Fixes to the federation rate limiter (#5621)

- Put the default window_size back to 1000ms (broken by #5181)
- Make the `rc_federation` config actually do something
- fix an off-by-one error in the 'concurrent' limit
- Avoid creating an unused `_PerHostRatelimiter` object for every single
  incoming request
This commit is contained in:
Richard van der Hoff 2019-07-05 11:10:19 +01:00 committed by GitHub
parent 0e5434264f
commit 9481707a52
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6 changed files with 148 additions and 16 deletions

1
changelog.d/5621.bugfix Normal file
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@ -0,0 +1 @@
Various minor fixes to the federation request rate limiter.

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@ -23,7 +23,7 @@ class RateLimitConfig(object):
class FederationRateLimitConfig(object):
_items_and_default = {
"window_size": 10000,
"window_size": 1000,
"sleep_limit": 10,
"sleep_delay": 500,
"reject_limit": 50,
@ -54,7 +54,7 @@ class RatelimitConfig(Config):
# Load the new-style federation config, if it exists. Otherwise, fall
# back to the old method.
if "federation_rc" in config:
if "rc_federation" in config:
self.rc_federation = FederationRateLimitConfig(**config["rc_federation"])
else:
self.rc_federation = FederationRateLimitConfig(

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@ -36,9 +36,11 @@ class FederationRateLimiter(object):
clock (Clock)
config (FederationRateLimitConfig)
"""
self.clock = clock
self._config = config
self.ratelimiters = {}
def new_limiter():
return _PerHostRatelimiter(clock=clock, config=config)
self.ratelimiters = collections.defaultdict(new_limiter)
def ratelimit(self, host):
"""Used to ratelimit an incoming request from given host
@ -53,11 +55,9 @@ class FederationRateLimiter(object):
host (str): Origin of incoming request.
Returns:
_PerHostRatelimiter
context manager which returns a deferred.
"""
return self.ratelimiters.setdefault(
host, _PerHostRatelimiter(clock=self.clock, config=self._config)
).ratelimit()
return self.ratelimiters[host].ratelimit()
class _PerHostRatelimiter(object):
@ -122,7 +122,7 @@ class _PerHostRatelimiter(object):
self.request_times.append(time_now)
def queue_request():
if len(self.current_processing) > self.concurrent_requests:
if len(self.current_processing) >= self.concurrent_requests:
queue_defer = defer.Deferred()
self.ready_request_queue[request_id] = queue_defer
logger.info(

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@ -0,0 +1,40 @@
# -*- coding: utf-8 -*-
# Copyright 2019 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 synapse.config.homeserver import HomeServerConfig
from tests.unittest import TestCase
from tests.utils import default_config
class RatelimitConfigTestCase(TestCase):
def test_parse_rc_federation(self):
config_dict = default_config("test")
config_dict["rc_federation"] = {
"window_size": 20000,
"sleep_limit": 693,
"sleep_delay": 252,
"reject_limit": 198,
"concurrent": 7,
}
config = HomeServerConfig()
config.parse_config_dict(config_dict, "", "")
config_obj = config.rc_federation
self.assertEqual(config_obj.window_size, 20000)
self.assertEqual(config_obj.sleep_limit, 693)
self.assertEqual(config_obj.sleep_delay, 252)
self.assertEqual(config_obj.reject_limit, 198)
self.assertEqual(config_obj.concurrent, 7)

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@ -0,0 +1,97 @@
# -*- coding: utf-8 -*-
# Copyright 2019 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 synapse.config.homeserver import HomeServerConfig
from synapse.util.ratelimitutils import FederationRateLimiter
from tests.server import get_clock
from tests.unittest import TestCase
from tests.utils import default_config
class FederationRateLimiterTestCase(TestCase):
def test_ratelimit(self):
"""A simple test with the default values"""
reactor, clock = get_clock()
rc_config = build_rc_config()
ratelimiter = FederationRateLimiter(clock, rc_config)
with ratelimiter.ratelimit("testhost") as d1:
# shouldn't block
self.successResultOf(d1)
def test_concurrent_limit(self):
"""Test what happens when we hit the concurrent limit"""
reactor, clock = get_clock()
rc_config = build_rc_config({"rc_federation": {"concurrent": 2}})
ratelimiter = FederationRateLimiter(clock, rc_config)
with ratelimiter.ratelimit("testhost") as d1:
# shouldn't block
self.successResultOf(d1)
cm2 = ratelimiter.ratelimit("testhost")
d2 = cm2.__enter__()
# also shouldn't block
self.successResultOf(d2)
cm3 = ratelimiter.ratelimit("testhost")
d3 = cm3.__enter__()
# this one should block, though ...
self.assertNoResult(d3)
# ... until we complete an earlier request
cm2.__exit__(None, None, None)
self.successResultOf(d3)
def test_sleep_limit(self):
"""Test what happens when we hit the sleep limit"""
reactor, clock = get_clock()
rc_config = build_rc_config(
{"rc_federation": {"sleep_limit": 2, "sleep_delay": 500}}
)
ratelimiter = FederationRateLimiter(clock, rc_config)
with ratelimiter.ratelimit("testhost") as d1:
# shouldn't block
self.successResultOf(d1)
with ratelimiter.ratelimit("testhost") as d2:
# nor this
self.successResultOf(d2)
with ratelimiter.ratelimit("testhost") as d3:
# this one should block, though ...
self.assertNoResult(d3)
sleep_time = _await_resolution(reactor, d3)
self.assertAlmostEqual(sleep_time, 500, places=3)
def _await_resolution(reactor, d):
"""advance the clock until the deferred completes.
Returns the number of milliseconds it took to complete.
"""
start_time = reactor.seconds()
while not d.called:
reactor.advance(0.01)
return (reactor.seconds() - start_time) * 1000
def build_rc_config(settings={}):
config_dict = default_config("test")
config_dict.update(settings)
config = HomeServerConfig()
config.parse_config_dict(config_dict, "", "")
return config.rc_federation

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@ -152,12 +152,6 @@ def default_config(name, parse=False):
"mau_stats_only": False,
"mau_limits_reserved_threepids": [],
"admin_contact": None,
"rc_federation": {
"reject_limit": 10,
"sleep_limit": 10,
"sleep_delay": 10,
"concurrent": 10,
},
"rc_message": {"per_second": 10000, "burst_count": 10000},
"rc_registration": {"per_second": 10000, "burst_count": 10000},
"rc_login": {