# -*- 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.util.logutils import log_function
from synapse.util.logcontext import PreserveLoggingContext
from synapse.util.async import run_on_reactor
import logging
logger = logging.getLogger(__name__)
class _NotificationListener(object):
""" This represents a single client connection to the events stream.
The events stream handler will have yielded to the deferred, so to
notify the handler it is sufficient to resolve the deferred.
This listener will also keep track of which rooms it is listening in
so that it can remove itself from the indexes in the Notifier class.
"""
def __init__(self, user, rooms, from_token, limit, timeout, deferred):
self.user = user
self.from_token = from_token
self.limit = limit
self.timeout = timeout
self.deferred = deferred
self.rooms = rooms
self.pending_notifications = []
def notify(self, notifier, events, start_token, end_token):
""" Inform whoever is listening about the new events. This will
also remove this listener from all the indexes in the Notifier
it knows about.
"""
result = (events, (start_token, end_token))
try:
self.deferred.callback(result)
except defer.AlreadyCalledError:
pass
for room in self.rooms:
lst = notifier.rooms_to_listeners.get(room, set())
lst.discard(self)
notifier.user_to_listeners.get(self.user, set()).discard(self)
class Notifier(object):
""" This class is responsible for notifying any listeners when there are
new events available for it.
Primarily used from the /events stream.
"""
def __init__(self, hs):
self.hs = hs
self.rooms_to_listeners = {}
self.user_to_listeners = {}
self.event_sources = hs.get_event_sources()
self.clock = hs.get_clock()
hs.get_distributor().observe(
"user_joined_room", self._user_joined_room
)
@log_function
@defer.inlineCallbacks
def on_new_room_event(self, event, extra_users=[]):
""" Used by handlers to inform the notifier something has happened
in the room, room event wise.
This triggers the notifier to wake up any listeners that are
listening to the room, and any listeners for the users in the
`extra_users` param.
"""
yield run_on_reactor()
room_id = event.room_id
room_source = self.event_sources.sources["room"]
listeners = self.rooms_to_listeners.get(room_id, set()).copy()
for user in extra_users:
listeners |= self.user_to_listeners.get(user, set()).copy()
logger.debug("on_new_room_event listeners %s", listeners)
# TODO (erikj): Can we make this more efficient by hitting the
# db once?
@defer.inlineCallbacks
def notify(listener):
events, end_key = yield room_source.get_new_events_for_user(
listener.user,
listener.from_token.room_key,
listener.limit,
)
if events:
end_token = listener.from_token.copy_and_replace(
"room_key", end_key
)
listener.notify(
self, events, listener.from_token, end_token
)
def eb(failure):
logger.exception("Failed to notify listener", failure)
with PreserveLoggingContext():
yield defer.DeferredList(
[notify(l).addErrback(eb) for l in listeners]
)
@defer.inlineCallbacks
@log_function
def on_new_user_event(self, users=[], rooms=[]):
""" Used to inform listeners that something has happend
presence/user event wise.
Will wake up all listeners for the given users and rooms.
"""
yield run_on_reactor()
presence_source = self.event_sources.sources["presence"]
listeners = set()
for user in users:
listeners |= self.user_to_listeners.get(user, set()).copy()
for room in rooms:
listeners |= self.rooms_to_listeners.get(room, set()).copy()
@defer.inlineCallbacks
def notify(listener):
events, end_key = yield presence_source.get_new_events_for_user(
listener.user,
listener.from_token.presence_key,
listener.limit,
)
if events:
end_token = listener.from_token.copy_and_replace(
"presence_key", end_key
)
listener.notify(
self, events, listener.from_token, end_token
)
def eb(failure):
logger.error(
"Failed to notify listener",
exc_info=(
failure.type,
failure.value,
failure.getTracebackObject())
)
with PreserveLoggingContext():
yield defer.DeferredList(
[notify(l).addErrback(eb) for l in listeners]
)
def get_events_for(self, user, rooms, pagination_config, timeout):
""" For the given user and rooms, return any new events for them. If
there are no new events wait for up to `timeout` milliseconds for any
new events to happen before returning.
"""
deferred = defer.Deferred()
self._get_events(
deferred, user, rooms, pagination_config.from_token,
pagination_config.limit, timeout
).addErrback(deferred.errback)
return deferred
@defer.inlineCallbacks
def _get_events(self, deferred, user, rooms, from_token, limit, timeout):
if not from_token:
from_token = yield self.event_sources.get_current_token()
listener = _NotificationListener(
user,
rooms,
from_token,
limit,
timeout,
deferred,
)
def _timeout_listener():
# TODO (erikj): We should probably set to_token to the current
# max rather than reusing from_token.
listener.notify(
self,
[],
listener.from_token,
listener.from_token,
)
if timeout:
self.clock.call_later(timeout/1000.0, _timeout_listener)
self._register_with_keys(listener)
yield self._check_for_updates(listener)
if not timeout:
_timeout_listener()
return
@log_function
def _register_with_keys(self, listener):
for room in listener.rooms:
s = self.rooms_to_listeners.setdefault(room, set())
s.add(listener)
self.user_to_listeners.setdefault(listener.user, set()).add(listener)
@defer.inlineCallbacks
@log_function
def _check_for_updates(self, listener):
# TODO (erikj): We need to think about limits across multiple sources
events = []
from_token = listener.from_token
limit = listener.limit
# TODO (erikj): DeferredList?
for name, source in self.event_sources.sources.items():
keyname = "%s_key" % name
stuff, new_key = yield source.get_new_events_for_user(
listener.user,
getattr(from_token, keyname),
limit,
)
events.extend(stuff)
from_token = from_token.copy_and_replace(keyname, new_key)
end_token = from_token
if events:
listener.notify(self, events, listener.from_token, end_token)
defer.returnValue(listener)
def _user_joined_room(self, user, room_id):
new_listeners = self.user_to_listeners.get(user, set())
listeners = self.rooms_to_listeners.setdefault(room_id, set())
listeners |= new_listeners