231 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			231 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			Python
		
	
	
| # -*- coding: utf-8 -*-
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| # Copyright 2017 Vector Creations Ltd
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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 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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| """A replication client for use by synapse workers.
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| """
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| import logging
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| from typing import TYPE_CHECKING, Dict, List, Tuple
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| 
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| from twisted.internet.defer import Deferred
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| from twisted.internet.protocol import ReconnectingClientFactory
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| 
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| from synapse.api.constants import EventTypes
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| from synapse.logging.context import PreserveLoggingContext, make_deferred_yieldable
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| from synapse.replication.tcp.protocol import ClientReplicationStreamProtocol
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| from synapse.replication.tcp.streams import TypingStream
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| from synapse.replication.tcp.streams.events import (
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|     EventsStream,
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|     EventsStreamEventRow,
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|     EventsStreamRow,
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| )
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| from synapse.util.async_helpers import timeout_deferred
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| from synapse.util.metrics import Measure
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| 
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| if TYPE_CHECKING:
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|     from synapse.replication.tcp.handler import ReplicationCommandHandler
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|     from synapse.server import HomeServer
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| 
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| logger = logging.getLogger(__name__)
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| 
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| 
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| # How long we allow callers to wait for replication updates before timing out.
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| _WAIT_FOR_REPLICATION_TIMEOUT_SECONDS = 30
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| 
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| 
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| class DirectTcpReplicationClientFactory(ReconnectingClientFactory):
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|     """Factory for building connections to the master. Will reconnect if the
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|     connection is lost.
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| 
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|     Accepts a handler that is passed to `ClientReplicationStreamProtocol`.
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|     """
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| 
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|     initialDelay = 0.1
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|     maxDelay = 1  # Try at least once every N seconds
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| 
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|     def __init__(
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|         self,
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|         hs: "HomeServer",
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|         client_name: str,
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|         command_handler: "ReplicationCommandHandler",
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|     ):
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|         self.client_name = client_name
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|         self.command_handler = command_handler
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|         self.server_name = hs.config.server_name
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|         self.hs = hs
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|         self._clock = hs.get_clock()  # As self.clock is defined in super class
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| 
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|         hs.get_reactor().addSystemEventTrigger("before", "shutdown", self.stopTrying)
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| 
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|     def startedConnecting(self, connector):
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|         logger.info("Connecting to replication: %r", connector.getDestination())
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| 
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|     def buildProtocol(self, addr):
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|         logger.info("Connected to replication: %r", addr)
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|         return ClientReplicationStreamProtocol(
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|             self.hs,
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|             self.client_name,
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|             self.server_name,
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|             self._clock,
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|             self.command_handler,
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|         )
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| 
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|     def clientConnectionLost(self, connector, reason):
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|         logger.error("Lost replication conn: %r", reason)
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|         ReconnectingClientFactory.clientConnectionLost(self, connector, reason)
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| 
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|     def clientConnectionFailed(self, connector, reason):
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|         logger.error("Failed to connect to replication: %r", reason)
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|         ReconnectingClientFactory.clientConnectionFailed(self, connector, reason)
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| 
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| 
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| class ReplicationDataHandler:
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|     """Handles incoming stream updates from replication.
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| 
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|     This instance notifies the slave data store about updates. Can be subclassed
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|     to handle updates in additional ways.
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|     """
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| 
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|     def __init__(self, hs: "HomeServer"):
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|         self.store = hs.get_datastore()
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|         self.pusher_pool = hs.get_pusherpool()
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|         self.notifier = hs.get_notifier()
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|         self._reactor = hs.get_reactor()
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|         self._clock = hs.get_clock()
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|         self._streams = hs.get_replication_streams()
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|         self._instance_name = hs.get_instance_name()
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|         self._typing_handler = hs.get_typing_handler()
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| 
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|         # Map from stream to list of deferreds waiting for the stream to
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|         # arrive at a particular position. The lists are sorted by stream position.
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|         self._streams_to_waiters = (
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|             {}
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|         )  # type: Dict[str, List[Tuple[int, Deferred[None]]]]
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| 
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|     async def on_rdata(
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|         self, stream_name: str, instance_name: str, token: int, rows: list
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|     ):
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|         """Called to handle a batch of replication data with a given stream token.
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| 
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|         By default this just pokes the slave store. Can be overridden in subclasses to
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|         handle more.
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| 
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|         Args:
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|             stream_name: name of the replication stream for this batch of rows
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|             instance_name: the instance that wrote the rows.
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|             token: stream token for this batch of rows
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|             rows: a list of Stream.ROW_TYPE objects as returned by Stream.parse_row.
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|         """
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|         self.store.process_replication_rows(stream_name, instance_name, token, rows)
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| 
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|         if stream_name == TypingStream.NAME:
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|             self._typing_handler.process_replication_rows(token, rows)
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|             self.notifier.on_new_event(
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|                 "typing_key", token, rooms=[row.room_id for row in rows]
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|             )
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| 
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|         if stream_name == EventsStream.NAME:
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|             # We shouldn't get multiple rows per token for events stream, so
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|             # we don't need to optimise this for multiple rows.
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|             for row in rows:
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|                 if row.type != EventsStreamEventRow.TypeId:
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|                     continue
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|                 assert isinstance(row, EventsStreamRow)
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| 
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|                 event = await self.store.get_event(
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|                     row.data.event_id, allow_rejected=True
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|                 )
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|                 if event.rejected_reason:
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|                     continue
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| 
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|                 extra_users = ()  # type: Tuple[str, ...]
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|                 if event.type == EventTypes.Member:
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|                     extra_users = (event.state_key,)
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|                 max_token = self.store.get_room_max_stream_ordering()
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|                 self.notifier.on_new_room_event(event, token, max_token, extra_users)
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| 
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|             await self.pusher_pool.on_new_notifications(token, token)
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| 
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|         # Notify any waiting deferreds. The list is ordered by position so we
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|         # just iterate through the list until we reach a position that is
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|         # greater than the received row position.
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|         waiting_list = self._streams_to_waiters.get(stream_name, [])
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| 
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|         # Index of first item with a position after the current token, i.e we
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|         # have called all deferreds before this index. If not overwritten by
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|         # loop below means either a) no items in list so no-op or b) all items
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|         # in list were called and so the list should be cleared. Setting it to
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|         # `len(list)` works for both cases.
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|         index_of_first_deferred_not_called = len(waiting_list)
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| 
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|         for idx, (position, deferred) in enumerate(waiting_list):
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|             if position <= token:
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|                 try:
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|                     with PreserveLoggingContext():
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|                         deferred.callback(None)
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|                 except Exception:
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|                     # The deferred has been cancelled or timed out.
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|                     pass
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|             else:
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|                 # The list is sorted by position so we don't need to continue
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|                 # checking any further entries in the list.
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|                 index_of_first_deferred_not_called = idx
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|                 break
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| 
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|         # Drop all entries in the waiting list that were called in the above
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|         # loop. (This maintains the order so no need to resort)
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|         waiting_list[:] = waiting_list[index_of_first_deferred_not_called:]
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| 
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|     async def on_position(self, stream_name: str, instance_name: str, token: int):
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|         self.store.process_replication_rows(stream_name, instance_name, token, [])
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| 
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|     def on_remote_server_up(self, server: str):
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|         """Called when get a new REMOTE_SERVER_UP command."""
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| 
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|     async def wait_for_stream_position(
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|         self, instance_name: str, stream_name: str, position: int
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|     ):
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|         """Wait until this instance has received updates up to and including
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|         the given stream position.
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|         """
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| 
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|         if instance_name == self._instance_name:
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|             # We don't get told about updates written by this process, and
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|             # anyway in that case we don't need to wait.
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|             return
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| 
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|         current_position = self._streams[stream_name].current_token(self._instance_name)
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|         if position <= current_position:
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|             # We're already past the position
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|             return
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| 
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|         # Create a new deferred that times out after N seconds, as we don't want
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|         # to wedge here forever.
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|         deferred = Deferred()
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|         deferred = timeout_deferred(
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|             deferred, _WAIT_FOR_REPLICATION_TIMEOUT_SECONDS, self._reactor
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|         )
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| 
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|         waiting_list = self._streams_to_waiters.setdefault(stream_name, [])
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| 
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|         waiting_list.append((position, deferred))
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|         waiting_list.sort(key=lambda t: t[0])
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| 
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|         # We measure here to get in flight counts and average waiting time.
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|         with Measure(self._clock, "repl.wait_for_stream_position"):
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|             logger.info("Waiting for repl stream %r to reach %s", stream_name, position)
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|             await make_deferred_yieldable(deferred)
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|             logger.info(
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|                 "Finished waiting for repl stream %r to reach %s", stream_name, position
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|             )
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