123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656 |
- # -*- coding: utf-8 -*-
- # Copyright 2014-2016 OpenMarket Ltd
- # Copyright 2018 New Vector Ltd
- #
- # 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 collections import namedtuple
- from six import iteritems, itervalues
- from frozendict import frozendict
- from twisted.internet import defer
- from synapse.api.constants import EventTypes, RoomVersions
- from synapse.events.snapshot import EventContext
- from synapse.state import v1
- from synapse.util.async import Linearizer
- from synapse.util.caches import CACHE_SIZE_FACTOR
- from synapse.util.caches.expiringcache import ExpiringCache
- from synapse.util.logutils import log_function
- from synapse.util.metrics import Measure
- logger = logging.getLogger(__name__)
- KeyStateTuple = namedtuple("KeyStateTuple", ("context", "type", "state_key"))
- SIZE_OF_CACHE = int(100000 * CACHE_SIZE_FACTOR)
- EVICTION_TIMEOUT_SECONDS = 60 * 60
- _NEXT_STATE_ID = 1
- POWER_KEY = (EventTypes.PowerLevels, "")
- def _gen_state_id():
- global _NEXT_STATE_ID
- s = "X%d" % (_NEXT_STATE_ID,)
- _NEXT_STATE_ID += 1
- return s
- class _StateCacheEntry(object):
- __slots__ = ["state", "state_group", "state_id", "prev_group", "delta_ids"]
- def __init__(self, state, state_group, prev_group=None, delta_ids=None):
- # dict[(str, str), str] map from (type, state_key) to event_id
- self.state = frozendict(state)
- # the ID of a state group if one and only one is involved.
- # otherwise, None otherwise?
- self.state_group = state_group
- self.prev_group = prev_group
- self.delta_ids = frozendict(delta_ids) if delta_ids is not None else None
- # The `state_id` is a unique ID we generate that can be used as ID for
- # this collection of state. Usually this would be the same as the
- # state group, but on worker instances we can't generate a new state
- # group each time we resolve state, so we generate a separate one that
- # isn't persisted and is used solely for caches.
- # `state_id` is either a state_group (and so an int) or a string. This
- # ensures we don't accidentally persist a state_id as a stateg_group
- if state_group:
- self.state_id = state_group
- else:
- self.state_id = _gen_state_id()
- def __len__(self):
- return len(self.state)
- class StateHandler(object):
- """Fetches bits of state from the stores, and does state resolution
- where necessary
- """
- def __init__(self, hs):
- self.clock = hs.get_clock()
- self.store = hs.get_datastore()
- self.hs = hs
- self._state_resolution_handler = hs.get_state_resolution_handler()
- def start_caching(self):
- # TODO: remove this shim
- self._state_resolution_handler.start_caching()
- @defer.inlineCallbacks
- def get_current_state(self, room_id, event_type=None, state_key="",
- latest_event_ids=None):
- """ Retrieves the current state for the room. This is done by
- calling `get_latest_events_in_room` to get the leading edges of the
- event graph and then resolving any of the state conflicts.
- This is equivalent to getting the state of an event that were to send
- next before receiving any new events.
- If `event_type` is specified, then the method returns only the one
- event (or None) with that `event_type` and `state_key`.
- Returns:
- map from (type, state_key) to event
- """
- if not latest_event_ids:
- latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
- logger.debug("calling resolve_state_groups from get_current_state")
- ret = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
- state = ret.state
- if event_type:
- event_id = state.get((event_type, state_key))
- event = None
- if event_id:
- event = yield self.store.get_event(event_id, allow_none=True)
- defer.returnValue(event)
- return
- state_map = yield self.store.get_events(list(state.values()),
- get_prev_content=False)
- state = {
- key: state_map[e_id] for key, e_id in iteritems(state) if e_id in state_map
- }
- defer.returnValue(state)
- @defer.inlineCallbacks
- def get_current_state_ids(self, room_id, latest_event_ids=None):
- """Get the current state, or the state at a set of events, for a room
- Args:
- room_id (str):
- latest_event_ids (iterable[str]|None): if given, the forward
- extremities to resolve. If None, we look them up from the
- database (via a cache)
- Returns:
- Deferred[dict[(str, str), str)]]: the state dict, mapping from
- (event_type, state_key) -> event_id
- """
- if not latest_event_ids:
- latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
- logger.debug("calling resolve_state_groups from get_current_state_ids")
- ret = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
- state = ret.state
- defer.returnValue(state)
- @defer.inlineCallbacks
- def get_current_user_in_room(self, room_id, latest_event_ids=None):
- if not latest_event_ids:
- latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
- logger.debug("calling resolve_state_groups from get_current_user_in_room")
- entry = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
- joined_users = yield self.store.get_joined_users_from_state(room_id, entry)
- defer.returnValue(joined_users)
- @defer.inlineCallbacks
- def get_current_hosts_in_room(self, room_id, latest_event_ids=None):
- if not latest_event_ids:
- latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
- logger.debug("calling resolve_state_groups from get_current_hosts_in_room")
- entry = yield self.resolve_state_groups_for_events(room_id, latest_event_ids)
- joined_hosts = yield self.store.get_joined_hosts(room_id, entry)
- defer.returnValue(joined_hosts)
- @defer.inlineCallbacks
- def compute_event_context(self, event, old_state=None):
- """Build an EventContext structure for the event.
- This works out what the current state should be for the event, and
- generates a new state group if necessary.
- Args:
- event (synapse.events.EventBase):
- old_state (dict|None): The state at the event if it can't be
- calculated from existing events. This is normally only specified
- when receiving an event from federation where we don't have the
- prev events for, e.g. when backfilling.
- Returns:
- synapse.events.snapshot.EventContext:
- """
- if event.internal_metadata.is_outlier():
- # If this is an outlier, then we know it shouldn't have any current
- # state. Certainly store.get_current_state won't return any, and
- # persisting the event won't store the state group.
- if old_state:
- prev_state_ids = {
- (s.type, s.state_key): s.event_id for s in old_state
- }
- if event.is_state():
- current_state_ids = dict(prev_state_ids)
- key = (event.type, event.state_key)
- current_state_ids[key] = event.event_id
- else:
- current_state_ids = prev_state_ids
- else:
- current_state_ids = {}
- prev_state_ids = {}
- # We don't store state for outliers, so we don't generate a state
- # group for it.
- context = EventContext.with_state(
- state_group=None,
- current_state_ids=current_state_ids,
- prev_state_ids=prev_state_ids,
- )
- defer.returnValue(context)
- if old_state:
- # We already have the state, so we don't need to calculate it.
- # Let's just correctly fill out the context and create a
- # new state group for it.
- prev_state_ids = {
- (s.type, s.state_key): s.event_id for s in old_state
- }
- if event.is_state():
- key = (event.type, event.state_key)
- if key in prev_state_ids:
- replaces = prev_state_ids[key]
- if replaces != event.event_id: # Paranoia check
- event.unsigned["replaces_state"] = replaces
- current_state_ids = dict(prev_state_ids)
- current_state_ids[key] = event.event_id
- else:
- current_state_ids = prev_state_ids
- state_group = yield self.store.store_state_group(
- event.event_id,
- event.room_id,
- prev_group=None,
- delta_ids=None,
- current_state_ids=current_state_ids,
- )
- context = EventContext.with_state(
- state_group=state_group,
- current_state_ids=current_state_ids,
- prev_state_ids=prev_state_ids,
- )
- defer.returnValue(context)
- logger.debug("calling resolve_state_groups from compute_event_context")
- if event.type == EventTypes.Create:
- room_version = event.content.get("room_version", RoomVersions.V1)
- else:
- room_version = None
- entry = yield self.resolve_state_groups_for_events(
- event.room_id, [e for e, _ in event.prev_events],
- explicit_room_version=room_version,
- )
- prev_state_ids = entry.state
- prev_group = None
- delta_ids = None
- if event.is_state():
- # If this is a state event then we need to create a new state
- # group for the state after this event.
- key = (event.type, event.state_key)
- if key in prev_state_ids:
- replaces = prev_state_ids[key]
- event.unsigned["replaces_state"] = replaces
- current_state_ids = dict(prev_state_ids)
- current_state_ids[key] = event.event_id
- if entry.state_group:
- # If the state at the event has a state group assigned then
- # we can use that as the prev group
- prev_group = entry.state_group
- delta_ids = {
- key: event.event_id
- }
- elif entry.prev_group:
- # If the state at the event only has a prev group, then we can
- # use that as a prev group too.
- prev_group = entry.prev_group
- delta_ids = dict(entry.delta_ids)
- delta_ids[key] = event.event_id
- state_group = yield self.store.store_state_group(
- event.event_id,
- event.room_id,
- prev_group=prev_group,
- delta_ids=delta_ids,
- current_state_ids=current_state_ids,
- )
- else:
- current_state_ids = prev_state_ids
- prev_group = entry.prev_group
- delta_ids = entry.delta_ids
- if entry.state_group is None:
- entry.state_group = yield self.store.store_state_group(
- event.event_id,
- event.room_id,
- prev_group=entry.prev_group,
- delta_ids=entry.delta_ids,
- current_state_ids=current_state_ids,
- )
- entry.state_id = entry.state_group
- state_group = entry.state_group
- context = EventContext.with_state(
- state_group=state_group,
- current_state_ids=current_state_ids,
- prev_state_ids=prev_state_ids,
- prev_group=prev_group,
- delta_ids=delta_ids,
- )
- defer.returnValue(context)
- @defer.inlineCallbacks
- def resolve_state_groups_for_events(self, room_id, event_ids,
- explicit_room_version=None):
- """ Given a list of event_ids this method fetches the state at each
- event, resolves conflicts between them and returns them.
- Args:
- room_id (str)
- event_ids (list[str])
- explicit_room_version (str|None): If set uses the the given room
- version to choose the resolution algorithm. If None, then
- checks the database for room version.
- Returns:
- Deferred[_StateCacheEntry]: resolved state
- """
- logger.debug("resolve_state_groups event_ids %s", event_ids)
- # map from state group id to the state in that state group (where
- # 'state' is a map from state key to event id)
- # dict[int, dict[(str, str), str]]
- state_groups_ids = yield self.store.get_state_groups_ids(
- room_id, event_ids
- )
- if len(state_groups_ids) == 1:
- name, state_list = list(state_groups_ids.items()).pop()
- prev_group, delta_ids = yield self.store.get_state_group_delta(name)
- defer.returnValue(_StateCacheEntry(
- state=state_list,
- state_group=name,
- prev_group=prev_group,
- delta_ids=delta_ids,
- ))
- room_version = explicit_room_version
- if not room_version:
- room_version = yield self.store.get_room_version(room_id)
- result = yield self._state_resolution_handler.resolve_state_groups(
- room_id, room_version, state_groups_ids, None,
- self._state_map_factory,
- )
- defer.returnValue(result)
- def _state_map_factory(self, ev_ids):
- return self.store.get_events(
- ev_ids, get_prev_content=False, check_redacted=False,
- )
- @defer.inlineCallbacks
- def resolve_events(self, room_version, state_sets, event):
- logger.info(
- "Resolving state for %s with %d groups", event.room_id, len(state_sets)
- )
- state_set_ids = [{
- (ev.type, ev.state_key): ev.event_id
- for ev in st
- } for st in state_sets]
- state_map = {
- ev.event_id: ev
- for st in state_sets
- for ev in st
- }
- room_version = yield self.store.get_room_version(event.room_id)
- with Measure(self.clock, "state._resolve_events"):
- new_state = resolve_events_with_state_map(
- room_version, state_set_ids, state_map,
- )
- new_state = {
- key: state_map[ev_id] for key, ev_id in iteritems(new_state)
- }
- defer.returnValue(new_state)
- class StateResolutionHandler(object):
- """Responsible for doing state conflict resolution.
- Note that the storage layer depends on this handler, so all functions must
- be storage-independent.
- """
- def __init__(self, hs):
- self.clock = hs.get_clock()
- # dict of set of event_ids -> _StateCacheEntry.
- self._state_cache = None
- self.resolve_linearizer = Linearizer(name="state_resolve_lock")
- def start_caching(self):
- logger.debug("start_caching")
- self._state_cache = ExpiringCache(
- cache_name="state_cache",
- clock=self.clock,
- max_len=SIZE_OF_CACHE,
- expiry_ms=EVICTION_TIMEOUT_SECONDS * 1000,
- iterable=True,
- reset_expiry_on_get=True,
- )
- self._state_cache.start()
- @defer.inlineCallbacks
- @log_function
- def resolve_state_groups(
- self, room_id, room_version, state_groups_ids, event_map, state_map_factory,
- ):
- """Resolves conflicts between a set of state groups
- Always generates a new state group (unless we hit the cache), so should
- not be called for a single state group
- Args:
- room_id (str): room we are resolving for (used for logging)
- room_version (str): version of the room
- state_groups_ids (dict[int, dict[(str, str), str]]):
- map from state group id to the state in that state group
- (where 'state' is a map from state key to event id)
- event_map(dict[str,FrozenEvent]|None):
- a dict from event_id to event, for any events that we happen to
- have in flight (eg, those currently being persisted). This will be
- used as a starting point fof finding the state we need; any missing
- events will be requested via state_map_factory.
- If None, all events will be fetched via state_map_factory.
- Returns:
- Deferred[_StateCacheEntry]: resolved state
- """
- logger.debug(
- "resolve_state_groups state_groups %s",
- state_groups_ids.keys()
- )
- group_names = frozenset(state_groups_ids.keys())
- with (yield self.resolve_linearizer.queue(group_names)):
- if self._state_cache is not None:
- cache = self._state_cache.get(group_names, None)
- if cache:
- defer.returnValue(cache)
- logger.info(
- "Resolving state for %s with %d groups", room_id, len(state_groups_ids)
- )
- # start by assuming we won't have any conflicted state, and build up the new
- # state map by iterating through the state groups. If we discover a conflict,
- # we give up and instead use `resolve_events_with_factory`.
- #
- # XXX: is this actually worthwhile, or should we just let
- # resolve_events_with_factory do it?
- new_state = {}
- conflicted_state = False
- for st in itervalues(state_groups_ids):
- for key, e_id in iteritems(st):
- if key in new_state:
- conflicted_state = True
- break
- new_state[key] = e_id
- if conflicted_state:
- break
- if conflicted_state:
- logger.info("Resolving conflicted state for %r", room_id)
- with Measure(self.clock, "state._resolve_events"):
- new_state = yield resolve_events_with_factory(
- room_version,
- list(itervalues(state_groups_ids)),
- event_map=event_map,
- state_map_factory=state_map_factory,
- )
- # if the new state matches any of the input state groups, we can
- # use that state group again. Otherwise we will generate a state_id
- # which will be used as a cache key for future resolutions, but
- # not get persisted.
- with Measure(self.clock, "state.create_group_ids"):
- cache = _make_state_cache_entry(new_state, state_groups_ids)
- if self._state_cache is not None:
- self._state_cache[group_names] = cache
- defer.returnValue(cache)
- def _make_state_cache_entry(
- new_state,
- state_groups_ids,
- ):
- """Given a resolved state, and a set of input state groups, pick one to base
- a new state group on (if any), and return an appropriately-constructed
- _StateCacheEntry.
- Args:
- new_state (dict[(str, str), str]): resolved state map (mapping from
- (type, state_key) to event_id)
- state_groups_ids (dict[int, dict[(str, str), str]]):
- map from state group id to the state in that state group
- (where 'state' is a map from state key to event id)
- Returns:
- _StateCacheEntry
- """
- # if the new state matches any of the input state groups, we can
- # use that state group again. Otherwise we will generate a state_id
- # which will be used as a cache key for future resolutions, but
- # not get persisted.
- # first look for exact matches
- new_state_event_ids = set(itervalues(new_state))
- for sg, state in iteritems(state_groups_ids):
- if len(new_state_event_ids) != len(state):
- continue
- old_state_event_ids = set(itervalues(state))
- if new_state_event_ids == old_state_event_ids:
- # got an exact match.
- return _StateCacheEntry(
- state=new_state,
- state_group=sg,
- )
- # TODO: We want to create a state group for this set of events, to
- # increase cache hits, but we need to make sure that it doesn't
- # end up as a prev_group without being added to the database
- # failing that, look for the closest match.
- prev_group = None
- delta_ids = None
- for old_group, old_state in iteritems(state_groups_ids):
- n_delta_ids = {
- k: v
- for k, v in iteritems(new_state)
- if old_state.get(k) != v
- }
- if not delta_ids or len(n_delta_ids) < len(delta_ids):
- prev_group = old_group
- delta_ids = n_delta_ids
- return _StateCacheEntry(
- state=new_state,
- state_group=None,
- prev_group=prev_group,
- delta_ids=delta_ids,
- )
- def resolve_events_with_state_map(room_version, state_sets, state_map):
- """
- Args:
- room_version(str): Version of the room
- state_sets(list): List of dicts of (type, state_key) -> event_id,
- which are the different state groups to resolve.
- state_map(dict): a dict from event_id to event, for all events in
- state_sets.
- Returns
- dict[(str, str), str]:
- a map from (type, state_key) to event_id.
- """
- if room_version in (RoomVersions.V1, RoomVersions.VDH_TEST,):
- return v1.resolve_events_with_state_map(
- state_sets, state_map,
- )
- else:
- # This should only happen if we added a version but forgot to add it to
- # the list above.
- raise Exception(
- "No state resolution algorithm defined for version %r" % (room_version,)
- )
- def resolve_events_with_factory(room_version, state_sets, event_map, state_map_factory):
- """
- Args:
- room_version(str): Version of the room
- state_sets(list): List of dicts of (type, state_key) -> event_id,
- which are the different state groups to resolve.
- event_map(dict[str,FrozenEvent]|None):
- a dict from event_id to event, for any events that we happen to
- have in flight (eg, those currently being persisted). This will be
- used as a starting point fof finding the state we need; any missing
- events will be requested via state_map_factory.
- If None, all events will be fetched via state_map_factory.
- state_map_factory(func): will be called
- with a list of event_ids that are needed, and should return with
- a Deferred of dict of event_id to event.
- Returns
- Deferred[dict[(str, str), str]]:
- a map from (type, state_key) to event_id.
- """
- if room_version in (RoomVersions.V1, RoomVersions.VDH_TEST,):
- return v1.resolve_events_with_factory(
- state_sets, event_map, state_map_factory,
- )
- else:
- # This should only happen if we added a version but forgot to add it to
- # the list above.
- raise Exception(
- "No state resolution algorithm defined for version %r" % (room_version,)
- )
|