# Copyright 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 logging from typing import TYPE_CHECKING, Dict, List, Optional from twisted.internet.error import AlreadyCalled, AlreadyCancelled from twisted.internet.interfaces import IDelayedCall from synapse.metrics.background_process_metrics import run_as_background_process from synapse.push import Pusher, PusherConfig, PusherConfigException, ThrottleParams from synapse.push.mailer import Mailer from synapse.push.push_types import EmailReason from synapse.storage.databases.main.event_push_actions import EmailPushAction from synapse.util.threepids import validate_email if TYPE_CHECKING: from synapse.server import HomeServer logger = logging.getLogger(__name__) # The amount of time we always wait before ever emailing about a notification # (to give the user a chance to respond to other push or notice the window) DELAY_BEFORE_MAIL_MS = 10 * 60 * 1000 # THROTTLE is the minimum time between mail notifications sent for a given room. # Each room maintains its own throttle counter, but each new mail notification # sends the pending notifications for all rooms. THROTTLE_START_MS = 10 * 60 * 1000 THROTTLE_MAX_MS = 24 * 60 * 60 * 1000 # 24h # THROTTLE_MULTIPLIER = 6 # 10 mins, 1 hour, 6 hours, 24 hours THROTTLE_MULTIPLIER = 144 # 10 mins, 24 hours - i.e. jump straight to 1 day # If no event triggers a notification for this long after the previous, # the throttle is released. # 12 hours - a gap of 12 hours in conversation is surely enough to merit a new # notification when things get going again... THROTTLE_RESET_AFTER_MS = 12 * 60 * 60 * 1000 # does each email include all unread notifs, or just the ones which have happened # since the last mail? # XXX: this is currently broken as it includes ones from parted rooms(!) INCLUDE_ALL_UNREAD_NOTIFS = False class EmailPusher(Pusher): """ A pusher that sends email notifications about events (approximately) when they happen. This shares quite a bit of code with httpusher: it would be good to factor out the common parts """ def __init__(self, hs: "HomeServer", pusher_config: PusherConfig, mailer: Mailer): super().__init__(hs, pusher_config) self.mailer = mailer self.store = self.hs.get_datastores().main self.email = pusher_config.pushkey self.timed_call: Optional[IDelayedCall] = None self.throttle_params: Dict[str, ThrottleParams] = {} self._inited = False self._is_processing = False # Make sure that the email is valid. try: validate_email(self.email) except ValueError: raise PusherConfigException("Invalid email") def on_started(self, should_check_for_notifs: bool) -> None: """Called when this pusher has been started. Args: should_check_for_notifs: Whether we should immediately check for push to send. Set to False only if it's known there is nothing to send """ if should_check_for_notifs and self.mailer is not None: self._start_processing() def on_stop(self) -> None: if self.timed_call: try: self.timed_call.cancel() except (AlreadyCalled, AlreadyCancelled): pass self.timed_call = None def on_new_receipts(self, min_stream_id: int, max_stream_id: int) -> None: # We could wake up and cancel the timer but there tend to be quite a # lot of read receipts so it's probably less work to just let the # timer fire pass def on_timer(self) -> None: self.timed_call = None self._start_processing() def _start_processing(self) -> None: if self._is_processing: return run_as_background_process("emailpush.process", self._process) def _pause_processing(self) -> None: """Used by tests to temporarily pause processing of events. Asserts that its not currently processing. """ assert not self._is_processing self._is_processing = True def _resume_processing(self) -> None: """Used by tests to resume processing of events after pausing.""" assert self._is_processing self._is_processing = False self._start_processing() async def _process(self) -> None: # we should never get here if we are already processing assert not self._is_processing try: self._is_processing = True if not self._inited: # this is our first loop: load up the throttle params assert self.pusher_id is not None self.throttle_params = await self.store.get_throttle_params_by_room( self.pusher_id ) self._inited = True # if the max ordering changes while we're running _unsafe_process, # call it again, and so on until we've caught up. while True: starting_max_ordering = self.max_stream_ordering try: await self._unsafe_process() except Exception: logger.exception("Exception processing notifs") if self.max_stream_ordering == starting_max_ordering: break finally: self._is_processing = False async def _unsafe_process(self) -> None: """ Main logic of the push loop without the wrapper function that sets up logging, measures and guards against multiple instances of it being run. """ start = 0 if INCLUDE_ALL_UNREAD_NOTIFS else self.last_stream_ordering unprocessed = ( await self.store.get_unread_push_actions_for_user_in_range_for_email( self.user_id, start, self.max_stream_ordering ) ) soonest_due_at: Optional[int] = None if not unprocessed: await self.save_last_stream_ordering_and_success(self.max_stream_ordering) return for push_action in unprocessed: received_at = push_action.received_ts if received_at is None: received_at = 0 notif_ready_at = received_at + DELAY_BEFORE_MAIL_MS room_ready_at = self.room_ready_to_notify_at(push_action.room_id) should_notify_at = max(notif_ready_at, room_ready_at) if should_notify_at <= self.clock.time_msec(): # one of our notifications is ready for sending, so we send # *one* email updating the user on their notifications, # we then consider all previously outstanding notifications # to be delivered. reason: EmailReason = { "room_id": push_action.room_id, "now": self.clock.time_msec(), "received_at": received_at, "delay_before_mail_ms": DELAY_BEFORE_MAIL_MS, "last_sent_ts": self.get_room_last_sent_ts(push_action.room_id), "throttle_ms": self.get_room_throttle_ms(push_action.room_id), } await self.send_notification(unprocessed, reason) await self.save_last_stream_ordering_and_success( max(ea.stream_ordering for ea in unprocessed) ) # we update the throttle on all the possible unprocessed push actions for ea in unprocessed: await self.sent_notif_update_throttle(ea.room_id, ea) break else: if soonest_due_at is None or should_notify_at < soonest_due_at: soonest_due_at = should_notify_at if self.timed_call is not None: try: self.timed_call.cancel() except (AlreadyCalled, AlreadyCancelled): pass self.timed_call = None if soonest_due_at is not None: self.timed_call = self.hs.get_reactor().callLater( self.seconds_until(soonest_due_at), self.on_timer ) async def save_last_stream_ordering_and_success( self, last_stream_ordering: int ) -> None: self.last_stream_ordering = last_stream_ordering pusher_still_exists = ( await self.store.update_pusher_last_stream_ordering_and_success( self.app_id, self.email, self.user_id, last_stream_ordering, self.clock.time_msec(), ) ) if not pusher_still_exists: # The pusher has been deleted while we were processing, so # lets just stop and return. self.on_stop() def seconds_until(self, ts_msec: int) -> float: secs = (ts_msec - self.clock.time_msec()) / 1000 return max(secs, 0) def get_room_throttle_ms(self, room_id: str) -> int: if room_id in self.throttle_params: return self.throttle_params[room_id].throttle_ms else: return 0 def get_room_last_sent_ts(self, room_id: str) -> int: if room_id in self.throttle_params: return self.throttle_params[room_id].last_sent_ts else: return 0 def room_ready_to_notify_at(self, room_id: str) -> int: """ Determines whether throttling should prevent us from sending an email for the given room Returns: The timestamp when we are next allowed to send an email notif for this room """ last_sent_ts = self.get_room_last_sent_ts(room_id) throttle_ms = self.get_room_throttle_ms(room_id) may_send_at = last_sent_ts + throttle_ms return may_send_at async def sent_notif_update_throttle( self, room_id: str, notified_push_action: EmailPushAction ) -> None: # We have sent a notification, so update the throttle accordingly. # If the event that triggered the notif happened more than # THROTTLE_RESET_AFTER_MS after the previous one that triggered a # notif, we release the throttle. Otherwise, the throttle is increased. time_of_previous_notifs = await self.store.get_time_of_last_push_action_before( notified_push_action.stream_ordering ) time_of_this_notifs = notified_push_action.received_ts if time_of_previous_notifs is not None and time_of_this_notifs is not None: gap = time_of_this_notifs - time_of_previous_notifs else: # if we don't know the arrival time of one of the notifs (it was not # stored prior to email notification code) then assume a gap of # zero which will just not reset the throttle gap = 0 current_throttle_ms = self.get_room_throttle_ms(room_id) if gap > THROTTLE_RESET_AFTER_MS: new_throttle_ms = THROTTLE_START_MS else: if current_throttle_ms == 0: new_throttle_ms = THROTTLE_START_MS else: new_throttle_ms = min( current_throttle_ms * THROTTLE_MULTIPLIER, THROTTLE_MAX_MS ) self.throttle_params[room_id] = ThrottleParams( self.clock.time_msec(), new_throttle_ms, ) assert self.pusher_id is not None await self.store.set_throttle_params( self.pusher_id, room_id, self.throttle_params[room_id] ) async def send_notification( self, push_actions: List[EmailPushAction], reason: EmailReason ) -> None: logger.info("Sending notif email for user %r", self.user_id) await self.mailer.send_notification_mail( self.app_id, self.user_id, self.email, push_actions, reason )