OpenStack Study: glance.py

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# Copyright 2013 OpenStack Foundation

# 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.

from oslo.config import cfg

from nova import exception

from nova.image import glance

from nova import utils

from nova.virt.xenapi import vm_utils

CONF = cfg.CONF

CONF.import_opt('glance_num_retries', 'nova.image.glance')

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class GlanceStore(object):

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    def _call_glance_plugin(self, session, fn, params):

        glance_api_servers = glance.get_api_servers()

        def pick_glance(kwargs):

            g_host, g_port, g_use_ssl = glance_api_servers.next()

            kwargs['glance_host'] = g_host

            kwargs['glance_port'] = g_port

            kwargs['glance_use_ssl'] = g_use_ssl

        return session.call_plugin_serialized_with_retry(

            'glance', fn, CONF.glance_num_retries, pick_glance, **params)

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        def pick_glance(kwargs):

            g_host, g_port, g_use_ssl = glance_api_servers.next()

            kwargs['glance_host'] = g_host

            kwargs['glance_port'] = g_port

            kwargs['glance_use_ssl'] = g_use_ssl

        return session.call_plugin_serialized_with_retry(

            'glance', fn, CONF.glance_num_retries, pick_glance, **params)

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    def _make_params(self, context, session, image_id):

        return {'image_id': image_id,

                'sr_path': vm_utils.get_sr_path(session),

                'extra_headers': glance.generate_identity_headers(context)}

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    def download_image(self, context, session, instance, image_id):

        params = self._make_params(context, session, image_id)

        params['uuid_stack'] = vm_utils._make_uuid_stack()

        try:

            vdis = self._call_glance_plugin(session, 'download_vhd', params)

        except exception.PluginRetriesExceeded:

            raise exception.CouldNotFetchImage(image_id=image_id)

        return vdis

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    def upload_image(self, context, session, instance, vdi_uuids, image_id):

        params = self._make_params(context, session, image_id)

        params['vdi_uuids'] = vdi_uuids

        props = params['properties'] = {}

        props['auto_disk_config'] = instance['auto_disk_config']

        props['os_type'] = instance.get('os_type', None) or (

                CONF.xenserver.default_os_type)

        compression_level = vm_utils.get_compression_level()

        if compression_level:

            props['xenapi_image_compression_level'] = compression_level

        auto_disk_config = utils.get_auto_disk_config_from_instance(instance)

        if utils.is_auto_disk_config_disabled(auto_disk_config):

            props["auto_disk_config"] = "disabled"

        try:

            self._call_glance_plugin(session, 'upload_vhd', params)

        except exception.PluginRetriesExceeded:

            raise exception.CouldNotUploadImage(image_id=image_id)