ironic-python-agent/ironic_python_agent/extensions/standby.py

# Copyright 2013 Rackspace, Inc.
#
# 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 hashlib
import os
import requests
import subprocess
import time

from ironic_python_agent import configdrive
from ironic_python_agent import errors
from ironic_python_agent.extensions import base
from ironic_python_agent import hardware
from ironic_python_agent.openstack.common import log

LOG = log.getLogger(__name__)


def _configdrive_location():
    return '/tmp/configdrive'


def _image_location(image_info):
    return '/tmp/{0}'.format(image_info['id'])


def _path_to_script(script):
    cwd = os.path.dirname(os.path.realpath(__file__))
    return os.path.join(cwd, script)


def _write_image(image_info, device):
    starttime = time.time()
    image = _image_location(image_info)

    script = _path_to_script('shell/write_image.sh')
    command = ['/bin/bash', script, image, device]
    LOG.info('Writing image with command: {0}'.format(' '.join(command)))
    exit_code = subprocess.call(command)
    if exit_code != 0:
        raise errors.ImageWriteError(exit_code, device)
    totaltime = time.time() - starttime
    LOG.info('Image {0} written to device {1} in {2} seconds'.format(
             image, device, totaltime))


def _copy_configdrive_to_disk(configdrive_dir, device):
    starttime = time.time()
    script = _path_to_script('shell/copy_configdrive_to_disk.sh')
    command = ['/bin/bash', script, configdrive_dir, device]
    LOG.info('copying configdrive to disk with command {0}'.format(
             ' '.join(command)))
    exit_code = subprocess.call(command)

    if exit_code != 0:
        raise errors.ConfigDriveWriteError(exit_code, device)

    totaltime = time.time() - starttime
    LOG.info('configdrive copied from {0} to {1} in {2} seconds'.format(
             configdrive_dir,
             device,
             totaltime))


def _request_url(image_info, url):
    resp = requests.get(url, stream=True)
    if resp.status_code != 200:
        raise errors.ImageDownloadError(image_info['id'])
    return resp


def _download_image(image_info):
    starttime = time.time()
    resp = None
    for url in image_info['urls']:
        try:
            LOG.info("Attempting to download image from {0}".format(url))
            resp = _request_url(image_info, url)
        except errors.ImageDownloadError:
            failtime = time.time() - starttime
            log_msg = "Image download failed. URL: {0}; time: {1} seconds"
            LOG.warning(log_msg.format(url, failtime))
            continue
        else:
            break
    if resp is None:
        raise errors.ImageDownloadError(image_info['id'])

    image_location = _image_location(image_info)
    with open(image_location, 'wb') as f:
        try:
            for chunk in resp.iter_content(1024 * 1024):
                f.write(chunk)
        except Exception:
            raise errors.ImageDownloadError(image_info['id'])

    totaltime = time.time() - starttime
    LOG.info("Image downloaded from {0} in {1} seconds".format(image_location,
                                                               totaltime))

    if not _verify_image(image_info, image_location):
        raise errors.ImageChecksumError(image_info['id'])


def _verify_image(image_info, image_location):
    hashes = image_info['hashes']
    for k, v in hashes.items():
        algo = getattr(hashlib, k, None)
        if algo is None:
            continue
        log_msg = 'Verifying image at {0} with algorithm {1} against hash {2}'
        LOG.debug(log_msg.format(image_location, k, v))
        hash_ = algo(open(image_location).read()).hexdigest()
        if hash_ == v:
            return True
        else:
            log_msg = ('Image verification failed. Location: {0};'
                       'algorithm: {1}; image hash: {2};'
                       'verification hash: {3}')
            LOG.warning(log_msg.format(image_location, k, hash_, v))
    return False


def _validate_image_info(ext, image_info=None, **kwargs):
    image_info = image_info or {}

    for field in ['id', 'urls', 'hashes']:
        if field not in image_info:
            msg = 'Image is missing \'{0}\' field.'.format(field)
            raise errors.InvalidCommandParamsError(msg)

    if type(image_info['urls']) != list or not image_info['urls']:
        raise errors.InvalidCommandParamsError(
            'Image \'urls\' must be a list with at least one element.')

    if type(image_info['hashes']) != dict or not image_info['hashes']:
        raise errors.InvalidCommandParamsError(
            'Image \'hashes\' must be a dictionary with at least one '
            'element.')


class StandbyExtension(base.BaseAgentExtension):
    def __init__(self):
        super(StandbyExtension, self).__init__()
        self.command_map['cache_image'] = self.cache_image
        self.command_map['prepare_image'] = self.prepare_image
        self.command_map['run_image'] = self.run_image

        self.cached_image_id = None

    @base.async_command(_validate_image_info)
    def cache_image(self, command_name, image_info=None, force=False):
        device = hardware.get_manager().get_os_install_device()

        if self.cached_image_id != image_info['id'] or force:
            _download_image(image_info)
            _write_image(image_info, device)
            self.cached_image_id = image_info['id']

    @base.async_command(_validate_image_info)
    def prepare_image(self,
                      command_name,
                      image_info=None,
                      metadata=None,
                      files=None):
        location = _configdrive_location()
        device = hardware.get_manager().get_os_install_device()

        # don't write image again if already cached
        if self.cached_image_id != image_info['id']:
            _download_image(image_info)
            _write_image(image_info, device)
            self.cached_image_id = image_info['id']

        LOG.debug('Writing configdrive to {0}'.format(location))
        configdrive.write_configdrive(location, metadata, files)
        _copy_configdrive_to_disk(location, device)

    @base.async_command()
    def run_image(self, command_name):
        script = _path_to_script('shell/reboot.sh')
        LOG.info('Rebooting system')
        command = ['/bin/bash', script]
        # this should never return if successful
        exit_code = subprocess.call(command)
        if exit_code != 0:
            raise errors.SystemRebootError(exit_code)