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
|
# -*- coding: utf-8 -*-
# Copyright 2017 Vector Creations Ltd
#
# 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.
"""A replication client for use by synapse workers.
"""
import heapq
import logging
from typing import TYPE_CHECKING, Dict, List, Tuple
from twisted.internet.defer import Deferred
from twisted.internet.protocol import ReconnectingClientFactory
from synapse.api.constants import EventTypes
from synapse.logging.context import PreserveLoggingContext, make_deferred_yieldable
from synapse.replication.tcp.protocol import ClientReplicationStreamProtocol
from synapse.replication.tcp.streams.events import (
EventsStream,
EventsStreamEventRow,
EventsStreamRow,
)
from synapse.util.async_helpers import timeout_deferred
from synapse.util.metrics import Measure
if TYPE_CHECKING:
from synapse.replication.tcp.handler import ReplicationCommandHandler
from synapse.server import HomeServer
logger = logging.getLogger(__name__)
# How long we allow callers to wait for replication updates before timing out.
_WAIT_FOR_REPLICATION_TIMEOUT_SECONDS = 30
class DirectTcpReplicationClientFactory(ReconnectingClientFactory):
"""Factory for building connections to the master. Will reconnect if the
connection is lost.
Accepts a handler that is passed to `ClientReplicationStreamProtocol`.
"""
initialDelay = 0.1
maxDelay = 1 # Try at least once every N seconds
def __init__(
self,
hs: "HomeServer",
client_name: str,
command_handler: "ReplicationCommandHandler",
):
self.client_name = client_name
self.command_handler = command_handler
self.server_name = hs.config.server_name
self.hs = hs
self._clock = hs.get_clock() # As self.clock is defined in super class
hs.get_reactor().addSystemEventTrigger("before", "shutdown", self.stopTrying)
def startedConnecting(self, connector):
logger.info("Connecting to replication: %r", connector.getDestination())
def buildProtocol(self, addr):
logger.info("Connected to replication: %r", addr)
return ClientReplicationStreamProtocol(
self.hs,
self.client_name,
self.server_name,
self._clock,
self.command_handler,
)
def clientConnectionLost(self, connector, reason):
logger.error("Lost replication conn: %r", reason)
ReconnectingClientFactory.clientConnectionLost(self, connector, reason)
def clientConnectionFailed(self, connector, reason):
logger.error("Failed to connect to replication: %r", reason)
ReconnectingClientFactory.clientConnectionFailed(self, connector, reason)
class ReplicationDataHandler:
"""Handles incoming stream updates from replication.
This instance notifies the slave data store about updates. Can be subclassed
to handle updates in additional ways.
"""
def __init__(self, hs: "HomeServer"):
self.store = hs.get_datastore()
self.pusher_pool = hs.get_pusherpool()
self.notifier = hs.get_notifier()
self._reactor = hs.get_reactor()
self._clock = hs.get_clock()
self._streams = hs.get_replication_streams()
self._instance_name = hs.get_instance_name()
# Map from stream to list of deferreds waiting for the stream to
# arrive at a particular position. The lists are sorted by stream position.
self._streams_to_waiters = (
{}
) # type: Dict[str, List[Tuple[int, Deferred[None]]]]
async def on_rdata(
self, stream_name: str, instance_name: str, token: int, rows: list
):
"""Called to handle a batch of replication data with a given stream token.
By default this just pokes the slave store. Can be overridden in subclasses to
handle more.
Args:
stream_name: name of the replication stream for this batch of rows
instance_name: the instance that wrote the rows.
token: stream token for this batch of rows
rows: a list of Stream.ROW_TYPE objects as returned by Stream.parse_row.
"""
self.store.process_replication_rows(stream_name, instance_name, token, rows)
if stream_name == EventsStream.NAME:
# We shouldn't get multiple rows per token for events stream, so
# we don't need to optimise this for multiple rows.
for row in rows:
if row.type != EventsStreamEventRow.TypeId:
continue
assert isinstance(row, EventsStreamRow)
event = await self.store.get_event(
row.data.event_id, allow_rejected=True
)
if event.rejected_reason:
continue
extra_users = () # type: Tuple[str, ...]
if event.type == EventTypes.Member:
extra_users = (event.state_key,)
max_token = self.store.get_room_max_stream_ordering()
self.notifier.on_new_room_event(event, token, max_token, extra_users)
await self.pusher_pool.on_new_notifications(token, token)
# Notify any waiting deferreds. The list is ordered by position so we
# just iterate through the list until we reach a position that is
# greater than the received row position.
waiting_list = self._streams_to_waiters.get(stream_name, [])
# Index of first item with a position after the current token, i.e we
# have called all deferreds before this index. If not overwritten by
# loop below means either a) no items in list so no-op or b) all items
# in list were called and so the list should be cleared. Setting it to
# `len(list)` works for both cases.
index_of_first_deferred_not_called = len(waiting_list)
for idx, (position, deferred) in enumerate(waiting_list):
if position <= token:
try:
with PreserveLoggingContext():
deferred.callback(None)
except Exception:
# The deferred has been cancelled or timed out.
pass
else:
# The list is sorted by position so we don't need to continue
# checking any further entries in the list.
index_of_first_deferred_not_called = idx
break
# Drop all entries in the waiting list that were called in the above
# loop. (This maintains the order so no need to resort)
waiting_list[:] = waiting_list[index_of_first_deferred_not_called:]
async def on_position(self, stream_name: str, instance_name: str, token: int):
self.store.process_replication_rows(stream_name, instance_name, token, [])
def on_remote_server_up(self, server: str):
"""Called when get a new REMOTE_SERVER_UP command."""
async def wait_for_stream_position(
self, instance_name: str, stream_name: str, position: int
):
"""Wait until this instance has received updates up to and including
the given stream position.
"""
if instance_name == self._instance_name:
# We don't get told about updates written by this process, and
# anyway in that case we don't need to wait.
return
current_position = self._streams[stream_name].current_token(self._instance_name)
if position <= current_position:
# We're already past the position
return
# Create a new deferred that times out after N seconds, as we don't want
# to wedge here forever.
deferred = Deferred()
deferred = timeout_deferred(
deferred, _WAIT_FOR_REPLICATION_TIMEOUT_SECONDS, self._reactor
)
waiting_list = self._streams_to_waiters.setdefault(stream_name, [])
# We insert into the list using heapq as it is more efficient than
# pushing then resorting each time.
heapq.heappush(waiting_list, (position, deferred))
# We measure here to get in flight counts and average waiting time.
with Measure(self._clock, "repl.wait_for_stream_position"):
logger.info("Waiting for repl stream %r to reach %s", stream_name, position)
await make_deferred_yieldable(deferred)
logger.info(
"Finished waiting for repl stream %r to reach %s", stream_name, position
)
|
