507 lines
23 KiB
Python
507 lines
23 KiB
Python
# Copyright (c) 2013 OpenStack Foundation
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import six
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from six.moves import urllib
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from swift.common import bufferedhttp
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from swift.common import exceptions
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from swift.common import http
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from swift.common.utils import config_true_value
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def encode_missing(object_hash, ts_data, ts_meta=None, ts_ctype=None,
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**kwargs):
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"""
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Returns a string representing the object hash, its data file timestamp,
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the delta forwards to its metafile and content-type timestamps, if
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non-zero, and its durability, in the form:
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``<hash> <ts_data> [m:<hex delta to ts_meta>[,t:<hex delta to ts_ctype>]
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[,durable:False]``
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The decoder for this line is
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:py:func:`~swift.obj.ssync_receiver.decode_missing`
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"""
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msg = ('%s %s'
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% (urllib.parse.quote(object_hash),
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urllib.parse.quote(ts_data.internal)))
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extra_parts = []
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if ts_meta and ts_meta != ts_data:
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delta = ts_meta.raw - ts_data.raw
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extra_parts.append('m:%x' % delta)
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if ts_ctype and ts_ctype != ts_data:
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delta = ts_ctype.raw - ts_data.raw
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extra_parts.append('t:%x' % delta)
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if 'durable' in kwargs and kwargs['durable'] is False:
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# only send durable in the less common case that it is False
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extra_parts.append('durable:%s' % kwargs['durable'])
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if extra_parts:
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msg = '%s %s' % (msg, ','.join(extra_parts))
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return msg.encode('ascii')
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def decode_wanted(parts):
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"""
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Parse missing_check line parts to determine which parts of local
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diskfile were wanted by the receiver.
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The encoder for parts is
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:py:func:`~swift.obj.ssync_receiver.encode_wanted`
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"""
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wanted = {}
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key_map = {'d': 'data', 'm': 'meta'}
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if parts:
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# receiver specified data and/or meta wanted, so use those as
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# conditions for sending PUT and/or POST subrequests
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for k in key_map:
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if k in parts[0]:
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wanted[key_map[k]] = True
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if not wanted:
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# assume legacy receiver which will only accept PUTs. There is no
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# way to send any meta file content without morphing the timestamp
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# of either the data or the metadata, so we just send data file
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# content to a legacy receiver. Once the receiver gets updated we
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# will be able to send it the meta file content.
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wanted['data'] = True
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return wanted
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class SsyncBufferedHTTPResponse(bufferedhttp.BufferedHTTPResponse, object):
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def __init__(self, *args, **kwargs):
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super(SsyncBufferedHTTPResponse, self).__init__(*args, **kwargs)
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self.ssync_response_buffer = b''
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self.ssync_response_chunk_left = 0
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def readline(self, size=1024):
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"""
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Reads a line from the SSYNC response body.
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httplib has no readline and will block on read(x) until x is
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read, so we have to do the work ourselves. A bit of this is
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taken from Python's httplib itself.
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"""
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data = self.ssync_response_buffer
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self.ssync_response_buffer = b''
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while b'\n' not in data and len(data) < size:
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if self.ssync_response_chunk_left == -1: # EOF-already indicator
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break
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if self.ssync_response_chunk_left == 0:
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line = self.fp.readline()
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i = line.find(b';')
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if i >= 0:
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line = line[:i] # strip chunk-extensions
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try:
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self.ssync_response_chunk_left = int(line.strip(), 16)
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except ValueError:
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# close the connection as protocol synchronisation is
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# probably lost
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self.close()
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raise exceptions.ReplicationException('Early disconnect')
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if self.ssync_response_chunk_left == 0:
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self.ssync_response_chunk_left = -1
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break
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chunk = self.fp.read(min(self.ssync_response_chunk_left,
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size - len(data)))
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if not chunk:
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# close the connection as protocol synchronisation is
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# probably lost
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self.close()
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raise exceptions.ReplicationException('Early disconnect')
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self.ssync_response_chunk_left -= len(chunk)
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if self.ssync_response_chunk_left == 0:
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self.fp.read(2) # discard the trailing \r\n
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data += chunk
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if b'\n' in data:
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data, self.ssync_response_buffer = data.split(b'\n', 1)
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data += b'\n'
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return data
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class SsyncBufferedHTTPConnection(bufferedhttp.BufferedHTTPConnection):
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response_class = SsyncBufferedHTTPResponse
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class Sender(object):
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"""
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Sends SSYNC requests to the object server.
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These requests are eventually handled by
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:py:mod:`.ssync_receiver` and full documentation about the
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process is there.
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"""
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def __init__(self, daemon, node, job, suffixes, remote_check_objs=None,
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include_non_durable=False):
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self.daemon = daemon
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self.df_mgr = self.daemon._df_router[job['policy']]
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self.node = node
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self.job = job
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self.suffixes = suffixes
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# When remote_check_objs is given in job, ssync_sender trys only to
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# make sure those objects exist or not in remote.
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self.remote_check_objs = remote_check_objs
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self.include_non_durable = include_non_durable
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def __call__(self):
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"""
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Perform ssync with remote node.
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:returns: a 2-tuple, in the form (success, can_delete_objs) where
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success is a boolean and can_delete_objs is the map of
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objects that are in sync with the receiver. Each entry in
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can_delete_objs maps a hash => timestamp of data file or
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tombstone file
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"""
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if not self.suffixes:
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return True, {}
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connection = response = None
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try:
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# Double try blocks in case our main error handler fails.
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try:
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# The general theme for these functions is that they should
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# raise exceptions.MessageTimeout for client timeouts and
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# exceptions.ReplicationException for common issues that will
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# abort the replication attempt and log a simple error. All
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# other exceptions will be logged with a full stack trace.
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connection, response = self.connect()
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# available_map has an entry for each object in given suffixes
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# that is available to be sync'd;
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# each entry is a hash => dict of timestamps of data file or
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# tombstone file and/or meta file
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# send_map has an entry for each object that the receiver wants
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# to be sync'ed;
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# each entry maps an object hash => dict of wanted parts
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available_map, send_map = self.missing_check(connection,
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response)
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if self.remote_check_objs is None:
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self.updates(connection, response, send_map)
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can_delete_obj = available_map
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else:
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# when we are initialized with remote_check_objs we don't
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# *send* any requested updates; instead we only collect
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# what's already in sync and safe for deletion
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in_sync_hashes = (set(available_map.keys()) -
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set(send_map.keys()))
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can_delete_obj = dict((hash_, available_map[hash_])
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for hash_ in in_sync_hashes)
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return True, can_delete_obj
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except (exceptions.MessageTimeout,
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exceptions.ReplicationException) as err:
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self.daemon.logger.error(
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'%s:%s/%s/%s %s', self.node.get('replication_ip'),
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self.node.get('replication_port'), self.node.get('device'),
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self.job.get('partition'), err)
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except Exception:
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# We don't want any exceptions to escape our code and possibly
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# mess up the original replicator code that called us since it
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# was originally written to shell out to rsync which would do
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# no such thing.
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self.daemon.logger.exception(
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'%s:%s/%s/%s EXCEPTION in ssync.Sender',
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self.node.get('replication_ip'),
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self.node.get('replication_port'),
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self.node.get('device'), self.job.get('partition'))
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finally:
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self.disconnect(connection)
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except Exception:
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# We don't want any exceptions to escape our code and possibly
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# mess up the original replicator code that called us since it
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# was originally written to shell out to rsync which would do
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# no such thing.
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# This particular exception handler does the minimal amount as it
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# would only get called if the above except Exception handler
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# failed (bad node or job data).
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self.daemon.logger.exception('EXCEPTION in ssync.Sender')
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return False, {}
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def connect(self):
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"""
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Establishes a connection and starts an SSYNC request
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with the object server.
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"""
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connection = response = None
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node_addr = '%s:%s' % (self.node['replication_ip'],
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self.node['replication_port'])
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with exceptions.MessageTimeout(
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self.daemon.conn_timeout, 'connect send'):
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connection = SsyncBufferedHTTPConnection(node_addr)
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connection.putrequest('SSYNC', '/%s/%s' % (
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self.node['device'], self.job['partition']))
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connection.putheader('Transfer-Encoding', 'chunked')
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connection.putheader('X-Backend-Storage-Policy-Index',
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int(self.job['policy']))
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# a sync job must use the node's backend_index for the frag_index
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# of the rebuilt fragments instead of the frag_index from the job
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# which will be rebuilding them
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frag_index = self.node.get('backend_index')
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if frag_index is not None:
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connection.putheader('X-Backend-Ssync-Frag-Index', frag_index)
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# Node-Index header is for backwards compat 2.4.0-2.20.0
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connection.putheader('X-Backend-Ssync-Node-Index', frag_index)
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connection.endheaders()
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with exceptions.MessageTimeout(
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self.daemon.node_timeout, 'connect receive'):
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response = connection.getresponse()
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if response.status != http.HTTP_OK:
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err_msg = response.read()[:1024]
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raise exceptions.ReplicationException(
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'Expected status %s; got %s (%s)' %
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(http.HTTP_OK, response.status, err_msg))
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if self.include_non_durable and not config_true_value(
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response.getheader('x-backend-accept-no-commit', False)):
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# fall back to legacy behaviour if receiver does not understand
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# X-Backend-Commit
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self.daemon.logger.warning(
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'ssync receiver %s does not accept non-durable fragments' %
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node_addr)
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self.include_non_durable = False
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return connection, response
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def missing_check(self, connection, response):
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"""
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Handles the sender-side of the MISSING_CHECK step of a
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SSYNC request.
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Full documentation of this can be found at
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:py:meth:`.Receiver.missing_check`.
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"""
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available_map = {}
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send_map = {}
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# First, send our list.
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with exceptions.MessageTimeout(
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self.daemon.node_timeout, 'missing_check start'):
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msg = b':MISSING_CHECK: START\r\n'
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connection.send(b'%x\r\n%s\r\n' % (len(msg), msg))
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# an empty frag_prefs list is sufficient to get non-durable frags
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# yielded, in which case an older durable frag will not be yielded
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frag_prefs = [] if self.include_non_durable else None
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hash_gen = self.df_mgr.yield_hashes(
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self.job['device'], self.job['partition'],
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self.job['policy'], self.suffixes,
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frag_index=self.job.get('frag_index'),
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frag_prefs=frag_prefs)
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if self.remote_check_objs is not None:
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hash_gen = six.moves.filter(
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lambda objhash_timestamps:
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objhash_timestamps[0] in
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self.remote_check_objs, hash_gen)
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for object_hash, timestamps in hash_gen:
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available_map[object_hash] = timestamps
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with exceptions.MessageTimeout(
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self.daemon.node_timeout,
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'missing_check send line'):
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msg = b'%s\r\n' % encode_missing(object_hash, **timestamps)
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connection.send(b'%x\r\n%s\r\n' % (len(msg), msg))
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with exceptions.MessageTimeout(
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self.daemon.node_timeout, 'missing_check end'):
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msg = b':MISSING_CHECK: END\r\n'
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connection.send(b'%x\r\n%s\r\n' % (len(msg), msg))
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# Now, retrieve the list of what they want.
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while True:
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with exceptions.MessageTimeout(
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self.daemon.http_timeout, 'missing_check start wait'):
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line = response.readline(size=self.daemon.network_chunk_size)
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if not line:
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raise exceptions.ReplicationException('Early disconnect')
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line = line.strip()
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if line == b':MISSING_CHECK: START':
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break
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elif line:
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if not six.PY2:
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try:
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line = line.decode('ascii')
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except UnicodeDecodeError:
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pass
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raise exceptions.ReplicationException(
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'Unexpected response: %r' % line[:1024])
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while True:
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with exceptions.MessageTimeout(
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self.daemon.http_timeout, 'missing_check line wait'):
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line = response.readline(size=self.daemon.network_chunk_size)
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if not line:
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raise exceptions.ReplicationException('Early disconnect')
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line = line.strip()
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if line == b':MISSING_CHECK: END':
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break
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parts = line.decode('ascii').split()
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if parts:
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send_map[parts[0]] = decode_wanted(parts[1:])
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return available_map, send_map
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def updates(self, connection, response, send_map):
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"""
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Handles the sender-side of the UPDATES step of an SSYNC
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request.
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Full documentation of this can be found at
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:py:meth:`.Receiver.updates`.
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"""
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# First, send all our subrequests based on the send_map.
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with exceptions.MessageTimeout(
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self.daemon.node_timeout, 'updates start'):
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msg = b':UPDATES: START\r\n'
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connection.send(b'%x\r\n%s\r\n' % (len(msg), msg))
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frag_prefs = [] if self.include_non_durable else None
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for object_hash, want in send_map.items():
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object_hash = urllib.parse.unquote(object_hash)
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try:
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df = self.df_mgr.get_diskfile_from_hash(
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self.job['device'], self.job['partition'], object_hash,
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self.job['policy'], frag_index=self.job.get('frag_index'),
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open_expired=True, frag_prefs=frag_prefs)
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except exceptions.DiskFileNotExist:
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continue
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url_path = urllib.parse.quote(
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'/%s/%s/%s' % (df.account, df.container, df.obj))
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try:
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df.open()
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if want.get('data'):
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is_durable = (df.durable_timestamp == df.data_timestamp)
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# EC reconstructor may have passed a callback to build an
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# alternative diskfile - construct it using the metadata
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# from the data file only.
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df_alt = self.job.get(
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'sync_diskfile_builder', lambda *args: df)(
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self.job, self.node, df.get_datafile_metadata())
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self.send_put(connection, url_path, df_alt,
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durable=is_durable)
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if want.get('meta') and df.data_timestamp != df.timestamp:
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self.send_post(connection, url_path, df)
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except exceptions.DiskFileDeleted as err:
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if want.get('data'):
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self.send_delete(connection, url_path, err.timestamp)
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except exceptions.DiskFileError:
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# DiskFileErrors are expected while opening the diskfile,
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# before any data is read and sent. Since there is no partial
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# state on the receiver it's ok to ignore this diskfile and
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# continue. The diskfile may however be deleted after a
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# successful ssync since it remains in the send_map.
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pass
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with exceptions.MessageTimeout(
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self.daemon.node_timeout, 'updates end'):
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msg = b':UPDATES: END\r\n'
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connection.send(b'%x\r\n%s\r\n' % (len(msg), msg))
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# Now, read their response for any issues.
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while True:
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with exceptions.MessageTimeout(
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self.daemon.http_timeout, 'updates start wait'):
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line = response.readline(size=self.daemon.network_chunk_size)
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if not line:
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raise exceptions.ReplicationException('Early disconnect')
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line = line.strip()
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if line == b':UPDATES: START':
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break
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elif line:
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if not six.PY2:
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try:
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line = line.decode('ascii')
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except UnicodeDecodeError:
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pass
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raise exceptions.ReplicationException(
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'Unexpected response: %r' % line[:1024])
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while True:
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with exceptions.MessageTimeout(
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self.daemon.http_timeout, 'updates line wait'):
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line = response.readline(size=self.daemon.network_chunk_size)
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if not line:
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raise exceptions.ReplicationException('Early disconnect')
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line = line.strip()
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if line == b':UPDATES: END':
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break
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elif line:
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if not six.PY2:
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try:
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line = line.decode('ascii')
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except UnicodeDecodeError:
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pass
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raise exceptions.ReplicationException(
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'Unexpected response: %r' % line[:1024])
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def send_subrequest(self, connection, method, url_path, headers, df):
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msg = [b'%s %s' % (method.encode('ascii'), url_path.encode('utf8'))]
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for key, value in sorted(headers.items()):
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if six.PY2:
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msg.append(b'%s: %s' % (key, value))
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else:
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msg.append(b'%s: %s' % (
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key.encode('utf8', 'surrogateescape'),
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str(value).encode('utf8', 'surrogateescape')))
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msg = b'\r\n'.join(msg) + b'\r\n\r\n'
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with exceptions.MessageTimeout(self.daemon.node_timeout,
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'send_%s' % method.lower()):
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connection.send(b'%x\r\n%s\r\n' % (len(msg), msg))
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if df:
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bytes_read = 0
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for chunk in df.reader():
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bytes_read += len(chunk)
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with exceptions.MessageTimeout(self.daemon.node_timeout,
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'send_%s chunk' %
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method.lower()):
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connection.send(b'%x\r\n%s\r\n' % (len(chunk), chunk))
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if bytes_read != df.content_length:
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# Since we may now have partial state on the receiver we have
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# to prevent the receiver finalising what may well be a bad or
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# partially written diskfile. Unfortunately we have no other
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# option than to pull the plug on this ssync session. If ssync
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# supported multiphase PUTs like the proxy uses for EC we could
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# send a bad etag in a footer of this subrequest, but that is
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|
# not supported.
|
|
raise exceptions.ReplicationException(
|
|
'Sent data length does not match content-length')
|
|
|
|
def send_delete(self, connection, url_path, timestamp):
|
|
"""
|
|
Sends a DELETE subrequest with the given information.
|
|
"""
|
|
headers = {'X-Timestamp': timestamp.internal}
|
|
self.send_subrequest(connection, 'DELETE', url_path, headers, None)
|
|
|
|
def send_put(self, connection, url_path, df, durable=True):
|
|
"""
|
|
Sends a PUT subrequest for the url_path using the source df
|
|
(DiskFile) and content_length.
|
|
"""
|
|
headers = {'Content-Length': str(df.content_length)}
|
|
if not durable:
|
|
# only send this header for the less common case; without this
|
|
# header object servers assume default commit behaviour
|
|
headers['X-Backend-No-Commit'] = 'True'
|
|
for key, value in df.get_datafile_metadata().items():
|
|
if key not in ('name', 'Content-Length'):
|
|
headers[key] = value
|
|
self.send_subrequest(connection, 'PUT', url_path, headers, df)
|
|
|
|
def send_post(self, connection, url_path, df):
|
|
metadata = df.get_metafile_metadata()
|
|
if metadata is None:
|
|
return
|
|
self.send_subrequest(connection, 'POST', url_path, metadata, None)
|
|
|
|
def disconnect(self, connection):
|
|
"""
|
|
Closes down the connection to the object server once done
|
|
with the SSYNC request.
|
|
"""
|
|
if not connection:
|
|
return
|
|
try:
|
|
with exceptions.MessageTimeout(
|
|
self.daemon.node_timeout, 'disconnect'):
|
|
connection.send(b'0\r\n\r\n')
|
|
except (Exception, exceptions.Timeout):
|
|
pass # We're okay with the above failing.
|
|
connection.close()
|