From dd8da8c5f6ac525a7456437913a03f68d4504605 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Tue, 26 Jan 2021 13:57:31 +0000 Subject: [PATCH] Precompute joined hosts and store in Redis (#9198) --- changelog.d/9198.misc | 1 + stubs/txredisapi.pyi | 12 ++- synapse/config/_base.pyi | 2 + synapse/federation/sender/__init__.py | 50 +++++++---- synapse/handlers/federation.py | 5 ++ synapse/handlers/message.py | 42 +++++++++ synapse/replication/tcp/external_cache.py | 105 ++++++++++++++++++++++ synapse/replication/tcp/handler.py | 15 +--- synapse/server.py | 30 +++++++ synapse/state/__init__.py | 11 ++- tests/replication/_base.py | 41 +++++---- 11 files changed, 265 insertions(+), 49 deletions(-) create mode 100644 changelog.d/9198.misc create mode 100644 synapse/replication/tcp/external_cache.py diff --git a/changelog.d/9198.misc b/changelog.d/9198.misc new file mode 100644 index 000000000..a6cb77fbb --- /dev/null +++ b/changelog.d/9198.misc @@ -0,0 +1 @@ +Precompute joined hosts and store in Redis. diff --git a/stubs/txredisapi.pyi b/stubs/txredisapi.pyi index bdc892ec8..618548a30 100644 --- a/stubs/txredisapi.pyi +++ b/stubs/txredisapi.pyi @@ -15,11 +15,21 @@ """Contains *incomplete* type hints for txredisapi. """ -from typing import List, Optional, Type, Union +from typing import Any, List, Optional, Type, Union class RedisProtocol: def publish(self, channel: str, message: bytes): ... async def ping(self) -> None: ... + async def set( + self, + key: str, + value: Any, + expire: Optional[int] = None, + pexpire: Optional[int] = None, + only_if_not_exists: bool = False, + only_if_exists: bool = False, + ) -> None: ... + async def get(self, key: str) -> Any: ... class SubscriberProtocol(RedisProtocol): def __init__(self, *args, **kwargs): ... diff --git a/synapse/config/_base.pyi b/synapse/config/_base.pyi index 29aa064e5..8ba669059 100644 --- a/synapse/config/_base.pyi +++ b/synapse/config/_base.pyi @@ -18,6 +18,7 @@ from synapse.config import ( password_auth_providers, push, ratelimiting, + redis, registration, repository, room_directory, @@ -79,6 +80,7 @@ class RootConfig: roomdirectory: room_directory.RoomDirectoryConfig thirdpartyrules: third_party_event_rules.ThirdPartyRulesConfig tracer: tracer.TracerConfig + redis: redis.RedisConfig config_classes: List = ... def __init__(self) -> None: ... diff --git a/synapse/federation/sender/__init__.py b/synapse/federation/sender/__init__.py index 604cfd193..643b26ae6 100644 --- a/synapse/federation/sender/__init__.py +++ b/synapse/federation/sender/__init__.py @@ -142,6 +142,8 @@ class FederationSender: self._wake_destinations_needing_catchup, ) + self._external_cache = hs.get_external_cache() + def _get_per_destination_queue(self, destination: str) -> PerDestinationQueue: """Get or create a PerDestinationQueue for the given destination @@ -197,22 +199,40 @@ class FederationSender: if not event.internal_metadata.should_proactively_send(): return - try: - # Get the state from before the event. - # We need to make sure that this is the state from before - # the event and not from after it. - # Otherwise if the last member on a server in a room is - # banned then it won't receive the event because it won't - # be in the room after the ban. - destinations = await self.state.get_hosts_in_room_at_events( - event.room_id, event_ids=event.prev_event_ids() - ) - except Exception: - logger.exception( - "Failed to calculate hosts in room for event: %s", - event.event_id, + destinations = None # type: Optional[Set[str]] + if not event.prev_event_ids(): + # If there are no prev event IDs then the state is empty + # and so no remote servers in the room + destinations = set() + else: + # We check the external cache for the destinations, which is + # stored per state group. + + sg = await self._external_cache.get( + "event_to_prev_state_group", event.event_id ) - return + if sg: + destinations = await self._external_cache.get( + "get_joined_hosts", str(sg) + ) + + if destinations is None: + try: + # Get the state from before the event. + # We need to make sure that this is the state from before + # the event and not from after it. + # Otherwise if the last member on a server in a room is + # banned then it won't receive the event because it won't + # be in the room after the ban. + destinations = await self.state.get_hosts_in_room_at_events( + event.room_id, event_ids=event.prev_event_ids() + ) + except Exception: + logger.exception( + "Failed to calculate hosts in room for event: %s", + event.event_id, + ) + return destinations = { d diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py index fd8de8696..b6dc7f99b 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py @@ -2093,6 +2093,11 @@ class FederationHandler(BaseHandler): if event.type == EventTypes.GuestAccess and not context.rejected: await self.maybe_kick_guest_users(event) + # If we are going to send this event over federation we precaclculate + # the joined hosts. + if event.internal_metadata.get_send_on_behalf_of(): + await self.event_creation_handler.cache_joined_hosts_for_event(event) + return context async def _check_for_soft_fail( diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py index 9dfeab09c..e2a7d567f 100644 --- a/synapse/handlers/message.py +++ b/synapse/handlers/message.py @@ -432,6 +432,8 @@ class EventCreationHandler: self._ephemeral_events_enabled = hs.config.enable_ephemeral_messages + self._external_cache = hs.get_external_cache() + async def create_event( self, requester: Requester, @@ -939,6 +941,8 @@ class EventCreationHandler: await self.action_generator.handle_push_actions_for_event(event, context) + await self.cache_joined_hosts_for_event(event) + try: # If we're a worker we need to hit out to the master. writer_instance = self._events_shard_config.get_instance(event.room_id) @@ -978,6 +982,44 @@ class EventCreationHandler: await self.store.remove_push_actions_from_staging(event.event_id) raise + async def cache_joined_hosts_for_event(self, event: EventBase) -> None: + """Precalculate the joined hosts at the event, when using Redis, so that + external federation senders don't have to recalculate it themselves. + """ + + if not self._external_cache.is_enabled(): + return + + # We actually store two mappings, event ID -> prev state group, + # state group -> joined hosts, which is much more space efficient + # than event ID -> joined hosts. + # + # Note: We have to cache event ID -> prev state group, as we don't + # store that in the DB. + # + # Note: We always set the state group -> joined hosts cache, even if + # we already set it, so that the expiry time is reset. + + state_entry = await self.state.resolve_state_groups_for_events( + event.room_id, event_ids=event.prev_event_ids() + ) + + if state_entry.state_group: + joined_hosts = await self.store.get_joined_hosts(event.room_id, state_entry) + + await self._external_cache.set( + "event_to_prev_state_group", + event.event_id, + state_entry.state_group, + expiry_ms=60 * 60 * 1000, + ) + await self._external_cache.set( + "get_joined_hosts", + str(state_entry.state_group), + list(joined_hosts), + expiry_ms=60 * 60 * 1000, + ) + async def _validate_canonical_alias( self, directory_handler, room_alias_str: str, expected_room_id: str ) -> None: diff --git a/synapse/replication/tcp/external_cache.py b/synapse/replication/tcp/external_cache.py new file mode 100644 index 000000000..34fa3ff5b --- /dev/null +++ b/synapse/replication/tcp/external_cache.py @@ -0,0 +1,105 @@ +# -*- coding: utf-8 -*- +# Copyright 2021 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 TYPE_CHECKING, Any, Optional + +from prometheus_client import Counter + +from synapse.logging.context import make_deferred_yieldable +from synapse.util import json_decoder, json_encoder + +if TYPE_CHECKING: + from synapse.server import HomeServer + +set_counter = Counter( + "synapse_external_cache_set", + "Number of times we set a cache", + labelnames=["cache_name"], +) + +get_counter = Counter( + "synapse_external_cache_get", + "Number of times we get a cache", + labelnames=["cache_name", "hit"], +) + + +logger = logging.getLogger(__name__) + + +class ExternalCache: + """A cache backed by an external Redis. Does nothing if no Redis is + configured. + """ + + def __init__(self, hs: "HomeServer"): + self._redis_connection = hs.get_outbound_redis_connection() + + def _get_redis_key(self, cache_name: str, key: str) -> str: + return "cache_v1:%s:%s" % (cache_name, key) + + def is_enabled(self) -> bool: + """Whether the external cache is used or not. + + It's safe to use the cache when this returns false, the methods will + just no-op, but the function is useful to avoid doing unnecessary work. + """ + return self._redis_connection is not None + + async def set(self, cache_name: str, key: str, value: Any, expiry_ms: int) -> None: + """Add the key/value to the named cache, with the expiry time given. + """ + + if self._redis_connection is None: + return + + set_counter.labels(cache_name).inc() + + # txredisapi requires the value to be string, bytes or numbers, so we + # encode stuff in JSON. + encoded_value = json_encoder.encode(value) + + logger.debug("Caching %s %s: %r", cache_name, key, encoded_value) + + return await make_deferred_yieldable( + self._redis_connection.set( + self._get_redis_key(cache_name, key), encoded_value, pexpire=expiry_ms, + ) + ) + + async def get(self, cache_name: str, key: str) -> Optional[Any]: + """Look up a key/value in the named cache. + """ + + if self._redis_connection is None: + return None + + result = await make_deferred_yieldable( + self._redis_connection.get(self._get_redis_key(cache_name, key)) + ) + + logger.debug("Got cache result %s %s: %r", cache_name, key, result) + + get_counter.labels(cache_name, result is not None).inc() + + if not result: + return None + + # For some reason the integers get magically converted back to integers + if isinstance(result, int): + return result + + return json_decoder.decode(result) diff --git a/synapse/replication/tcp/handler.py b/synapse/replication/tcp/handler.py index 58d46a595..8ea8dcd58 100644 --- a/synapse/replication/tcp/handler.py +++ b/synapse/replication/tcp/handler.py @@ -286,13 +286,6 @@ class ReplicationCommandHandler: if hs.config.redis.redis_enabled: from synapse.replication.tcp.redis import ( RedisDirectTcpReplicationClientFactory, - lazyConnection, - ) - - 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. @@ -303,13 +296,7 @@ class ReplicationCommandHandler: # connection after SUBSCRIBE is called). # First create the connection for sending commands. - outbound_redis_connection = lazyConnection( - hs=hs, - host=hs.config.redis_host, - port=hs.config.redis_port, - password=hs.config.redis.redis_password, - reconnect=True, - ) + outbound_redis_connection = hs.get_outbound_redis_connection() # Now create the factory/connection for the subscription stream. self._factory = RedisDirectTcpReplicationClientFactory( diff --git a/synapse/server.py b/synapse/server.py index 9cdda83aa..9bdd3177d 100644 --- a/synapse/server.py +++ b/synapse/server.py @@ -103,6 +103,7 @@ from synapse.notifier import Notifier from synapse.push.action_generator import ActionGenerator from synapse.push.pusherpool import PusherPool from synapse.replication.tcp.client import ReplicationDataHandler +from synapse.replication.tcp.external_cache import ExternalCache from synapse.replication.tcp.handler import ReplicationCommandHandler from synapse.replication.tcp.resource import ReplicationStreamer from synapse.replication.tcp.streams import STREAMS_MAP, Stream @@ -128,6 +129,8 @@ from synapse.util.stringutils import random_string logger = logging.getLogger(__name__) if TYPE_CHECKING: + from txredisapi import RedisProtocol + from synapse.handlers.oidc_handler import OidcHandler from synapse.handlers.saml_handler import SamlHandler @@ -716,6 +719,33 @@ class HomeServer(metaclass=abc.ABCMeta): def get_account_data_handler(self) -> AccountDataHandler: return AccountDataHandler(self) + @cache_in_self + def get_external_cache(self) -> ExternalCache: + return ExternalCache(self) + + @cache_in_self + def get_outbound_redis_connection(self) -> Optional["RedisProtocol"]: + if not self.config.redis.redis_enabled: + return None + + # We only want to import redis module if we're using it, as we have + # `txredisapi` as an optional dependency. + from synapse.replication.tcp.redis import lazyConnection + + logger.info( + "Connecting to redis (host=%r port=%r) for external cache", + self.config.redis_host, + self.config.redis_port, + ) + + return lazyConnection( + hs=self, + host=self.config.redis_host, + port=self.config.redis_port, + password=self.config.redis.redis_password, + reconnect=True, + ) + async def remove_pusher(self, app_id: str, push_key: str, user_id: str): return await self.get_pusherpool().remove_pusher(app_id, push_key, user_id) diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py index 84f59c7d8..3bd9ff8ca 100644 --- a/synapse/state/__init__.py +++ b/synapse/state/__init__.py @@ -310,6 +310,7 @@ class StateHandler: state_group_before_event = None state_group_before_event_prev_group = None deltas_to_state_group_before_event = None + entry = None else: # otherwise, we'll need to resolve the state across the prev_events. @@ -340,9 +341,13 @@ class StateHandler: current_state_ids=state_ids_before_event, ) - # XXX: can we update the state cache entry for the new state group? or - # could we set a flag on resolve_state_groups_for_events to tell it to - # always make a state group? + # Assign the new state group to the cached state entry. + # + # Note that this can race in that we could generate multiple state + # groups for the same state entry, but that is just inefficient + # rather than dangerous. + if entry and entry.state_group is None: + entry.state_group = state_group_before_event # # now if it's not a state event, we're done diff --git a/tests/replication/_base.py b/tests/replication/_base.py index 337918978..d5dce1f83 100644 --- a/tests/replication/_base.py +++ b/tests/replication/_base.py @@ -212,6 +212,9 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase): # Fake in memory Redis server that servers can connect to. self._redis_server = FakeRedisPubSubServer() + # We may have an attempt to connect to redis for the external cache already. + self.connect_any_redis_attempts() + store = self.hs.get_datastore() self.database_pool = store.db_pool @@ -401,25 +404,23 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase): fake one. """ clients = self.reactor.tcpClients - self.assertEqual(len(clients), 1) - (host, port, client_factory, _timeout, _bindAddress) = clients.pop(0) - self.assertEqual(host, "localhost") - self.assertEqual(port, 6379) + while clients: + (host, port, client_factory, _timeout, _bindAddress) = clients.pop(0) + self.assertEqual(host, "localhost") + self.assertEqual(port, 6379) - client_protocol = client_factory.buildProtocol(None) - server_protocol = self._redis_server.buildProtocol(None) + client_protocol = client_factory.buildProtocol(None) + server_protocol = self._redis_server.buildProtocol(None) - client_to_server_transport = FakeTransport( - server_protocol, self.reactor, client_protocol - ) - client_protocol.makeConnection(client_to_server_transport) - - server_to_client_transport = FakeTransport( - client_protocol, self.reactor, server_protocol - ) - server_protocol.makeConnection(server_to_client_transport) + client_to_server_transport = FakeTransport( + server_protocol, self.reactor, client_protocol + ) + client_protocol.makeConnection(client_to_server_transport) - return client_to_server_transport, server_to_client_transport + server_to_client_transport = FakeTransport( + client_protocol, self.reactor, server_protocol + ) + server_protocol.makeConnection(server_to_client_transport) class TestReplicationDataHandler(GenericWorkerReplicationHandler): @@ -624,6 +625,12 @@ class FakeRedisPubSubProtocol(Protocol): (channel,) = args self._server.add_subscriber(self) self.send(["subscribe", channel, 1]) + + # Since we use SET/GET to cache things we can safely no-op them. + elif command == b"SET": + self.send("OK") + elif command == b"GET": + self.send(None) else: raise Exception("Unknown command") @@ -645,6 +652,8 @@ class FakeRedisPubSubProtocol(Protocol): # We assume bytes are just unicode strings. obj = obj.decode("utf-8") + if obj is None: + return "$-1\r\n" if isinstance(obj, str): return "${len}\r\n{str}\r\n".format(len=len(obj), str=obj) if isinstance(obj, int):