118 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			118 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			Python
		
	
	
| # -*- coding: utf-8 -*-
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| # Copyright 2019 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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| 
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| import itertools
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| import logging
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| 
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| from twisted.internet import defer
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| 
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| logger = logging.getLogger(__name__)
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| 
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| 
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| class PurgeEventsStorage(object):
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|     """High level interface for purging rooms and event history.
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|     """
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| 
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|     def __init__(self, hs, stores):
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|         self.stores = stores
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| 
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|     @defer.inlineCallbacks
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|     def purge_room(self, room_id: str):
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|         """Deletes all record of a room
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|         """
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| 
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|         state_groups_to_delete = yield self.stores.main.purge_room(room_id)
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|         yield self.stores.state.purge_room_state(room_id, state_groups_to_delete)
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| 
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|     @defer.inlineCallbacks
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|     def purge_history(self, room_id, token, delete_local_events):
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|         """Deletes room history before a certain point
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| 
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|         Args:
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|             room_id (str):
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| 
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|             token (str): A topological token to delete events before
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| 
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|             delete_local_events (bool):
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|                 if True, we will delete local events as well as remote ones
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|                 (instead of just marking them as outliers and deleting their
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|                 state groups).
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|         """
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|         state_groups = yield self.stores.main.purge_history(
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|             room_id, token, delete_local_events
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|         )
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| 
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|         logger.info("[purge] finding state groups that can be deleted")
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| 
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|         sg_to_delete = yield self._find_unreferenced_groups(state_groups)
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| 
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|         yield self.stores.state.purge_unreferenced_state_groups(room_id, sg_to_delete)
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| 
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|     @defer.inlineCallbacks
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|     def _find_unreferenced_groups(self, state_groups):
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|         """Used when purging history to figure out which state groups can be
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|         deleted.
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| 
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|         Args:
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|             state_groups (set[int]): Set of state groups referenced by events
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|                 that are going to be deleted.
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| 
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|         Returns:
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|             Deferred[set[int]] The set of state groups that can be deleted.
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|         """
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|         # Graph of state group -> previous group
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|         graph = {}
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| 
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|         # Set of events that we have found to be referenced by events
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|         referenced_groups = set()
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| 
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|         # Set of state groups we've already seen
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|         state_groups_seen = set(state_groups)
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| 
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|         # Set of state groups to handle next.
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|         next_to_search = set(state_groups)
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|         while next_to_search:
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|             # We bound size of groups we're looking up at once, to stop the
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|             # SQL query getting too big
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|             if len(next_to_search) < 100:
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|                 current_search = next_to_search
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|                 next_to_search = set()
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|             else:
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|                 current_search = set(itertools.islice(next_to_search, 100))
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|                 next_to_search -= current_search
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| 
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|             referenced = yield self.stores.main.get_referenced_state_groups(
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|                 current_search
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|             )
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|             referenced_groups |= referenced
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| 
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|             # We don't continue iterating up the state group graphs for state
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|             # groups that are referenced.
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|             current_search -= referenced
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| 
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|             edges = yield self.stores.state.get_previous_state_groups(current_search)
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| 
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|             prevs = set(edges.values())
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|             # We don't bother re-handling groups we've already seen
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|             prevs -= state_groups_seen
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|             next_to_search |= prevs
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|             state_groups_seen |= prevs
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| 
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|             graph.update(edges)
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| 
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|         to_delete = state_groups_seen - referenced_groups
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| 
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|         return to_delete
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