forked from MirrorHub/synapse
Merge pull request #5836 from matrix-org/erikj/lower_bound_ttl_well_known
Add a lower bound to well-known TTL.
This commit is contained in:
commit
e9906b0772
1
changelog.d/5836.misc
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1
changelog.d/5836.misc
Normal file
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@ -0,0 +1 @@
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Add a lower bound to well-known lookup cache time to avoid repeated lookups.
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@ -12,10 +12,8 @@
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import json
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import logging
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import random
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import time
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import attr
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from netaddr import IPAddress
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@ -24,31 +22,16 @@ from zope.interface import implementer
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from twisted.internet import defer
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from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
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from twisted.internet.interfaces import IStreamClientEndpoint
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from twisted.web.client import URI, Agent, HTTPConnectionPool, RedirectAgent, readBody
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from twisted.web.http import stringToDatetime
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from twisted.web.client import URI, Agent, HTTPConnectionPool
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from twisted.web.http_headers import Headers
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from twisted.web.iweb import IAgent
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from synapse.http.federation.srv_resolver import SrvResolver, pick_server_from_list
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from synapse.http.federation.well_known_resolver import WellKnownResolver
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from synapse.logging.context import make_deferred_yieldable
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from synapse.util import Clock
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from synapse.util.caches.ttlcache import TTLCache
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from synapse.util.metrics import Measure
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# period to cache .well-known results for by default
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WELL_KNOWN_DEFAULT_CACHE_PERIOD = 24 * 3600
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# jitter to add to the .well-known default cache ttl
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WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER = 10 * 60
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# period to cache failure to fetch .well-known for
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WELL_KNOWN_INVALID_CACHE_PERIOD = 1 * 3600
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# cap for .well-known cache period
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WELL_KNOWN_MAX_CACHE_PERIOD = 48 * 3600
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logger = logging.getLogger(__name__)
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well_known_cache = TTLCache("well-known")
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@implementer(IAgent)
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@ -78,7 +61,7 @@ class MatrixFederationAgent(object):
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reactor,
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tls_client_options_factory,
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_srv_resolver=None,
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_well_known_cache=well_known_cache,
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_well_known_cache=None,
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):
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self._reactor = reactor
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self._clock = Clock(reactor)
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@ -93,20 +76,15 @@ class MatrixFederationAgent(object):
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self._pool.maxPersistentPerHost = 5
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self._pool.cachedConnectionTimeout = 2 * 60
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_well_known_agent = RedirectAgent(
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Agent(
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self._well_known_resolver = WellKnownResolver(
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self._reactor,
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agent=Agent(
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self._reactor,
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pool=self._pool,
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contextFactory=tls_client_options_factory,
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)
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),
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well_known_cache=_well_known_cache,
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)
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self._well_known_agent = _well_known_agent
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# our cache of .well-known lookup results, mapping from server name
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# to delegated name. The values can be:
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# `bytes`: a valid server-name
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# `None`: there is no (valid) .well-known here
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self._well_known_cache = _well_known_cache
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@defer.inlineCallbacks
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def request(self, method, uri, headers=None, bodyProducer=None):
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@ -217,7 +195,10 @@ class MatrixFederationAgent(object):
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if lookup_well_known:
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# try a .well-known lookup
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well_known_server = yield self._get_well_known(parsed_uri.host)
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well_known_result = yield self._well_known_resolver.get_well_known(
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parsed_uri.host
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)
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well_known_server = well_known_result.delegated_server
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if well_known_server:
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# if we found a .well-known, start again, but don't do another
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@ -280,85 +261,6 @@ class MatrixFederationAgent(object):
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target_port=port,
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)
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@defer.inlineCallbacks
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def _get_well_known(self, server_name):
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"""Attempt to fetch and parse a .well-known file for the given server
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Args:
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server_name (bytes): name of the server, from the requested url
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Returns:
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Deferred[bytes|None]: either the new server name, from the .well-known, or
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None if there was no .well-known file.
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"""
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try:
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result = self._well_known_cache[server_name]
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except KeyError:
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# TODO: should we linearise so that we don't end up doing two .well-known
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# requests for the same server in parallel?
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with Measure(self._clock, "get_well_known"):
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result, cache_period = yield self._do_get_well_known(server_name)
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if cache_period > 0:
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self._well_known_cache.set(server_name, result, cache_period)
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return result
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@defer.inlineCallbacks
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def _do_get_well_known(self, server_name):
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"""Actually fetch and parse a .well-known, without checking the cache
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Args:
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server_name (bytes): name of the server, from the requested url
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Returns:
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Deferred[Tuple[bytes|None|object],int]:
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result, cache period, where result is one of:
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- the new server name from the .well-known (as a `bytes`)
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- None if there was no .well-known file.
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- INVALID_WELL_KNOWN if the .well-known was invalid
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"""
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uri = b"https://%s/.well-known/matrix/server" % (server_name,)
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uri_str = uri.decode("ascii")
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logger.info("Fetching %s", uri_str)
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try:
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response = yield make_deferred_yieldable(
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self._well_known_agent.request(b"GET", uri)
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)
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body = yield make_deferred_yieldable(readBody(response))
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if response.code != 200:
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raise Exception("Non-200 response %s" % (response.code,))
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parsed_body = json.loads(body.decode("utf-8"))
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logger.info("Response from .well-known: %s", parsed_body)
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if not isinstance(parsed_body, dict):
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raise Exception("not a dict")
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if "m.server" not in parsed_body:
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raise Exception("Missing key 'm.server'")
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except Exception as e:
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logger.info("Error fetching %s: %s", uri_str, e)
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# add some randomness to the TTL to avoid a stampeding herd every hour
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# after startup
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cache_period = WELL_KNOWN_INVALID_CACHE_PERIOD
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cache_period += random.uniform(0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER)
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return (None, cache_period)
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result = parsed_body["m.server"].encode("ascii")
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cache_period = _cache_period_from_headers(
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response.headers, time_now=self._reactor.seconds
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)
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if cache_period is None:
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cache_period = WELL_KNOWN_DEFAULT_CACHE_PERIOD
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# add some randomness to the TTL to avoid a stampeding herd every 24 hours
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# after startup
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cache_period += random.uniform(0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER)
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else:
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cache_period = min(cache_period, WELL_KNOWN_MAX_CACHE_PERIOD)
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return (result, cache_period)
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@implementer(IStreamClientEndpoint)
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class LoggingHostnameEndpoint(object):
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@ -374,44 +276,6 @@ class LoggingHostnameEndpoint(object):
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return self.ep.connect(protocol_factory)
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def _cache_period_from_headers(headers, time_now=time.time):
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cache_controls = _parse_cache_control(headers)
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if b"no-store" in cache_controls:
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return 0
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if b"max-age" in cache_controls:
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try:
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max_age = int(cache_controls[b"max-age"])
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return max_age
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except ValueError:
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pass
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expires = headers.getRawHeaders(b"expires")
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if expires is not None:
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try:
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expires_date = stringToDatetime(expires[-1])
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return expires_date - time_now()
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except ValueError:
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# RFC7234 says 'A cache recipient MUST interpret invalid date formats,
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# especially the value "0", as representing a time in the past (i.e.,
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# "already expired").
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return 0
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return None
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def _parse_cache_control(headers):
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cache_controls = {}
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for hdr in headers.getRawHeaders(b"cache-control", []):
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for directive in hdr.split(b","):
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splits = [x.strip() for x in directive.split(b"=", 1)]
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k = splits[0].lower()
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v = splits[1] if len(splits) > 1 else None
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cache_controls[k] = v
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return cache_controls
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@attr.s
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class _RoutingResult(object):
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"""The result returned by `_route_matrix_uri`.
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187
synapse/http/federation/well_known_resolver.py
Normal file
187
synapse/http/federation/well_known_resolver.py
Normal file
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@ -0,0 +1,187 @@
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# -*- coding: utf-8 -*-
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# Copyright 2019 The Matrix.org Foundation C.I.C.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import json
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import logging
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import random
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import time
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import attr
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from twisted.internet import defer
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from twisted.web.client import RedirectAgent, readBody
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from twisted.web.http import stringToDatetime
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from synapse.logging.context import make_deferred_yieldable
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from synapse.util import Clock
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from synapse.util.caches.ttlcache import TTLCache
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from synapse.util.metrics import Measure
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# period to cache .well-known results for by default
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WELL_KNOWN_DEFAULT_CACHE_PERIOD = 24 * 3600
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# jitter to add to the .well-known default cache ttl
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WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER = 10 * 60
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# period to cache failure to fetch .well-known for
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WELL_KNOWN_INVALID_CACHE_PERIOD = 1 * 3600
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# cap for .well-known cache period
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WELL_KNOWN_MAX_CACHE_PERIOD = 48 * 3600
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# lower bound for .well-known cache period
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WELL_KNOWN_MIN_CACHE_PERIOD = 5 * 60
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logger = logging.getLogger(__name__)
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_well_known_cache = TTLCache("well-known")
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@attr.s(slots=True, frozen=True)
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class WellKnownLookupResult(object):
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delegated_server = attr.ib()
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class WellKnownResolver(object):
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"""Handles well-known lookups for matrix servers.
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"""
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def __init__(self, reactor, agent, well_known_cache=None):
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self._reactor = reactor
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self._clock = Clock(reactor)
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if well_known_cache is None:
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well_known_cache = _well_known_cache
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self._well_known_cache = well_known_cache
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self._well_known_agent = RedirectAgent(agent)
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@defer.inlineCallbacks
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def get_well_known(self, server_name):
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"""Attempt to fetch and parse a .well-known file for the given server
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Args:
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server_name (bytes): name of the server, from the requested url
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Returns:
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Deferred[WellKnownLookupResult]: The result of the lookup
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"""
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try:
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result = self._well_known_cache[server_name]
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except KeyError:
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# TODO: should we linearise so that we don't end up doing two .well-known
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# requests for the same server in parallel?
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with Measure(self._clock, "get_well_known"):
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result, cache_period = yield self._do_get_well_known(server_name)
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if cache_period > 0:
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self._well_known_cache.set(server_name, result, cache_period)
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return WellKnownLookupResult(delegated_server=result)
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@defer.inlineCallbacks
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def _do_get_well_known(self, server_name):
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"""Actually fetch and parse a .well-known, without checking the cache
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|
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Args:
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server_name (bytes): name of the server, from the requested url
|
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|
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Returns:
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Deferred[Tuple[bytes|None|object],int]:
|
||||
result, cache period, where result is one of:
|
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- the new server name from the .well-known (as a `bytes`)
|
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- None if there was no .well-known file.
|
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- INVALID_WELL_KNOWN if the .well-known was invalid
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"""
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uri = b"https://%s/.well-known/matrix/server" % (server_name,)
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uri_str = uri.decode("ascii")
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logger.info("Fetching %s", uri_str)
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try:
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response = yield make_deferred_yieldable(
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self._well_known_agent.request(b"GET", uri)
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)
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body = yield make_deferred_yieldable(readBody(response))
|
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if response.code != 200:
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raise Exception("Non-200 response %s" % (response.code,))
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|
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parsed_body = json.loads(body.decode("utf-8"))
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logger.info("Response from .well-known: %s", parsed_body)
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if not isinstance(parsed_body, dict):
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raise Exception("not a dict")
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if "m.server" not in parsed_body:
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raise Exception("Missing key 'm.server'")
|
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except Exception as e:
|
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logger.info("Error fetching %s: %s", uri_str, e)
|
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|
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# add some randomness to the TTL to avoid a stampeding herd every hour
|
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# after startup
|
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cache_period = WELL_KNOWN_INVALID_CACHE_PERIOD
|
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cache_period += random.uniform(0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER)
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return (None, cache_period)
|
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|
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result = parsed_body["m.server"].encode("ascii")
|
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|
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cache_period = _cache_period_from_headers(
|
||||
response.headers, time_now=self._reactor.seconds
|
||||
)
|
||||
if cache_period is None:
|
||||
cache_period = WELL_KNOWN_DEFAULT_CACHE_PERIOD
|
||||
# add some randomness to the TTL to avoid a stampeding herd every 24 hours
|
||||
# after startup
|
||||
cache_period += random.uniform(0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER)
|
||||
else:
|
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cache_period = min(cache_period, WELL_KNOWN_MAX_CACHE_PERIOD)
|
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cache_period = max(cache_period, WELL_KNOWN_MIN_CACHE_PERIOD)
|
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|
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return (result, cache_period)
|
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|
||||
|
||||
def _cache_period_from_headers(headers, time_now=time.time):
|
||||
cache_controls = _parse_cache_control(headers)
|
||||
|
||||
if b"no-store" in cache_controls:
|
||||
return 0
|
||||
|
||||
if b"max-age" in cache_controls:
|
||||
try:
|
||||
max_age = int(cache_controls[b"max-age"])
|
||||
return max_age
|
||||
except ValueError:
|
||||
pass
|
||||
|
||||
expires = headers.getRawHeaders(b"expires")
|
||||
if expires is not None:
|
||||
try:
|
||||
expires_date = stringToDatetime(expires[-1])
|
||||
return expires_date - time_now()
|
||||
except ValueError:
|
||||
# RFC7234 says 'A cache recipient MUST interpret invalid date formats,
|
||||
# especially the value "0", as representing a time in the past (i.e.,
|
||||
# "already expired").
|
||||
return 0
|
||||
|
||||
return None
|
||||
|
||||
|
||||
def _parse_cache_control(headers):
|
||||
cache_controls = {}
|
||||
for hdr in headers.getRawHeaders(b"cache-control", []):
|
||||
for directive in hdr.split(b","):
|
||||
splits = [x.strip() for x in directive.split(b"=", 1)]
|
||||
k = splits[0].lower()
|
||||
v = splits[1] if len(splits) > 1 else None
|
||||
cache_controls[k] = v
|
||||
return cache_controls
|
|
@ -25,17 +25,19 @@ from twisted.internet._sslverify import ClientTLSOptions, OpenSSLCertificateOpti
|
|||
from twisted.internet.protocol import Factory
|
||||
from twisted.protocols.tls import TLSMemoryBIOFactory
|
||||
from twisted.web._newclient import ResponseNeverReceived
|
||||
from twisted.web.client import Agent
|
||||
from twisted.web.http import HTTPChannel
|
||||
from twisted.web.http_headers import Headers
|
||||
from twisted.web.iweb import IPolicyForHTTPS
|
||||
|
||||
from synapse.config.homeserver import HomeServerConfig
|
||||
from synapse.crypto.context_factory import ClientTLSOptionsFactory
|
||||
from synapse.http.federation.matrix_federation_agent import (
|
||||
MatrixFederationAgent,
|
||||
from synapse.http.federation.matrix_federation_agent import MatrixFederationAgent
|
||||
from synapse.http.federation.srv_resolver import Server
|
||||
from synapse.http.federation.well_known_resolver import (
|
||||
WellKnownResolver,
|
||||
_cache_period_from_headers,
|
||||
)
|
||||
from synapse.http.federation.srv_resolver import Server
|
||||
from synapse.logging.context import LoggingContext
|
||||
from synapse.util.caches.ttlcache import TTLCache
|
||||
|
||||
|
@ -79,9 +81,10 @@ class MatrixFederationAgentTests(TestCase):
|
|||
self._config = config = HomeServerConfig()
|
||||
config.parse_config_dict(config_dict, "", "")
|
||||
|
||||
self.tls_factory = ClientTLSOptionsFactory(config)
|
||||
self.agent = MatrixFederationAgent(
|
||||
reactor=self.reactor,
|
||||
tls_client_options_factory=ClientTLSOptionsFactory(config),
|
||||
tls_client_options_factory=self.tls_factory,
|
||||
_srv_resolver=self.mock_resolver,
|
||||
_well_known_cache=self.well_known_cache,
|
||||
)
|
||||
|
@ -928,20 +931,16 @@ class MatrixFederationAgentTests(TestCase):
|
|||
self.reactor.pump((0.1,))
|
||||
self.successResultOf(test_d)
|
||||
|
||||
@defer.inlineCallbacks
|
||||
def do_get_well_known(self, serv):
|
||||
try:
|
||||
result = yield self.agent._get_well_known(serv)
|
||||
logger.info("Result from well-known fetch: %s", result)
|
||||
except Exception as e:
|
||||
logger.warning("Error fetching well-known: %s", e)
|
||||
raise
|
||||
return result
|
||||
|
||||
def test_well_known_cache(self):
|
||||
well_known_resolver = WellKnownResolver(
|
||||
self.reactor,
|
||||
Agent(self.reactor, contextFactory=self.tls_factory),
|
||||
well_known_cache=self.well_known_cache,
|
||||
)
|
||||
|
||||
self.reactor.lookups["testserv"] = "1.2.3.4"
|
||||
|
||||
fetch_d = self.do_get_well_known(b"testserv")
|
||||
fetch_d = well_known_resolver.get_well_known(b"testserv")
|
||||
|
||||
# there should be an attempt to connect on port 443 for the .well-known
|
||||
clients = self.reactor.tcpClients
|
||||
|
@ -953,26 +952,26 @@ class MatrixFederationAgentTests(TestCase):
|
|||
well_known_server = self._handle_well_known_connection(
|
||||
client_factory,
|
||||
expected_sni=b"testserv",
|
||||
response_headers={b"Cache-Control": b"max-age=10"},
|
||||
response_headers={b"Cache-Control": b"max-age=1000"},
|
||||
content=b'{ "m.server": "target-server" }',
|
||||
)
|
||||
|
||||
r = self.successResultOf(fetch_d)
|
||||
self.assertEqual(r, b"target-server")
|
||||
self.assertEqual(r.delegated_server, b"target-server")
|
||||
|
||||
# close the tcp connection
|
||||
well_known_server.loseConnection()
|
||||
|
||||
# repeat the request: it should hit the cache
|
||||
fetch_d = self.do_get_well_known(b"testserv")
|
||||
fetch_d = well_known_resolver.get_well_known(b"testserv")
|
||||
r = self.successResultOf(fetch_d)
|
||||
self.assertEqual(r, b"target-server")
|
||||
self.assertEqual(r.delegated_server, b"target-server")
|
||||
|
||||
# expire the cache
|
||||
self.reactor.pump((10.0,))
|
||||
self.reactor.pump((1000.0,))
|
||||
|
||||
# now it should connect again
|
||||
fetch_d = self.do_get_well_known(b"testserv")
|
||||
fetch_d = well_known_resolver.get_well_known(b"testserv")
|
||||
|
||||
self.assertEqual(len(clients), 1)
|
||||
(host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)
|
||||
|
@ -986,7 +985,7 @@ class MatrixFederationAgentTests(TestCase):
|
|||
)
|
||||
|
||||
r = self.successResultOf(fetch_d)
|
||||
self.assertEqual(r, b"other-server")
|
||||
self.assertEqual(r.delegated_server, b"other-server")
|
||||
|
||||
|
||||
class TestCachePeriodFromHeaders(TestCase):
|
||||
|
|
Loading…
Reference in a new issue