/usr/lib/python2.7/dist-packages/swift/common/middleware/dlo.py is in python-swift 2.7.0-0ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 | # Copyright (c) 2013 OpenStack Foundation
#
# 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.
"""
Middleware that will provide Dynamic Large Object (DLO) support.
---------------
Using ``swift``
---------------
The quickest way to try out this feature is use the ``swift`` Swift Tool
included with the `python-swiftclient`_ library. You can use the ``-S``
option to specify the segment size to use when splitting a large file. For
example::
swift upload test_container -S 1073741824 large_file
This would split the large_file into 1G segments and begin uploading those
segments in parallel. Once all the segments have been uploaded, ``swift`` will
then create the manifest file so the segments can be downloaded as one.
So now, the following ``swift`` command would download the entire large
object::
swift download test_container large_file
``swift`` command uses a strict convention for its segmented object
support. In the above example it will upload all the segments into a
second container named test_container_segments. These segments will
have names like large_file/1290206778.25/21474836480/00000000,
large_file/1290206778.25/21474836480/00000001, etc.
The main benefit for using a separate container is that the main container
listings will not be polluted with all the segment names. The reason for using
the segment name format of <name>/<timestamp>/<size>/<segment> is so that an
upload of a new file with the same name won't overwrite the contents of the
first until the last moment when the manifest file is updated.
``swift`` will manage these segment files for you, deleting old segments on
deletes and overwrites, etc. You can override this behavior with the
``--leave-segments`` option if desired; this is useful if you want to have
multiple versions of the same large object available.
.. _`python-swiftclient`: http://github.com/openstack/python-swiftclient
----------
Direct API
----------
You can also work with the segments and manifests directly with HTTP
requests instead of having ``swift`` do that for you. You can just
upload the segments like you would any other object and the manifest
is just a zero-byte (not enforced) file with an extra
``X-Object-Manifest`` header.
All the object segments need to be in the same container, have a common object
name prefix, and sort in the order in which they should be concatenated.
Object names are sorted lexicographically as UTF-8 byte strings.
They don't have to be in the same container as the manifest file will be, which
is useful to keep container listings clean as explained above with ``swift``.
The manifest file is simply a zero-byte (not enforced) file with the extra
``X-Object-Manifest: <container>/<prefix>`` header, where ``<container>`` is
the container the object segments are in and ``<prefix>`` is the common prefix
for all the segments.
It is best to upload all the segments first and then create or update the
manifest. In this way, the full object won't be available for downloading
until the upload is complete. Also, you can upload a new set of segments to
a second location and then update the manifest to point to this new location.
During the upload of the new segments, the original manifest will still be
available to download the first set of segments.
.. note::
The manifest file should have no content. However, this is not enforced.
If the manifest path itself conforms to container/prefix specified in
X-Object-Manifest, and if manifest has some content/data in it, it would
also be considered as segment and manifest's content will be part of the
concatenated GET response. The order of concatenation follows the usual DLO
logic which is - the order of concatenation adheres to order returned when
segment names are sorted.
Here's an example using ``curl`` with tiny 1-byte segments::
# First, upload the segments
curl -X PUT -H 'X-Auth-Token: <token>' \
http://<storage_url>/container/myobject/00000001 --data-binary '1'
curl -X PUT -H 'X-Auth-Token: <token>' \
http://<storage_url>/container/myobject/00000002 --data-binary '2'
curl -X PUT -H 'X-Auth-Token: <token>' \
http://<storage_url>/container/myobject/00000003 --data-binary '3'
# Next, create the manifest file
curl -X PUT -H 'X-Auth-Token: <token>' \
-H 'X-Object-Manifest: container/myobject/' \
http://<storage_url>/container/myobject --data-binary ''
# And now we can download the segments as a single object
curl -H 'X-Auth-Token: <token>' \
http://<storage_url>/container/myobject
"""
import json
import os
import six
from six.moves.configparser import ConfigParser, NoSectionError, NoOptionError
from six.moves.urllib.parse import unquote
from hashlib import md5
from swift.common import constraints
from swift.common.exceptions import ListingIterError, SegmentError
from swift.common.http import is_success
from swift.common.swob import Request, Response, \
HTTPRequestedRangeNotSatisfiable, HTTPBadRequest, HTTPConflict
from swift.common.utils import get_logger, \
RateLimitedIterator, read_conf_dir, quote, close_if_possible, \
closing_if_possible
from swift.common.request_helpers import SegmentedIterable
from swift.common.wsgi import WSGIContext, make_subrequest
class GetContext(WSGIContext):
def __init__(self, dlo, logger):
super(GetContext, self).__init__(dlo.app)
self.dlo = dlo
self.logger = logger
def _get_container_listing(self, req, version, account, container,
prefix, marker=''):
con_req = make_subrequest(
req.environ, path='/'.join(['', version, account, container]),
method='GET',
headers={'x-auth-token': req.headers.get('x-auth-token')},
agent=('%(orig)s ' + 'DLO MultipartGET'), swift_source='DLO')
con_req.query_string = 'format=json&prefix=%s' % quote(prefix)
if marker:
con_req.query_string += '&marker=%s' % quote(marker)
con_resp = con_req.get_response(self.dlo.app)
if not is_success(con_resp.status_int):
return con_resp, None
with closing_if_possible(con_resp.app_iter):
return None, json.loads(''.join(con_resp.app_iter))
def _segment_listing_iterator(self, req, version, account, container,
prefix, segments, first_byte=None,
last_byte=None):
# It's sort of hokey that this thing takes in the first page of
# segments as an argument, but we need to compute the etag and content
# length from the first page, and it's better to have a hokey
# interface than to make redundant requests.
if first_byte is None:
first_byte = 0
if last_byte is None:
last_byte = float("inf")
marker = ''
while True:
for segment in segments:
seg_length = int(segment['bytes'])
if first_byte >= seg_length:
# don't need any bytes from this segment
first_byte = max(first_byte - seg_length, -1)
last_byte = max(last_byte - seg_length, -1)
continue
elif last_byte < 0:
# no bytes are needed from this or any future segment
break
seg_name = segment['name']
if isinstance(seg_name, six.text_type):
seg_name = seg_name.encode("utf-8")
# (obj path, etag, size, first byte, last byte)
yield ("/" + "/".join((version, account, container,
seg_name)),
# We deliberately omit the etag and size here;
# SegmentedIterable will check size and etag if
# specified, but we don't want it to. DLOs only care
# that the objects' names match the specified prefix.
None, None,
(None if first_byte <= 0 else first_byte),
(None if last_byte >= seg_length - 1 else last_byte))
first_byte = max(first_byte - seg_length, -1)
last_byte = max(last_byte - seg_length, -1)
if len(segments) < constraints.CONTAINER_LISTING_LIMIT:
# a short page means that we're done with the listing
break
elif last_byte < 0:
break
marker = segments[-1]['name']
error_response, segments = self._get_container_listing(
req, version, account, container, prefix, marker)
if error_response:
# we've already started sending the response body to the
# client, so all we can do is raise an exception to make the
# WSGI server close the connection early
close_if_possible(error_response.app_iter)
raise ListingIterError(
"Got status %d listing container /%s/%s" %
(error_response.status_int, account, container))
def get_or_head_response(self, req, x_object_manifest,
response_headers=None):
if response_headers is None:
response_headers = self._response_headers
container, obj_prefix = x_object_manifest.split('/', 1)
container = unquote(container)
obj_prefix = unquote(obj_prefix)
# manifest might point to a different container
req.acl = None
version, account, _junk = req.split_path(2, 3, True)
error_response, segments = self._get_container_listing(
req, version, account, container, obj_prefix)
if error_response:
return error_response
have_complete_listing = len(segments) < \
constraints.CONTAINER_LISTING_LIMIT
first_byte = last_byte = None
actual_content_length = None
content_length_for_swob_range = None
if req.range and len(req.range.ranges) == 1:
content_length_for_swob_range = sum(o['bytes'] for o in segments)
# This is a hack to handle suffix byte ranges (e.g. "bytes=-5"),
# which we can't honor unless we have a complete listing.
_junk, range_end = req.range.ranges_for_length(float("inf"))[0]
# If this is all the segments, we know whether or not this
# range request is satisfiable.
#
# Alternately, we may not have all the segments, but this range
# falls entirely within the first page's segments, so we know
# that it is satisfiable.
if (have_complete_listing
or range_end < content_length_for_swob_range):
byteranges = req.range.ranges_for_length(
content_length_for_swob_range)
if not byteranges:
return HTTPRequestedRangeNotSatisfiable(request=req)
first_byte, last_byte = byteranges[0]
# For some reason, swob.Range.ranges_for_length adds 1 to the
# last byte's position.
last_byte -= 1
actual_content_length = last_byte - first_byte + 1
else:
# The range may or may not be satisfiable, but we can't tell
# based on just one page of listing, and we're not going to go
# get more pages because that would use up too many resources,
# so we ignore the Range header and return the whole object.
actual_content_length = None
content_length_for_swob_range = None
req.range = None
response_headers = [
(h, v) for h, v in response_headers
if h.lower() not in ("content-length", "content-range")]
if content_length_for_swob_range is not None:
# Here, we have to give swob a big-enough content length so that
# it can compute the actual content length based on the Range
# header. This value will not be visible to the client; swob will
# substitute its own Content-Length.
#
# Note: if the manifest points to at least CONTAINER_LISTING_LIMIT
# segments, this may be less than the sum of all the segments'
# sizes. However, it'll still be greater than the last byte in the
# Range header, so it's good enough for swob.
response_headers.append(('Content-Length',
str(content_length_for_swob_range)))
elif have_complete_listing:
actual_content_length = sum(o['bytes'] for o in segments)
response_headers.append(('Content-Length',
str(actual_content_length)))
if have_complete_listing:
response_headers = [(h, v) for h, v in response_headers
if h.lower() != "etag"]
etag = md5()
for seg_dict in segments:
etag.update(seg_dict['hash'].strip('"'))
response_headers.append(('Etag', '"%s"' % etag.hexdigest()))
app_iter = None
if req.method == 'GET':
listing_iter = RateLimitedIterator(
self._segment_listing_iterator(
req, version, account, container, obj_prefix, segments,
first_byte=first_byte, last_byte=last_byte),
self.dlo.rate_limit_segments_per_sec,
limit_after=self.dlo.rate_limit_after_segment)
app_iter = SegmentedIterable(
req, self.dlo.app, listing_iter, ua_suffix="DLO MultipartGET",
swift_source="DLO", name=req.path, logger=self.logger,
max_get_time=self.dlo.max_get_time,
response_body_length=actual_content_length)
try:
app_iter.validate_first_segment()
except (SegmentError, ListingIterError):
return HTTPConflict(request=req)
resp = Response(request=req, headers=response_headers,
conditional_response=True,
app_iter=app_iter)
return resp
def handle_request(self, req, start_response):
"""
Take a GET or HEAD request, and if it is for a dynamic large object
manifest, return an appropriate response.
Otherwise, simply pass it through.
"""
resp_iter = self._app_call(req.environ)
# make sure this response is for a dynamic large object manifest
for header, value in self._response_headers:
if (header.lower() == 'x-object-manifest'):
close_if_possible(resp_iter)
response = self.get_or_head_response(req, value)
return response(req.environ, start_response)
else:
# Not a dynamic large object manifest; just pass it through.
start_response(self._response_status,
self._response_headers,
self._response_exc_info)
return resp_iter
class DynamicLargeObject(object):
def __init__(self, app, conf):
self.app = app
self.logger = get_logger(conf, log_route='dlo')
# DLO functionality used to live in the proxy server, not middleware,
# so let's try to go find config values in the proxy's config section
# to ease cluster upgrades.
self._populate_config_from_old_location(conf)
self.max_get_time = int(conf.get('max_get_time', '86400'))
self.rate_limit_after_segment = int(conf.get(
'rate_limit_after_segment', '10'))
self.rate_limit_segments_per_sec = int(conf.get(
'rate_limit_segments_per_sec', '1'))
def _populate_config_from_old_location(self, conf):
if ('rate_limit_after_segment' in conf or
'rate_limit_segments_per_sec' in conf or
'max_get_time' in conf or
'__file__' not in conf):
return
cp = ConfigParser()
if os.path.isdir(conf['__file__']):
read_conf_dir(cp, conf['__file__'])
else:
cp.read(conf['__file__'])
try:
pipe = cp.get("pipeline:main", "pipeline")
except (NoSectionError, NoOptionError):
return
proxy_name = pipe.rsplit(None, 1)[-1]
proxy_section = "app:" + proxy_name
for setting in ('rate_limit_after_segment',
'rate_limit_segments_per_sec',
'max_get_time'):
try:
conf[setting] = cp.get(proxy_section, setting)
except (NoSectionError, NoOptionError):
pass
def __call__(self, env, start_response):
"""
WSGI entry point
"""
req = Request(env)
try:
vrs, account, container, obj = req.split_path(4, 4, True)
except ValueError:
return self.app(env, start_response)
# install our COPY-callback hook
env['swift.copy_hook'] = self.copy_hook(
env.get('swift.copy_hook',
lambda src_req, src_resp, sink_req: src_resp))
if ((req.method == 'GET' or req.method == 'HEAD') and
req.params.get('multipart-manifest') != 'get'):
return GetContext(self, self.logger).\
handle_request(req, start_response)
elif req.method == 'PUT':
error_response = self._validate_x_object_manifest_header(req)
if error_response:
return error_response(env, start_response)
return self.app(env, start_response)
def _validate_x_object_manifest_header(self, req):
"""
Make sure that X-Object-Manifest is valid if present.
"""
if 'X-Object-Manifest' in req.headers:
value = req.headers['X-Object-Manifest']
container = prefix = None
try:
container, prefix = value.split('/', 1)
except ValueError:
pass
if not container or not prefix or '?' in value or '&' in value or \
prefix.startswith('/'):
return HTTPBadRequest(
request=req,
body=('X-Object-Manifest must be in the '
'format container/prefix'))
def copy_hook(self, inner_hook):
def dlo_copy_hook(source_req, source_resp, sink_req):
x_o_m = source_resp.headers.get('X-Object-Manifest')
if x_o_m:
if source_req.params.get('multipart-manifest') == 'get':
# To copy the manifest, we let the copy proceed as normal,
# but ensure that X-Object-Manifest is set on the new
# object.
sink_req.headers['X-Object-Manifest'] = x_o_m
else:
ctx = GetContext(self, self.logger)
source_resp = ctx.get_or_head_response(
source_req, x_o_m, source_resp.headers.items())
return inner_hook(source_req, source_resp, sink_req)
return dlo_copy_hook
def filter_factory(global_conf, **local_conf):
conf = global_conf.copy()
conf.update(local_conf)
def dlo_filter(app):
return DynamicLargeObject(app, conf)
return dlo_filter
|