-builder <builder_file> validate
    Just runs the validation routines on the ring.
        """
        builder.validate()
        exit(EXIT_RING_UNCHANGED)

    def write_ring():
        """
swift-ring-builder <builder_file> write_ring
    Just rewrites the distributable ring file. This is done automatically after
    a successful rebalance, so really this is only useful after one or more
    'set_info' calls when no rebalance is needed but you want to send out the
    new device information.
        """
        ring_data = builder.get_ring()
        if not ring_data._replica2part2dev_id:
            if ring_data.devs:
                print 'Warning: Writing a ring with no partition ' \
                      'assignments but with devices; did you forget to run ' \
                      '"rebalance"?'
            else:
                print 'Warning: Writing an empty ring'
        pickle.dump(ring_data,
                    GzipFile(pathjoin(backup_dir, '%d.' % time() +
                        basename(ring_file)), 'wb'), protocol=2)
        pickle.dump(ring_data, GzipFile(ring_file, 'wb'), protocol=2)
        exit(EXIT_RING_CHANGED)

    def pretend_min_part_hours_passed():
        builder.pretend_min_part_hours_passed()
        pickle.dump(builder, open(argv[1], 'wb'), protocol=2)
        exit(EXIT_RING_UNCHANGED)

    def set_min_part_hours():
        """
swift-ring-builder <builder_file> set_min_part_hours <hours>
    Changes the <min_part_hours> to the given <hours>. This should be set to
    however long a full replication/update cycle takes. We're working on a way
    to determine this more easily than scanning logs.
        """
        if len(argv) < 4:
            print Commands.set_min_part_hours.__doc__.strip()
            exit(EXIT_RING_UNCHANGED)
        builder.change_min_part_hours(int(argv[3]))
        print 'The minimum number of hours before a partition can be ' \
              'reassigned is now set to %s' % argv[3]
        pickle.dump(builder, open(argv[1], 'wb'), protocol=2)
        exit(EXIT_RING_UNCHANGED)


if __name__ == '__main__':
    if len(argv) < 2:
        print "swift-ring-builder %(MAJOR_VERSION)s.%(MINOR_VERSION)s\n" % \
              globals()
        print Commands.default.__doc__.strip()
        print
        cmds = [c for c, f in Commands.__dict__.iteritems()
                    if f.__doc__ and c[0] != '_' and c != 'default']
        cmds.sort()
        for cmd in cmds:
            print Commands.__dict__[cmd].__doc__.strip()
            print
        print search_devs.__doc__.strip()
        print
        for line in wrap(' '.join(cmds), 79, initial_indent='Quick list: ',
                         subsequent_indent='            '):
            print line
        print 'Exit codes: 0 = ring changed, 1 = ring did not change, ' \
              '2 = error'
        exit(EXIT_RING_UNCHANGED)

    if exists(argv[1]):
        builder = pickle.load(open(argv[1], 'rb'))
        for dev in builder.devs:
            if dev and 'meta' not in dev:
                dev['meta'] = ''
    elif len(argv) < 3 or argv[2] != 'create':
        print 'Ring Builder file does not exist: %s' % argv[1]
        exit(EXIT_ERROR)

    backup_dir = pathjoin(dirname(argv[1]), 'backups')
    try:
        mkdir(backup_dir)
    except OSError, err:
        if err.errno != EEXIST:
            raise

    ring_file = argv[1]
    if ring_file.endswith('.builder'):
        ring_file = ring_file[:-len('.builder')]
    ring_file += '.ring.gz'

    if len(argv) == 2:
        command = "default"
    else:
        command = argv[2]
    Commands.__dict__.get(command, Commands.unknown)()
