swift/swift/obj/server.py

736 lines
34 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.
""" Object Server for Swift """
import cPickle as pickle
import os
import multiprocessing
import time
import traceback
import socket
import math
from swift import gettext_ as _
from hashlib import md5
from eventlet import sleep, Timeout
from swift.common.utils import public, get_logger, \
config_true_value, timing_stats, replication, \
normalize_delete_at_timestamp, get_log_line, Timestamp
from swift.common.bufferedhttp import http_connect
from swift.common.constraints import check_object_creation, \
valid_timestamp, check_utf8
from swift.common.exceptions import ConnectionTimeout, DiskFileQuarantined, \
DiskFileNotExist, DiskFileCollision, DiskFileNoSpace, DiskFileDeleted, \
DiskFileDeviceUnavailable, DiskFileExpired, ChunkReadTimeout
from swift.obj import ssync_receiver
from swift.common.http import is_success
from swift.common.request_helpers import get_name_and_placement, is_user_meta
from swift.common.swob import HTTPAccepted, HTTPBadRequest, HTTPCreated, \
HTTPInternalServerError, HTTPNoContent, HTTPNotFound, \
HTTPPreconditionFailed, HTTPRequestTimeout, HTTPUnprocessableEntity, \
HTTPClientDisconnect, HTTPMethodNotAllowed, Request, Response, \
HTTPInsufficientStorage, HTTPForbidden, HTTPException, HeaderKeyDict, \
HTTPConflict
from swift.obj.diskfile import DATAFILE_SYSTEM_META, DiskFileManager
class ObjectController(object):
"""Implements the WSGI application for the Swift Object Server."""
def __init__(self, conf, logger=None):
"""
Creates a new WSGI application for the Swift Object Server. An
example configuration is given at
<source-dir>/etc/object-server.conf-sample or
/etc/swift/object-server.conf-sample.
"""
self.logger = logger or get_logger(conf, log_route='object-server')
self.node_timeout = int(conf.get('node_timeout', 3))
self.conn_timeout = float(conf.get('conn_timeout', 0.5))
self.client_timeout = int(conf.get('client_timeout', 60))
self.disk_chunk_size = int(conf.get('disk_chunk_size', 65536))
self.network_chunk_size = int(conf.get('network_chunk_size', 65536))
self.log_requests = config_true_value(conf.get('log_requests', 'true'))
self.max_upload_time = int(conf.get('max_upload_time', 86400))
self.slow = int(conf.get('slow', 0))
self.keep_cache_private = \
config_true_value(conf.get('keep_cache_private', 'false'))
replication_server = conf.get('replication_server', None)
if replication_server is not None:
replication_server = config_true_value(replication_server)
self.replication_server = replication_server
default_allowed_headers = '''
content-disposition,
content-encoding,
x-delete-at,
x-object-manifest,
x-static-large-object,
'''
extra_allowed_headers = [
header.strip().lower() for header in conf.get(
'allowed_headers', default_allowed_headers).split(',')
if header.strip()
]
self.allowed_headers = set()
for header in extra_allowed_headers:
if header not in DATAFILE_SYSTEM_META:
self.allowed_headers.add(header)
self.auto_create_account_prefix = \
conf.get('auto_create_account_prefix') or '.'
self.expiring_objects_account = self.auto_create_account_prefix + \
(conf.get('expiring_objects_account_name') or 'expiring_objects')
self.expiring_objects_container_divisor = \
int(conf.get('expiring_objects_container_divisor') or 86400)
# Initialization was successful, so now apply the network chunk size
# parameter as the default read / write buffer size for the network
# sockets.
#
# NOTE WELL: This is a class setting, so until we get set this on a
# per-connection basis, this affects reading and writing on ALL
# sockets, those between the proxy servers and external clients, and
# those between the proxy servers and the other internal servers.
#
# ** Because the primary motivation for this is to optimize how data
# is written back to the proxy server, we could use the value from the
# disk_chunk_size parameter. However, it affects all created sockets
# using this class so we have chosen to tie it to the
# network_chunk_size parameter value instead.
socket._fileobject.default_bufsize = self.network_chunk_size
# Provide further setup specific to an object server implementation.
self.setup(conf)
def setup(self, conf):
"""
Implementation specific setup. This method is called at the very end
by the constructor to allow a specific implementation to modify
existing attributes or add its own attributes.
:param conf: WSGI configuration parameter
"""
# Common on-disk hierarchy shared across account, container and object
# servers.
self._diskfile_mgr = DiskFileManager(conf, self.logger)
# This is populated by global_conf_callback way below as the semaphore
# is shared by all workers.
if 'replication_semaphore' in conf:
# The value was put in a list so it could get past paste
self.replication_semaphore = conf['replication_semaphore'][0]
else:
self.replication_semaphore = None
self.replication_failure_threshold = int(
conf.get('replication_failure_threshold') or 100)
self.replication_failure_ratio = float(
conf.get('replication_failure_ratio') or 1.0)
def get_diskfile(self, device, partition, account, container, obj,
policy_idx, **kwargs):
"""
Utility method for instantiating a DiskFile object supporting a given
REST API.
An implementation of the object server that wants to use a different
DiskFile class would simply over-ride this method to provide that
behavior.
"""
return self._diskfile_mgr.get_diskfile(
device, partition, account, container, obj, policy_idx, **kwargs)
def async_update(self, op, account, container, obj, host, partition,
contdevice, headers_out, objdevice, policy_index):
"""
Sends or saves an async update.
:param op: operation performed (ex: 'PUT', or 'DELETE')
:param account: account name for the object
:param container: container name for the object
:param obj: object name
:param host: host that the container is on
:param partition: partition that the container is on
:param contdevice: device name that the container is on
:param headers_out: dictionary of headers to send in the container
request
:param objdevice: device name that the object is in
:param policy_index: the associated storage policy index
"""
headers_out['user-agent'] = 'obj-server %s' % os.getpid()
full_path = '/%s/%s/%s' % (account, container, obj)
if all([host, partition, contdevice]):
try:
with ConnectionTimeout(self.conn_timeout):
ip, port = host.rsplit(':', 1)
conn = http_connect(ip, port, contdevice, partition, op,
full_path, headers_out)
with Timeout(self.node_timeout):
response = conn.getresponse()
response.read()
if is_success(response.status):
return
else:
self.logger.error(_(
'ERROR Container update failed '
'(saving for async update later): %(status)d '
'response from %(ip)s:%(port)s/%(dev)s'),
{'status': response.status, 'ip': ip, 'port': port,
'dev': contdevice})
except (Exception, Timeout):
self.logger.exception(_(
'ERROR container update failed with '
'%(ip)s:%(port)s/%(dev)s (saving for async update later)'),
{'ip': ip, 'port': port, 'dev': contdevice})
data = {'op': op, 'account': account, 'container': container,
'obj': obj, 'headers': headers_out}
timestamp = headers_out['x-timestamp']
self._diskfile_mgr.pickle_async_update(objdevice, account, container,
obj, data, timestamp,
policy_index)
def container_update(self, op, account, container, obj, request,
headers_out, objdevice, policy_idx):
"""
Update the container when objects are updated.
:param op: operation performed (ex: 'PUT', or 'DELETE')
:param account: account name for the object
:param container: container name for the object
:param obj: object name
:param request: the original request object driving the update
:param headers_out: dictionary of headers to send in the container
request(s)
:param objdevice: device name that the object is in
"""
headers_in = request.headers
conthosts = [h.strip() for h in
headers_in.get('X-Container-Host', '').split(',')]
contdevices = [d.strip() for d in
headers_in.get('X-Container-Device', '').split(',')]
contpartition = headers_in.get('X-Container-Partition', '')
if len(conthosts) != len(contdevices):
# This shouldn't happen unless there's a bug in the proxy,
# but if there is, we want to know about it.
self.logger.error(_('ERROR Container update failed: different '
'numbers of hosts and devices in request: '
'"%s" vs "%s"') %
(headers_in.get('X-Container-Host', ''),
headers_in.get('X-Container-Device', '')))
return
if contpartition:
updates = zip(conthosts, contdevices)
else:
updates = []
headers_out['x-trans-id'] = headers_in.get('x-trans-id', '-')
headers_out['referer'] = request.as_referer()
headers_out['X-Backend-Storage-Policy-Index'] = policy_idx
for conthost, contdevice in updates:
self.async_update(op, account, container, obj, conthost,
contpartition, contdevice, headers_out,
objdevice, policy_idx)
def delete_at_update(self, op, delete_at, account, container, obj,
request, objdevice, policy_index):
"""
Update the expiring objects container when objects are updated.
:param op: operation performed (ex: 'PUT', or 'DELETE')
:param delete_at: scheduled delete in UNIX seconds, int
:param account: account name for the object
:param container: container name for the object
:param obj: object name
:param request: the original request driving the update
:param objdevice: device name that the object is in
:param policy_index: the policy index to be used for tmp dir
"""
if config_true_value(
request.headers.get('x-backend-replication', 'f')):
return
delete_at = normalize_delete_at_timestamp(delete_at)
updates = [(None, None)]
partition = None
hosts = contdevices = [None]
headers_in = request.headers
headers_out = HeaderKeyDict({
# system accounts are always Policy-0
'X-Backend-Storage-Policy-Index': 0,
'x-timestamp': request.timestamp.internal,
'x-trans-id': headers_in.get('x-trans-id', '-'),
'referer': request.as_referer()})
if op != 'DELETE':
delete_at_container = headers_in.get('X-Delete-At-Container', None)
if not delete_at_container:
self.logger.warning(
'X-Delete-At-Container header must be specified for '
'expiring objects background %s to work properly. Making '
'best guess as to the container name for now.' % op)
# TODO(gholt): In a future release, change the above warning to
# a raised exception and remove the guess code below.
delete_at_container = (
int(delete_at) / self.expiring_objects_container_divisor *
self.expiring_objects_container_divisor)
partition = headers_in.get('X-Delete-At-Partition', None)
hosts = headers_in.get('X-Delete-At-Host', '')
contdevices = headers_in.get('X-Delete-At-Device', '')
updates = [upd for upd in
zip((h.strip() for h in hosts.split(',')),
(c.strip() for c in contdevices.split(',')))
if all(upd) and partition]
if not updates:
updates = [(None, None)]
headers_out['x-size'] = '0'
headers_out['x-content-type'] = 'text/plain'
headers_out['x-etag'] = 'd41d8cd98f00b204e9800998ecf8427e'
else:
# DELETEs of old expiration data have no way of knowing what the
# old X-Delete-At-Container was at the time of the initial setting
# of the data, so a best guess is made here.
# Worst case is a DELETE is issued now for something that doesn't
# exist there and the original data is left where it is, where
# it will be ignored when the expirer eventually tries to issue the
# object DELETE later since the X-Delete-At value won't match up.
delete_at_container = str(
int(delete_at) / self.expiring_objects_container_divisor *
self.expiring_objects_container_divisor)
delete_at_container = normalize_delete_at_timestamp(
delete_at_container)
for host, contdevice in updates:
self.async_update(
op, self.expiring_objects_account, delete_at_container,
'%s-%s/%s/%s' % (delete_at, account, container, obj),
host, partition, contdevice, headers_out, objdevice,
policy_index)
@public
@timing_stats()
def POST(self, request):
"""Handle HTTP POST requests for the Swift Object Server."""
device, partition, account, container, obj, policy_idx = \
get_name_and_placement(request, 5, 5, True)
req_timestamp = valid_timestamp(request)
new_delete_at = int(request.headers.get('X-Delete-At') or 0)
if new_delete_at and new_delete_at < time.time():
return HTTPBadRequest(body='X-Delete-At in past', request=request,
content_type='text/plain')
try:
disk_file = self.get_diskfile(
device, partition, account, container, obj,
policy_idx=policy_idx)
except DiskFileDeviceUnavailable:
return HTTPInsufficientStorage(drive=device, request=request)
try:
orig_metadata = disk_file.read_metadata()
except (DiskFileNotExist, DiskFileQuarantined):
return HTTPNotFound(request=request)
orig_timestamp = Timestamp(orig_metadata.get('X-Timestamp', 0))
if orig_timestamp >= req_timestamp:
return HTTPConflict(request=request)
metadata = {'X-Timestamp': req_timestamp.internal}
metadata.update(val for val in request.headers.iteritems()
if is_user_meta('object', val[0]))
for header_key in self.allowed_headers:
if header_key in request.headers:
header_caps = header_key.title()
metadata[header_caps] = request.headers[header_key]
orig_delete_at = int(orig_metadata.get('X-Delete-At') or 0)
if orig_delete_at != new_delete_at:
if new_delete_at:
self.delete_at_update('PUT', new_delete_at, account, container,
obj, request, device, policy_idx)
if orig_delete_at:
self.delete_at_update('DELETE', orig_delete_at, account,
container, obj, request, device,
policy_idx)
disk_file.write_metadata(metadata)
return HTTPAccepted(request=request)
@public
@timing_stats()
def PUT(self, request):
"""Handle HTTP PUT requests for the Swift Object Server."""
device, partition, account, container, obj, policy_idx = \
get_name_and_placement(request, 5, 5, True)
req_timestamp = valid_timestamp(request)
error_response = check_object_creation(request, obj)
if error_response:
return error_response
new_delete_at = int(request.headers.get('X-Delete-At') or 0)
if new_delete_at and new_delete_at < time.time():
return HTTPBadRequest(body='X-Delete-At in past', request=request,
content_type='text/plain')
try:
fsize = request.message_length()
except ValueError as e:
return HTTPBadRequest(body=str(e), request=request,
content_type='text/plain')
try:
disk_file = self.get_diskfile(
device, partition, account, container, obj,
policy_idx=policy_idx)
except DiskFileDeviceUnavailable:
return HTTPInsufficientStorage(drive=device, request=request)
try:
orig_metadata = disk_file.read_metadata()
except (DiskFileNotExist, DiskFileQuarantined):
orig_metadata = {}
# Checks for If-None-Match
if request.if_none_match is not None and orig_metadata:
if '*' in request.if_none_match:
# File exists already so return 412
return HTTPPreconditionFailed(request=request)
if orig_metadata.get('ETag') in request.if_none_match:
# The current ETag matches, so return 412
return HTTPPreconditionFailed(request=request)
orig_timestamp = Timestamp(orig_metadata.get('X-Timestamp', 0))
if orig_timestamp and orig_timestamp >= req_timestamp:
return HTTPConflict(request=request)
orig_delete_at = int(orig_metadata.get('X-Delete-At') or 0)
upload_expiration = time.time() + self.max_upload_time
etag = md5()
elapsed_time = 0
try:
with disk_file.create(size=fsize) as writer:
upload_size = 0
def timeout_reader():
with ChunkReadTimeout(self.client_timeout):
return request.environ['wsgi.input'].read(
self.network_chunk_size)
try:
for chunk in iter(lambda: timeout_reader(), ''):
start_time = time.time()
if start_time > upload_expiration:
self.logger.increment('PUT.timeouts')
return HTTPRequestTimeout(request=request)
etag.update(chunk)
upload_size = writer.write(chunk)
elapsed_time += time.time() - start_time
except ChunkReadTimeout:
return HTTPRequestTimeout(request=request)
if upload_size:
self.logger.transfer_rate(
'PUT.' + device + '.timing', elapsed_time,
upload_size)
if fsize is not None and fsize != upload_size:
return HTTPClientDisconnect(request=request)
etag = etag.hexdigest()
if 'etag' in request.headers and \
request.headers['etag'].lower() != etag:
return HTTPUnprocessableEntity(request=request)
metadata = {
'X-Timestamp': request.timestamp.internal,
'Content-Type': request.headers['content-type'],
'ETag': etag,
'Content-Length': str(upload_size),
}
metadata.update(val for val in request.headers.iteritems()
if is_user_meta('object', val[0]))
for header_key in (
request.headers.get('X-Backend-Replication-Headers') or
self.allowed_headers):
if header_key in request.headers:
header_caps = header_key.title()
metadata[header_caps] = request.headers[header_key]
writer.put(metadata)
except DiskFileNoSpace:
return HTTPInsufficientStorage(drive=device, request=request)
if orig_delete_at != new_delete_at:
if new_delete_at:
self.delete_at_update(
'PUT', new_delete_at, account, container, obj, request,
device, policy_idx)
if orig_delete_at:
self.delete_at_update(
'DELETE', orig_delete_at, account, container, obj,
request, device, policy_idx)
self.container_update(
'PUT', account, container, obj, request,
HeaderKeyDict({
'x-size': metadata['Content-Length'],
'x-content-type': metadata['Content-Type'],
'x-timestamp': metadata['X-Timestamp'],
'x-etag': metadata['ETag']}),
device, policy_idx)
return HTTPCreated(request=request, etag=etag)
@public
@timing_stats()
def GET(self, request):
"""Handle HTTP GET requests for the Swift Object Server."""
device, partition, account, container, obj, policy_idx = \
get_name_and_placement(request, 5, 5, True)
keep_cache = self.keep_cache_private or (
'X-Auth-Token' not in request.headers and
'X-Storage-Token' not in request.headers)
try:
disk_file = self.get_diskfile(
device, partition, account, container, obj,
policy_idx=policy_idx)
except DiskFileDeviceUnavailable:
return HTTPInsufficientStorage(drive=device, request=request)
try:
with disk_file.open():
metadata = disk_file.get_metadata()
obj_size = int(metadata['Content-Length'])
file_x_ts = Timestamp(metadata['X-Timestamp'])
keep_cache = (self.keep_cache_private or
('X-Auth-Token' not in request.headers and
'X-Storage-Token' not in request.headers))
response = Response(
app_iter=disk_file.reader(keep_cache=keep_cache),
request=request, conditional_response=True)
response.headers['Content-Type'] = metadata.get(
'Content-Type', 'application/octet-stream')
for key, value in metadata.iteritems():
if is_user_meta('object', key) or \
key.lower() in self.allowed_headers:
response.headers[key] = value
response.etag = metadata['ETag']
response.last_modified = math.ceil(float(file_x_ts))
response.content_length = obj_size
try:
response.content_encoding = metadata[
'Content-Encoding']
except KeyError:
pass
response.headers['X-Timestamp'] = file_x_ts.normal
response.headers['X-Backend-Timestamp'] = file_x_ts.internal
resp = request.get_response(response)
except (DiskFileNotExist, DiskFileQuarantined) as e:
headers = {}
if hasattr(e, 'timestamp'):
headers['X-Backend-Timestamp'] = e.timestamp.internal
resp = HTTPNotFound(request=request, headers=headers,
conditional_response=True)
return resp
@public
@timing_stats(sample_rate=0.8)
def HEAD(self, request):
"""Handle HTTP HEAD requests for the Swift Object Server."""
device, partition, account, container, obj, policy_idx = \
get_name_and_placement(request, 5, 5, True)
try:
disk_file = self.get_diskfile(
device, partition, account, container, obj,
policy_idx=policy_idx)
except DiskFileDeviceUnavailable:
return HTTPInsufficientStorage(drive=device, request=request)
try:
metadata = disk_file.read_metadata()
except (DiskFileNotExist, DiskFileQuarantined) as e:
headers = {}
if hasattr(e, 'timestamp'):
headers['X-Backend-Timestamp'] = e.timestamp.internal
return HTTPNotFound(request=request, headers=headers,
conditional_response=True)
response = Response(request=request, conditional_response=True)
response.headers['Content-Type'] = metadata.get(
'Content-Type', 'application/octet-stream')
for key, value in metadata.iteritems():
if is_user_meta('object', key) or \
key.lower() in self.allowed_headers:
response.headers[key] = value
response.etag = metadata['ETag']
ts = Timestamp(metadata['X-Timestamp'])
response.last_modified = math.ceil(float(ts))
# Needed for container sync feature
response.headers['X-Timestamp'] = ts.normal
response.headers['X-Backend-Timestamp'] = ts.internal
response.content_length = int(metadata['Content-Length'])
try:
response.content_encoding = metadata['Content-Encoding']
except KeyError:
pass
return response
@public
@timing_stats()
def DELETE(self, request):
"""Handle HTTP DELETE requests for the Swift Object Server."""
device, partition, account, container, obj, policy_idx = \
get_name_and_placement(request, 5, 5, True)
req_timestamp = valid_timestamp(request)
try:
disk_file = self.get_diskfile(
device, partition, account, container, obj,
policy_idx=policy_idx)
except DiskFileDeviceUnavailable:
return HTTPInsufficientStorage(drive=device, request=request)
try:
orig_metadata = disk_file.read_metadata()
except DiskFileExpired as e:
orig_timestamp = e.timestamp
orig_metadata = e.metadata
response_class = HTTPNotFound
except DiskFileDeleted as e:
orig_timestamp = e.timestamp
orig_metadata = {}
response_class = HTTPNotFound
except (DiskFileNotExist, DiskFileQuarantined):
orig_timestamp = 0
orig_metadata = {}
response_class = HTTPNotFound
else:
orig_timestamp = Timestamp(orig_metadata.get('X-Timestamp', 0))
if orig_timestamp < req_timestamp:
response_class = HTTPNoContent
else:
response_class = HTTPConflict
orig_delete_at = int(orig_metadata.get('X-Delete-At') or 0)
try:
req_if_delete_at_val = request.headers['x-if-delete-at']
req_if_delete_at = int(req_if_delete_at_val)
except KeyError:
pass
except ValueError:
return HTTPBadRequest(
request=request,
body='Bad X-If-Delete-At header value')
else:
# request includes x-if-delete-at; we must not place a tombstone
# if we can not verify the x-if-delete-at time
if not orig_timestamp:
# no object found at all
return HTTPNotFound()
if orig_delete_at != req_if_delete_at:
return HTTPPreconditionFailed(
request=request,
body='X-If-Delete-At and X-Delete-At do not match')
else:
# differentiate success from no object at all
response_class = HTTPNoContent
if orig_delete_at:
self.delete_at_update('DELETE', orig_delete_at, account,
container, obj, request, device,
policy_idx)
if orig_timestamp < req_timestamp:
disk_file.delete(req_timestamp)
self.container_update(
'DELETE', account, container, obj, request,
HeaderKeyDict({'x-timestamp': req_timestamp.internal}),
device, policy_idx)
return response_class(request=request)
@public
@replication
@timing_stats(sample_rate=0.1)
def REPLICATE(self, request):
"""
Handle REPLICATE requests for the Swift Object Server. This is used
by the object replicator to get hashes for directories.
"""
device, partition, suffix, policy_idx = \
get_name_and_placement(request, 2, 3, True)
try:
hashes = self._diskfile_mgr.get_hashes(device, partition, suffix,
policy_idx)
except DiskFileDeviceUnavailable:
resp = HTTPInsufficientStorage(drive=device, request=request)
else:
resp = Response(body=pickle.dumps(hashes))
return resp
@public
@replication
@timing_stats(sample_rate=0.1)
def REPLICATION(self, request):
return Response(app_iter=ssync_receiver.Receiver(self, request)())
def __call__(self, env, start_response):
"""WSGI Application entry point for the Swift Object Server."""
start_time = time.time()
req = Request(env)
self.logger.txn_id = req.headers.get('x-trans-id', None)
if not check_utf8(req.path_info):
res = HTTPPreconditionFailed(body='Invalid UTF8 or contains NULL')
else:
try:
# disallow methods which have not been marked 'public'
try:
method = getattr(self, req.method)
getattr(method, 'publicly_accessible')
replication_method = getattr(method, 'replication', False)
if (self.replication_server is not None and
self.replication_server != replication_method):
raise AttributeError('Not allowed method.')
except AttributeError:
res = HTTPMethodNotAllowed()
else:
res = method(req)
except DiskFileCollision:
res = HTTPForbidden(request=req)
except HTTPException as error_response:
res = error_response
except (Exception, Timeout):
self.logger.exception(_(
'ERROR __call__ error with %(method)s'
' %(path)s '), {'method': req.method, 'path': req.path})
res = HTTPInternalServerError(body=traceback.format_exc())
trans_time = time.time() - start_time
if self.log_requests:
log_line = get_log_line(req, res, trans_time, '')
if req.method in ('REPLICATE', 'REPLICATION') or \
'X-Backend-Replication' in req.headers:
self.logger.debug(log_line)
else:
self.logger.info(log_line)
if req.method in ('PUT', 'DELETE'):
slow = self.slow - trans_time
if slow > 0:
sleep(slow)
return res(env, start_response)
def global_conf_callback(preloaded_app_conf, global_conf):
"""
Callback for swift.common.wsgi.run_wsgi during the global_conf
creation so that we can add our replication_semaphore, used to
limit the number of concurrent REPLICATION_REQUESTS across all
workers.
:param preloaded_app_conf: The preloaded conf for the WSGI app.
This conf instance will go away, so
just read from it, don't write.
:param global_conf: The global conf that will eventually be
passed to the app_factory function later.
This conf is created before the worker
subprocesses are forked, so can be useful to
set up semaphores, shared memory, etc.
"""
replication_concurrency = int(
preloaded_app_conf.get('replication_concurrency') or 4)
if replication_concurrency:
# Have to put the value in a list so it can get past paste
global_conf['replication_semaphore'] = [
multiprocessing.BoundedSemaphore(replication_concurrency)]
def app_factory(global_conf, **local_conf):
"""paste.deploy app factory for creating WSGI object server apps"""
conf = global_conf.copy()
conf.update(local_conf)
return ObjectController(conf)