diff --git a/synapse/http/federation/matrix_federation_agent.py b/synapse/http/federation/matrix_federation_agent.py
index 79e488c942..71a15f434d 100644
--- a/synapse/http/federation/matrix_federation_agent.py
+++ b/synapse/http/federation/matrix_federation_agent.py
@@ -12,10 +12,8 @@
# 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 json
+
import logging
-import random
-import time
import attr
from netaddr import IPAddress
@@ -24,34 +22,16 @@ from zope.interface import implementer
from twisted.internet import defer
from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
from twisted.internet.interfaces import IStreamClientEndpoint
-from twisted.web.client import URI, Agent, HTTPConnectionPool, RedirectAgent, readBody
-from twisted.web.http import stringToDatetime
+from twisted.web.client import URI, Agent, HTTPConnectionPool
from twisted.web.http_headers import Headers
from twisted.web.iweb import IAgent
from synapse.http.federation.srv_resolver import SrvResolver, pick_server_from_list
+from synapse.http.federation.well_known_resolver import WellKnownResolver
from synapse.logging.context import make_deferred_yieldable
from synapse.util import Clock
-from synapse.util.caches.ttlcache import TTLCache
-from synapse.util.metrics import Measure
-
-# period to cache .well-known results for by default
-WELL_KNOWN_DEFAULT_CACHE_PERIOD = 24 * 3600
-
-# jitter to add to the .well-known default cache ttl
-WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER = 10 * 60
-
-# period to cache failure to fetch .well-known for
-WELL_KNOWN_INVALID_CACHE_PERIOD = 1 * 3600
-
-# cap for .well-known cache period
-WELL_KNOWN_MAX_CACHE_PERIOD = 48 * 3600
-
-# lower bound for .well-known cache period
-WELL_KNOWN_MIN_CACHE_PERIOD = 5 * 60
logger = logging.getLogger(__name__)
-well_known_cache = TTLCache("well-known")
@implementer(IAgent)
@@ -81,7 +61,7 @@ class MatrixFederationAgent(object):
reactor,
tls_client_options_factory,
_srv_resolver=None,
- _well_known_cache=well_known_cache,
+ _well_known_cache=None,
):
self._reactor = reactor
self._clock = Clock(reactor)
@@ -96,20 +76,15 @@ class MatrixFederationAgent(object):
self._pool.maxPersistentPerHost = 5
self._pool.cachedConnectionTimeout = 2 * 60
- _well_known_agent = RedirectAgent(
- Agent(
+ self._well_known_resolver = WellKnownResolver(
+ self._reactor,
+ agent=Agent(
self._reactor,
pool=self._pool,
contextFactory=tls_client_options_factory,
- )
+ ),
+ well_known_cache=_well_known_cache,
)
- self._well_known_agent = _well_known_agent
-
- # our cache of .well-known lookup results, mapping from server name
- # to delegated name. The values can be:
- # `bytes`: a valid server-name
- # `None`: there is no (valid) .well-known here
- self._well_known_cache = _well_known_cache
@defer.inlineCallbacks
def request(self, method, uri, headers=None, bodyProducer=None):
@@ -220,7 +195,10 @@ class MatrixFederationAgent(object):
if lookup_well_known:
# try a .well-known lookup
- well_known_server = yield self._get_well_known(parsed_uri.host)
+ well_known_result = yield self._well_known_resolver.get_well_known(
+ parsed_uri.host
+ )
+ well_known_server = well_known_result.delegated_server
if well_known_server:
# if we found a .well-known, start again, but don't do another
@@ -283,86 +261,6 @@ class MatrixFederationAgent(object):
target_port=port,
)
- @defer.inlineCallbacks
- def _get_well_known(self, server_name):
- """Attempt to fetch and parse a .well-known file for the given server
-
- Args:
- server_name (bytes): name of the server, from the requested url
-
- Returns:
- Deferred[bytes|None]: either the new server name, from the .well-known, or
- None if there was no .well-known file.
- """
- try:
- result = self._well_known_cache[server_name]
- except KeyError:
- # TODO: should we linearise so that we don't end up doing two .well-known
- # requests for the same server in parallel?
- with Measure(self._clock, "get_well_known"):
- result, cache_period = yield self._do_get_well_known(server_name)
-
- if cache_period > 0:
- self._well_known_cache.set(server_name, result, cache_period)
-
- return result
-
- @defer.inlineCallbacks
- def _do_get_well_known(self, server_name):
- """Actually fetch and parse a .well-known, without checking the cache
-
- Args:
- server_name (bytes): name of the server, from the requested url
-
- Returns:
- Deferred[Tuple[bytes|None|object],int]:
- result, cache period, where result is one of:
- - the new server name from the .well-known (as a `bytes`)
- - None if there was no .well-known file.
- - INVALID_WELL_KNOWN if the .well-known was invalid
- """
- uri = b"https://%s/.well-known/matrix/server" % (server_name,)
- uri_str = uri.decode("ascii")
- logger.info("Fetching %s", uri_str)
- try:
- response = yield make_deferred_yieldable(
- self._well_known_agent.request(b"GET", uri)
- )
- body = yield make_deferred_yieldable(readBody(response))
- if response.code != 200:
- raise Exception("Non-200 response %s" % (response.code,))
-
- parsed_body = json.loads(body.decode("utf-8"))
- logger.info("Response from .well-known: %s", parsed_body)
- if not isinstance(parsed_body, dict):
- raise Exception("not a dict")
- if "m.server" not in parsed_body:
- raise Exception("Missing key 'm.server'")
- except Exception as e:
- logger.info("Error fetching %s: %s", uri_str, e)
-
- # add some randomness to the TTL to avoid a stampeding herd every hour
- # after startup
- cache_period = WELL_KNOWN_INVALID_CACHE_PERIOD
- cache_period += random.uniform(0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER)
- return (None, cache_period)
-
- result = parsed_body["m.server"].encode("ascii")
-
- 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:
- cache_period = min(cache_period, WELL_KNOWN_MAX_CACHE_PERIOD)
- cache_period = max(cache_period, WELL_KNOWN_MIN_CACHE_PERIOD)
-
- return (result, cache_period)
-
@implementer(IStreamClientEndpoint)
class LoggingHostnameEndpoint(object):
@@ -378,44 +276,6 @@ class LoggingHostnameEndpoint(object):
return self.ep.connect(protocol_factory)
-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
-
-
@attr.s
class _RoutingResult(object):
"""The result returned by `_route_matrix_uri`.
diff --git a/synapse/http/federation/well_known_resolver.py b/synapse/http/federation/well_known_resolver.py
new file mode 100644
index 0000000000..bab4ab015e
--- /dev/null
+++ b/synapse/http/federation/well_known_resolver.py
@@ -0,0 +1,184 @@
+# -*- 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.
+
+import json
+import logging
+import random
+import time
+
+import attr
+
+from twisted.internet import defer
+from twisted.web.client import RedirectAgent, readBody
+from twisted.web.http import stringToDatetime
+
+from synapse.logging.context import make_deferred_yieldable
+from synapse.util import Clock
+from synapse.util.caches.ttlcache import TTLCache
+from synapse.util.metrics import Measure
+
+# period to cache .well-known results for by default
+WELL_KNOWN_DEFAULT_CACHE_PERIOD = 24 * 3600
+
+# jitter to add to the .well-known default cache ttl
+WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER = 10 * 60
+
+# period to cache failure to fetch .well-known for
+WELL_KNOWN_INVALID_CACHE_PERIOD = 1 * 3600
+
+# cap for .well-known cache period
+WELL_KNOWN_MAX_CACHE_PERIOD = 48 * 3600
+
+# lower bound for .well-known cache period
+WELL_KNOWN_MIN_CACHE_PERIOD = 5 * 60
+
+logger = logging.getLogger(__name__)
+
+
+@attr.s(slots=True, frozen=True)
+class WellKnownLookupResult(object):
+ delegated_server = attr.ib()
+
+
+class WellKnownResolver(object):
+ """Handles well-known lookups for matrix servers.
+ """
+
+ def __init__(self, reactor, agent, well_known_cache=None):
+ self._reactor = reactor
+ self._clock = Clock(reactor)
+
+ if well_known_cache is None:
+ well_known_cache = TTLCache("well-known")
+
+ self._well_known_cache = well_known_cache
+ self._well_known_agent = RedirectAgent(agent)
+
+ @defer.inlineCallbacks
+ def get_well_known(self, server_name):
+ """Attempt to fetch and parse a .well-known file for the given server
+
+ Args:
+ server_name (bytes): name of the server, from the requested url
+
+ Returns:
+ Deferred[WellKnownLookupResult]: The result of the lookup
+ """
+ try:
+ result = self._well_known_cache[server_name]
+ except KeyError:
+ # TODO: should we linearise so that we don't end up doing two .well-known
+ # requests for the same server in parallel?
+ with Measure(self._clock, "get_well_known"):
+ result, cache_period = yield self._do_get_well_known(server_name)
+
+ if cache_period > 0:
+ self._well_known_cache.set(server_name, result, cache_period)
+
+ return WellKnownLookupResult(delegated_server=result)
+
+ @defer.inlineCallbacks
+ def _do_get_well_known(self, server_name):
+ """Actually fetch and parse a .well-known, without checking the cache
+
+ Args:
+ server_name (bytes): name of the server, from the requested url
+
+ Returns:
+ Deferred[Tuple[bytes|None|object],int]:
+ result, cache period, where result is one of:
+ - the new server name from the .well-known (as a `bytes`)
+ - None if there was no .well-known file.
+ - INVALID_WELL_KNOWN if the .well-known was invalid
+ """
+ uri = b"https://%s/.well-known/matrix/server" % (server_name,)
+ uri_str = uri.decode("ascii")
+ logger.info("Fetching %s", uri_str)
+ try:
+ response = yield make_deferred_yieldable(
+ self._well_known_agent.request(b"GET", uri)
+ )
+ body = yield make_deferred_yieldable(readBody(response))
+ if response.code != 200:
+ raise Exception("Non-200 response %s" % (response.code,))
+
+ parsed_body = json.loads(body.decode("utf-8"))
+ logger.info("Response from .well-known: %s", parsed_body)
+ if not isinstance(parsed_body, dict):
+ raise Exception("not a dict")
+ if "m.server" not in parsed_body:
+ raise Exception("Missing key 'm.server'")
+ except Exception as e:
+ logger.info("Error fetching %s: %s", uri_str, e)
+
+ # add some randomness to the TTL to avoid a stampeding herd every hour
+ # after startup
+ cache_period = WELL_KNOWN_INVALID_CACHE_PERIOD
+ cache_period += random.uniform(0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER)
+ return (None, cache_period)
+
+ result = parsed_body["m.server"].encode("ascii")
+
+ 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:
+ cache_period = min(cache_period, WELL_KNOWN_MAX_CACHE_PERIOD)
+ cache_period = max(cache_period, WELL_KNOWN_MIN_CACHE_PERIOD)
+
+ return (result, cache_period)
+
+
+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
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