synapse-product/synapse/push/__init__.py

# -*- coding: utf-8 -*-
# Copyright 2014 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

from synapse.streams.config import PaginationConfig
from synapse.types import StreamToken

import synapse.util.async

import logging

logger = logging.getLogger(__name__)


class Pusher(object):
    INITIAL_BACKOFF = 1000
    MAX_BACKOFF = 60 * 60 * 1000
    GIVE_UP_AFTER = 24 * 60 * 60 * 1000

    def __init__(self, _hs, instance_handle, user_name, app_id,
                 app_display_name, device_display_name, pushkey, pushkey_ts,
                 data, last_token, last_success, failing_since):
        self.hs = _hs
        self.evStreamHandler = self.hs.get_handlers().event_stream_handler
        self.store = self.hs.get_datastore()
        self.clock = self.hs.get_clock()
        self.instance_handle = instance_handle,
        self.user_name = user_name
        self.app_id = app_id
        self.app_display_name = app_display_name
        self.device_display_name = device_display_name
        self.pushkey = pushkey
        self.pushkey_ts = pushkey_ts
        self.data = data
        self.last_token = last_token
        self.last_success = last_success  # not actually used
        self.backoff_delay = Pusher.INITIAL_BACKOFF
        self.failing_since = failing_since
        self.alive = True

    def _should_notify_for_event(self, ev):
        """
        This should take into account notification settings that the user
        has configured both globally and per-room when we have the ability
        to do such things.
        """
        if ev['user_id'] == self.user_name:
            # let's assume you probably know about messages you sent yourself
            return False
        return True

    @defer.inlineCallbacks
    def get_context_for_event(self, ev):
        name_aliases = yield self.store.get_room_name_and_aliases(
            ev['room_id']
        )

        ctx = {'aliases': name_aliases[1]}
        if name_aliases[0] is not None:
            ctx['name'] = name_aliases[0]

        defer.returnValue(ctx)


    @defer.inlineCallbacks
    def start(self):
        if not self.last_token:
            # First-time setup: get a token to start from (we can't
            # just start from no token, ie. 'now'
            # because we need the result to be reproduceable in case
            # we fail to dispatch the push)
            config = PaginationConfig(from_token=None, limit='1')
            chunk = yield self.evStreamHandler.get_stream(
                self.user_name, config, timeout=0)
            self.last_token = chunk['end']
            self.store.update_pusher_last_token(
                self.user_name, self.pushkey, self.last_token)
            logger.info("Pusher %s for user %s starting from token %s",
                        self.pushkey, self.user_name, self.last_token)

        while self.alive:
            from_tok = StreamToken.from_string(self.last_token)
            config = PaginationConfig(from_token=from_tok, limit='1')
            chunk = yield self.evStreamHandler.get_stream(
                self.user_name, config,
                timeout=100*365*24*60*60*1000, affect_presence=False
            )

            # limiting to 1 may get 1 event plus 1 presence event, so
            # pick out the actual event
            single_event = None
            for c in chunk['chunk']:
                if 'event_id' in c:  # Hmmm...
                    single_event = c
                    break
            if not single_event:
                self.last_token = chunk['end']
                continue

            if not self.alive:
                continue

            processed = False
            if self._should_notify_for_event(single_event):
                rejected = yield self.dispatch_push(single_event)
                if not rejected == False:
                    processed = True
                    for pk in rejected:
                        if pk != self.pushkey:
                            # for sanity, we only remove the pushkey if it
                            # was the one we actually sent...
                            logger.warn(
                                ("Ignoring rejected pushkey %s because we" +
                                "didn't send it"), (pk,)
                            )
                        else:
                            logger.info(
                                "Pushkey %s was rejected: removing",
                                pk
                            )
                            yield self.hs.get_pusherpool().remove_pusher(
                                self.app_id, pk
                            )
            else:
                processed = True

            if not self.alive:
                continue

            if processed:
                self.backoff_delay = Pusher.INITIAL_BACKOFF
                self.last_token = chunk['end']
                self.store.update_pusher_last_token_and_success(
                    self.user_name,
                    self.pushkey,
                    self.last_token,
                    self.clock.time_msec()
                )
                if self.failing_since:
                    self.failing_since = None
                    self.store.update_pusher_failing_since(
                        self.user_name,
                        self.pushkey,
                        self.failing_since)
            else:
                if not self.failing_since:
                    self.failing_since = self.clock.time_msec()
                    self.store.update_pusher_failing_since(
                        self.user_name,
                        self.pushkey,
                        self.failing_since
                    )

                if self.failing_since and \
                   self.failing_since < \
                   self.clock.time_msec() - Pusher.GIVE_UP_AFTER:
                    # we really only give up so that if the URL gets
                    # fixed, we don't suddenly deliver a load
                    # of old notifications.
                    logger.warn("Giving up on a notification to user %s, "
                                "pushkey %s",
                                self.user_name, self.pushkey)
                    self.backoff_delay = Pusher.INITIAL_BACKOFF
                    self.last_token = chunk['end']
                    self.store.update_pusher_last_token(
                        self.user_name,
                        self.pushkey,
                        self.last_token
                    )

                    self.failing_since = None
                    self.store.update_pusher_failing_since(
                        self.user_name,
                        self.pushkey,
                        self.failing_since
                    )
                else:
                    logger.warn("Failed to dispatch push for user %s "
                                "(failing for %dms)."
                                "Trying again in %dms",
                                self.user_name,
                                self.clock.time_msec() - self.failing_since,
                                self.backoff_delay
                                )
                    yield synapse.util.async.sleep(self.backoff_delay / 1000.0)
                    self.backoff_delay *= 2
                    if self.backoff_delay > Pusher.MAX_BACKOFF:
                        self.backoff_delay = Pusher.MAX_BACKOFF

    def stop(self):
        self.alive = False

    def dispatch_push(self, p):
        """
        Overridden by implementing classes to actually deliver the notification
        :param p: The event to notify for as a single event from the event stream
        :return: If the notification was delivered, an array containing any
                 pushkeys that were rejected by the push gateway.
                 False if the notification could not be delivered (ie.
                 should be retried).
        """
        pass


class PusherConfigException(Exception):
    def __init__(self, msg):
        super(PusherConfigException, self).__init__(msg)