# Copyright (C) 2012 Yahoo! Inc.

#

# Author: Joshua Harlow <harlowja@yahoo-inc.com>

#

# This file is part of cloud-init. See LICENSE file for license information.

"""

Migrator

--------

**Summary:** migrate old versions of cloud-init data to new

This module handles moving old versions of cloud-init data to newer ones.

Currently, it only handles renaming cloud-init's per-frequency semaphore files

to canonicalized name and renaming legacy semaphore names to newer ones. This

module is enabled by default, but can be disabled by specifying ``migrate:

false`` in config.

**Internal name:** ``cc_migrator``

**Module frequency:** per always

**Supported distros:** all

**Config keys**::

    migrate: <true/false>

"""

import os

import shutil

from cloudinit import helpers

from cloudinit import util

from cloudinit.settings import PER_ALWAYS

frequency = PER_ALWAYS

def _migrate_canon_sems(cloud):

    paths = (cloud.paths.get_ipath('sem'), cloud.paths.get_cpath('sem'))

    am_adjusted = 0

    for sem_path in paths:

        if not sem_path or not os.path.exists(sem_path):

            continue

        for p in os.listdir(sem_path):

            full_path = os.path.join(sem_path, p)

            if os.path.isfile(full_path):

                (name, ext) = os.path.splitext(p)

                canon_name = helpers.canon_sem_name(name)

                if canon_name != name:

                    new_path = os.path.join(sem_path, canon_name + ext)

                    shutil.move(full_path, new_path)

                    am_adjusted += 1

    return am_adjusted

def _migrate_legacy_sems(cloud, log):

    legacy_adjust = {

        'apt-update-upgrade': [

            'apt-configure',

            'package-update-upgrade-install',

        ],

    }

    paths = (cloud.paths.get_ipath('sem'), cloud.paths.get_cpath('sem'))

    for sem_path in paths:

        if not sem_path or not os.path.exists(sem_path):

            continue

        sem_helper = helpers.FileSemaphores(sem_path)

        for (mod_name, migrate_to) in legacy_adjust.items():

            possibles = [mod_name, helpers.canon_sem_name(mod_name)]

            old_exists = []

            for p in os.listdir(sem_path):

                (name, _ext) = os.path.splitext(p)

                if name in possibles and os.path.isfile(p):

                    old_exists.append(p)

            for p in old_exists:

                util.del_file(os.path.join(sem_path, p))

                (_name, freq) = os.path.splitext(p)

                for m in migrate_to:

                    log.debug("Migrating %s => %s with the same frequency",

                              p, m)

                    with sem_helper.lock(m, freq):

                        pass

def handle(name, cfg, cloud, log, _args):

    do_migrate = util.get_cfg_option_str(cfg, "migrate", True)

    if not util.translate_bool(do_migrate):

        log.debug("Skipping module named %s, migration disabled", name)

        return

    sems_moved = _migrate_canon_sems(cloud)

    log.debug("Migrated %s semaphore files to there canonicalized names",

              sems_moved)

    _migrate_legacy_sems(cloud, log)

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