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Diffstat (limited to 'synapse/replication/tcp/handler.py')
| -rw-r--r-- | synapse/replication/tcp/handler.py | 596 |
1 files changed, 596 insertions, 0 deletions
diff --git a/synapse/replication/tcp/handler.py b/synapse/replication/tcp/handler.py new file mode 100644 index 0000000000..cbcf46f3ae --- /dev/null +++ b/synapse/replication/tcp/handler.py @@ -0,0 +1,596 @@ +# -*- 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]] + + # 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 |