forked-synapse/synapse/push/bulk_push_rule_evaluator.py
2020-12-11 11:43:53 -05:00

537 lines
20 KiB
Python

# -*- coding: utf-8 -*-
# Copyright 2015 OpenMarket Ltd
# Copyright 2017 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 typing import TYPE_CHECKING, Any, Dict, List, Optional, Set, Tuple, Union
import attr
from prometheus_client import Counter
from synapse.api.constants import EventTypes, Membership, RelationTypes
from synapse.event_auth import get_user_power_level
from synapse.events import EventBase
from synapse.events.snapshot import EventContext
from synapse.state import POWER_KEY
from synapse.util.async_helpers import Linearizer
from synapse.util.caches import CacheMetric, register_cache
from synapse.util.caches.descriptors import lru_cache
from synapse.util.caches.lrucache import LruCache
from .push_rule_evaluator import PushRuleEvaluatorForEvent
if TYPE_CHECKING:
from synapse.app.homeserver import HomeServer
logger = logging.getLogger(__name__)
push_rules_invalidation_counter = Counter(
"synapse_push_bulk_push_rule_evaluator_push_rules_invalidation_counter", ""
)
push_rules_state_size_counter = Counter(
"synapse_push_bulk_push_rule_evaluator_push_rules_state_size_counter", ""
)
# Measures whether we use the fast path of using state deltas, or if we have to
# recalculate from scratch
push_rules_delta_state_cache_metric = register_cache(
"cache",
"push_rules_delta_state_cache_metric",
cache=[], # Meaningless size, as this isn't a cache that stores values
resizable=False,
)
STATE_EVENT_TYPES_TO_MARK_UNREAD = {
EventTypes.Topic,
EventTypes.Name,
EventTypes.RoomAvatar,
EventTypes.Tombstone,
}
def _should_count_as_unread(event: EventBase, context: EventContext) -> bool:
# Exclude rejected and soft-failed events.
if context.rejected or event.internal_metadata.is_soft_failed():
return False
# Exclude notices.
if (
not event.is_state()
and event.type == EventTypes.Message
and event.content.get("msgtype") == "m.notice"
):
return False
# Exclude edits.
relates_to = event.content.get("m.relates_to", {})
if relates_to.get("rel_type") == RelationTypes.REPLACE:
return False
# Mark events that have a non-empty string body as unread.
body = event.content.get("body")
if isinstance(body, str) and body:
return True
# Mark some state events as unread.
if event.is_state() and event.type in STATE_EVENT_TYPES_TO_MARK_UNREAD:
return True
# Mark encrypted events as unread.
if not event.is_state() and event.type == EventTypes.Encrypted:
return True
return False
class BulkPushRuleEvaluator:
"""Calculates the outcome of push rules for an event for all users in the
room at once.
"""
def __init__(self, hs: "HomeServer"):
self.hs = hs
self.store = hs.get_datastore()
self.auth = hs.get_auth()
self.room_push_rule_cache_metrics = register_cache(
"cache",
"room_push_rule_cache",
cache=[], # Meaningless size, as this isn't a cache that stores values,
resizable=False,
)
async def _get_rules_for_event(
self, event: EventBase, context: EventContext
) -> Dict[str, List[Dict[str, Any]]]:
"""This gets the rules for all users in the room at the time of the event,
as well as the push rules for the invitee if the event is an invite.
Returns:
dict of user_id -> push_rules
"""
room_id = event.room_id
rules_for_room = self._get_rules_for_room(room_id)
rules_by_user = await rules_for_room.get_rules(event, context)
# if this event is an invite event, we may need to run rules for the user
# who's been invited, otherwise they won't get told they've been invited
if event.type == "m.room.member" and event.content["membership"] == "invite":
invited = event.state_key
if invited and self.hs.is_mine_id(invited):
has_pusher = await self.store.user_has_pusher(invited)
if has_pusher:
rules_by_user = dict(rules_by_user)
rules_by_user[invited] = await self.store.get_push_rules_for_user(
invited
)
return rules_by_user
@lru_cache()
def _get_rules_for_room(self, room_id: str) -> "RulesForRoom":
"""Get the current RulesForRoom object for the given room id
"""
# It's important that RulesForRoom gets added to self._get_rules_for_room.cache
# before any lookup methods get called on it as otherwise there may be
# a race if invalidate_all gets called (which assumes its in the cache)
return RulesForRoom(
self.hs,
room_id,
self._get_rules_for_room.cache,
self.room_push_rule_cache_metrics,
)
async def _get_power_levels_and_sender_level(
self, event: EventBase, context: EventContext
) -> Tuple[dict, int]:
prev_state_ids = await context.get_prev_state_ids()
pl_event_id = prev_state_ids.get(POWER_KEY)
if pl_event_id:
# fastpath: if there's a power level event, that's all we need, and
# not having a power level event is an extreme edge case
auth_events = {POWER_KEY: await self.store.get_event(pl_event_id)}
else:
auth_events_ids = self.auth.compute_auth_events(
event, prev_state_ids, for_verification=False
)
auth_events_dict = await self.store.get_events(auth_events_ids)
auth_events = {(e.type, e.state_key): e for e in auth_events_dict.values()}
sender_level = get_user_power_level(event.sender, auth_events)
pl_event = auth_events.get(POWER_KEY)
return pl_event.content if pl_event else {}, sender_level
async def action_for_event_by_user(
self, event: EventBase, context: EventContext
) -> None:
"""Given an event and context, evaluate the push rules, check if the message
should increment the unread count, and insert the results into the
event_push_actions_staging table.
"""
count_as_unread = _should_count_as_unread(event, context)
rules_by_user = await self._get_rules_for_event(event, context)
actions_by_user = {} # type: Dict[str, List[Union[dict, str]]]
room_members = await self.store.get_joined_users_from_context(event, context)
(
power_levels,
sender_power_level,
) = await self._get_power_levels_and_sender_level(event, context)
evaluator = PushRuleEvaluatorForEvent(
event, len(room_members), sender_power_level, power_levels
)
condition_cache = {} # type: Dict[str, bool]
for uid, rules in rules_by_user.items():
if event.sender == uid:
continue
if not event.is_state():
is_ignored = await self.store.is_ignored_by(event.sender, uid)
if is_ignored:
continue
display_name = None
profile_info = room_members.get(uid)
if profile_info:
display_name = profile_info.display_name
if not display_name:
# Handle the case where we are pushing a membership event to
# that user, as they might not be already joined.
if event.type == EventTypes.Member and event.state_key == uid:
display_name = event.content.get("displayname", None)
if count_as_unread:
# Add an element for the current user if the event needs to be marked as
# unread, so that add_push_actions_to_staging iterates over it.
# If the event shouldn't be marked as unread but should notify the
# current user, it'll be added to the dict later.
actions_by_user[uid] = []
for rule in rules:
if "enabled" in rule and not rule["enabled"]:
continue
matches = _condition_checker(
evaluator, rule["conditions"], uid, display_name, condition_cache
)
if matches:
actions = [x for x in rule["actions"] if x != "dont_notify"]
if actions and "notify" in actions:
# Push rules say we should notify the user of this event
actions_by_user[uid] = actions
break
# Mark in the DB staging area the push actions for users who should be
# notified for this event. (This will then get handled when we persist
# the event)
await self.store.add_push_actions_to_staging(
event.event_id, actions_by_user, count_as_unread,
)
def _condition_checker(
evaluator: PushRuleEvaluatorForEvent,
conditions: List[dict],
uid: str,
display_name: str,
cache: Dict[str, bool],
) -> bool:
for cond in conditions:
_id = cond.get("_id", None)
if _id:
res = cache.get(_id, None)
if res is False:
return False
elif res is True:
continue
res = evaluator.matches(cond, uid, display_name)
if _id:
cache[_id] = bool(res)
if not res:
return False
return True
class RulesForRoom:
"""Caches push rules for users in a room.
This efficiently handles users joining/leaving the room by not invalidating
the entire cache for the room.
"""
def __init__(
self,
hs: "HomeServer",
room_id: str,
rules_for_room_cache: LruCache,
room_push_rule_cache_metrics: CacheMetric,
):
"""
Args:
hs: The HomeServer object.
room_id: The room ID.
rules_for_room_cache: The cache object that caches these
RoomsForUser objects.
room_push_rule_cache_metrics: The metrics object
"""
self.room_id = room_id
self.is_mine_id = hs.is_mine_id
self.store = hs.get_datastore()
self.room_push_rule_cache_metrics = room_push_rule_cache_metrics
self.linearizer = Linearizer(name="rules_for_room")
# event_id -> (user_id, state)
self.member_map = {} # type: Dict[str, Tuple[str, str]]
# user_id -> rules
self.rules_by_user = {} # type: Dict[str, List[Dict[str, dict]]]
# The last state group we updated the caches for. If the state_group of
# a new event comes along, we know that we can just return the cached
# result.
# On invalidation of the rules themselves (if the user changes them),
# we invalidate everything and set state_group to `object()`
self.state_group = object()
# A sequence number to keep track of when we're allowed to update the
# cache. We bump the sequence number when we invalidate the cache. If
# the sequence number changes while we're calculating stuff we should
# not update the cache with it.
self.sequence = 0
# A cache of user_ids that we *know* aren't interesting, e.g. user_ids
# owned by AS's, or remote users, etc. (I.e. users we will never need to
# calculate push for)
# These never need to be invalidated as we will never set up push for
# them.
self.uninteresting_user_set = set() # type: Set[str]
# We need to be clever on the invalidating caches callbacks, as
# otherwise the invalidation callback holds a reference to the object,
# potentially causing it to leak.
# To get around this we pass a function that on invalidations looks ups
# the RoomsForUser entry in the cache, rather than keeping a reference
# to self around in the callback.
self.invalidate_all_cb = _Invalidation(rules_for_room_cache, room_id)
async def get_rules(
self, event: EventBase, context: EventContext
) -> Dict[str, List[Dict[str, dict]]]:
"""Given an event context return the rules for all users who are
currently in the room.
"""
state_group = context.state_group
if state_group and self.state_group == state_group:
logger.debug("Using cached rules for %r", self.room_id)
self.room_push_rule_cache_metrics.inc_hits()
return self.rules_by_user
with (await self.linearizer.queue(())):
if state_group and self.state_group == state_group:
logger.debug("Using cached rules for %r", self.room_id)
self.room_push_rule_cache_metrics.inc_hits()
return self.rules_by_user
self.room_push_rule_cache_metrics.inc_misses()
ret_rules_by_user = {}
missing_member_event_ids = {}
if state_group and self.state_group == context.prev_group:
# If we have a simple delta then we can reuse most of the previous
# results.
ret_rules_by_user = self.rules_by_user
current_state_ids = context.delta_ids
push_rules_delta_state_cache_metric.inc_hits()
else:
current_state_ids = await context.get_current_state_ids()
push_rules_delta_state_cache_metric.inc_misses()
# Ensure the state IDs exist.
assert current_state_ids is not None
push_rules_state_size_counter.inc(len(current_state_ids))
logger.debug(
"Looking for member changes in %r %r", state_group, current_state_ids
)
# Loop through to see which member events we've seen and have rules
# for and which we need to fetch
for key in current_state_ids:
typ, user_id = key
if typ != EventTypes.Member:
continue
if user_id in self.uninteresting_user_set:
continue
if not self.is_mine_id(user_id):
self.uninteresting_user_set.add(user_id)
continue
if self.store.get_if_app_services_interested_in_user(user_id):
self.uninteresting_user_set.add(user_id)
continue
event_id = current_state_ids[key]
res = self.member_map.get(event_id, None)
if res:
user_id, state = res
if state == Membership.JOIN:
rules = self.rules_by_user.get(user_id, None)
if rules:
ret_rules_by_user[user_id] = rules
continue
# If a user has left a room we remove their push rule. If they
# joined then we re-add it later in _update_rules_with_member_event_ids
ret_rules_by_user.pop(user_id, None)
missing_member_event_ids[user_id] = event_id
if missing_member_event_ids:
# If we have some member events we haven't seen, look them up
# and fetch push rules for them if appropriate.
logger.debug("Found new member events %r", missing_member_event_ids)
await self._update_rules_with_member_event_ids(
ret_rules_by_user, missing_member_event_ids, state_group, event
)
else:
# The push rules didn't change but lets update the cache anyway
self.update_cache(
self.sequence,
members={}, # There were no membership changes
rules_by_user=ret_rules_by_user,
state_group=state_group,
)
if logger.isEnabledFor(logging.DEBUG):
logger.debug(
"Returning push rules for %r %r", self.room_id, ret_rules_by_user.keys()
)
return ret_rules_by_user
async def _update_rules_with_member_event_ids(
self,
ret_rules_by_user: Dict[str, list],
member_event_ids: Dict[str, str],
state_group: Optional[int],
event: EventBase,
) -> None:
"""Update the partially filled rules_by_user dict by fetching rules for
any newly joined users in the `member_event_ids` list.
Args:
ret_rules_by_user: Partially filled dict of push rules. Gets
updated with any new rules.
member_event_ids: Dict of user id to event id for membership events
that have happened since the last time we filled rules_by_user
state_group: The state group we are currently computing push rules
for. Used when updating the cache.
event: The event we are currently computing push rules for.
"""
sequence = self.sequence
rows = await self.store.get_membership_from_event_ids(member_event_ids.values())
members = {row["event_id"]: (row["user_id"], row["membership"]) for row in rows}
# If the event is a join event then it will be in current state evnts
# map but not in the DB, so we have to explicitly insert it.
if event.type == EventTypes.Member:
for event_id in member_event_ids.values():
if event_id == event.event_id:
members[event_id] = (event.state_key, event.membership)
if logger.isEnabledFor(logging.DEBUG):
logger.debug("Found members %r: %r", self.room_id, members.values())
joined_user_ids = {
user_id
for user_id, membership in members.values()
if membership == Membership.JOIN
}
logger.debug("Joined: %r", joined_user_ids)
# Previously we only considered users with pushers or read receipts in that
# room. We can't do this anymore because we use push actions to calculate unread
# counts, which don't rely on the user having pushers or sent a read receipt into
# the room. Therefore we just need to filter for local users here.
user_ids = list(filter(self.is_mine_id, joined_user_ids))
rules_by_user = await self.store.bulk_get_push_rules(
user_ids, on_invalidate=self.invalidate_all_cb
)
ret_rules_by_user.update(
item for item in rules_by_user.items() if item[0] is not None
)
self.update_cache(sequence, members, ret_rules_by_user, state_group)
def invalidate_all(self) -> None:
# Note: Don't hand this function directly to an invalidation callback
# as it keeps a reference to self and will stop this instance from being
# GC'd if it gets dropped from the rules_to_user cache. Instead use
# `self.invalidate_all_cb`
logger.debug("Invalidating RulesForRoom for %r", self.room_id)
self.sequence += 1
self.state_group = object()
self.member_map = {}
self.rules_by_user = {}
push_rules_invalidation_counter.inc()
def update_cache(self, sequence, members, rules_by_user, state_group) -> None:
if sequence == self.sequence:
self.member_map.update(members)
self.rules_by_user = rules_by_user
self.state_group = state_group
@attr.attrs(slots=True, frozen=True)
class _Invalidation:
# _Invalidation is passed as an `on_invalidate` callback to bulk_get_push_rules,
# which means that it it is stored on the bulk_get_push_rules cache entry. In order
# to ensure that we don't accumulate lots of redunant callbacks on the cache entry,
# we need to ensure that two _Invalidation objects are "equal" if they refer to the
# same `cache` and `room_id`.
#
# attrs provides suitable __hash__ and __eq__ methods, provided we remember to
# set `frozen=True`.
cache = attr.ib(type=LruCache)
room_id = attr.ib(type=str)
def __call__(self) -> None:
rules = self.cache.get(self.room_id, None, update_metrics=False)
if rules:
rules.invalidate_all()