155 lines
5.8 KiB
Python
155 lines
5.8 KiB
Python
# Copyright (c) 2010-2012 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.
|
|
|
|
from swift import gettext_ as _
|
|
|
|
from swift.common.swob import Request, HTTPServerError
|
|
from swift.common.utils import get_logger, generate_trans_id, close_if_possible
|
|
from swift.common.wsgi import WSGIContext
|
|
|
|
|
|
class BadResponseLength(Exception):
|
|
pass
|
|
|
|
|
|
def enforce_byte_count(inner_iter, nbytes):
|
|
"""
|
|
Enforces that inner_iter yields exactly <nbytes> bytes before
|
|
exhaustion.
|
|
|
|
If inner_iter fails to do so, BadResponseLength is raised.
|
|
|
|
:param inner_iter: iterable of bytestrings
|
|
:param nbytes: number of bytes expected
|
|
"""
|
|
try:
|
|
bytes_left = nbytes
|
|
for chunk in inner_iter:
|
|
if bytes_left >= len(chunk):
|
|
yield chunk
|
|
bytes_left -= len(chunk)
|
|
else:
|
|
yield chunk[:bytes_left]
|
|
raise BadResponseLength(
|
|
"Too many bytes; truncating after %d bytes "
|
|
"with at least %d surplus bytes remaining" % (
|
|
nbytes, len(chunk) - bytes_left))
|
|
|
|
if bytes_left:
|
|
raise BadResponseLength('Expected another %d bytes' % (
|
|
bytes_left,))
|
|
finally:
|
|
close_if_possible(inner_iter)
|
|
|
|
|
|
class CatchErrorsContext(WSGIContext):
|
|
|
|
def __init__(self, app, logger, trans_id_suffix=''):
|
|
super(CatchErrorsContext, self).__init__(app)
|
|
self.logger = logger
|
|
self.trans_id_suffix = trans_id_suffix
|
|
|
|
def handle_request(self, env, start_response):
|
|
trans_id_suffix = self.trans_id_suffix
|
|
trans_id_extra = env.get('HTTP_X_TRANS_ID_EXTRA')
|
|
if trans_id_extra:
|
|
trans_id_suffix += '-' + trans_id_extra[:32]
|
|
|
|
trans_id = generate_trans_id(trans_id_suffix)
|
|
env['swift.trans_id'] = trans_id
|
|
self.logger.txn_id = trans_id
|
|
try:
|
|
# catch any errors in the pipeline
|
|
resp = self._app_call(env)
|
|
except: # noqa
|
|
self.logger.exception(_('Error: An error occurred'))
|
|
resp = HTTPServerError(request=Request(env),
|
|
body=b'An error occurred',
|
|
content_type='text/plain')
|
|
resp.headers['X-Trans-Id'] = trans_id
|
|
resp.headers['X-Openstack-Request-Id'] = trans_id
|
|
return resp(env, start_response)
|
|
|
|
# If the app specified a Content-Length, enforce that it sends that
|
|
# many bytes.
|
|
#
|
|
# If an app gives too few bytes, then the client will wait for the
|
|
# remainder before sending another HTTP request on the same socket;
|
|
# since no more bytes are coming, this will result in either an
|
|
# infinite wait or a timeout. In this case, we want to raise an
|
|
# exception to signal to the WSGI server that it should close the
|
|
# TCP connection.
|
|
#
|
|
# If an app gives too many bytes, then we can deadlock with the
|
|
# client; if the client reads its N bytes and then sends a large-ish
|
|
# request (enough to fill TCP buffers), it'll block until we read
|
|
# some of the request. However, we won't read the request since
|
|
# we'll be trying to shove the rest of our oversized response out
|
|
# the socket. In that case, we truncate the response body at N bytes
|
|
# and raise an exception to stop any more bytes from being
|
|
# generated and also to kill the TCP connection.
|
|
if env['REQUEST_METHOD'] == 'HEAD':
|
|
resp = enforce_byte_count(resp, 0)
|
|
|
|
elif self._response_headers:
|
|
content_lengths = [val for header, val in self._response_headers
|
|
if header.lower() == "content-length"]
|
|
if len(content_lengths) == 1:
|
|
try:
|
|
content_length = int(content_lengths[0])
|
|
except ValueError:
|
|
pass
|
|
else:
|
|
resp = enforce_byte_count(resp, content_length)
|
|
|
|
# make sure the response has the trans_id
|
|
if self._response_headers is None:
|
|
self._response_headers = []
|
|
self._response_headers.append(('X-Trans-Id', trans_id))
|
|
self._response_headers.append(('X-Openstack-Request-Id', trans_id))
|
|
start_response(self._response_status, self._response_headers,
|
|
self._response_exc_info)
|
|
return resp
|
|
|
|
|
|
class CatchErrorMiddleware(object):
|
|
"""
|
|
Middleware that provides high-level error handling and ensures that a
|
|
transaction id will be set for every request.
|
|
"""
|
|
|
|
def __init__(self, app, conf):
|
|
self.app = app
|
|
self.logger = get_logger(conf, log_route='catch-errors')
|
|
self.trans_id_suffix = conf.get('trans_id_suffix', '')
|
|
|
|
def __call__(self, env, start_response):
|
|
"""
|
|
If used, this should be the first middleware in pipeline.
|
|
"""
|
|
context = CatchErrorsContext(self.app,
|
|
self.logger,
|
|
self.trans_id_suffix)
|
|
return context.handle_request(env, start_response)
|
|
|
|
|
|
def filter_factory(global_conf, **local_conf):
|
|
conf = global_conf.copy()
|
|
conf.update(local_conf)
|
|
|
|
def except_filter(app):
|
|
return CatchErrorMiddleware(app, conf)
|
|
return except_filter
|