207 lines
7.9 KiB
Python
207 lines
7.9 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2020 The Matrix.org Foundation C.I.C.
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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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import logging
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from typing import TYPE_CHECKING
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from synapse.events.utils import prune_event_dict
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from synapse.metrics.background_process_metrics import wrap_as_background_process
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from synapse.storage._base import SQLBaseStore
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from synapse.storage.database import DatabasePool
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from synapse.storage.databases.main.cache import CacheInvalidationWorkerStore
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from synapse.storage.databases.main.events_worker import EventsWorkerStore
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from synapse.util import json_encoder
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if TYPE_CHECKING:
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from synapse.server import HomeServer
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logger = logging.getLogger(__name__)
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class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBaseStore):
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def __init__(self, database: DatabasePool, db_conn, hs: "HomeServer"):
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super().__init__(database, db_conn, hs)
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if (
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hs.config.run_background_tasks
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and self.hs.config.redaction_retention_period is not None
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):
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hs.get_clock().looping_call(self._censor_redactions, 5 * 60 * 1000)
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@wrap_as_background_process("_censor_redactions")
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async def _censor_redactions(self):
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"""Censors all redactions older than the configured period that haven't
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been censored yet.
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By censor we mean update the event_json table with the redacted event.
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"""
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if self.hs.config.redaction_retention_period is None:
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return
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if not (
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await self.db_pool.updates.has_completed_background_update(
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"redactions_have_censored_ts_idx"
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)
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):
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# We don't want to run this until the appropriate index has been
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# created.
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return
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before_ts = self._clock.time_msec() - self.hs.config.redaction_retention_period
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# We fetch all redactions that:
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# 1. point to an event we have,
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# 2. has a received_ts from before the cut off, and
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# 3. we haven't yet censored.
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#
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# This is limited to 100 events to ensure that we don't try and do too
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# much at once. We'll get called again so this should eventually catch
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# up.
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sql = """
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SELECT redactions.event_id, redacts FROM redactions
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LEFT JOIN events AS original_event ON (
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redacts = original_event.event_id
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)
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WHERE NOT have_censored
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AND redactions.received_ts <= ?
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ORDER BY redactions.received_ts ASC
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LIMIT ?
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"""
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rows = await self.db_pool.execute(
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"_censor_redactions_fetch", None, sql, before_ts, 100
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)
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updates = []
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for redaction_id, event_id in rows:
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redaction_event = await self.get_event(redaction_id, allow_none=True)
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original_event = await self.get_event(
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event_id, allow_rejected=True, allow_none=True
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)
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# The SQL above ensures that we have both the redaction and
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# original event, so if the `get_event` calls return None it
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# means that the redaction wasn't allowed. Either way we know that
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# the result won't change so we mark the fact that we've checked.
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if (
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redaction_event
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and original_event
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and original_event.internal_metadata.is_redacted()
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):
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# Redaction was allowed
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pruned_json = json_encoder.encode(
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prune_event_dict(
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original_event.room_version, original_event.get_dict()
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)
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)
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else:
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# Redaction wasn't allowed
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pruned_json = None
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updates.append((redaction_id, event_id, pruned_json))
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def _update_censor_txn(txn):
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for redaction_id, event_id, pruned_json in updates:
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if pruned_json:
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self._censor_event_txn(txn, event_id, pruned_json)
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self.db_pool.simple_update_one_txn(
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txn,
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table="redactions",
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keyvalues={"event_id": redaction_id},
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updatevalues={"have_censored": True},
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)
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await self.db_pool.runInteraction("_update_censor_txn", _update_censor_txn)
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def _censor_event_txn(self, txn, event_id, pruned_json):
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"""Censor an event by replacing its JSON in the event_json table with the
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provided pruned JSON.
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Args:
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txn (LoggingTransaction): The database transaction.
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event_id (str): The ID of the event to censor.
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pruned_json (str): The pruned JSON
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"""
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self.db_pool.simple_update_one_txn(
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txn,
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table="event_json",
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keyvalues={"event_id": event_id},
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updatevalues={"json": pruned_json},
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)
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async def expire_event(self, event_id: str) -> None:
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"""Retrieve and expire an event that has expired, and delete its associated
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expiry timestamp. If the event can't be retrieved, delete its associated
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timestamp so we don't try to expire it again in the future.
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Args:
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event_id: The ID of the event to delete.
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"""
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# Try to retrieve the event's content from the database or the event cache.
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event = await self.get_event(event_id)
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def delete_expired_event_txn(txn):
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# Delete the expiry timestamp associated with this event from the database.
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self._delete_event_expiry_txn(txn, event_id)
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if not event:
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# If we can't find the event, log a warning and delete the expiry date
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# from the database so that we don't try to expire it again in the
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# future.
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logger.warning(
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"Can't expire event %s because we don't have it.", event_id
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)
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return
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# Prune the event's dict then convert it to JSON.
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pruned_json = json_encoder.encode(
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prune_event_dict(event.room_version, event.get_dict())
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)
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# Update the event_json table to replace the event's JSON with the pruned
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# JSON.
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self._censor_event_txn(txn, event.event_id, pruned_json)
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# We need to invalidate the event cache entry for this event because we
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# changed its content in the database. We can't call
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# self._invalidate_cache_and_stream because self.get_event_cache isn't of the
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# right type.
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txn.call_after(self._get_event_cache.invalidate, (event.event_id,))
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# Send that invalidation to replication so that other workers also invalidate
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# the event cache.
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self._send_invalidation_to_replication(
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txn, "_get_event_cache", (event.event_id,)
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)
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await self.db_pool.runInteraction(
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"delete_expired_event", delete_expired_event_txn
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)
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def _delete_event_expiry_txn(self, txn, event_id):
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"""Delete the expiry timestamp associated with an event ID without deleting the
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actual event.
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Args:
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txn (LoggingTransaction): The transaction to use to perform the deletion.
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event_id (str): The event ID to delete the associated expiry timestamp of.
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"""
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return self.db_pool.simple_delete_txn(
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txn=txn, table="event_expiry", keyvalues={"event_id": event_id}
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)
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