From af03ecf35223f93971596f38393c62f4694705fa Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Wed, 6 Apr 2016 15:44:22 +0100 Subject: [PATCH] Deduplicate joins --- synapse/handlers/room_member.py | 31 +++++++++++++++++++ synapse/util/async.py | 42 +++++++++++++++++++++++++ synapse/util/caches/response_cache.py | 2 +- tests/util/test_linearizer.py | 44 +++++++++++++++++++++++++++ 4 files changed, 118 insertions(+), 1 deletion(-) create mode 100644 tests/util/test_linearizer.py diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py index fe2315df8f..0fcc9445a8 100644 --- a/synapse/handlers/room_member.py +++ b/synapse/handlers/room_member.py @@ -24,6 +24,7 @@ from synapse.api.constants import ( ) from synapse.api.errors import AuthError, SynapseError, Codes from synapse.util.logcontext import preserve_context_over_fn +from synapse.util.async import Linearizer from signedjson.sign import verify_signed_json from signedjson.key import decode_verify_key_bytes @@ -60,6 +61,8 @@ class RoomMemberHandler(BaseHandler): def __init__(self, hs): super(RoomMemberHandler, self).__init__(hs) + self.member_linearizer = Linearizer() + self.clock = hs.get_clock() self.distributor = hs.get_distributor() @@ -182,6 +185,34 @@ class RoomMemberHandler(BaseHandler): remote_room_hosts=None, third_party_signed=None, ratelimit=True, + ): + key = (target, room_id,) + + with (yield self.member_linearizer.queue(key)): + result = yield self._update_membership( + requester, + target, + room_id, + action, + txn_id=txn_id, + remote_room_hosts=remote_room_hosts, + third_party_signed=third_party_signed, + ratelimit=ratelimit, + ) + + defer.returnValue(result) + + @defer.inlineCallbacks + def _update_membership( + self, + requester, + target, + room_id, + action, + txn_id=None, + remote_room_hosts=None, + third_party_signed=None, + ratelimit=True, ): effective_membership_state = action if action in ["kick", "unban"]: diff --git a/synapse/util/async.py b/synapse/util/async.py index cd4d90f3cf..408c86be91 100644 --- a/synapse/util/async.py +++ b/synapse/util/async.py @@ -19,6 +19,8 @@ from twisted.internet import defer, reactor from .logcontext import PreserveLoggingContext, preserve_fn from synapse.util import unwrapFirstError +from contextlib import contextmanager + @defer.inlineCallbacks def sleep(seconds): @@ -137,3 +139,43 @@ def concurrently_execute(func, args, limit): preserve_fn(_concurrently_execute_inner)() for _ in xrange(limit) ], consumeErrors=True).addErrback(unwrapFirstError) + + +@contextmanager +def _trigger_defer_manager(d): + try: + yield + finally: + d.callback(None) + + +class Linearizer(object): + """Linearizes access to resources based on a key. Useful to ensure only one + thing is happening at a time on a given resource. + + Example: + + with (yield linearizer.queue("test_key")): + # do some work. + + """ + def __init__(self): + self.key_to_defer = {} + + @defer.inlineCallbacks + def queue(self, key): + current_defer = self.key_to_defer.get(key) + + new_defer = defer.Deferred() + self.key_to_defer[key] = new_defer + + def remove_if_current(_): + d = self.key_to_defer.get(key) + if d is new_defer: + self.key_to_defer.pop(key, None) + + new_defer.addBoth(remove_if_current) + + yield current_defer + + defer.returnValue(_trigger_defer_manager(new_defer)) diff --git a/synapse/util/caches/response_cache.py b/synapse/util/caches/response_cache.py index be310ba320..36686b479e 100644 --- a/synapse/util/caches/response_cache.py +++ b/synapse/util/caches/response_cache.py @@ -35,7 +35,7 @@ class ResponseCache(object): return None def set(self, key, deferred): - result = ObservableDeferred(deferred) + result = ObservableDeferred(deferred, consumeErrors=True) self.pending_result_cache[key] = result def remove(r): diff --git a/tests/util/test_linearizer.py b/tests/util/test_linearizer.py new file mode 100644 index 0000000000..afcba482f9 --- /dev/null +++ b/tests/util/test_linearizer.py @@ -0,0 +1,44 @@ +# -*- 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 tests import unittest + +from twisted.internet import defer + +from synapse.util.async import Linearizer + + +class LinearizerTestCase(unittest.TestCase): + + @defer.inlineCallbacks + def test_linearizer(self): + linearizer = Linearizer() + + key = object() + + d1 = linearizer.queue(key) + cm1 = yield d1 + + d2 = linearizer.queue(key) + self.assertFalse(d2.called) + + with cm1: + self.assertFalse(d2.called) + + self.assertTrue(d2.called) + + with (yield d2): + pass