# -*- coding: utf-8 -*- # Copyright 2018 New Vector # # 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 twisted.internet import defer from synapse.util.caches.descriptors import cached from ._base import SQLBaseStore logger = logging.getLogger(__name__) # Number of msec of granularity to store the monthly_active_user timestamp # This means it is not necessary to update the table on every request LAST_SEEN_GRANULARITY = 60 * 60 * 1000 class MonthlyActiveUsersStore(SQLBaseStore): def __init__(self, dbconn, hs): super(MonthlyActiveUsersStore, self).__init__(None, hs) self._clock = hs.get_clock() self.hs = hs self.reserved_users = () @defer.inlineCallbacks def initialise_reserved_users(self, threepids): # TODO Why can't I do this in init? store = self.hs.get_datastore() reserved_user_list = [] # Do not add more reserved users than the total allowable number for tp in threepids[:self.hs.config.max_mau_value]: user_id = yield store.get_user_id_by_threepid( tp["medium"], tp["address"] ) if user_id: self.upsert_monthly_active_user(user_id) reserved_user_list.append(user_id) else: logger.warning( "mau limit reserved threepid %s not found in db" % tp ) self.reserved_users = tuple(reserved_user_list) @defer.inlineCallbacks def reap_monthly_active_users(self): """ Cleans out monthly active user table to ensure that no stale entries exist. Returns: Deferred[] """ def _reap_users(txn): thirty_days_ago = ( int(self._clock.time_msec()) - (1000 * 60 * 60 * 24 * 30) ) # Purge stale users # questionmarks is a hack to overcome sqlite not supporting # tuples in 'WHERE IN %s' questionmarks = '?' * len(self.reserved_users) query_args = [thirty_days_ago] query_args.extend(self.reserved_users) sql = """ DELETE FROM monthly_active_users WHERE timestamp < ? AND user_id NOT IN ({}) """.format(','.join(questionmarks)) txn.execute(sql, query_args) # If MAU user count still exceeds the MAU threshold, then delete on # a least recently active basis. # Note it is not possible to write this query using OFFSET due to # incompatibilities in how sqlite an postgres support the feature. # sqlite requires 'LIMIT -1 OFFSET ?', the LIMIT must be present # While Postgres does not require 'LIMIT', but also does not support # negative LIMIT values. So there is no way to write it that both can # support query_args = [self.hs.config.max_mau_value] query_args.extend(self.reserved_users) sql = """ DELETE FROM monthly_active_users WHERE user_id NOT IN ( SELECT user_id FROM monthly_active_users ORDER BY timestamp DESC LIMIT ? ) AND user_id NOT IN ({}) """.format(','.join(questionmarks)) txn.execute(sql, query_args) yield self.runInteraction("reap_monthly_active_users", _reap_users) # It seems poor to invalidate the whole cache, Postgres supports # 'Returning' which would allow me to invalidate only the # specific users, but sqlite has no way to do this and instead # I would need to SELECT and the DELETE which without locking # is racy. # Have resolved to invalidate the whole cache for now and do # something about it if and when the perf becomes significant self._user_last_seen_monthly_active.invalidate_all() self.get_monthly_active_count.invalidate_all() @cached(num_args=0) def get_monthly_active_count(self): """Generates current count of monthly active users Returns: Defered[int]: Number of current monthly active users """ def _count_users(txn): sql = "SELECT COALESCE(count(*), 0) FROM monthly_active_users" txn.execute(sql) count, = txn.fetchone() return count return self.runInteraction("count_users", _count_users) def upsert_monthly_active_user(self, user_id): """ Updates or inserts monthly active user member Arguments: user_id (str): user to add/update Deferred[bool]: True if a new entry was created, False if an existing one was updated. """ is_insert = self._simple_upsert( desc="upsert_monthly_active_user", table="monthly_active_users", keyvalues={ "user_id": user_id, }, values={ "timestamp": int(self._clock.time_msec()), }, lock=False, ) if is_insert: self._user_last_seen_monthly_active.invalidate((user_id,)) self.get_monthly_active_count.invalidate(()) @cached(num_args=1) def _user_last_seen_monthly_active(self, user_id): """ Checks if a given user is part of the monthly active user group Arguments: user_id (str): user to add/update Return: Deferred[int] : timestamp since last seen, None if never seen """ return(self._simple_select_one_onecol( table="monthly_active_users", keyvalues={ "user_id": user_id, }, retcol="timestamp", allow_none=True, desc="_user_last_seen_monthly_active", )) @defer.inlineCallbacks def populate_monthly_active_users(self, user_id): """Checks on the state of monthly active user limits and optionally add the user to the monthly active tables Args: user_id(str): the user_id to query """ if self.hs.config.limit_usage_by_mau: last_seen_timestamp = yield self._user_last_seen_monthly_active(user_id) now = self.hs.get_clock().time_msec() # We want to reduce to the total number of db writes, and are happy # to trade accuracy of timestamp in order to lighten load. This means # We always insert new users (where MAU threshold has not been reached), # but only update if we have not previously seen the user for # LAST_SEEN_GRANULARITY ms if last_seen_timestamp is None: count = yield self.get_monthly_active_count() if count < self.hs.config.max_mau_value: yield self.upsert_monthly_active_user(user_id) elif now - last_seen_timestamp > LAST_SEEN_GRANULARITY: yield self.upsert_monthly_active_user(user_id)