# Copyright 2010 OpenStack Foundation
# Copyright 2013 Hewlett-Packard Development Company, L.P.
# 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.
import abc
import datetime
from http import client as http_client
import os
import shutil
from urllib import parse as urlparse
from oslo_log import log
from oslo_utils import strutils
from oslo_utils import uuidutils
import requests
from ironic.common import exception
from ironic.common.glance_service.image_service import GlanceImageService
from ironic.common.i18n import _
from ironic.common import utils
from ironic.conf import CONF
IMAGE_CHUNK_SIZE = 1024 * 1024 # 1mb
LOG = log.getLogger(__name__)
[docs]class BaseImageService(object, metaclass=abc.ABCMeta):
"""Provides retrieval of disk images."""
[docs] @abc.abstractmethod
def validate_href(self, image_href):
"""Validate image reference.
:param image_href: Image reference.
:raises: exception.ImageRefValidationFailed.
:returns: Information needed to further operate with an image.
"""
[docs] @abc.abstractmethod
def download(self, image_href, image_file):
"""Downloads image to specified location.
:param image_href: Image reference.
:param image_file: File object to write data to.
:raises: exception.ImageRefValidationFailed.
:raises: exception.ImageDownloadFailed.
"""
[docs] @abc.abstractmethod
def show(self, image_href):
"""Get dictionary of image properties.
:param image_href: Image reference.
:raises: exception.ImageRefValidationFailed.
:returns: dictionary of image properties. It has three of them: 'size',
'updated_at' and 'properties'. 'updated_at' attribute is a naive
UTC datetime object.
"""
[docs]class HttpImageService(BaseImageService):
"""Provides retrieval of disk images using HTTP."""
[docs] def validate_href(self, image_href, secret=False):
"""Validate HTTP image reference.
:param image_href: Image reference.
:param secret: Specify if image_href being validated should not be
shown in exception message.
:raises: exception.ImageRefValidationFailed if HEAD request failed or
returned response code not equal to 200.
:raises: exception.ImageRefIsARedirect if the supplied URL is a
redirect to a different URL. The caller may be able to handle
this.
:returns: Response to HEAD request.
"""
output_url = 'secreturl' if secret else image_href
try:
verify = strutils.bool_from_string(CONF.webserver_verify_ca,
strict=True)
except ValueError:
verify = CONF.webserver_verify_ca
try:
# NOTE(TheJulia): Head requests do not work on things that are not
# files, but they can be responded with redirects or a 200 OK....
# We don't want to permit endless redirects either, thus not
# request an override to the requests default to try and resolve
# redirects as otherwise we might end up with something like
# HTTPForbidden or a list of files. Both should be okay to at
# least know things are okay in a limited fashion.
response = requests.head(image_href, verify=verify,
timeout=CONF.webserver_connection_timeout)
if response.status_code == http_client.MOVED_PERMANENTLY:
# NOTE(TheJulia): In the event we receive a redirect, we need
# to notify the caller. Before this we would just fail,
# but a url which is missing a trailing slash results in a
# redirect to a target path, and the caller *may* actually
# care about that.
redirect = requests.Session().get_redirect_target(response)
# Extra guard because this is pointless if there is no
# location in the field. Requests also properly formats
# our string for us, or gives us None.
if redirect:
raise exception.ImageRefIsARedirect(
image_ref=image_href,
redirect_url=redirect)
if (response.status_code == http_client.FORBIDDEN
and str(image_href).endswith('/')):
LOG.warning('Attempted to validate a URL %s, however we '
'received an HTTP Forbidden response and the '
'url ends with trailing slash (/), suggesting '
'non-image deploy may be in progress with '
'a webserver which is not permitting an index '
'to be generated. We will treat this as valid, '
'but return the response.', image_href)
return response
# NOTE(TheJulia): Any file list reply will proceed past here just
# fine as they are conveyed as an HTTP 200 OK response with a
# server rendered HTML document payload.
if response.status_code != http_client.OK:
raise exception.ImageRefValidationFailed(
image_href=output_url,
reason=_("Got HTTP code %s instead of 200 in response "
"to HEAD request.") % response.status_code)
except (OSError, requests.ConnectionError,
requests.RequestException) as e:
raise exception.ImageRefValidationFailed(image_href=output_url,
reason=str(e))
return response
[docs] def download(self, image_href, image_file):
"""Downloads image to specified location.
:param image_href: Image reference.
:param image_file: File object to write data to.
:raises: exception.ImageRefValidationFailed if GET request returned
response code not equal to 200.
:raises: exception.ImageDownloadFailed if:
* IOError happened during file write;
* GET request failed.
"""
try:
verify = strutils.bool_from_string(CONF.webserver_verify_ca,
strict=True)
except ValueError:
verify = CONF.webserver_verify_ca
try:
response = requests.get(image_href, stream=True, verify=verify,
timeout=CONF.webserver_connection_timeout)
if response.status_code != http_client.OK:
raise exception.ImageRefValidationFailed(
image_href=image_href,
reason=_("Got HTTP code %s instead of 200 in response "
"to GET request.") % response.status_code)
with response.raw as input_img:
shutil.copyfileobj(input_img, image_file, IMAGE_CHUNK_SIZE)
except (OSError, requests.ConnectionError, requests.RequestException,
IOError) as e:
raise exception.ImageDownloadFailed(image_href=image_href,
reason=str(e))
[docs] def show(self, image_href):
"""Get dictionary of image properties.
:param image_href: Image reference.
:raises: exception.ImageRefValidationFailed if:
* HEAD request failed;
* HEAD request returned response code not equal to 200;
* Content-Length header not found in response to HEAD request.
:returns: dictionary of image properties. It has three of them: 'size',
'updated_at' and 'properties'. 'updated_at' attribute is a naive
UTC datetime object.
"""
response = self.validate_href(image_href)
image_size = response.headers.get('Content-Length')
if image_size is None:
raise exception.ImageRefValidationFailed(
image_href=image_href,
reason=_("Cannot determine image size as there is no "
"Content-Length header specified in response "
"to HEAD request."))
# Parse last-modified header to return naive datetime object
str_date = response.headers.get('Last-Modified')
date = None
if str_date:
http_date_format_strings = [
'%a, %d %b %Y %H:%M:%S GMT', # RFC 822
'%A, %d-%b-%y %H:%M:%S GMT', # RFC 850
'%a %b %d %H:%M:%S %Y' # ANSI C
]
for fmt in http_date_format_strings:
try:
date = datetime.datetime.strptime(str_date, fmt)
break
except ValueError:
continue
no_cache = 'no-store' in response.headers.get('Cache-Control', '')
return {
'size': int(image_size),
'updated_at': date,
'properties': {},
'no_cache': no_cache,
}
[docs]class FileImageService(BaseImageService):
"""Provides retrieval of disk images available locally on the conductor."""
[docs] def validate_href(self, image_href):
"""Validate local image reference.
:param image_href: Image reference.
:raises: exception.ImageRefValidationFailed if source image file
doesn't exist.
:returns: Path to image file if it exists.
"""
image_path = urlparse.urlparse(image_href).path
if not os.path.isfile(image_path):
raise exception.ImageRefValidationFailed(
image_href=image_href,
reason=_("Specified image file not found."))
return image_path
[docs] def download(self, image_href, image_file):
"""Downloads image to specified location.
:param image_href: Image reference.
:param image_file: File object to write data to.
:raises: exception.ImageRefValidationFailed if source image file
doesn't exist.
:raises: exception.ImageDownloadFailed if exceptions were raised while
writing to file or creating hard link.
"""
source_image_path = self.validate_href(image_href)
dest_image_path = image_file.name
try:
image_file.close()
os.remove(dest_image_path)
try:
os.link(source_image_path, dest_image_path)
except OSError as exc:
LOG.debug('Could not create a link from %(src)s to %(dest)s, '
'will copy the content instead. Error: %(exc)s.',
{'src': source_image_path, 'dest': dest_image_path,
'exc': exc})
else:
return
# NOTE(dtantsur): starting with Python 3.8, copyfile() uses
# efficient copying (i.e. sendfile) under the hood.
shutil.copyfile(source_image_path, dest_image_path)
except Exception as e:
raise exception.ImageDownloadFailed(image_href=image_href,
reason=str(e))
[docs] def show(self, image_href):
"""Get dictionary of image properties.
:param image_href: Image reference.
:raises: exception.ImageRefValidationFailed if image file specified
doesn't exist.
:returns: dictionary of image properties. It has three of them: 'size',
'updated_at' and 'properties'. 'updated_at' attribute is a naive
UTC datetime object.
"""
source_image_path = self.validate_href(image_href)
return {
'size': os.path.getsize(source_image_path),
'updated_at': utils.unix_file_modification_datetime(
source_image_path),
'properties': {},
# No point in caching local file images
'no_cache': True,
}
protocol_mapping = {
'http': HttpImageService,
'https': HttpImageService,
'file': FileImageService,
'glance': GlanceImageService,
}
[docs]def get_image_service(image_href, client=None, context=None):
"""Get image service instance to download the image.
:param image_href: String containing href to get image service for.
:param client: Glance client to be used for download, used only if
image_href is Glance href.
:param context: request context, used only if image_href is Glance href.
:raises: exception.ImageRefValidationFailed if no image service can
handle specified href.
:returns: Instance of an image service class that is able to download
specified image.
"""
scheme = urlparse.urlparse(image_href).scheme.lower()
if not scheme:
if uuidutils.is_uuid_like(str(image_href)):
cls = GlanceImageService
else:
raise exception.ImageRefValidationFailed(
image_href=image_href,
reason=_('Scheme-less image href is not a UUID.'))
else:
cls = protocol_mapping.get(scheme)
if not cls:
raise exception.ImageRefValidationFailed(
image_href=image_href,
reason=_('Image download protocol %s is not supported.'
) % scheme)
if cls == GlanceImageService:
return cls(client, context)
return cls()
