Respect the @cancellable flag for ReplicationEndpoints (#12700)

While `ReplicationEndpoint`s register themselves via `JsonResource`,
they pass a method that calls the handler, instead of the handler itself,
to `register_paths`. As a result, `JsonResource` will not correctly pick
up the `@cancellable` flag and we have to apply it ourselves.

Signed-off-by: Sean Quah <seanq@element.io>
This commit is contained in:
Sean Quah 2022-05-11 12:25:39 +01:00 committed by GitHub
parent 9d8e380d2e
commit a559c8b0d9
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4 changed files with 139 additions and 2 deletions

1
changelog.d/12700.misc Normal file
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@ -0,0 +1 @@
Respect the `@cancellable` flag for `ReplicationEndpoint`s.

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@ -26,7 +26,8 @@ from twisted.web.server import Request
from synapse.api.errors import HttpResponseException, SynapseError
from synapse.http import RequestTimedOutError
from synapse.http.server import HttpServer
from synapse.http.server import HttpServer, is_method_cancellable
from synapse.http.site import SynapseRequest
from synapse.logging import opentracing
from synapse.logging.opentracing import trace
from synapse.types import JsonDict
@ -310,6 +311,12 @@ class ReplicationEndpoint(metaclass=abc.ABCMeta):
url_args = list(self.PATH_ARGS)
method = self.METHOD
if self.CACHE and is_method_cancellable(self._handle_request):
raise Exception(
f"{self.__class__.__name__} has been marked as cancellable, but CACHE "
"is set. The cancellable flag would have no effect."
)
if self.CACHE:
url_args.append("txn_id")
@ -324,7 +331,7 @@ class ReplicationEndpoint(metaclass=abc.ABCMeta):
)
async def _check_auth_and_handle(
self, request: Request, **kwargs: Any
self, request: SynapseRequest, **kwargs: Any
) -> Tuple[int, JsonDict]:
"""Called on new incoming requests when caching is enabled. Checks
if there is a cached response for the request and returns that,
@ -340,8 +347,18 @@ class ReplicationEndpoint(metaclass=abc.ABCMeta):
if self.CACHE:
txn_id = kwargs.pop("txn_id")
# We ignore the `@cancellable` flag, since cancellation wouldn't interupt
# `_handle_request` and `ResponseCache` does not handle cancellation
# correctly yet. In particular, there may be issues to do with logging
# context lifetimes.
return await self.response_cache.wrap(
txn_id, self._handle_request, request, **kwargs
)
# The `@cancellable` decorator may be applied to `_handle_request`. But we
# told `HttpServer.register_paths` that our handler is `_check_auth_and_handle`,
# so we have to set up the cancellable flag ourselves.
request.is_render_cancellable = is_method_cancellable(self._handle_request)
return await self._handle_request(request, **kwargs)

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@ -0,0 +1,13 @@
# Copyright 2022 The Matrix.org Foundation C.I.C.
#
# 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.

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@ -0,0 +1,106 @@
# Copyright 2022 The Matrix.org Foundation C.I.C.
#
# 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 http import HTTPStatus
from typing import Tuple
from twisted.web.server import Request
from synapse.api.errors import Codes
from synapse.http.server import JsonResource, cancellable
from synapse.replication.http import REPLICATION_PREFIX
from synapse.replication.http._base import ReplicationEndpoint
from synapse.server import HomeServer
from synapse.types import JsonDict
from tests import unittest
from tests.http.server._base import EndpointCancellationTestHelperMixin
class CancellableReplicationEndpoint(ReplicationEndpoint):
NAME = "cancellable_sleep"
PATH_ARGS = ()
CACHE = False
def __init__(self, hs: HomeServer):
super().__init__(hs)
self.clock = hs.get_clock()
@staticmethod
async def _serialize_payload() -> JsonDict:
return {}
@cancellable
async def _handle_request( # type: ignore[override]
self, request: Request
) -> Tuple[int, JsonDict]:
await self.clock.sleep(1.0)
return HTTPStatus.OK, {"result": True}
class UncancellableReplicationEndpoint(ReplicationEndpoint):
NAME = "uncancellable_sleep"
PATH_ARGS = ()
CACHE = False
def __init__(self, hs: HomeServer):
super().__init__(hs)
self.clock = hs.get_clock()
@staticmethod
async def _serialize_payload() -> JsonDict:
return {}
async def _handle_request( # type: ignore[override]
self, request: Request
) -> Tuple[int, JsonDict]:
await self.clock.sleep(1.0)
return HTTPStatus.OK, {"result": True}
class ReplicationEndpointCancellationTestCase(
unittest.HomeserverTestCase, EndpointCancellationTestHelperMixin
):
"""Tests for `ReplicationEndpoint` cancellation."""
def create_test_resource(self):
"""Overrides `HomeserverTestCase.create_test_resource`."""
resource = JsonResource(self.hs)
CancellableReplicationEndpoint(self.hs).register(resource)
UncancellableReplicationEndpoint(self.hs).register(resource)
return resource
def test_cancellable_disconnect(self) -> None:
"""Test that handlers with the `@cancellable` flag can be cancelled."""
path = f"{REPLICATION_PREFIX}/{CancellableReplicationEndpoint.NAME}/"
channel = self.make_request("POST", path, await_result=False)
self._test_disconnect(
self.reactor,
channel,
expect_cancellation=True,
expected_body={"error": "Request cancelled", "errcode": Codes.UNKNOWN},
)
def test_uncancellable_disconnect(self) -> None:
"""Test that handlers without the `@cancellable` flag cannot be cancelled."""
path = f"{REPLICATION_PREFIX}/{UncancellableReplicationEndpoint.NAME}/"
channel = self.make_request("POST", path, await_result=False)
self._test_disconnect(
self.reactor,
channel,
expect_cancellation=False,
expected_body={"result": True},
)