anonymousland-synapse/synapse/push/emailpusher.py
2020-09-04 06:54:56 -04:00

318 lines
12 KiB
Python

# -*- 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, min_stream_ordering, 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
)