326 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			326 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			Python
		
	
	
| # -*- coding: utf-8 -*-
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| # Copyright 2016 OpenMarket Ltd
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| #
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| # Licensed under the Apache License, Version 2.0 (the "License");
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| # you may not use this file except in compliance with the License.
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| # You may obtain a copy of the License at
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| #
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| #     http://www.apache.org/licenses/LICENSE-2.0
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| #
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| # Unless required by applicable law or agreed to in writing, software
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| # distributed under the License is distributed on an "AS IS" BASIS,
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| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| # See the License for the specific language governing permissions and
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| # limitations under the License.
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| 
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| import logging
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| 
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| from twisted.internet import defer
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| from twisted.internet.error import AlreadyCalled, AlreadyCancelled
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| 
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| from synapse.metrics.background_process_metrics import run_as_background_process
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| 
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| logger = logging.getLogger(__name__)
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| 
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| # The amount of time we always wait before ever emailing about a notification
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| # (to give the user a chance to respond to other push or notice the window)
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| DELAY_BEFORE_MAIL_MS = 10 * 60 * 1000
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| 
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| # THROTTLE is the minimum time between mail notifications sent for a given room.
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| # Each room maintains its own throttle counter, but each new mail notification
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| # sends the pending notifications for all rooms.
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| THROTTLE_START_MS = 10 * 60 * 1000
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| THROTTLE_MAX_MS = 24 * 60 * 60 * 1000  # 24h
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| # THROTTLE_MULTIPLIER = 6              # 10 mins, 1 hour, 6 hours, 24 hours
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| THROTTLE_MULTIPLIER = 144  # 10 mins, 24 hours - i.e. jump straight to 1 day
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| 
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| # If no event triggers a notification for this long after the previous,
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| # the throttle is released.
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| # 12 hours - a gap of 12 hours in conversation is surely enough to merit a new
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| # notification when things get going again...
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| THROTTLE_RESET_AFTER_MS = 12 * 60 * 60 * 1000
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| 
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| # does each email include all unread notifs, or just the ones which have happened
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| # since the last mail?
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| # XXX: this is currently broken as it includes ones from parted rooms(!)
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| INCLUDE_ALL_UNREAD_NOTIFS = False
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| 
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| 
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| class EmailPusher(object):
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|     """
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|     A pusher that sends email notifications about events (approximately)
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|     when they happen.
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|     This shares quite a bit of code with httpusher: it would be good to
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|     factor out the common parts
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|     """
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| 
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|     def __init__(self, hs, pusherdict, mailer):
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|         self.hs = hs
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|         self.mailer = mailer
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| 
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|         self.store = self.hs.get_datastore()
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|         self.clock = self.hs.get_clock()
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|         self.pusher_id = pusherdict["id"]
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|         self.user_id = pusherdict["user_name"]
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|         self.app_id = pusherdict["app_id"]
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|         self.email = pusherdict["pushkey"]
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|         self.last_stream_ordering = pusherdict["last_stream_ordering"]
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|         self.timed_call = None
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|         self.throttle_params = None
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| 
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|         # See httppusher
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|         self.max_stream_ordering = None
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| 
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|         self._is_processing = False
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| 
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|     def on_started(self, should_check_for_notifs):
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|         """Called when this pusher has been started.
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| 
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|         Args:
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|             should_check_for_notifs (bool): Whether we should immediately
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|                 check for push to send. Set to False only if it's known there
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|                 is nothing to send
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|         """
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|         if should_check_for_notifs and self.mailer is not None:
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|             self._start_processing()
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| 
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|     def on_stop(self):
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|         if self.timed_call:
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|             try:
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|                 self.timed_call.cancel()
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|             except (AlreadyCalled, AlreadyCancelled):
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|                 pass
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|             self.timed_call = None
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| 
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|     def on_new_notifications(self, min_stream_ordering, max_stream_ordering):
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|         if self.max_stream_ordering:
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|             self.max_stream_ordering = max(
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|                 max_stream_ordering, self.max_stream_ordering
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|             )
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|         else:
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|             self.max_stream_ordering = max_stream_ordering
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|         self._start_processing()
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| 
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|     def on_new_receipts(self, min_stream_id, max_stream_id):
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|         # We could wake up and cancel the timer but there tend to be quite a
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|         # lot of read receipts so it's probably less work to just let the
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|         # timer fire
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|         pass
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| 
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|     def on_timer(self):
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|         self.timed_call = None
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|         self._start_processing()
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| 
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|     def _start_processing(self):
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|         if self._is_processing:
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|             return
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| 
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|         run_as_background_process("emailpush.process", self._process)
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| 
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|     def _pause_processing(self):
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|         """Used by tests to temporarily pause processing of events.
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| 
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|         Asserts that its not currently processing.
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|         """
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|         assert not self._is_processing
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|         self._is_processing = True
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| 
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|     def _resume_processing(self):
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|         """Used by tests to resume processing of events after pausing.
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|         """
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|         assert self._is_processing
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|         self._is_processing = False
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|         self._start_processing()
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| 
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|     @defer.inlineCallbacks
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|     def _process(self):
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|         # we should never get here if we are already processing
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|         assert not self._is_processing
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| 
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|         try:
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|             self._is_processing = True
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| 
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|             if self.throttle_params is None:
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|                 # this is our first loop: load up the throttle params
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|                 self.throttle_params = yield self.store.get_throttle_params_by_room(
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|                     self.pusher_id
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|                 )
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| 
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|             # if the max ordering changes while we're running _unsafe_process,
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|             # call it again, and so on until we've caught up.
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|             while True:
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|                 starting_max_ordering = self.max_stream_ordering
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|                 try:
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|                     yield self._unsafe_process()
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|                 except Exception:
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|                     logger.exception("Exception processing notifs")
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|                 if self.max_stream_ordering == starting_max_ordering:
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|                     break
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|         finally:
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|             self._is_processing = False
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| 
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|     @defer.inlineCallbacks
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|     def _unsafe_process(self):
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|         """
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|         Main logic of the push loop without the wrapper function that sets
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|         up logging, measures and guards against multiple instances of it
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|         being run.
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|         """
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|         start = 0 if INCLUDE_ALL_UNREAD_NOTIFS else self.last_stream_ordering
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|         fn = self.store.get_unread_push_actions_for_user_in_range_for_email
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|         unprocessed = yield fn(self.user_id, start, self.max_stream_ordering)
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| 
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|         soonest_due_at = None
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| 
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|         if not unprocessed:
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|             yield self.save_last_stream_ordering_and_success(self.max_stream_ordering)
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|             return
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| 
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|         for push_action in unprocessed:
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|             received_at = push_action["received_ts"]
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|             if received_at is None:
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|                 received_at = 0
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|             notif_ready_at = received_at + DELAY_BEFORE_MAIL_MS
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| 
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|             room_ready_at = self.room_ready_to_notify_at(push_action["room_id"])
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| 
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|             should_notify_at = max(notif_ready_at, room_ready_at)
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| 
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|             if should_notify_at < self.clock.time_msec():
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|                 # one of our notifications is ready for sending, so we send
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|                 # *one* email updating the user on their notifications,
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|                 # we then consider all previously outstanding notifications
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|                 # to be delivered.
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| 
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|                 reason = {
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|                     "room_id": push_action["room_id"],
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|                     "now": self.clock.time_msec(),
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|                     "received_at": received_at,
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|                     "delay_before_mail_ms": DELAY_BEFORE_MAIL_MS,
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|                     "last_sent_ts": self.get_room_last_sent_ts(push_action["room_id"]),
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|                     "throttle_ms": self.get_room_throttle_ms(push_action["room_id"]),
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|                 }
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| 
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|                 yield self.send_notification(unprocessed, reason)
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| 
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|                 yield self.save_last_stream_ordering_and_success(
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|                     max([ea["stream_ordering"] for ea in unprocessed])
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|                 )
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| 
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|                 # we update the throttle on all the possible unprocessed push actions
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|                 for ea in unprocessed:
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|                     yield self.sent_notif_update_throttle(ea["room_id"], ea)
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|                 break
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|             else:
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|                 if soonest_due_at is None or should_notify_at < soonest_due_at:
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|                     soonest_due_at = should_notify_at
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| 
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|                 if self.timed_call is not None:
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|                     try:
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|                         self.timed_call.cancel()
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|                     except (AlreadyCalled, AlreadyCancelled):
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|                         pass
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|                     self.timed_call = None
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| 
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|         if soonest_due_at is not None:
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|             self.timed_call = self.hs.get_reactor().callLater(
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|                 self.seconds_until(soonest_due_at), self.on_timer
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|             )
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| 
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|     @defer.inlineCallbacks
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|     def save_last_stream_ordering_and_success(self, last_stream_ordering):
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|         if last_stream_ordering is None:
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|             # This happens if we haven't yet processed anything
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|             return
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| 
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|         self.last_stream_ordering = last_stream_ordering
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|         pusher_still_exists = (
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|             yield self.store.update_pusher_last_stream_ordering_and_success(
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|                 self.app_id,
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|                 self.email,
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|                 self.user_id,
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|                 last_stream_ordering,
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|                 self.clock.time_msec(),
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|             )
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|         )
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|         if not pusher_still_exists:
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|             # The pusher has been deleted while we were processing, so
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|             # lets just stop and return.
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|             self.on_stop()
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| 
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|     def seconds_until(self, ts_msec):
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|         secs = (ts_msec - self.clock.time_msec()) / 1000
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|         return max(secs, 0)
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| 
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|     def get_room_throttle_ms(self, room_id):
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|         if room_id in self.throttle_params:
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|             return self.throttle_params[room_id]["throttle_ms"]
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|         else:
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|             return 0
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| 
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|     def get_room_last_sent_ts(self, room_id):
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|         if room_id in self.throttle_params:
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|             return self.throttle_params[room_id]["last_sent_ts"]
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|         else:
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|             return 0
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| 
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|     def room_ready_to_notify_at(self, room_id):
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|         """
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|         Determines whether throttling should prevent us from sending an email
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|         for the given room
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|         Returns: The timestamp when we are next allowed to send an email notif
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|         for this room
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|         """
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|         last_sent_ts = self.get_room_last_sent_ts(room_id)
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|         throttle_ms = self.get_room_throttle_ms(room_id)
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| 
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|         may_send_at = last_sent_ts + throttle_ms
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|         return may_send_at
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| 
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|     @defer.inlineCallbacks
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|     def sent_notif_update_throttle(self, room_id, notified_push_action):
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|         # We have sent a notification, so update the throttle accordingly.
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|         # If the event that triggered the notif happened more than
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|         # THROTTLE_RESET_AFTER_MS after the previous one that triggered a
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|         # notif, we release the throttle. Otherwise, the throttle is increased.
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|         time_of_previous_notifs = yield self.store.get_time_of_last_push_action_before(
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|             notified_push_action["stream_ordering"]
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|         )
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| 
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|         time_of_this_notifs = notified_push_action["received_ts"]
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| 
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|         if time_of_previous_notifs is not None and time_of_this_notifs is not None:
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|             gap = time_of_this_notifs - time_of_previous_notifs
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|         else:
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|             # if we don't know the arrival time of one of the notifs (it was not
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|             # stored prior to email notification code) then assume a gap of
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|             # zero which will just not reset the throttle
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|             gap = 0
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| 
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|         current_throttle_ms = self.get_room_throttle_ms(room_id)
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| 
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|         if gap > THROTTLE_RESET_AFTER_MS:
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|             new_throttle_ms = THROTTLE_START_MS
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|         else:
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|             if current_throttle_ms == 0:
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|                 new_throttle_ms = THROTTLE_START_MS
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|             else:
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|                 new_throttle_ms = min(
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|                     current_throttle_ms * THROTTLE_MULTIPLIER, THROTTLE_MAX_MS
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|                 )
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|         self.throttle_params[room_id] = {
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|             "last_sent_ts": self.clock.time_msec(),
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|             "throttle_ms": new_throttle_ms,
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|         }
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|         yield self.store.set_throttle_params(
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|             self.pusher_id, room_id, self.throttle_params[room_id]
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|         )
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| 
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|     @defer.inlineCallbacks
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|     def send_notification(self, push_actions, reason):
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|         logger.info("Sending notif email for user %r", self.user_id)
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| 
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|         yield self.mailer.send_notification_mail(
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|             self.app_id, self.user_id, self.email, push_actions, reason
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|         )
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