From b37c4724191995eec4f5bc9d64f176b2a315f777 Mon Sep 17 00:00:00 2001 From: Amber Brown Date: Fri, 10 Aug 2018 23:50:21 +1000 Subject: Rename async to async_helpers because `async` is a keyword on Python 3.7 (#3678) --- synapse/app/federation_sender.py | 2 +- synapse/federation/federation_server.py | 8 +- synapse/handlers/device.py | 2 +- synapse/handlers/federation.py | 2 +- synapse/handlers/initial_sync.py | 2 +- synapse/handlers/message.py | 2 +- synapse/handlers/pagination.py | 2 +- synapse/handlers/presence.py | 2 +- synapse/handlers/read_marker.py | 2 +- synapse/handlers/register.py | 2 +- synapse/handlers/room_list.py | 2 +- synapse/handlers/room_member.py | 2 +- synapse/handlers/sync.py | 2 +- synapse/http/client.py | 2 +- synapse/http/matrixfederationclient.py | 2 +- synapse/notifier.py | 2 +- synapse/push/bulk_push_rule_evaluator.py | 2 +- synapse/push/mailer.py | 2 +- synapse/rest/client/transactions.py | 2 +- synapse/rest/media/v1/media_repository.py | 2 +- synapse/rest/media/v1/preview_url_resource.py | 2 +- synapse/state.py | 2 +- synapse/storage/events.py | 2 +- synapse/storage/roommember.py | 2 +- synapse/util/async.py | 415 -------------------------- synapse/util/async_helpers.py | 415 ++++++++++++++++++++++++++ synapse/util/caches/descriptors.py | 2 +- synapse/util/caches/response_cache.py | 2 +- synapse/util/caches/snapshot_cache.py | 2 +- synapse/util/logcontext.py | 2 +- 30 files changed, 446 insertions(+), 446 deletions(-) delete mode 100644 synapse/util/async.py create mode 100644 synapse/util/async_helpers.py (limited to 'synapse') diff --git a/synapse/app/federation_sender.py b/synapse/app/federation_sender.py index e082d45c94..7bbf0ad082 100644 --- a/synapse/app/federation_sender.py +++ b/synapse/app/federation_sender.py @@ -40,7 +40,7 @@ from synapse.replication.slave.storage.transactions import TransactionStore from synapse.replication.tcp.client import ReplicationClientHandler from synapse.server import HomeServer from synapse.storage.engines import create_engine -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.httpresourcetree import create_resource_tree from synapse.util.logcontext import LoggingContext, run_in_background from synapse.util.manhole import manhole diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py index 2b62f687b6..a23136784a 100644 --- a/synapse/federation/federation_server.py +++ b/synapse/federation/federation_server.py @@ -40,7 +40,7 @@ from synapse.federation.persistence import TransactionActions from synapse.federation.units import Edu, Transaction from synapse.http.endpoint import parse_server_name from synapse.types import get_domain_from_id -from synapse.util import async +from synapse.util.async_helpers import Linearizer, concurrently_execute from synapse.util.caches.response_cache import ResponseCache from synapse.util.logutils import log_function @@ -67,8 +67,8 @@ class FederationServer(FederationBase): self.auth = hs.get_auth() self.handler = hs.get_handlers().federation_handler - self._server_linearizer = async.Linearizer("fed_server") - self._transaction_linearizer = async.Linearizer("fed_txn_handler") + self._server_linearizer = Linearizer("fed_server") + self._transaction_linearizer = Linearizer("fed_txn_handler") self.transaction_actions = TransactionActions(self.store) @@ -200,7 +200,7 @@ class FederationServer(FederationBase): event_id, f.getTraceback().rstrip(), ) - yield async.concurrently_execute( + yield concurrently_execute( process_pdus_for_room, pdus_by_room.keys(), TRANSACTION_CONCURRENCY_LIMIT, ) diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py index 2d44f15da3..9e017116a9 100644 --- a/synapse/handlers/device.py +++ b/synapse/handlers/device.py @@ -23,7 +23,7 @@ from synapse.api.constants import EventTypes from synapse.api.errors import FederationDeniedError from synapse.types import RoomStreamToken, get_domain_from_id from synapse.util import stringutils -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.caches.expiringcache import ExpiringCache from synapse.util.metrics import measure_func from synapse.util.retryutils import NotRetryingDestination diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py index 0dffd44e22..2380d17f4e 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py @@ -52,7 +52,7 @@ from synapse.events.validator import EventValidator from synapse.state import resolve_events_with_factory from synapse.types import UserID, get_domain_from_id from synapse.util import logcontext, unwrapFirstError -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.distributor import user_joined_room from synapse.util.frozenutils import unfreeze from synapse.util.logutils import log_function diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py index 40e7580a61..1fb17fd9a5 100644 --- a/synapse/handlers/initial_sync.py +++ b/synapse/handlers/initial_sync.py @@ -25,7 +25,7 @@ from synapse.handlers.presence import format_user_presence_state from synapse.streams.config import PaginationConfig from synapse.types import StreamToken, UserID from synapse.util import unwrapFirstError -from synapse.util.async import concurrently_execute +from synapse.util.async_helpers import concurrently_execute from synapse.util.caches.snapshot_cache import SnapshotCache from synapse.util.logcontext import make_deferred_yieldable, run_in_background from synapse.visibility import filter_events_for_client diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py index bcb093ba3e..01a362360e 100644 --- a/synapse/handlers/message.py +++ b/synapse/handlers/message.py @@ -32,7 +32,7 @@ from synapse.events.utils import serialize_event from synapse.events.validator import EventValidator from synapse.replication.http.send_event import ReplicationSendEventRestServlet from synapse.types import RoomAlias, UserID -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.frozenutils import frozendict_json_encoder from synapse.util.logcontext import run_in_background from synapse.util.metrics import measure_func diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py index b2849783ed..a97d43550f 100644 --- a/synapse/handlers/pagination.py +++ b/synapse/handlers/pagination.py @@ -22,7 +22,7 @@ from synapse.api.constants import Membership from synapse.api.errors import SynapseError from synapse.events.utils import serialize_event from synapse.types import RoomStreamToken -from synapse.util.async import ReadWriteLock +from synapse.util.async_helpers import ReadWriteLock from synapse.util.logcontext import run_in_background from synapse.util.stringutils import random_string from synapse.visibility import filter_events_for_client diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py index 3732830194..20fc3b0323 100644 --- a/synapse/handlers/presence.py +++ b/synapse/handlers/presence.py @@ -36,7 +36,7 @@ from synapse.api.errors import SynapseError from synapse.metrics import LaterGauge from synapse.storage.presence import UserPresenceState from synapse.types import UserID, get_domain_from_id -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.caches.descriptors import cachedInlineCallbacks from synapse.util.logcontext import run_in_background from synapse.util.logutils import log_function diff --git a/synapse/handlers/read_marker.py b/synapse/handlers/read_marker.py index 995460f82a..32108568c6 100644 --- a/synapse/handlers/read_marker.py +++ b/synapse/handlers/read_marker.py @@ -17,7 +17,7 @@ import logging from twisted.internet import defer -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from ._base import BaseHandler diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py index 0e16bbe0ee..3526b20d5a 100644 --- a/synapse/handlers/register.py +++ b/synapse/handlers/register.py @@ -28,7 +28,7 @@ from synapse.api.errors import ( ) from synapse.http.client import CaptchaServerHttpClient from synapse.types import RoomAlias, RoomID, UserID, create_requester -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.threepids import check_3pid_allowed from ._base import BaseHandler diff --git a/synapse/handlers/room_list.py b/synapse/handlers/room_list.py index 828229f5c3..37e41afd61 100644 --- a/synapse/handlers/room_list.py +++ b/synapse/handlers/room_list.py @@ -26,7 +26,7 @@ from twisted.internet import defer from synapse.api.constants import EventTypes, JoinRules from synapse.types import ThirdPartyInstanceID -from synapse.util.async import concurrently_execute +from synapse.util.async_helpers import concurrently_execute from synapse.util.caches.descriptors import cachedInlineCallbacks from synapse.util.caches.response_cache import ResponseCache diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py index 0d4a3f4677..fb94b5d7d4 100644 --- a/synapse/handlers/room_member.py +++ b/synapse/handlers/room_member.py @@ -30,7 +30,7 @@ import synapse.types from synapse.api.constants import EventTypes, Membership from synapse.api.errors import AuthError, Codes, SynapseError from synapse.types import RoomID, UserID -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.distributor import user_joined_room, user_left_room logger = logging.getLogger(__name__) diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py index dff1f67dcb..6393a9674b 100644 --- a/synapse/handlers/sync.py +++ b/synapse/handlers/sync.py @@ -25,7 +25,7 @@ from twisted.internet import defer from synapse.api.constants import EventTypes, Membership from synapse.push.clientformat import format_push_rules_for_user from synapse.types import RoomStreamToken -from synapse.util.async import concurrently_execute +from synapse.util.async_helpers import concurrently_execute from synapse.util.caches.expiringcache import ExpiringCache from synapse.util.caches.lrucache import LruCache from synapse.util.caches.response_cache import ResponseCache diff --git a/synapse/http/client.py b/synapse/http/client.py index 3771e0b3f6..ab4fbf59b2 100644 --- a/synapse/http/client.py +++ b/synapse/http/client.py @@ -42,7 +42,7 @@ from twisted.web.http_headers import Headers from synapse.api.errors import Codes, HttpResponseException, SynapseError from synapse.http import cancelled_to_request_timed_out_error, redact_uri from synapse.http.endpoint import SpiderEndpoint -from synapse.util.async import add_timeout_to_deferred +from synapse.util.async_helpers import add_timeout_to_deferred from synapse.util.caches import CACHE_SIZE_FACTOR from synapse.util.logcontext import make_deferred_yieldable diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py index 762273f59b..44b61e70a4 100644 --- a/synapse/http/matrixfederationclient.py +++ b/synapse/http/matrixfederationclient.py @@ -43,7 +43,7 @@ from synapse.api.errors import ( from synapse.http import cancelled_to_request_timed_out_error from synapse.http.endpoint import matrix_federation_endpoint from synapse.util import logcontext -from synapse.util.async import add_timeout_to_deferred +from synapse.util.async_helpers import add_timeout_to_deferred from synapse.util.logcontext import make_deferred_yieldable logger = logging.getLogger(__name__) diff --git a/synapse/notifier.py b/synapse/notifier.py index e650c3e494..82f391481c 100644 --- a/synapse/notifier.py +++ b/synapse/notifier.py @@ -25,7 +25,7 @@ from synapse.api.errors import AuthError from synapse.handlers.presence import format_user_presence_state from synapse.metrics import LaterGauge from synapse.types import StreamToken -from synapse.util.async import ( +from synapse.util.async_helpers import ( DeferredTimeoutError, ObservableDeferred, add_timeout_to_deferred, diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py index 1d14d3639c..8f9a76147f 100644 --- a/synapse/push/bulk_push_rule_evaluator.py +++ b/synapse/push/bulk_push_rule_evaluator.py @@ -26,7 +26,7 @@ from twisted.internet import defer from synapse.api.constants import EventTypes, Membership from synapse.event_auth import get_user_power_level from synapse.state import POWER_KEY -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.caches import register_cache from synapse.util.caches.descriptors import cached diff --git a/synapse/push/mailer.py b/synapse/push/mailer.py index 9d601208fd..bfa6df7b68 100644 --- a/synapse/push/mailer.py +++ b/synapse/push/mailer.py @@ -35,7 +35,7 @@ from synapse.push.presentable_names import ( name_from_member_event, ) from synapse.types import UserID -from synapse.util.async import concurrently_execute +from synapse.util.async_helpers import concurrently_execute from synapse.visibility import filter_events_for_client logger = logging.getLogger(__name__) diff --git a/synapse/rest/client/transactions.py b/synapse/rest/client/transactions.py index 00b1b3066e..511e96ab00 100644 --- a/synapse/rest/client/transactions.py +++ b/synapse/rest/client/transactions.py @@ -17,7 +17,7 @@ to ensure idempotency when performing PUTs using the REST API.""" import logging -from synapse.util.async import ObservableDeferred +from synapse.util.async_helpers import ObservableDeferred from synapse.util.logcontext import make_deferred_yieldable, run_in_background logger = logging.getLogger(__name__) diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py index 8fb413d825..4c589e05e0 100644 --- a/synapse/rest/media/v1/media_repository.py +++ b/synapse/rest/media/v1/media_repository.py @@ -36,7 +36,7 @@ from synapse.api.errors import ( ) from synapse.http.matrixfederationclient import MatrixFederationHttpClient from synapse.metrics.background_process_metrics import run_as_background_process -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.logcontext import make_deferred_yieldable from synapse.util.retryutils import NotRetryingDestination from synapse.util.stringutils import is_ascii, random_string diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py index 27aa0def2f..778ef97337 100644 --- a/synapse/rest/media/v1/preview_url_resource.py +++ b/synapse/rest/media/v1/preview_url_resource.py @@ -42,7 +42,7 @@ from synapse.http.server import ( ) from synapse.http.servlet import parse_integer, parse_string from synapse.metrics.background_process_metrics import run_as_background_process -from synapse.util.async import ObservableDeferred +from synapse.util.async_helpers import ObservableDeferred from synapse.util.caches.expiringcache import ExpiringCache from synapse.util.logcontext import make_deferred_yieldable, run_in_background from synapse.util.stringutils import is_ascii, random_string diff --git a/synapse/state.py b/synapse/state.py index e1092b97a9..8b92d4057a 100644 --- a/synapse/state.py +++ b/synapse/state.py @@ -28,7 +28,7 @@ from synapse import event_auth from synapse.api.constants import EventTypes from synapse.api.errors import AuthError from synapse.events.snapshot import EventContext -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.caches import CACHE_SIZE_FACTOR from synapse.util.caches.expiringcache import ExpiringCache from synapse.util.logutils import log_function diff --git a/synapse/storage/events.py b/synapse/storage/events.py index ce32e8fefd..d4aa192a0a 100644 --- a/synapse/storage/events.py +++ b/synapse/storage/events.py @@ -38,7 +38,7 @@ from synapse.storage.background_updates import BackgroundUpdateStore from synapse.storage.event_federation import EventFederationStore from synapse.storage.events_worker import EventsWorkerStore from synapse.types import RoomStreamToken, get_domain_from_id -from synapse.util.async import ObservableDeferred +from synapse.util.async_helpers import ObservableDeferred from synapse.util.caches.descriptors import cached, cachedInlineCallbacks from synapse.util.frozenutils import frozendict_json_encoder from synapse.util.logcontext import PreserveLoggingContext, make_deferred_yieldable diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py index 10dce21cea..9b4e6d6aa8 100644 --- a/synapse/storage/roommember.py +++ b/synapse/storage/roommember.py @@ -26,7 +26,7 @@ from twisted.internet import defer from synapse.api.constants import EventTypes, Membership from synapse.storage.events_worker import EventsWorkerStore from synapse.types import get_domain_from_id -from synapse.util.async import Linearizer +from synapse.util.async_helpers import Linearizer from synapse.util.caches import intern_string from synapse.util.caches.descriptors import cached, cachedInlineCallbacks from synapse.util.stringutils import to_ascii diff --git a/synapse/util/async.py b/synapse/util/async.py deleted file mode 100644 index a7094e2fb4..0000000000 --- a/synapse/util/async.py +++ /dev/null @@ -1,415 +0,0 @@ -# -*- coding: utf-8 -*- -# Copyright 2014-2016 OpenMarket Ltd -# Copyright 2018 New Vector 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. -import collections -import logging -from contextlib import contextmanager - -from six.moves import range - -from twisted.internet import defer -from twisted.internet.defer import CancelledError -from twisted.python import failure - -from synapse.util import Clock, logcontext, unwrapFirstError - -from .logcontext import ( - PreserveLoggingContext, - make_deferred_yieldable, - run_in_background, -) - -logger = logging.getLogger(__name__) - - -class ObservableDeferred(object): - """Wraps a deferred object so that we can add observer deferreds. These - observer deferreds do not affect the callback chain of the original - deferred. - - If consumeErrors is true errors will be captured from the origin deferred. - - Cancelling or otherwise resolving an observer will not affect the original - ObservableDeferred. - - NB that it does not attempt to do anything with logcontexts; in general - you should probably make_deferred_yieldable the deferreds - returned by `observe`, and ensure that the original deferred runs its - callbacks in the sentinel logcontext. - """ - - __slots__ = ["_deferred", "_observers", "_result"] - - def __init__(self, deferred, consumeErrors=False): - object.__setattr__(self, "_deferred", deferred) - object.__setattr__(self, "_result", None) - object.__setattr__(self, "_observers", set()) - - def callback(r): - object.__setattr__(self, "_result", (True, r)) - while self._observers: - try: - # TODO: Handle errors here. - self._observers.pop().callback(r) - except Exception: - pass - return r - - def errback(f): - object.__setattr__(self, "_result", (False, f)) - while self._observers: - try: - # TODO: Handle errors here. - self._observers.pop().errback(f) - except Exception: - pass - - if consumeErrors: - return None - else: - return f - - deferred.addCallbacks(callback, errback) - - def observe(self): - """Observe the underlying deferred. - - Can return either a deferred if the underlying deferred is still pending - (or has failed), or the actual value. Callers may need to use maybeDeferred. - """ - if not self._result: - d = defer.Deferred() - - def remove(r): - self._observers.discard(d) - return r - d.addBoth(remove) - - self._observers.add(d) - return d - else: - success, res = self._result - return res if success else defer.fail(res) - - def observers(self): - return self._observers - - def has_called(self): - return self._result is not None - - def has_succeeded(self): - return self._result is not None and self._result[0] is True - - def get_result(self): - return self._result[1] - - def __getattr__(self, name): - return getattr(self._deferred, name) - - def __setattr__(self, name, value): - setattr(self._deferred, name, value) - - def __repr__(self): - return "" % ( - id(self), self._result, self._deferred, - ) - - -def concurrently_execute(func, args, limit): - """Executes the function with each argument conncurrently while limiting - the number of concurrent executions. - - Args: - func (func): Function to execute, should return a deferred. - args (list): List of arguments to pass to func, each invocation of func - gets a signle argument. - limit (int): Maximum number of conccurent executions. - - Returns: - deferred: Resolved when all function invocations have finished. - """ - it = iter(args) - - @defer.inlineCallbacks - def _concurrently_execute_inner(): - try: - while True: - yield func(next(it)) - except StopIteration: - pass - - return logcontext.make_deferred_yieldable(defer.gatherResults([ - run_in_background(_concurrently_execute_inner) - for _ in range(limit) - ], consumeErrors=True)).addErrback(unwrapFirstError) - - -class Linearizer(object): - """Limits concurrent access to resources based on a key. Useful to ensure - only a few things happen at a time on a given resource. - - Example: - - with (yield limiter.queue("test_key")): - # do some work. - - """ - def __init__(self, name=None, max_count=1, clock=None): - """ - Args: - max_count(int): The maximum number of concurrent accesses - """ - if name is None: - self.name = id(self) - else: - self.name = name - - if not clock: - from twisted.internet import reactor - clock = Clock(reactor) - self._clock = clock - self.max_count = max_count - - # key_to_defer is a map from the key to a 2 element list where - # the first element is the number of things executing, and - # the second element is an OrderedDict, where the keys are deferreds for the - # things blocked from executing. - self.key_to_defer = {} - - @defer.inlineCallbacks - def queue(self, key): - entry = self.key_to_defer.setdefault(key, [0, collections.OrderedDict()]) - - # If the number of things executing is greater than the maximum - # then add a deferred to the list of blocked items - # When on of the things currently executing finishes it will callback - # this item so that it can continue executing. - if entry[0] >= self.max_count: - new_defer = defer.Deferred() - entry[1][new_defer] = 1 - - logger.info( - "Waiting to acquire linearizer lock %r for key %r", self.name, key, - ) - try: - yield make_deferred_yieldable(new_defer) - except Exception as e: - if isinstance(e, CancelledError): - logger.info( - "Cancelling wait for linearizer lock %r for key %r", - self.name, key, - ) - else: - logger.warn( - "Unexpected exception waiting for linearizer lock %r for key %r", - self.name, key, - ) - - # we just have to take ourselves back out of the queue. - del entry[1][new_defer] - raise - - logger.info("Acquired linearizer lock %r for key %r", self.name, key) - entry[0] += 1 - - # if the code holding the lock completes synchronously, then it - # will recursively run the next claimant on the list. That can - # relatively rapidly lead to stack exhaustion. This is essentially - # the same problem as http://twistedmatrix.com/trac/ticket/9304. - # - # In order to break the cycle, we add a cheeky sleep(0) here to - # ensure that we fall back to the reactor between each iteration. - # - # (This needs to happen while we hold the lock, and the context manager's exit - # code must be synchronous, so this is the only sensible place.) - yield self._clock.sleep(0) - - else: - logger.info( - "Acquired uncontended linearizer lock %r for key %r", self.name, key, - ) - entry[0] += 1 - - @contextmanager - def _ctx_manager(): - try: - yield - finally: - logger.info("Releasing linearizer lock %r for key %r", self.name, key) - - # We've finished executing so check if there are any things - # blocked waiting to execute and start one of them - entry[0] -= 1 - - if entry[1]: - (next_def, _) = entry[1].popitem(last=False) - - # we need to run the next thing in the sentinel context. - with PreserveLoggingContext(): - next_def.callback(None) - elif entry[0] == 0: - # We were the last thing for this key: remove it from the - # map. - del self.key_to_defer[key] - - defer.returnValue(_ctx_manager()) - - -class ReadWriteLock(object): - """A deferred style read write lock. - - Example: - - with (yield read_write_lock.read("test_key")): - # do some work - """ - - # IMPLEMENTATION NOTES - # - # We track the most recent queued reader and writer deferreds (which get - # resolved when they release the lock). - # - # Read: We know its safe to acquire a read lock when the latest writer has - # been resolved. The new reader is appeneded to the list of latest readers. - # - # Write: We know its safe to acquire the write lock when both the latest - # writers and readers have been resolved. The new writer replaces the latest - # writer. - - def __init__(self): - # Latest readers queued - self.key_to_current_readers = {} - - # Latest writer queued - self.key_to_current_writer = {} - - @defer.inlineCallbacks - def read(self, key): - new_defer = defer.Deferred() - - curr_readers = self.key_to_current_readers.setdefault(key, set()) - curr_writer = self.key_to_current_writer.get(key, None) - - curr_readers.add(new_defer) - - # We wait for the latest writer to finish writing. We can safely ignore - # any existing readers... as they're readers. - yield make_deferred_yieldable(curr_writer) - - @contextmanager - def _ctx_manager(): - try: - yield - finally: - new_defer.callback(None) - self.key_to_current_readers.get(key, set()).discard(new_defer) - - defer.returnValue(_ctx_manager()) - - @defer.inlineCallbacks - def write(self, key): - new_defer = defer.Deferred() - - curr_readers = self.key_to_current_readers.get(key, set()) - curr_writer = self.key_to_current_writer.get(key, None) - - # We wait on all latest readers and writer. - to_wait_on = list(curr_readers) - if curr_writer: - to_wait_on.append(curr_writer) - - # We can clear the list of current readers since the new writer waits - # for them to finish. - curr_readers.clear() - self.key_to_current_writer[key] = new_defer - - yield make_deferred_yieldable(defer.gatherResults(to_wait_on)) - - @contextmanager - def _ctx_manager(): - try: - yield - finally: - new_defer.callback(None) - if self.key_to_current_writer[key] == new_defer: - self.key_to_current_writer.pop(key) - - defer.returnValue(_ctx_manager()) - - -class DeferredTimeoutError(Exception): - """ - This error is raised by default when a L{Deferred} times out. - """ - - -def add_timeout_to_deferred(deferred, timeout, reactor, on_timeout_cancel=None): - """ - Add a timeout to a deferred by scheduling it to be cancelled after - timeout seconds. - - This is essentially a backport of deferred.addTimeout, which was introduced - in twisted 16.5. - - If the deferred gets timed out, it errbacks with a DeferredTimeoutError, - unless a cancelable function was passed to its initialization or unless - a different on_timeout_cancel callable is provided. - - Args: - deferred (defer.Deferred): deferred to be timed out - timeout (Number): seconds to time out after - reactor (twisted.internet.reactor): the Twisted reactor to use - - on_timeout_cancel (callable): A callable which is called immediately - after the deferred times out, and not if this deferred is - otherwise cancelled before the timeout. - - It takes an arbitrary value, which is the value of the deferred at - that exact point in time (probably a CancelledError Failure), and - the timeout. - - The default callable (if none is provided) will translate a - CancelledError Failure into a DeferredTimeoutError. - """ - timed_out = [False] - - def time_it_out(): - timed_out[0] = True - deferred.cancel() - - delayed_call = reactor.callLater(timeout, time_it_out) - - def convert_cancelled(value): - if timed_out[0]: - to_call = on_timeout_cancel or _cancelled_to_timed_out_error - return to_call(value, timeout) - return value - - deferred.addBoth(convert_cancelled) - - def cancel_timeout(result): - # stop the pending call to cancel the deferred if it's been fired - if delayed_call.active(): - delayed_call.cancel() - return result - - deferred.addBoth(cancel_timeout) - - -def _cancelled_to_timed_out_error(value, timeout): - if isinstance(value, failure.Failure): - value.trap(CancelledError) - raise DeferredTimeoutError(timeout, "Deferred") - return value diff --git a/synapse/util/async_helpers.py b/synapse/util/async_helpers.py new file mode 100644 index 0000000000..a7094e2fb4 --- /dev/null +++ b/synapse/util/async_helpers.py @@ -0,0 +1,415 @@ +# -*- coding: utf-8 -*- +# Copyright 2014-2016 OpenMarket Ltd +# Copyright 2018 New Vector 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. +import collections +import logging +from contextlib import contextmanager + +from six.moves import range + +from twisted.internet import defer +from twisted.internet.defer import CancelledError +from twisted.python import failure + +from synapse.util import Clock, logcontext, unwrapFirstError + +from .logcontext import ( + PreserveLoggingContext, + make_deferred_yieldable, + run_in_background, +) + +logger = logging.getLogger(__name__) + + +class ObservableDeferred(object): + """Wraps a deferred object so that we can add observer deferreds. These + observer deferreds do not affect the callback chain of the original + deferred. + + If consumeErrors is true errors will be captured from the origin deferred. + + Cancelling or otherwise resolving an observer will not affect the original + ObservableDeferred. + + NB that it does not attempt to do anything with logcontexts; in general + you should probably make_deferred_yieldable the deferreds + returned by `observe`, and ensure that the original deferred runs its + callbacks in the sentinel logcontext. + """ + + __slots__ = ["_deferred", "_observers", "_result"] + + def __init__(self, deferred, consumeErrors=False): + object.__setattr__(self, "_deferred", deferred) + object.__setattr__(self, "_result", None) + object.__setattr__(self, "_observers", set()) + + def callback(r): + object.__setattr__(self, "_result", (True, r)) + while self._observers: + try: + # TODO: Handle errors here. + self._observers.pop().callback(r) + except Exception: + pass + return r + + def errback(f): + object.__setattr__(self, "_result", (False, f)) + while self._observers: + try: + # TODO: Handle errors here. + self._observers.pop().errback(f) + except Exception: + pass + + if consumeErrors: + return None + else: + return f + + deferred.addCallbacks(callback, errback) + + def observe(self): + """Observe the underlying deferred. + + Can return either a deferred if the underlying deferred is still pending + (or has failed), or the actual value. Callers may need to use maybeDeferred. + """ + if not self._result: + d = defer.Deferred() + + def remove(r): + self._observers.discard(d) + return r + d.addBoth(remove) + + self._observers.add(d) + return d + else: + success, res = self._result + return res if success else defer.fail(res) + + def observers(self): + return self._observers + + def has_called(self): + return self._result is not None + + def has_succeeded(self): + return self._result is not None and self._result[0] is True + + def get_result(self): + return self._result[1] + + def __getattr__(self, name): + return getattr(self._deferred, name) + + def __setattr__(self, name, value): + setattr(self._deferred, name, value) + + def __repr__(self): + return "" % ( + id(self), self._result, self._deferred, + ) + + +def concurrently_execute(func, args, limit): + """Executes the function with each argument conncurrently while limiting + the number of concurrent executions. + + Args: + func (func): Function to execute, should return a deferred. + args (list): List of arguments to pass to func, each invocation of func + gets a signle argument. + limit (int): Maximum number of conccurent executions. + + Returns: + deferred: Resolved when all function invocations have finished. + """ + it = iter(args) + + @defer.inlineCallbacks + def _concurrently_execute_inner(): + try: + while True: + yield func(next(it)) + except StopIteration: + pass + + return logcontext.make_deferred_yieldable(defer.gatherResults([ + run_in_background(_concurrently_execute_inner) + for _ in range(limit) + ], consumeErrors=True)).addErrback(unwrapFirstError) + + +class Linearizer(object): + """Limits concurrent access to resources based on a key. Useful to ensure + only a few things happen at a time on a given resource. + + Example: + + with (yield limiter.queue("test_key")): + # do some work. + + """ + def __init__(self, name=None, max_count=1, clock=None): + """ + Args: + max_count(int): The maximum number of concurrent accesses + """ + if name is None: + self.name = id(self) + else: + self.name = name + + if not clock: + from twisted.internet import reactor + clock = Clock(reactor) + self._clock = clock + self.max_count = max_count + + # key_to_defer is a map from the key to a 2 element list where + # the first element is the number of things executing, and + # the second element is an OrderedDict, where the keys are deferreds for the + # things blocked from executing. + self.key_to_defer = {} + + @defer.inlineCallbacks + def queue(self, key): + entry = self.key_to_defer.setdefault(key, [0, collections.OrderedDict()]) + + # If the number of things executing is greater than the maximum + # then add a deferred to the list of blocked items + # When on of the things currently executing finishes it will callback + # this item so that it can continue executing. + if entry[0] >= self.max_count: + new_defer = defer.Deferred() + entry[1][new_defer] = 1 + + logger.info( + "Waiting to acquire linearizer lock %r for key %r", self.name, key, + ) + try: + yield make_deferred_yieldable(new_defer) + except Exception as e: + if isinstance(e, CancelledError): + logger.info( + "Cancelling wait for linearizer lock %r for key %r", + self.name, key, + ) + else: + logger.warn( + "Unexpected exception waiting for linearizer lock %r for key %r", + self.name, key, + ) + + # we just have to take ourselves back out of the queue. + del entry[1][new_defer] + raise + + logger.info("Acquired linearizer lock %r for key %r", self.name, key) + entry[0] += 1 + + # if the code holding the lock completes synchronously, then it + # will recursively run the next claimant on the list. That can + # relatively rapidly lead to stack exhaustion. This is essentially + # the same problem as http://twistedmatrix.com/trac/ticket/9304. + # + # In order to break the cycle, we add a cheeky sleep(0) here to + # ensure that we fall back to the reactor between each iteration. + # + # (This needs to happen while we hold the lock, and the context manager's exit + # code must be synchronous, so this is the only sensible place.) + yield self._clock.sleep(0) + + else: + logger.info( + "Acquired uncontended linearizer lock %r for key %r", self.name, key, + ) + entry[0] += 1 + + @contextmanager + def _ctx_manager(): + try: + yield + finally: + logger.info("Releasing linearizer lock %r for key %r", self.name, key) + + # We've finished executing so check if there are any things + # blocked waiting to execute and start one of them + entry[0] -= 1 + + if entry[1]: + (next_def, _) = entry[1].popitem(last=False) + + # we need to run the next thing in the sentinel context. + with PreserveLoggingContext(): + next_def.callback(None) + elif entry[0] == 0: + # We were the last thing for this key: remove it from the + # map. + del self.key_to_defer[key] + + defer.returnValue(_ctx_manager()) + + +class ReadWriteLock(object): + """A deferred style read write lock. + + Example: + + with (yield read_write_lock.read("test_key")): + # do some work + """ + + # IMPLEMENTATION NOTES + # + # We track the most recent queued reader and writer deferreds (which get + # resolved when they release the lock). + # + # Read: We know its safe to acquire a read lock when the latest writer has + # been resolved. The new reader is appeneded to the list of latest readers. + # + # Write: We know its safe to acquire the write lock when both the latest + # writers and readers have been resolved. The new writer replaces the latest + # writer. + + def __init__(self): + # Latest readers queued + self.key_to_current_readers = {} + + # Latest writer queued + self.key_to_current_writer = {} + + @defer.inlineCallbacks + def read(self, key): + new_defer = defer.Deferred() + + curr_readers = self.key_to_current_readers.setdefault(key, set()) + curr_writer = self.key_to_current_writer.get(key, None) + + curr_readers.add(new_defer) + + # We wait for the latest writer to finish writing. We can safely ignore + # any existing readers... as they're readers. + yield make_deferred_yieldable(curr_writer) + + @contextmanager + def _ctx_manager(): + try: + yield + finally: + new_defer.callback(None) + self.key_to_current_readers.get(key, set()).discard(new_defer) + + defer.returnValue(_ctx_manager()) + + @defer.inlineCallbacks + def write(self, key): + new_defer = defer.Deferred() + + curr_readers = self.key_to_current_readers.get(key, set()) + curr_writer = self.key_to_current_writer.get(key, None) + + # We wait on all latest readers and writer. + to_wait_on = list(curr_readers) + if curr_writer: + to_wait_on.append(curr_writer) + + # We can clear the list of current readers since the new writer waits + # for them to finish. + curr_readers.clear() + self.key_to_current_writer[key] = new_defer + + yield make_deferred_yieldable(defer.gatherResults(to_wait_on)) + + @contextmanager + def _ctx_manager(): + try: + yield + finally: + new_defer.callback(None) + if self.key_to_current_writer[key] == new_defer: + self.key_to_current_writer.pop(key) + + defer.returnValue(_ctx_manager()) + + +class DeferredTimeoutError(Exception): + """ + This error is raised by default when a L{Deferred} times out. + """ + + +def add_timeout_to_deferred(deferred, timeout, reactor, on_timeout_cancel=None): + """ + Add a timeout to a deferred by scheduling it to be cancelled after + timeout seconds. + + This is essentially a backport of deferred.addTimeout, which was introduced + in twisted 16.5. + + If the deferred gets timed out, it errbacks with a DeferredTimeoutError, + unless a cancelable function was passed to its initialization or unless + a different on_timeout_cancel callable is provided. + + Args: + deferred (defer.Deferred): deferred to be timed out + timeout (Number): seconds to time out after + reactor (twisted.internet.reactor): the Twisted reactor to use + + on_timeout_cancel (callable): A callable which is called immediately + after the deferred times out, and not if this deferred is + otherwise cancelled before the timeout. + + It takes an arbitrary value, which is the value of the deferred at + that exact point in time (probably a CancelledError Failure), and + the timeout. + + The default callable (if none is provided) will translate a + CancelledError Failure into a DeferredTimeoutError. + """ + timed_out = [False] + + def time_it_out(): + timed_out[0] = True + deferred.cancel() + + delayed_call = reactor.callLater(timeout, time_it_out) + + def convert_cancelled(value): + if timed_out[0]: + to_call = on_timeout_cancel or _cancelled_to_timed_out_error + return to_call(value, timeout) + return value + + deferred.addBoth(convert_cancelled) + + def cancel_timeout(result): + # stop the pending call to cancel the deferred if it's been fired + if delayed_call.active(): + delayed_call.cancel() + return result + + deferred.addBoth(cancel_timeout) + + +def _cancelled_to_timed_out_error(value, timeout): + if isinstance(value, failure.Failure): + value.trap(CancelledError) + raise DeferredTimeoutError(timeout, "Deferred") + return value diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py index 861c24809c..187510576a 100644 --- a/synapse/util/caches/descriptors.py +++ b/synapse/util/caches/descriptors.py @@ -25,7 +25,7 @@ from six import itervalues, string_types from twisted.internet import defer from synapse.util import logcontext, unwrapFirstError -from synapse.util.async import ObservableDeferred +from synapse.util.async_helpers import ObservableDeferred from synapse.util.caches import get_cache_factor_for from synapse.util.caches.lrucache import LruCache from synapse.util.caches.treecache import TreeCache, iterate_tree_cache_entry diff --git a/synapse/util/caches/response_cache.py b/synapse/util/caches/response_cache.py index a8491b42d5..afb03b2e1b 100644 --- a/synapse/util/caches/response_cache.py +++ b/synapse/util/caches/response_cache.py @@ -16,7 +16,7 @@ import logging from twisted.internet import defer -from synapse.util.async import ObservableDeferred +from synapse.util.async_helpers import ObservableDeferred from synapse.util.caches import register_cache from synapse.util.logcontext import make_deferred_yieldable, run_in_background diff --git a/synapse/util/caches/snapshot_cache.py b/synapse/util/caches/snapshot_cache.py index d03678b8c8..8318db8d2c 100644 --- a/synapse/util/caches/snapshot_cache.py +++ b/synapse/util/caches/snapshot_cache.py @@ -13,7 +13,7 @@ # See the License for the specific language governing permissions and # limitations under the License. -from synapse.util.async import ObservableDeferred +from synapse.util.async_helpers import ObservableDeferred class SnapshotCache(object): diff --git a/synapse/util/logcontext.py b/synapse/util/logcontext.py index 8dcae50b39..07e83fadda 100644 --- a/synapse/util/logcontext.py +++ b/synapse/util/logcontext.py @@ -526,7 +526,7 @@ _to_ignore = [ "synapse.util.logcontext", "synapse.http.server", "synapse.storage._base", - "synapse.util.async", + "synapse.util.async_helpers", ] -- cgit 1.4.1