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- # -*- coding: utf-8 -*-
- # 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 twisted.internet.error import AlreadyCalled, AlreadyCancelled
- from synapse.metrics.background_process_metrics import run_as_background_process
- 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:
- """
- 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, pusherdict, mailer):
- self.hs = hs
- self.mailer = mailer
- self.store = self.hs.get_datastore()
- self.clock = self.hs.get_clock()
- self.pusher_id = pusherdict["id"]
- self.user_id = pusherdict["user_name"]
- self.app_id = pusherdict["app_id"]
- self.email = pusherdict["pushkey"]
- self.last_stream_ordering = pusherdict["last_stream_ordering"]
- self.timed_call = None
- self.throttle_params = None
- # See httppusher
- self.max_stream_ordering = None
- self._is_processing = False
- def on_started(self, should_check_for_notifs):
- """Called when this pusher has been started.
- Args:
- should_check_for_notifs (bool): 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):
- if self.timed_call:
- try:
- self.timed_call.cancel()
- except (AlreadyCalled, AlreadyCancelled):
- pass
- self.timed_call = None
- def on_new_notifications(self, max_stream_ordering):
- if self.max_stream_ordering:
- self.max_stream_ordering = max(
- max_stream_ordering, self.max_stream_ordering
- )
- else:
- self.max_stream_ordering = max_stream_ordering
- self._start_processing()
- def on_new_receipts(self, min_stream_id, max_stream_id):
- # 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):
- self.timed_call = None
- self._start_processing()
- def _start_processing(self):
- if self._is_processing:
- return
- run_as_background_process("emailpush.process", self._process)
- def _pause_processing(self):
- """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):
- """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):
- # we should never get here if we are already processing
- assert not self._is_processing
- try:
- self._is_processing = True
- if self.throttle_params is None:
- # this is our first loop: load up the throttle params
- self.throttle_params = await self.store.get_throttle_params_by_room(
- self.pusher_id
- )
- # 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):
- """
- 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
- fn = self.store.get_unread_push_actions_for_user_in_range_for_email
- unprocessed = await fn(self.user_id, start, self.max_stream_ordering)
- soonest_due_at = 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 = {
- "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):
- if last_stream_ordering is None:
- # This happens if we haven't yet processed anything
- return
- 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):
- secs = (ts_msec - self.clock.time_msec()) / 1000
- return max(secs, 0)
- def get_room_throttle_ms(self, room_id):
- 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):
- 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):
- """
- 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, notified_push_action):
- # 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] = {
- "last_sent_ts": self.clock.time_msec(),
- "throttle_ms": new_throttle_ms,
- }
- await self.store.set_throttle_params(
- self.pusher_id, room_id, self.throttle_params[room_id]
- )
- async def send_notification(self, push_actions, reason):
- 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
- )
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