# -*- coding: utf-8 -*- # Copyright 2017 Vector Creations Ltd # Copyright 2020 The Matrix.org Foundation C.I.C. # # 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. import logging from typing import Any, Dict, Iterable, Iterator, List, Optional, Set, Tuple, TypeVar from prometheus_client import Counter from twisted.internet.protocol import ReconnectingClientFactory from synapse.metrics import LaterGauge from synapse.replication.tcp.client import DirectTcpReplicationClientFactory from synapse.replication.tcp.commands import ( ClearUserSyncsCommand, Command, FederationAckCommand, PositionCommand, RdataCommand, RemoteServerUpCommand, RemovePusherCommand, ReplicateCommand, UserIpCommand, UserSyncCommand, ) from synapse.replication.tcp.protocol import AbstractConnection from synapse.replication.tcp.streams import ( STREAMS_MAP, BackfillStream, CachesStream, EventsStream, FederationStream, Stream, ) from synapse.util.async_helpers import Linearizer logger = logging.getLogger(__name__) # number of updates received for each RDATA stream inbound_rdata_count = Counter( "synapse_replication_tcp_protocol_inbound_rdata_count", "", ["stream_name"] ) user_sync_counter = Counter("synapse_replication_tcp_resource_user_sync", "") federation_ack_counter = Counter("synapse_replication_tcp_resource_federation_ack", "") remove_pusher_counter = Counter("synapse_replication_tcp_resource_remove_pusher", "") invalidate_cache_counter = Counter( "synapse_replication_tcp_resource_invalidate_cache", "" ) user_ip_cache_counter = Counter("synapse_replication_tcp_resource_user_ip_cache", "") class ReplicationCommandHandler: """Handles incoming commands from replication as well as sending commands back out to connections. """ def __init__(self, hs): self._replication_data_handler = hs.get_replication_data_handler() self._presence_handler = hs.get_presence_handler() self._store = hs.get_datastore() self._notifier = hs.get_notifier() self._clock = hs.get_clock() self._instance_id = hs.get_instance_id() self._instance_name = hs.get_instance_name() self._streams = { stream.NAME: stream(hs) for stream in STREAMS_MAP.values() } # type: Dict[str, Stream] # List of streams that this instance is the source of self._streams_to_replicate = [] # type: List[Stream] for stream in self._streams.values(): if stream.NAME == CachesStream.NAME: # All workers can write to the cache invalidation stream. self._streams_to_replicate.append(stream) continue if isinstance(stream, (EventsStream, BackfillStream)): # Only add EventStream and BackfillStream as a source on the # instance in charge of event persistence. if hs.config.worker.writers.events == hs.get_instance_name(): self._streams_to_replicate.append(stream) continue # Only add any other streams if we're on master. if hs.config.worker_app is not None: continue if stream.NAME == FederationStream.NAME and hs.config.send_federation: # We only support federation stream if federation sending # has been disabled on the master. continue self._streams_to_replicate.append(stream) self._position_linearizer = Linearizer( "replication_position", clock=self._clock ) # Map of stream to batched updates. See RdataCommand for info on how # batching works. self._pending_batches = {} # type: Dict[str, List[Any]] self._queued_events = {} # type: Dict[str, List[Any]] # The factory used to create connections. self._factory = None # type: Optional[ReconnectingClientFactory] # The currently connected connections. (The list of places we need to send # outgoing replication commands to.) self._connections = [] # type: List[AbstractConnection] # For each connection, the incoming streams that are coming from that connection self._streams_by_connection = {} # type: Dict[AbstractConnection, Set[str]] LaterGauge( "synapse_replication_tcp_resource_total_connections", "", [], lambda: len(self._connections), ) self._is_master = hs.config.worker_app is None self._federation_sender = None if self._is_master and not hs.config.send_federation: self._federation_sender = hs.get_federation_sender() self._server_notices_sender = None if self._is_master: self._server_notices_sender = hs.get_server_notices_sender() def start_replication(self, hs): """Helper method to start a replication connection to the remote server using TCP. """ if hs.config.redis.redis_enabled: from synapse.replication.tcp.redis import ( RedisDirectTcpReplicationClientFactory, ) import txredisapi logger.info( "Connecting to redis (host=%r port=%r)", hs.config.redis_host, hs.config.redis_port, ) # First let's ensure that we have a ReplicationStreamer started. hs.get_replication_streamer() # We need two connections to redis, one for the subscription stream and # one to send commands to (as you can't send further redis commands to a # connection after SUBSCRIBE is called). # First create the connection for sending commands. outbound_redis_connection = txredisapi.lazyConnection( host=hs.config.redis_host, port=hs.config.redis_port, password=hs.config.redis.redis_password, reconnect=True, ) # Now create the factory/connection for the subscription stream. self._factory = RedisDirectTcpReplicationClientFactory( hs, outbound_redis_connection ) hs.get_reactor().connectTCP( hs.config.redis.redis_host, hs.config.redis.redis_port, self._factory, ) else: client_name = hs.get_instance_name() self._factory = DirectTcpReplicationClientFactory(hs, client_name, self) host = hs.config.worker_replication_host port = hs.config.worker_replication_port hs.get_reactor().connectTCP(host, port, self._factory) def get_streams(self) -> Dict[str, Stream]: """Get a map from stream name to all streams. """ return self._streams def get_streams_to_replicate(self) -> List[Stream]: """Get a list of streams that this instances replicates. """ return self._streams_to_replicate async def on_REPLICATE(self, conn: AbstractConnection, cmd: ReplicateCommand): self.send_positions_to_connection(conn) def send_positions_to_connection(self, conn: AbstractConnection): """Send current position of all streams this process is source of to the connection. """ # We respond with current position of all streams this instance # replicates. for stream in self.get_streams_to_replicate(): self.send_command( PositionCommand( stream.NAME, self._instance_name, stream.current_token(self._instance_name), ) ) async def on_USER_SYNC(self, conn: AbstractConnection, cmd: UserSyncCommand): user_sync_counter.inc() if self._is_master: await self._presence_handler.update_external_syncs_row( cmd.instance_id, cmd.user_id, cmd.is_syncing, cmd.last_sync_ms ) async def on_CLEAR_USER_SYNC( self, conn: AbstractConnection, cmd: ClearUserSyncsCommand ): if self._is_master: await self._presence_handler.update_external_syncs_clear(cmd.instance_id) async def on_FEDERATION_ACK( self, conn: AbstractConnection, cmd: FederationAckCommand ): federation_ack_counter.inc() if self._federation_sender: self._federation_sender.federation_ack(cmd.token) async def on_REMOVE_PUSHER( self, conn: AbstractConnection, cmd: RemovePusherCommand ): remove_pusher_counter.inc() if self._is_master: await self._store.delete_pusher_by_app_id_pushkey_user_id( app_id=cmd.app_id, pushkey=cmd.push_key, user_id=cmd.user_id ) self._notifier.on_new_replication_data() async def on_USER_IP(self, conn: AbstractConnection, cmd: UserIpCommand): user_ip_cache_counter.inc() if self._is_master: await self._store.insert_client_ip( cmd.user_id, cmd.access_token, cmd.ip, cmd.user_agent, cmd.device_id, cmd.last_seen, ) if self._server_notices_sender: await self._server_notices_sender.on_user_ip(cmd.user_id) async def on_RDATA(self, conn: AbstractConnection, cmd: RdataCommand): if cmd.instance_name == self._instance_name: # Ignore RDATA that are just our own echoes return stream_name = cmd.stream_name inbound_rdata_count.labels(stream_name).inc() try: row = STREAMS_MAP[stream_name].parse_row(cmd.row) except Exception: logger.exception("Failed to parse RDATA: %r %r", stream_name, cmd.row) raise # We linearize here for two reasons: # 1. so we don't try and concurrently handle multiple rows for the # same stream, and # 2. so we don't race with getting a POSITION command and fetching # missing RDATA. with await self._position_linearizer.queue(cmd.stream_name): # make sure that we've processed a POSITION for this stream *on this # connection*. (A POSITION on another connection is no good, as there # is no guarantee that we have seen all the intermediate updates.) sbc = self._streams_by_connection.get(conn) if not sbc or stream_name not in sbc: # Let's drop the row for now, on the assumption we'll receive a # `POSITION` soon and we'll catch up correctly then. logger.debug( "Discarding RDATA for unconnected stream %s -> %s", stream_name, cmd.token, ) return if cmd.token is None: # I.e. this is part of a batch of updates for this stream (in # which case batch until we get an update for the stream with a non # None token). self._pending_batches.setdefault(stream_name, []).append(row) else: # Check if this is the last of a batch of updates rows = self._pending_batches.pop(stream_name, []) rows.append(row) await self.on_rdata(stream_name, cmd.instance_name, cmd.token, rows) 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. 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. """ logger.debug("Received rdata %s (%s) -> %s", stream_name, instance_name, token) await self._replication_data_handler.on_rdata( stream_name, instance_name, token, rows ) async def on_POSITION(self, conn: AbstractConnection, cmd: PositionCommand): if cmd.instance_name == self._instance_name: # Ignore POSITION that are just our own echoes return logger.info("Handling '%s %s'", cmd.NAME, cmd.to_line()) stream_name = cmd.stream_name stream = self._streams.get(stream_name) if not stream: logger.error("Got POSITION for unknown stream: %s", stream_name) return # We protect catching up with a linearizer in case the replication # connection reconnects under us. with await self._position_linearizer.queue(stream_name): # We're about to go and catch up with the stream, so remove from set # of connected streams. for streams in self._streams_by_connection.values(): streams.discard(stream_name) # We clear the pending batches for the stream as the fetching of the # missing updates below will fetch all rows in the batch. self._pending_batches.pop(stream_name, []) # Find where we previously streamed up to. current_token = stream.current_token(cmd.instance_name) # If the position token matches our current token then we're up to # date and there's nothing to do. Otherwise, fetch all updates # between then and now. missing_updates = cmd.token != current_token while missing_updates: logger.info( "Fetching replication rows for '%s' between %i and %i", stream_name, current_token, cmd.token, ) ( updates, current_token, missing_updates, ) = await stream.get_updates_since( cmd.instance_name, current_token, cmd.token ) # TODO: add some tests for this # Some streams return multiple rows with the same stream IDs, # which need to be processed in batches. for token, rows in _batch_updates(updates): await self.on_rdata( stream_name, cmd.instance_name, token, [stream.parse_row(row) for row in rows], ) logger.info("Caught up with stream '%s' to %i", stream_name, cmd.token) # We've now caught up to position sent to us, notify handler. await self._replication_data_handler.on_position( cmd.stream_name, cmd.instance_name, cmd.token ) self._streams_by_connection.setdefault(conn, set()).add(stream_name) async def on_REMOTE_SERVER_UP( self, conn: AbstractConnection, cmd: RemoteServerUpCommand ): """"Called when get a new REMOTE_SERVER_UP command.""" self._replication_data_handler.on_remote_server_up(cmd.data) self._notifier.notify_remote_server_up(cmd.data) # We relay to all other connections to ensure every instance gets the # notification. # # When configured to use redis we'll always only have one connection and # so this is a no-op (all instances will have already received the same # REMOTE_SERVER_UP command). # # For direct TCP connections this will relay to all other connections # connected to us. When on master this will correctly fan out to all # other direct TCP clients and on workers there'll only be the one # connection to master. # # (The logic here should also be sound if we have a mix of Redis and # direct TCP connections so long as there is only one traffic route # between two instances, but that is not currently supported). self.send_command(cmd, ignore_conn=conn) def new_connection(self, connection: AbstractConnection): """Called when we have a new connection. """ self._connections.append(connection) # If we are connected to replication as a client (rather than a server) # we need to reset the reconnection delay on the client factory (which # is used to do exponential back off when the connection drops). # # Ideally we would reset the delay when we've "fully established" the # connection (for some definition thereof) to stop us from tightlooping # on reconnection if something fails after this point and we drop the # connection. Unfortunately, we don't really have a better definition of # "fully established" than the connection being established. if self._factory: self._factory.resetDelay() # Tell the other end if we have any users currently syncing. currently_syncing = ( self._presence_handler.get_currently_syncing_users_for_replication() ) now = self._clock.time_msec() for user_id in currently_syncing: connection.send_command( UserSyncCommand(self._instance_id, user_id, True, now) ) def lost_connection(self, connection: AbstractConnection): """Called when a connection is closed/lost. """ # we no longer need _streams_by_connection for this connection. streams = self._streams_by_connection.pop(connection, None) if streams: logger.info( "Lost replication connection; streams now disconnected: %s", streams ) try: self._connections.remove(connection) except ValueError: pass def connected(self) -> bool: """Do we have any replication connections open? Is used by e.g. `ReplicationStreamer` to no-op if nothing is connected. """ return bool(self._connections) def send_command( self, cmd: Command, ignore_conn: Optional[AbstractConnection] = None ): """Send a command to all connected connections. Args: cmd ignore_conn: If set don't send command to the given connection. Used when relaying commands from one connection to all others. """ if self._connections: for connection in self._connections: if connection == ignore_conn: continue try: connection.send_command(cmd) except Exception: # We probably want to catch some types of exceptions here # and log them as warnings (e.g. connection gone), but I # can't find what those exception types they would be. logger.exception( "Failed to write command %s to connection %s", cmd.NAME, connection, ) else: logger.warning("Dropping command as not connected: %r", cmd.NAME) def send_federation_ack(self, token: int): """Ack data for the federation stream. This allows the master to drop data stored purely in memory. """ self.send_command(FederationAckCommand(token)) def send_user_sync( self, instance_id: str, user_id: str, is_syncing: bool, last_sync_ms: int ): """Poke the master that a user has started/stopped syncing. """ self.send_command( UserSyncCommand(instance_id, user_id, is_syncing, last_sync_ms) ) def send_remove_pusher(self, app_id: str, push_key: str, user_id: str): """Poke the master to remove a pusher for a user """ cmd = RemovePusherCommand(app_id, push_key, user_id) self.send_command(cmd) def send_user_ip( self, user_id: str, access_token: str, ip: str, user_agent: str, device_id: str, last_seen: int, ): """Tell the master that the user made a request. """ cmd = UserIpCommand(user_id, access_token, ip, user_agent, device_id, last_seen) self.send_command(cmd) def send_remote_server_up(self, server: str): self.send_command(RemoteServerUpCommand(server)) def stream_update(self, stream_name: str, token: str, data: Any): """Called when a new update is available to stream to clients. We need to check if the client is interested in the stream or not """ self.send_command(RdataCommand(stream_name, self._instance_name, token, data)) UpdateToken = TypeVar("UpdateToken") UpdateRow = TypeVar("UpdateRow") def _batch_updates( updates: Iterable[Tuple[UpdateToken, UpdateRow]] ) -> Iterator[Tuple[UpdateToken, List[UpdateRow]]]: """Collect stream updates with the same token together Given a series of updates returned by Stream.get_updates_since(), collects the updates which share the same stream_id together. For example: [(1, a), (1, b), (2, c), (3, d), (3, e)] becomes: [ (1, [a, b]), (2, [c]), (3, [d, e]), ] """ update_iter = iter(updates) first_update = next(update_iter, None) if first_update is None: # empty input return current_batch_token = first_update[0] current_batch = [first_update[1]] for token, row in update_iter: if token != current_batch_token: # different token to the previous row: flush the previous # batch and start anew yield current_batch_token, current_batch current_batch_token = token current_batch = [] current_batch.append(row) # flush the final batch yield current_batch_token, current_batch