Add config option to forget rooms automatically when users leave them (#15224)

This is largely based off the stats and user directory updater code.

Signed-off-by: Sean Quah <seanq@matrix.org>
This commit is contained in:
Sean Quah 2023-05-03 12:27:33 +01:00 committed by GitHub
parent 0e8aa2a1b2
commit 04e79e6a18
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9 changed files with 259 additions and 47 deletions

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@ -0,0 +1 @@
Add `forget_rooms_on_leave` config option to automatically forget rooms when users leave them or are removed from them.

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@ -3699,6 +3699,16 @@ default_power_level_content_override:
trusted_private_chat: null
public_chat: null
```
---
### `forget_rooms_on_leave`
Set to true to automatically forget rooms for users when they leave them, either
normally or via a kick or ban. Defaults to false.
Example configuration:
```yaml
forget_rooms_on_leave: false
```
---
## Opentracing

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@ -75,3 +75,7 @@ class RoomConfig(Config):
% preset
)
# We validate the actual overrides when we try to apply them.
# When enabled, users will forget rooms when they leave them, either via a
# leave, kick or ban.
self.forget_on_leave = config.get("forget_rooms_on_leave", False)

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@ -16,7 +16,7 @@ import abc
import logging
import random
from http import HTTPStatus
from typing import TYPE_CHECKING, Iterable, List, Optional, Set, Tuple
from typing import TYPE_CHECKING, Any, Dict, Iterable, List, Optional, Set, Tuple
from synapse import types
from synapse.api.constants import (
@ -38,7 +38,10 @@ from synapse.event_auth import get_named_level, get_power_level_event
from synapse.events import EventBase
from synapse.events.snapshot import EventContext
from synapse.handlers.profile import MAX_AVATAR_URL_LEN, MAX_DISPLAYNAME_LEN
from synapse.handlers.state_deltas import MatchChange, StateDeltasHandler
from synapse.logging import opentracing
from synapse.metrics import event_processing_positions
from synapse.metrics.background_process_metrics import run_as_background_process
from synapse.module_api import NOT_SPAM
from synapse.types import (
JsonDict,
@ -280,9 +283,25 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
"""
raise NotImplementedError()
@abc.abstractmethod
async def forget(self, user: UserID, room_id: str) -> None:
raise NotImplementedError()
user_id = user.to_string()
member = await self._storage_controllers.state.get_current_state_event(
room_id=room_id, event_type=EventTypes.Member, state_key=user_id
)
membership = member.membership if member else None
if membership is not None and membership not in [
Membership.LEAVE,
Membership.BAN,
]:
raise SynapseError(400, "User %s in room %s" % (user_id, room_id))
# In normal case this call is only required if `membership` is not `None`.
# But: After the last member had left the room, the background update
# `_background_remove_left_rooms` is deleting rows related to this room from
# the table `current_state_events` and `get_current_state_events` is `None`.
await self.store.forget(user_id, room_id)
async def ratelimit_multiple_invites(
self,
@ -2046,25 +2065,141 @@ class RoomMemberMasterHandler(RoomMemberHandler):
"""Implements RoomMemberHandler._user_left_room"""
user_left_room(self.distributor, target, room_id)
async def forget(self, user: UserID, room_id: str) -> None:
user_id = user.to_string()
member = await self._storage_controllers.state.get_current_state_event(
room_id=room_id, event_type=EventTypes.Member, state_key=user_id
)
membership = member.membership if member else None
class RoomForgetterHandler(StateDeltasHandler):
"""Forgets rooms when they are left, when enabled in the homeserver config.
if membership is not None and membership not in [
Membership.LEAVE,
Membership.BAN,
]:
raise SynapseError(400, "User %s in room %s" % (user_id, room_id))
For the purposes of this feature, kicks, bans and "leaves" via state resolution
weirdness are all considered to be leaves.
# In normal case this call is only required if `membership` is not `None`.
# But: After the last member had left the room, the background update
# `_background_remove_left_rooms` is deleting rows related to this room from
# the table `current_state_events` and `get_current_state_events` is `None`.
await self.store.forget(user_id, room_id)
Derived from `StatsHandler` and `UserDirectoryHandler`.
"""
def __init__(self, hs: "HomeServer"):
super().__init__(hs)
self._hs = hs
self._store = hs.get_datastores().main
self._storage_controllers = hs.get_storage_controllers()
self._clock = hs.get_clock()
self._notifier = hs.get_notifier()
self._room_member_handler = hs.get_room_member_handler()
# The current position in the current_state_delta stream
self.pos: Optional[int] = None
# Guard to ensure we only process deltas one at a time
self._is_processing = False
if hs.config.worker.run_background_tasks:
self._notifier.add_replication_callback(self.notify_new_event)
# We kick this off to pick up outstanding work from before the last restart.
self._clock.call_later(0, self.notify_new_event)
def notify_new_event(self) -> None:
"""Called when there may be more deltas to process"""
if self._is_processing:
return
self._is_processing = True
async def process() -> None:
try:
await self._unsafe_process()
finally:
self._is_processing = False
run_as_background_process("room_forgetter.notify_new_event", process)
async def _unsafe_process(self) -> None:
# If self.pos is None then means we haven't fetched it from DB
if self.pos is None:
self.pos = await self._store.get_room_forgetter_stream_pos()
room_max_stream_ordering = self._store.get_room_max_stream_ordering()
if self.pos > room_max_stream_ordering:
# apparently, we've processed more events than exist in the database!
# this can happen if events are removed with history purge or similar.
logger.warning(
"Event stream ordering appears to have gone backwards (%i -> %i): "
"rewinding room forgetter processor",
self.pos,
room_max_stream_ordering,
)
self.pos = room_max_stream_ordering
if not self._hs.config.room.forget_on_leave:
# Update the processing position, so that if the server admin turns the
# feature on at a later date, we don't decide to forget every room that
# has ever been left in the past.
self.pos = self._store.get_room_max_stream_ordering()
await self._store.update_room_forgetter_stream_pos(self.pos)
return
# Loop round handling deltas until we're up to date
while True:
# Be sure to read the max stream_ordering *before* checking if there are any outstanding
# deltas, since there is otherwise a chance that we could miss updates which arrive
# after we check the deltas.
room_max_stream_ordering = self._store.get_room_max_stream_ordering()
if self.pos == room_max_stream_ordering:
break
logger.debug(
"Processing room forgetting %s->%s", self.pos, room_max_stream_ordering
)
(
max_pos,
deltas,
) = await self._storage_controllers.state.get_current_state_deltas(
self.pos, room_max_stream_ordering
)
logger.debug("Handling %d state deltas", len(deltas))
await self._handle_deltas(deltas)
self.pos = max_pos
# Expose current event processing position to prometheus
event_processing_positions.labels("room_forgetter").set(max_pos)
await self._store.update_room_forgetter_stream_pos(max_pos)
async def _handle_deltas(self, deltas: List[Dict[str, Any]]) -> None:
"""Called with the state deltas to process"""
for delta in deltas:
typ = delta["type"]
state_key = delta["state_key"]
room_id = delta["room_id"]
event_id = delta["event_id"]
prev_event_id = delta["prev_event_id"]
if typ != EventTypes.Member:
continue
if not self._hs.is_mine_id(state_key):
continue
change = await self._get_key_change(
prev_event_id,
event_id,
key_name="membership",
public_value=Membership.JOIN,
)
is_leave = change is MatchChange.now_false
if is_leave:
try:
await self._room_member_handler.forget(
UserID.from_string(state_key), room_id
)
except SynapseError as e:
if e.code == 400:
# The user is back in the room.
pass
else:
raise
def get_users_which_can_issue_invite(auth_events: StateMap[EventBase]) -> List[str]:

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@ -137,6 +137,3 @@ class RoomMemberWorkerHandler(RoomMemberHandler):
await self._notify_change_client(
user_id=target.to_string(), room_id=room_id, change="left"
)
async def forget(self, target: UserID, room_id: str) -> None:
raise RuntimeError("Cannot forget rooms on workers.")

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@ -94,7 +94,11 @@ from synapse.handlers.room import (
)
from synapse.handlers.room_batch import RoomBatchHandler
from synapse.handlers.room_list import RoomListHandler
from synapse.handlers.room_member import RoomMemberHandler, RoomMemberMasterHandler
from synapse.handlers.room_member import (
RoomForgetterHandler,
RoomMemberHandler,
RoomMemberMasterHandler,
)
from synapse.handlers.room_member_worker import RoomMemberWorkerHandler
from synapse.handlers.room_summary import RoomSummaryHandler
from synapse.handlers.search import SearchHandler
@ -233,6 +237,7 @@ class HomeServer(metaclass=abc.ABCMeta):
"message",
"pagination",
"profile",
"room_forgetter",
"stats",
]
@ -847,6 +852,10 @@ class HomeServer(metaclass=abc.ABCMeta):
def get_push_rules_handler(self) -> PushRulesHandler:
return PushRulesHandler(self)
@cache_in_self
def get_room_forgetter_handler(self) -> RoomForgetterHandler:
return RoomForgetterHandler(self)
@cache_in_self
def get_outbound_redis_connection(self) -> "ConnectionHandler":
"""

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@ -82,7 +82,7 @@ class EventIdMembership:
membership: str
class RoomMemberWorkerStore(EventsWorkerStore):
class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore):
def __init__(
self,
database: DatabasePool,
@ -1372,6 +1372,50 @@ class RoomMemberWorkerStore(EventsWorkerStore):
_is_local_host_in_room_ignoring_users_txn,
)
async def forget(self, user_id: str, room_id: str) -> None:
"""Indicate that user_id wishes to discard history for room_id."""
def f(txn: LoggingTransaction) -> None:
self.db_pool.simple_update_txn(
txn,
table="room_memberships",
keyvalues={"user_id": user_id, "room_id": room_id},
updatevalues={"forgotten": 1},
)
self._invalidate_cache_and_stream(txn, self.did_forget, (user_id, room_id))
self._invalidate_cache_and_stream(
txn, self.get_forgotten_rooms_for_user, (user_id,)
)
await self.db_pool.runInteraction("forget_membership", f)
async def get_room_forgetter_stream_pos(self) -> int:
"""Get the stream position of the background process to forget rooms when left
by users.
"""
return await self.db_pool.simple_select_one_onecol(
table="room_forgetter_stream_pos",
keyvalues={},
retcol="stream_id",
desc="room_forgetter_stream_pos",
)
async def update_room_forgetter_stream_pos(self, stream_id: int) -> None:
"""Update the stream position of the background process to forget rooms when
left by users.
Must only be used by the worker running the background process.
"""
assert self.hs.config.worker.run_background_tasks
await self.db_pool.simple_update_one(
table="room_forgetter_stream_pos",
keyvalues={},
updatevalues={"stream_id": stream_id},
desc="room_forgetter_stream_pos",
)
class RoomMemberBackgroundUpdateStore(SQLBaseStore):
def __init__(
@ -1553,29 +1597,6 @@ class RoomMemberStore(
):
super().__init__(database, db_conn, hs)
async def forget(self, user_id: str, room_id: str) -> None:
"""Indicate that user_id wishes to discard history for room_id."""
def f(txn: LoggingTransaction) -> None:
sql = (
"UPDATE"
" room_memberships"
" SET"
" forgotten = 1"
" WHERE"
" user_id = ?"
" AND"
" room_id = ?"
)
txn.execute(sql, (user_id, room_id))
self._invalidate_cache_and_stream(txn, self.did_forget, (user_id, room_id))
self._invalidate_cache_and_stream(
txn, self.get_forgotten_rooms_for_user, (user_id,)
)
await self.db_pool.runInteraction("forget_membership", f)
def extract_heroes_from_room_summary(
details: Mapping[str, MemberSummary], me: str

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@ -0,0 +1,24 @@
/* Copyright 2023 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.
*/
CREATE TABLE room_forgetter_stream_pos (
Lock CHAR(1) NOT NULL DEFAULT 'X' UNIQUE, -- Makes sure this table only has one row.
stream_id BIGINT NOT NULL,
CHECK (Lock='X')
);
INSERT INTO room_forgetter_stream_pos (
stream_id
) SELECT COALESCE(MAX(stream_ordering), 0) from events;

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@ -333,6 +333,17 @@ class RoomMemberMasterHandlerTestCase(HomeserverTestCase):
self.get_success(self.store.is_locally_forgotten_room(self.room_id))
)
@override_config({"forget_rooms_on_leave": True})
def test_leave_and_auto_forget(self) -> None:
"""Tests the `forget_rooms_on_leave` config option."""
self.helper.join(self.room_id, user=self.bob, tok=self.bob_token)
# alice is not the last room member that leaves and forgets the room
self.helper.leave(self.room_id, user=self.alice, tok=self.alice_token)
self.assertTrue(
self.get_success(self.store.did_forget(self.alice, self.room_id))
)
def test_leave_and_forget_last_user(self) -> None:
"""Tests that forget a room is successfully when the last user has left the room."""