diff options
Diffstat (limited to 'synapse/state.py')
| -rw-r--r-- | synapse/state.py | 866 |
1 files changed, 0 insertions, 866 deletions
diff --git a/synapse/state.py b/synapse/state.py deleted file mode 100644 index e1092b97a9..0000000000 --- a/synapse/state.py +++ /dev/null @@ -1,866 +0,0 @@ -# -*- coding: utf-8 -*- -# Copyright 2014-2016 OpenMarket 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 hashlib -import logging -from collections import namedtuple - -from six import iteritems, iterkeys, itervalues - -from frozendict import frozendict - -from twisted.internet import defer - -from synapse import event_auth -from synapse.api.constants import EventTypes -from synapse.api.errors import AuthError -from synapse.events.snapshot import EventContext -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") - entry = yield self.resolve_state_groups_for_events( - event.room_id, [e for e, _ in event.prev_events], - ) - - 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): - """ 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]): - - 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, - )) - - result = yield self._state_resolution_handler.resolve_state_groups( - room_id, 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, - ) - - def resolve_events(self, 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 - } - - with Measure(self.clock, "state._resolve_events"): - new_state = resolve_events_with_state_map(state_set_ids, state_map) - - new_state = { - key: state_map[ev_id] for key, ev_id in iteritems(new_state) - } - - return 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, 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) - 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( - 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 _ordered_events(events): - def key_func(e): - return -int(e.depth), hashlib.sha1(e.event_id.encode('ascii')).hexdigest() - - return sorted(events, key=key_func) - - -def resolve_events_with_state_map(state_sets, state_map): - """ - Args: - 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 len(state_sets) == 1: - return state_sets[0] - - unconflicted_state, conflicted_state = _seperate( - state_sets, - ) - - auth_events = _create_auth_events_from_maps( - unconflicted_state, conflicted_state, state_map - ) - - return _resolve_with_state( - unconflicted_state, conflicted_state, auth_events, state_map - ) - - -def _seperate(state_sets): - """Takes the state_sets and figures out which keys are conflicted and - which aren't. i.e., which have multiple different event_ids associated - with them in different state sets. - - Args: - state_sets(iterable[dict[(str, str), str]]): - List of dicts of (type, state_key) -> event_id, which are the - different state groups to resolve. - - Returns: - (dict[(str, str), str], dict[(str, str), set[str]]): - A tuple of (unconflicted_state, conflicted_state), where: - - unconflicted_state is a dict mapping (type, state_key)->event_id - for unconflicted state keys. - - conflicted_state is a dict mapping (type, state_key) to a set of - event ids for conflicted state keys. - """ - state_set_iterator = iter(state_sets) - unconflicted_state = dict(next(state_set_iterator)) - conflicted_state = {} - - for state_set in state_set_iterator: - for key, value in iteritems(state_set): - # Check if there is an unconflicted entry for the state key. - unconflicted_value = unconflicted_state.get(key) - if unconflicted_value is None: - # There isn't an unconflicted entry so check if there is a - # conflicted entry. - ls = conflicted_state.get(key) - if ls is None: - # There wasn't a conflicted entry so haven't seen this key before. - # Therefore it isn't conflicted yet. - unconflicted_state[key] = value - else: - # This key is already conflicted, add our value to the conflict set. - ls.add(value) - elif unconflicted_value != value: - # If the unconflicted value is not the same as our value then we - # have a new conflict. So move the key from the unconflicted_state - # to the conflicted state. - conflicted_state[key] = {value, unconflicted_value} - unconflicted_state.pop(key, None) - - return unconflicted_state, conflicted_state - - -@defer.inlineCallbacks -def resolve_events_with_factory(state_sets, event_map, state_map_factory): - """ - Args: - 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 len(state_sets) == 1: - defer.returnValue(state_sets[0]) - - unconflicted_state, conflicted_state = _seperate( - state_sets, - ) - - needed_events = set( - event_id - for event_ids in itervalues(conflicted_state) - for event_id in event_ids - ) - if event_map is not None: - needed_events -= set(iterkeys(event_map)) - - logger.info("Asking for %d conflicted events", len(needed_events)) - - # dict[str, FrozenEvent]: a map from state event id to event. Only includes - # the state events which are in conflict (and those in event_map) - state_map = yield state_map_factory(needed_events) - if event_map is not None: - state_map.update(event_map) - - # get the ids of the auth events which allow us to authenticate the - # conflicted state, picking only from the unconflicting state. - # - # dict[(str, str), str]: a map from state key to event id - auth_events = _create_auth_events_from_maps( - unconflicted_state, conflicted_state, state_map - ) - - new_needed_events = set(itervalues(auth_events)) - new_needed_events -= needed_events - if event_map is not None: - new_needed_events -= set(iterkeys(event_map)) - - logger.info("Asking for %d auth events", len(new_needed_events)) - - state_map_new = yield state_map_factory(new_needed_events) - state_map.update(state_map_new) - - defer.returnValue(_resolve_with_state( - unconflicted_state, conflicted_state, auth_events, state_map - )) - - -def _create_auth_events_from_maps(unconflicted_state, conflicted_state, state_map): - auth_events = {} - for event_ids in itervalues(conflicted_state): - for event_id in event_ids: - if event_id in state_map: - keys = event_auth.auth_types_for_event(state_map[event_id]) - for key in keys: - if key not in auth_events: - event_id = unconflicted_state.get(key, None) - if event_id: - auth_events[key] = event_id - return auth_events - - -def _resolve_with_state(unconflicted_state_ids, conflicted_state_ids, auth_event_ids, - state_map): - conflicted_state = {} - for key, event_ids in iteritems(conflicted_state_ids): - events = [state_map[ev_id] for ev_id in event_ids if ev_id in state_map] - if len(events) > 1: - conflicted_state[key] = events - elif len(events) == 1: - unconflicted_state_ids[key] = events[0].event_id - - auth_events = { - key: state_map[ev_id] - for key, ev_id in iteritems(auth_event_ids) - if ev_id in state_map - } - - try: - resolved_state = _resolve_state_events( - conflicted_state, auth_events - ) - except Exception: - logger.exception("Failed to resolve state") - raise - - new_state = unconflicted_state_ids - for key, event in iteritems(resolved_state): - new_state[key] = event.event_id - - return new_state - - -def _resolve_state_events(conflicted_state, auth_events): - """ This is where we actually decide which of the conflicted state to - use. - - We resolve conflicts in the following order: - 1. power levels - 2. join rules - 3. memberships - 4. other events. - """ - resolved_state = {} - if POWER_KEY in conflicted_state: - events = conflicted_state[POWER_KEY] - logger.debug("Resolving conflicted power levels %r", events) - resolved_state[POWER_KEY] = _resolve_auth_events( - events, auth_events) - - auth_events.update(resolved_state) - - for key, events in iteritems(conflicted_state): - if key[0] == EventTypes.JoinRules: - logger.debug("Resolving conflicted join rules %r", events) - resolved_state[key] = _resolve_auth_events( - events, - auth_events - ) - - auth_events.update(resolved_state) - - for key, events in iteritems(conflicted_state): - if key[0] == EventTypes.Member: - logger.debug("Resolving conflicted member lists %r", events) - resolved_state[key] = _resolve_auth_events( - events, - auth_events - ) - - auth_events.update(resolved_state) - - for key, events in iteritems(conflicted_state): - if key not in resolved_state: - logger.debug("Resolving conflicted state %r:%r", key, events) - resolved_state[key] = _resolve_normal_events( - events, auth_events - ) - - return resolved_state - - -def _resolve_auth_events(events, auth_events): - reverse = [i for i in reversed(_ordered_events(events))] - - auth_keys = set( - key - for event in events - for key in event_auth.auth_types_for_event(event) - ) - - new_auth_events = {} - for key in auth_keys: - auth_event = auth_events.get(key, None) - if auth_event: - new_auth_events[key] = auth_event - - auth_events = new_auth_events - - prev_event = reverse[0] - for event in reverse[1:]: - auth_events[(prev_event.type, prev_event.state_key)] = prev_event - try: - # The signatures have already been checked at this point - event_auth.check(event, auth_events, do_sig_check=False, do_size_check=False) - prev_event = event - except AuthError: - return prev_event - - return event - - -def _resolve_normal_events(events, auth_events): - for event in _ordered_events(events): - try: - # The signatures have already been checked at this point - event_auth.check(event, auth_events, do_sig_check=False, do_size_check=False) - return event - except AuthError: - pass - - # Use the last event (the one with the least depth) if they all fail - # the auth check. - return event |