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Diffstat (limited to 'synapse/push/emailpusher.py')
| -rw-r--r-- | synapse/push/emailpusher.py | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py new file mode 100644 index 0000000000..3a13c7485a --- /dev/null +++ b/synapse/push/emailpusher.py @@ -0,0 +1,251 @@ +# -*- 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. + +from twisted.internet import defer, reactor + +import logging + +from synapse.util.metrics import Measure +from synapse.util.logcontext import LoggingContext + +from mailer import Mailer + +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 = 2 * 60 * 1000 + +THROTTLE_START_MS = 2 * 60 * 1000 +THROTTLE_MAX_MS = (2 * 60 * 1000) * (2 ** 11) # ~3 days +THROTTLE_MULTIPLIER = 2 + +# If no event triggers a notification for this long after the previous, +# the throttle is released. +THROTTLE_RESET_AFTER_MS = (2 * 60 * 1000) * (2 ** 11) # ~3 days + + +class EmailPusher(object): + """ + 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): + self.hs = hs + 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.processing = False + + if self.hs.config.email_enable_notifs: + self.mailer = Mailer(self.hs) + else: + self.mailer = None + + @defer.inlineCallbacks + def on_started(self): + if self.mailer is not None: + self.throttle_params = yield self.store.get_throttle_params_by_room( + self.pusher_id + ) + yield self._process() + + def on_stop(self): + if self.timed_call: + self.timed_call.cancel() + + @defer.inlineCallbacks + def on_new_notifications(self, min_stream_ordering, max_stream_ordering): + self.max_stream_ordering = max(max_stream_ordering, self.max_stream_ordering) + yield self._process() + + 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 + return defer.succeed(None) + + @defer.inlineCallbacks + def on_timer(self): + self.timed_call = None + yield self._process() + + @defer.inlineCallbacks + def _process(self): + if self.processing: + return + + with LoggingContext("emailpush._process"): + with Measure(self.clock, "emailpush._process"): + try: + self.processing = 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: + yield self._unsafe_process() + except: + logger.exception("Exception processing notifs") + if self.max_stream_ordering == starting_max_ordering: + break + finally: + self.processing = False + + @defer.inlineCallbacks + 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. + """ + unprocessed = yield self.store.get_unread_push_actions_for_user_in_range( + self.user_id, self.last_stream_ordering, self.max_stream_ordering + ) + + soonest_due_at = None + + 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. + yield self.send_notification(unprocessed) + + yield self.save_last_stream_ordering_and_success(max([ + ea['stream_ordering'] for ea in unprocessed + ])) + yield self.sent_notif_update_throttle( + push_action['room_id'], push_action + ) + 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: + self.timed_call.cancel() + self.timed_call = None + + if soonest_due_at is not None: + self.timed_call = reactor.callLater( + self.seconds_until(soonest_due_at), self.on_timer + ) + + @defer.inlineCallbacks + def save_last_stream_ordering_and_success(self, last_stream_ordering): + self.last_stream_ordering = last_stream_ordering + yield self.store.update_pusher_last_stream_ordering_and_success( + self.app_id, self.email, self.user_id, + last_stream_ordering, self.clock.time_msec() + ) + + def seconds_until(self, ts_msec): + return (ts_msec - self.clock.time_msec()) / 1000 + + 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: True if we should send, False if we should not + """ + 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 + + @defer.inlineCallbacks + 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 = yield 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 + } + yield self.store.set_throttle_params( + self.pusher_id, room_id, self.throttle_params[room_id] + ) + + @defer.inlineCallbacks + def send_notification(self, push_actions): + logger.info("Sending notif email for user %r", self.user_id) + yield self.mailer.send_notification_mail( + self.user_id, self.email, push_actions + ) |