Merge branch 'erikj/get_pdu_versions' into erikj/require_format_version

changelog.d/4384.feature

@@ -0,0 +1 @@
+Synapse can now automatically provision TLS certificates via ACME (the protocol used by CAs like Let's Encrypt).

changelog.d/4428.misc

@@ -0,0 +1 @@
+Move SRV logic into the Agent layer

changelog.d/4432.misc

@@ -0,0 +1 @@
+Apply a unique index to the user_ips table, preventing duplicates.

changelog.d/4433.misc

@@ -0,0 +1 @@
+debian package: symlink to explicit python version

changelog.d/4445.feature

@@ -0,0 +1 @@
+Add a metric for tracking event stream position of the user directory.

changelog.d/4448.misc

@@ -0,0 +1 @@
+Add infrastructure to support different event formats

debian/build_virtualenv

@@ -6,7 +6,16 @@
 set -e
 
 export DH_VIRTUALENV_INSTALL_ROOT=/opt/venvs
-SNAKE=/usr/bin/python3
+
+# make sure that the virtualenv links to the specific version of python, by
+# dereferencing the python3 symlink.
+#
+# Otherwise, if somebody tries to install (say) the stretch package on buster,
+# they will get a confusing error about "No module named 'synapse'", because
+# python won't look in the right directory. At least this way, the error will
+# be a *bit* more obvious.
+#
+SNAKE=`readlink -e /usr/bin/python3`
 
 # try to set the CFLAGS so any compiled C extensions are compiled with the most
 # generic as possible x64 instructions, so that compiling it on a new Intel chip
@@ -46,3 +55,7 @@ cp -r tests "$tmpdir"
 PYTHONPATH="$tmpdir" \
     debian/matrix-synapse-py3/opt/venvs/matrix-synapse/bin/python \
         -B -m twisted.trial --reporter=text -j2 tests
+
+# add a dependency on the right version of python to substvars.
+PYPKG=`basename $SNAKE`
+echo "synapse:pydepends=$PYPKG" >> debian/matrix-synapse-py3.substvars

debian/control

@@ -27,8 +27,8 @@ Depends:
  adduser,
  debconf,
  python3-distutils|libpython3-stdlib (<< 3.6),
- python3,
  ${misc:Depends},
+ ${synapse:pydepends},
 # some of our scripts use perl, but none of them are important,
 # so we put perl:Depends in Suggests rather than Depends.
 Suggests:

scripts-dev/build_debian_packages

@@ -10,12 +10,12 @@
 # can be passed on the commandline for debugging.
 
 import argparse
-from concurrent.futures import ThreadPoolExecutor
 import os
 import signal
 import subprocess
 import sys
 import threading
+from concurrent.futures import ThreadPoolExecutor
 
 DISTS = (
     "debian:stretch",

synapse/app/homeserver.py

@@ -13,10 +13,12 @@
 # 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 gc
 import logging
 import os
 import sys
+import traceback
 
 from six import iteritems
 
@@ -324,17 +326,12 @@ def setup(config_options):
 
     events.USE_FROZEN_DICTS = config.use_frozen_dicts
 
-    tls_server_context_factory = context_factory.ServerContextFactory(config)
-    tls_client_options_factory = context_factory.ClientTLSOptionsFactory(config)
-
     database_engine = create_engine(config.database_config)
     config.database_config["args"]["cp_openfun"] = database_engine.on_new_connection
 
     hs = SynapseHomeServer(
         config.server_name,
         db_config=config.database_config,
-        tls_server_context_factory=tls_server_context_factory,
-        tls_client_options_factory=tls_client_options_factory,
         config=config,
         version_string="Synapse/" + get_version_string(synapse),
         database_engine=database_engine,
@@ -361,12 +358,53 @@ def setup(config_options):
     logger.info("Database prepared in %s.", config.database_config['name'])
 
     hs.setup()
-    hs.start_listening()
 
+    @defer.inlineCallbacks
     def start():
+        try:
+            # Check if the certificate is still valid.
+            cert_days_remaining = hs.config.is_disk_cert_valid()
+
+            if hs.config.acme_enabled:
+                # If ACME is enabled, we might need to provision a certificate
+                # before starting.
+                acme = hs.get_acme_handler()
+
+                # Start up the webservices which we will respond to ACME
+                # challenges with.
+                yield acme.start_listening()
+
+                # We want to reprovision if cert_days_remaining is None (meaning no
+                # certificate exists), or the days remaining number it returns
+                # is less than our re-registration threshold.
+                if (cert_days_remaining is None) or (
+                    not cert_days_remaining > hs.config.acme_reprovision_threshold
+                ):
+                    yield acme.provision_certificate()
+
+            # Read the certificate from disk and build the context factories for
+            # TLS.
+            hs.config.read_certificate_from_disk()
+            hs.tls_server_context_factory = context_factory.ServerContextFactory(config)
+            hs.tls_client_options_factory = context_factory.ClientTLSOptionsFactory(
+                config
+            )
+
+            # It is now safe to start your Synapse.
+            hs.start_listening()
             hs.get_pusherpool().start()
             hs.get_datastore().start_profiling()
             hs.get_datastore().start_doing_background_updates()
+        except Exception as e:
+            # If a DeferredList failed (like in listening on the ACME listener),
+            # we need to print the subfailure explicitly.
+            if isinstance(e, defer.FirstError):
+                e.subFailure.printTraceback(sys.stderr)
+                sys.exit(1)
+
+            # Something else went wrong when starting. Print it and bail out.
+            traceback.print_exc(file=sys.stderr)
+            sys.exit(1)
 
     reactor.callWhenRunning(start)
 

synapse/config/_base.py

@@ -367,7 +367,7 @@ class Config(object):
         if not keys_directory:
             keys_directory = os.path.dirname(config_files[-1])
 
-        config_dir_path = os.path.abspath(keys_directory)
+        self.config_dir_path = os.path.abspath(keys_directory)
 
         specified_config = {}
         for config_file in config_files:
@@ -379,7 +379,7 @@ class Config(object):
 
         server_name = specified_config["server_name"]
         config_string = self.generate_config(
-            config_dir_path=config_dir_path,
+            config_dir_path=self.config_dir_path,
             data_dir_path=os.getcwd(),
             server_name=server_name,
             generate_secrets=False,

synapse/config/tls.py

@@ -13,45 +13,38 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
 import os
+from datetime import datetime
 from hashlib import sha256
 
 from unpaddedbase64 import encode_base64
 
 from OpenSSL import crypto
 
-from ._base import Config
+from synapse.config._base import Config
+
+logger = logging.getLogger()
 
 
 class TlsConfig(Config):
     def read_config(self, config):
-        self.tls_certificate = self.read_tls_certificate(
-            config.get("tls_certificate_path")
-        )
-        self.tls_certificate_file = config.get("tls_certificate_path")
 
+        acme_config = config.get("acme", {})
+        self.acme_enabled = acme_config.get("enabled", False)
+        self.acme_url = acme_config.get(
+            "url", "https://acme-v01.api.letsencrypt.org/directory"
+        )
+        self.acme_port = acme_config.get("port", 8449)
+        self.acme_bind_addresses = acme_config.get("bind_addresses", ["127.0.0.1"])
+        self.acme_reprovision_threshold = acme_config.get("reprovision_threshold", 30)
+
+        self.tls_certificate_file = os.path.abspath(config.get("tls_certificate_path"))
+        self.tls_private_key_file = os.path.abspath(config.get("tls_private_key_path"))
+        self._original_tls_fingerprints = config["tls_fingerprints"]
+        self.tls_fingerprints = list(self._original_tls_fingerprints)
         self.no_tls = config.get("no_tls", False)
 
-        if self.no_tls:
-            self.tls_private_key = None
-        else:
-            self.tls_private_key = self.read_tls_private_key(
-                config.get("tls_private_key_path")
-            )
-
-        self.tls_fingerprints = config["tls_fingerprints"]
-
-        # Check that our own certificate is included in the list of fingerprints
-        # and include it if it is not.
-        x509_certificate_bytes = crypto.dump_certificate(
-            crypto.FILETYPE_ASN1,
-            self.tls_certificate
-        )
-        sha256_fingerprint = encode_base64(sha256(x509_certificate_bytes).digest())
-        sha256_fingerprints = set(f["sha256"] for f in self.tls_fingerprints)
-        if sha256_fingerprint not in sha256_fingerprints:
-            self.tls_fingerprints.append({u"sha256": sha256_fingerprint})
-
         # This config option applies to non-federation HTTP clients
         # (e.g. for talking to recaptcha, identity servers, and such)
         # It should never be used in production, and is intended for
@@ -60,13 +53,70 @@ class TlsConfig(Config):
             "use_insecure_ssl_client_just_for_testing_do_not_use"
         )
 
+        self.tls_certificate = None
+        self.tls_private_key = None
+
+    def is_disk_cert_valid(self):
+        """
+        Is the certificate we have on disk valid, and if so, for how long?
+
+        Returns:
+            int: Days remaining of certificate validity.
+            None: No certificate exists.
+        """
+        if not os.path.exists(self.tls_certificate_file):
+            return None
+
+        try:
+            with open(self.tls_certificate_file, 'rb') as f:
+                cert_pem = f.read()
+        except Exception:
+            logger.exception("Failed to read existing certificate off disk!")
+            raise
+
+        try:
+            tls_certificate = crypto.load_certificate(crypto.FILETYPE_PEM, cert_pem)
+        except Exception:
+            logger.exception("Failed to parse existing certificate off disk!")
+            raise
+
+        # YYYYMMDDhhmmssZ -- in UTC
+        expires_on = datetime.strptime(
+            tls_certificate.get_notAfter().decode('ascii'), "%Y%m%d%H%M%SZ"
+        )
+        now = datetime.utcnow()
+        days_remaining = (expires_on - now).days
+        return days_remaining
+
+    def read_certificate_from_disk(self):
+        """
+        Read the certificates from disk.
+        """
+        self.tls_certificate = self.read_tls_certificate(self.tls_certificate_file)
+
+        if not self.no_tls:
+            self.tls_private_key = self.read_tls_private_key(self.tls_private_key_file)
+
+        self.tls_fingerprints = list(self._original_tls_fingerprints)
+
+        # Check that our own certificate is included in the list of fingerprints
+        # and include it if it is not.
+        x509_certificate_bytes = crypto.dump_certificate(
+            crypto.FILETYPE_ASN1, self.tls_certificate
+        )
+        sha256_fingerprint = encode_base64(sha256(x509_certificate_bytes).digest())
+        sha256_fingerprints = set(f["sha256"] for f in self.tls_fingerprints)
+        if sha256_fingerprint not in sha256_fingerprints:
+            self.tls_fingerprints.append({u"sha256": sha256_fingerprint})
+
     def default_config(self, config_dir_path, server_name, **kwargs):
         base_key_name = os.path.join(config_dir_path, server_name)
 
         tls_certificate_path = base_key_name + ".tls.crt"
         tls_private_key_path = base_key_name + ".tls.key"
 
-        return """\
+        return (
+            """\
         # PEM encoded X509 certificate for TLS.
         # You can replace the self-signed certificate that synapse
         # autogenerates on launch with your own SSL certificate + key pair
@@ -107,7 +157,24 @@ class TlsConfig(Config):
         #
         tls_fingerprints: []
         # tls_fingerprints: [{"sha256": "<base64_encoded_sha256_fingerprint>"}]
-        """ % locals()
+
+        ## Support for ACME certificate auto-provisioning.
+        # acme:
+        #    enabled: false
+        ##   ACME path.
+        ##   If you only want to test, use the staging url:
+        ##   https://acme-staging.api.letsencrypt.org/directory
+        #    url: 'https://acme-v01.api.letsencrypt.org/directory'
+        ##   Port number (to listen for the HTTP-01 challenge).
+        ##   Using port 80 requires utilising something like authbind, or proxying to it.
+        #    port: 8449
+        ##   Hosts to bind to.
+        #    bind_addresses: ['127.0.0.1']
+        ##   How many days remaining on a certificate before it is renewed.
+        #    reprovision_threshold: 30
+        """
+            % locals()
+        )
 
     def read_tls_certificate(self, cert_path):
         cert_pem = self.read_file(cert_path, "tls_certificate")

synapse/federation/federation_base.py

@@ -43,8 +43,8 @@ class FederationBase(object):
         self._clock = hs.get_clock()
 
     @defer.inlineCallbacks
-    def _check_sigs_and_hash_and_fetch(self, origin, pdus, outlier=False,
+    def _check_sigs_and_hash_and_fetch(self, origin, pdus, room_version,
-                                       include_none=False):
+                                       outlier=False, include_none=False):
         """Takes a list of PDUs and checks the signatures and hashs of each
         one. If a PDU fails its signature check then we check if we have it in
         the database and if not then request if from the originating server of
@@ -56,8 +56,12 @@ class FederationBase(object):
         a new list.
 
         Args:
+            origin (str)
             pdu (list)
-            outlier (bool)
+            room_version (str)
+            outlier (bool): Whether the events are outliers or not
+            include_none (str): Whether to include None in the returned list
+                for events that have failed their checks
 
         Returns:
             Deferred : A list of PDUs that have valid signatures and hashes.
@@ -84,6 +88,7 @@ class FederationBase(object):
                     res = yield self.get_pdu(
                         destinations=[pdu.origin],
                         event_id=pdu.event_id,
+                        room_version=room_version,
                         outlier=outlier,
                         timeout=10000,
                     )

synapse/federation/federation_client.py

@@ -207,7 +207,8 @@ class FederationClient(FederationBase):
 
     @defer.inlineCallbacks
     @log_function
-    def get_pdu(self, destinations, event_id, outlier=False, timeout=None):
+    def get_pdu(self, destinations, event_id, room_version, outlier=False,
+                timeout=None):
         """Requests the PDU with given origin and ID from the remote home
         servers.
 
@@ -217,6 +218,7 @@ class FederationClient(FederationBase):
         Args:
             destinations (list): Which home servers to query
             event_id (str): event to fetch
+            room_version (str): version of the room
             outlier (bool): Indicates whether the PDU is an `outlier`, i.e. if
                 it's from an arbitary point in the context as opposed to part
                 of the current block of PDUs. Defaults to `False`
@@ -357,10 +359,13 @@ class FederationClient(FederationBase):
             ev.event_id for ev in itertools.chain(pdus, auth_chain)
         ])
 
+        room_version = yield self.store.get_room_version(room_id)
+
         signed_pdus = yield self._check_sigs_and_hash_and_fetch(
             destination,
             [p for p in pdus if p.event_id not in seen_events],
-            outlier=True
+            outlier=True,
+            room_version=room_version,
         )
         signed_pdus.extend(
             seen_events[p.event_id] for p in pdus if p.event_id in seen_events
@@ -369,7 +374,8 @@ class FederationClient(FederationBase):
         signed_auth = yield self._check_sigs_and_hash_and_fetch(
             destination,
             [p for p in auth_chain if p.event_id not in seen_events],
-            outlier=True
+            outlier=True,
+            room_version=room_version,
         )
         signed_auth.extend(
             seen_events[p.event_id] for p in auth_chain if p.event_id in seen_events
@@ -416,6 +422,8 @@ class FederationClient(FederationBase):
             random.shuffle(srvs)
             return srvs
 
+        room_version = yield self.store.get_room_version(room_id)
+
         batch_size = 20
         missing_events = list(missing_events)
         for i in range(0, len(missing_events), batch_size):
@@ -426,6 +434,7 @@ class FederationClient(FederationBase):
                     self.get_pdu,
                     destinations=random_server_list(),
                     event_id=e_id,
+                    room_version=room_version,
                 )
                 for e_id in batch
             ]
@@ -455,8 +464,11 @@ class FederationClient(FederationBase):
             for p in res["auth_chain"]
         ]
 
+        room_version = yield self.store.get_room_version(room_id)
+
         signed_auth = yield self._check_sigs_and_hash_and_fetch(
-            destination, auth_chain, outlier=True
+            destination, auth_chain,
+            outlier=True, room_version=room_version,
         )
 
         signed_auth.sort(key=lambda e: e.depth)
@@ -661,9 +673,20 @@ class FederationClient(FederationBase):
                 for p in itertools.chain(state, auth_chain)
             }
 
+            room_version = None
+            for e in state:
+                if (e.type, e.state_key) == (EventTypes.Create, ""):
+                    room_version = e.content.get("room_version", RoomVersions.V1)
+                    break
+
+            if room_version is None:
+                # We use this error has that is what
+                raise SynapseError(400, "No create event in state")
+
             valid_pdus = yield self._check_sigs_and_hash_and_fetch(
                 destination, list(pdus.values()),
                 outlier=True,
+                room_version=room_version,
             )
 
             valid_pdus_map = {
@@ -801,8 +824,10 @@ class FederationClient(FederationBase):
             for e in content["auth_chain"]
         ]
 
+        room_version = yield self.store.get_room_version(room_id)
+
         signed_auth = yield self._check_sigs_and_hash_and_fetch(
-            destination, auth_chain, outlier=True
+            destination, auth_chain, outlier=True, room_version=room_version,
         )
 
         signed_auth.sort(key=lambda e: e.depth)
@@ -849,8 +874,10 @@ class FederationClient(FederationBase):
                 for e in content.get("events", [])
             ]
 
+            room_version = yield self.store.get_room_version(room_id)
+
             signed_events = yield self._check_sigs_and_hash_and_fetch(
-                destination, events, outlier=False
+                destination, events, outlier=False, room_version=room_version,
             )
         except HttpResponseException as e:
             if not e.code == 400:

synapse/federation/federation_server.py

@@ -463,8 +463,10 @@ class FederationServer(FederationBase):
                 for e in content["auth_chain"]
             ]
 
+            room_version = yield self.store.get_room_version(room_id)
+
             signed_auth = yield self._check_sigs_and_hash_and_fetch(
-                origin, auth_chain, outlier=True
+                origin, auth_chain, outlier=True, room_version=room_version,
             )
 
             ret = yield self.handler.on_query_auth(

synapse/handlers/acme.py

@@ -0,0 +1,147 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 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 logging
+
+import attr
+from zope.interface import implementer
+
+from twisted.internet import defer
+from twisted.internet.endpoints import serverFromString
+from twisted.python.filepath import FilePath
+from twisted.python.url import URL
+from twisted.web import server, static
+from twisted.web.resource import Resource
+
+logger = logging.getLogger(__name__)
+
+try:
+    from txacme.interfaces import ICertificateStore
+
+    @attr.s
+    @implementer(ICertificateStore)
+    class ErsatzStore(object):
+        """
+        A store that only stores in memory.
+        """
+
+        certs = attr.ib(default=attr.Factory(dict))
+
+        def store(self, server_name, pem_objects):
+            self.certs[server_name] = [o.as_bytes() for o in pem_objects]
+            return defer.succeed(None)
+
+
+except ImportError:
+    # txacme is missing
+    pass
+
+
+class AcmeHandler(object):
+    def __init__(self, hs):
+        self.hs = hs
+        self.reactor = hs.get_reactor()
+
+    @defer.inlineCallbacks
+    def start_listening(self):
+
+        # Configure logging for txacme, if you need to debug
+        # from eliot import add_destinations
+        # from eliot.twisted import TwistedDestination
+        #
+        # add_destinations(TwistedDestination())
+
+        from txacme.challenges import HTTP01Responder
+        from txacme.service import AcmeIssuingService
+        from txacme.endpoint import load_or_create_client_key
+        from txacme.client import Client
+        from josepy.jwa import RS256
+
+        self._store = ErsatzStore()
+        responder = HTTP01Responder()
+
+        self._issuer = AcmeIssuingService(
+            cert_store=self._store,
+            client_creator=(
+                lambda: Client.from_url(
+                    reactor=self.reactor,
+                    url=URL.from_text(self.hs.config.acme_url),
+                    key=load_or_create_client_key(
+                        FilePath(self.hs.config.config_dir_path)
+                    ),
+                    alg=RS256,
+                )
+            ),
+            clock=self.reactor,
+            responders=[responder],
+        )
+
+        well_known = Resource()
+        well_known.putChild(b'acme-challenge', responder.resource)
+        responder_resource = Resource()
+        responder_resource.putChild(b'.well-known', well_known)
+        responder_resource.putChild(b'check', static.Data(b'OK', b'text/plain'))
+
+        srv = server.Site(responder_resource)
+
+        listeners = []
+
+        for host in self.hs.config.acme_bind_addresses:
+            logger.info(
+                "Listening for ACME requests on %s:%s", host, self.hs.config.acme_port
+            )
+            endpoint = serverFromString(
+                self.reactor, "tcp:%s:interface=%s" % (self.hs.config.acme_port, host)
+            )
+            listeners.append(endpoint.listen(srv))
+
+        # Make sure we are registered to the ACME server. There's no public API
+        # for this, it is usually triggered by startService, but since we don't
+        # want it to control where we save the certificates, we have to reach in
+        # and trigger the registration machinery ourselves.
+        self._issuer._registered = False
+        yield self._issuer._ensure_registered()
+
+        # Return a Deferred that will fire when all the servers have started up.
+        yield defer.DeferredList(listeners, fireOnOneErrback=True, consumeErrors=True)
+
+    @defer.inlineCallbacks
+    def provision_certificate(self):
+
+        logger.warning("Reprovisioning %s", self.hs.hostname)
+
+        try:
+            yield self._issuer.issue_cert(self.hs.hostname)
+        except Exception:
+            logger.exception("Fail!")
+            raise
+        logger.warning("Reprovisioned %s, saving.", self.hs.hostname)
+        cert_chain = self._store.certs[self.hs.hostname]
+
+        try:
+            with open(self.hs.config.tls_private_key_file, "wb") as private_key_file:
+                for x in cert_chain:
+                    if x.startswith(b"-----BEGIN RSA PRIVATE KEY-----"):
+                        private_key_file.write(x)
+
+            with open(self.hs.config.tls_certificate_file, "wb") as certificate_file:
+                for x in cert_chain:
+                    if x.startswith(b"-----BEGIN CERTIFICATE-----"):
+                        certificate_file.write(x)
+        except Exception:
+            logger.exception("Failed saving!")
+            raise
+
+        defer.returnValue(True)

synapse/handlers/federation.py

@@ -34,6 +34,7 @@ from synapse.api.constants import (
     EventTypes,
     Membership,
     RejectedReason,
+    RoomVersions,
 )
 from synapse.api.errors import (
     AuthError,
@@ -342,6 +343,8 @@ class FederationHandler(BaseHandler):
                             room_id, event_id, p,
                         )
 
+                        room_version = yield self.store.get_room_version(room_id)
+
                         with logcontext.nested_logging_context(p):
                             # note that if any of the missing prevs share missing state or
                             # auth events, the requests to fetch those events are deduped
@@ -355,7 +358,7 @@ class FederationHandler(BaseHandler):
                             # we want the state *after* p; get_state_for_room returns the
                             # state *before* p.
                             remote_event = yield self.federation_client.get_pdu(
-                                [origin], p, outlier=True,
+                                [origin], p, room_version, outlier=True,
                             )
 
                             if remote_event is None:
@@ -379,7 +382,6 @@ class FederationHandler(BaseHandler):
                             for x in remote_state:
                                 event_map[x.event_id] = x
 
-                    room_version = yield self.store.get_room_version(room_id)
                     state_map = yield resolve_events_with_store(
                         room_version, state_maps, event_map,
                         state_res_store=StateResolutionStore(self.store),
@@ -655,6 +657,8 @@ class FederationHandler(BaseHandler):
         if dest == self.server_name:
             raise SynapseError(400, "Can't backfill from self.")
 
+        room_version = yield self.store.get_room_version(room_id)
+
         events = yield self.federation_client.backfill(
             dest,
             room_id,
@@ -748,6 +752,7 @@ class FederationHandler(BaseHandler):
                             self.federation_client.get_pdu,
                             [dest],
                             event_id,
+                            room_version=room_version,
                             outlier=True,
                             timeout=10000,
                         )
@@ -1659,6 +1664,8 @@ class FederationHandler(BaseHandler):
                 create_event = e
                 break
 
+        room_version = create_event.content.get("room_version", RoomVersions.V1)
+
         missing_auth_events = set()
         for e in itertools.chain(auth_events, state, [event]):
             for e_id in e.auth_event_ids():
@@ -1669,6 +1676,7 @@ class FederationHandler(BaseHandler):
             m_ev = yield self.federation_client.get_pdu(
                 [origin],
                 e_id,
+                room_version=room_version,
                 outlier=True,
                 timeout=10000,
             )

synapse/handlers/user_directory.py

@@ -19,6 +19,7 @@ from six import iteritems
 
 from twisted.internet import defer
 
+import synapse.metrics
 from synapse.api.constants import EventTypes, JoinRules, Membership
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage.roommember import ProfileInfo
@@ -163,6 +164,11 @@ class UserDirectoryHandler(object):
                 yield self._handle_deltas(deltas)
 
                 self.pos = deltas[-1]["stream_id"]
+
+                # Expose current event processing position to prometheus
+                synapse.metrics.event_processing_positions.labels(
+                    "user_dir").set(self.pos)
+
                 yield self.store.update_user_directory_stream_pos(self.pos)
 
     @defer.inlineCallbacks

synapse/http/endpoint.py

@@ -13,15 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-import random
 import re
 
-from twisted.internet import defer
-from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
-from twisted.internet.error import ConnectError
-
-from synapse.http.federation.srv_resolver import Server, resolve_service
-
 logger = logging.getLogger(__name__)
 
 
@@ -88,140 +81,3 @@ def parse_and_validate_server_name(server_name):
         ))
 
     return host, port
-
-
-def matrix_federation_endpoint(reactor, destination, tls_client_options_factory=None,
-                               timeout=None):
-    """Construct an endpoint for the given matrix destination.
-
-    Args:
-        reactor: Twisted reactor.
-        destination (unicode): The name of the server to connect to.
-        tls_client_options_factory
-            (synapse.crypto.context_factory.ClientTLSOptionsFactory):
-            Factory which generates TLS options for client connections.
-        timeout (int): connection timeout in seconds
-    """
-
-    domain, port = parse_server_name(destination)
-
-    endpoint_kw_args = {}
-
-    if timeout is not None:
-        endpoint_kw_args.update(timeout=timeout)
-
-    if tls_client_options_factory is None:
-        transport_endpoint = HostnameEndpoint
-        default_port = 8008
-    else:
-        # the SNI string should be the same as the Host header, minus the port.
-        # as per https://github.com/matrix-org/synapse/issues/2525#issuecomment-336896777,
-        # the Host header and SNI should therefore be the server_name of the remote
-        # server.
-        tls_options = tls_client_options_factory.get_options(domain)
-
-        def transport_endpoint(reactor, host, port, timeout):
-            return wrapClientTLS(
-                tls_options,
-                HostnameEndpoint(reactor, host, port, timeout=timeout),
-            )
-        default_port = 8448
-
-    if port is None:
-        return SRVClientEndpoint(
-            reactor, "matrix", domain, protocol="tcp",
-            default_port=default_port, endpoint=transport_endpoint,
-            endpoint_kw_args=endpoint_kw_args
-        )
-    else:
-        return transport_endpoint(
-            reactor, domain, port, **endpoint_kw_args
-        )
-
-
-class SRVClientEndpoint(object):
-    """An endpoint which looks up SRV records for a service.
-    Cycles through the list of servers starting with each call to connect
-    picking the next server.
-    Implements twisted.internet.interfaces.IStreamClientEndpoint.
-    """
-
-    def __init__(self, reactor, service, domain, protocol="tcp",
-                 default_port=None, endpoint=HostnameEndpoint,
-                 endpoint_kw_args={}):
-        self.reactor = reactor
-        self.service_name = "_%s._%s.%s" % (service, protocol, domain)
-
-        if default_port is not None:
-            self.default_server = Server(
-                host=domain,
-                port=default_port,
-            )
-        else:
-            self.default_server = None
-
-        self.endpoint = endpoint
-        self.endpoint_kw_args = endpoint_kw_args
-
-        self.servers = None
-        self.used_servers = None
-
-    @defer.inlineCallbacks
-    def fetch_servers(self):
-        self.used_servers = []
-        self.servers = yield resolve_service(self.service_name)
-
-    def pick_server(self):
-        if not self.servers:
-            if self.used_servers:
-                self.servers = self.used_servers
-                self.used_servers = []
-                self.servers.sort()
-            elif self.default_server:
-                return self.default_server
-            else:
-                raise ConnectError(
-                    "No server available for %s" % self.service_name
-                )
-
-        # look for all servers with the same priority
-        min_priority = self.servers[0].priority
-        weight_indexes = list(
-            (index, server.weight + 1)
-            for index, server in enumerate(self.servers)
-            if server.priority == min_priority
-        )
-
-        total_weight = sum(weight for index, weight in weight_indexes)
-        target_weight = random.randint(0, total_weight)
-        for index, weight in weight_indexes:
-            target_weight -= weight
-            if target_weight <= 0:
-                server = self.servers[index]
-                # XXX: this looks totally dubious:
-                #
-                # (a) we never reuse a server until we have been through
-                #     all of the servers at the same priority, so if the
-                #     weights are A: 100, B:1, we always do ABABAB instead of
-                #     AAAA...AAAB (approximately).
-                #
-                # (b) After using all the servers at the lowest priority,
-                #     we move onto the next priority. We should only use the
-                #     second priority if servers at the top priority are
-                #     unreachable.
-                #
-                del self.servers[index]
-                self.used_servers.append(server)
-                return server
-
-    @defer.inlineCallbacks
-    def connect(self, protocolFactory):
-        if self.servers is None:
-            yield self.fetch_servers()
-        server = self.pick_server()
-        logger.info("Connecting to %s:%s", server.host, server.port)
-        endpoint = self.endpoint(
-            self.reactor, server.host, server.port, **self.endpoint_kw_args
-        )
-        connection = yield endpoint.connect(protocolFactory)
-        defer.returnValue(connection)

synapse/http/federation/matrix_federation_agent.py

@@ -0,0 +1,124 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 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 logging
+
+from zope.interface import implementer
+
+from twisted.internet import defer
+from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
+from twisted.web.client import URI, Agent, HTTPConnectionPool
+from twisted.web.iweb import IAgent
+
+from synapse.http.endpoint import parse_server_name
+from synapse.http.federation.srv_resolver import SrvResolver, pick_server_from_list
+from synapse.util.logcontext import make_deferred_yieldable
+
+logger = logging.getLogger(__name__)
+
+
+@implementer(IAgent)
+class MatrixFederationAgent(object):
+    """An Agent-like thing which provides a `request` method which will look up a matrix
+    server and send an HTTP request to it.
+
+    Doesn't implement any retries. (Those are done in MatrixFederationHttpClient.)
+
+    Args:
+        reactor (IReactor): twisted reactor to use for underlying requests
+
+        tls_client_options_factory (ClientTLSOptionsFactory|None):
+            factory to use for fetching client tls options, or none to disable TLS.
+
+        srv_resolver (SrvResolver|None):
+            SRVResolver impl to use for looking up SRV records. None to use a default
+            implementation.
+    """
+
+    def __init__(
+        self, reactor, tls_client_options_factory, _srv_resolver=None,
+    ):
+        self._reactor = reactor
+        self._tls_client_options_factory = tls_client_options_factory
+        if _srv_resolver is None:
+            _srv_resolver = SrvResolver()
+        self._srv_resolver = _srv_resolver
+
+        self._pool = HTTPConnectionPool(reactor)
+        self._pool.retryAutomatically = False
+        self._pool.maxPersistentPerHost = 5
+        self._pool.cachedConnectionTimeout = 2 * 60
+
+    @defer.inlineCallbacks
+    def request(self, method, uri, headers=None, bodyProducer=None):
+        """
+        Args:
+            method (bytes): HTTP method: GET/POST/etc
+
+            uri (bytes): Absolute URI to be retrieved
+
+            headers (twisted.web.http_headers.Headers|None):
+                HTTP headers to send with the request, or None to
+                send no extra headers.
+
+            bodyProducer (twisted.web.iweb.IBodyProducer|None):
+                An object which can generate bytes to make up the
+                body of this request (for example, the properly encoded contents of
+                a file for a file upload).  Or None if the request is to have
+                no body.
+
+        Returns:
+            Deferred[twisted.web.iweb.IResponse]:
+                fires when the header of the response has been received (regardless of the
+                response status code). Fails if there is any problem which prevents that
+                response from being received (including problems that prevent the request
+                from being sent).
+        """
+
+        parsed_uri = URI.fromBytes(uri)
+        server_name_bytes = parsed_uri.netloc
+        host, port = parse_server_name(server_name_bytes.decode("ascii"))
+
+        # XXX disabling TLS is really only supported here for the benefit of the
+        # unit tests. We should make the UTs cope with TLS rather than having to make
+        # the code support the unit tests.
+        if self._tls_client_options_factory is None:
+            tls_options = None
+        else:
+            tls_options = self._tls_client_options_factory.get_options(host)
+
+        if port is not None:
+            target = (host, port)
+        else:
+            server_list = yield self._srv_resolver.resolve_service(server_name_bytes)
+            if not server_list:
+                target = (host, 8448)
+                logger.debug("No SRV record for %s, using %s", host, target)
+            else:
+                target = pick_server_from_list(server_list)
+
+        class EndpointFactory(object):
+            @staticmethod
+            def endpointForURI(_uri):
+                logger.info("Connecting to %s:%s", target[0], target[1])
+                ep = HostnameEndpoint(self._reactor, host=target[0], port=target[1])
+                if tls_options is not None:
+                    ep = wrapClientTLS(tls_options, ep)
+                return ep
+
+        agent = Agent.usingEndpointFactory(self._reactor, EndpointFactory(), self._pool)
+        res = yield make_deferred_yieldable(
+            agent.request(method, uri, headers, bodyProducer)
+        )
+        defer.returnValue(res)

synapse/http/federation/srv_resolver.py

@@ -15,6 +15,7 @@
 # limitations under the License.
 
 import logging
+import random
 import time
 
 import attr
@@ -51,34 +52,79 @@ class Server(object):
     expires = attr.ib(default=0)
 
 
-@defer.inlineCallbacks
+def pick_server_from_list(server_list):
-def resolve_service(service_name, dns_client=client, cache=SERVER_CACHE, clock=time):
+    """Randomly choose a server from the server list
-    """Look up a SRV record, with caching
+
+    Args:
+        server_list (list[Server]): list of candidate servers
+
+    Returns:
+        Tuple[bytes, int]: (host, port) pair for the chosen server
+    """
+    if not server_list:
+        raise RuntimeError("pick_server_from_list called with empty list")
+
+    # TODO: currently we only use the lowest-priority servers. We should maintain a
+    # cache of servers known to be "down" and filter them out
+
+    min_priority = min(s.priority for s in server_list)
+    eligible_servers = list(s for s in server_list if s.priority == min_priority)
+    total_weight = sum(s.weight for s in eligible_servers)
+    target_weight = random.randint(0, total_weight)
+
+    for s in eligible_servers:
+        target_weight -= s.weight
+
+        if target_weight <= 0:
+            return s.host, s.port
+
+    # this should be impossible.
+    raise RuntimeError(
+        "pick_server_from_list got to end of eligible server list.",
+    )
+
+
+class SrvResolver(object):
+    """Interface to the dns client to do SRV lookups, with result caching.
 
     The default resolver in twisted.names doesn't do any caching (it has a CacheResolver,
     but the cache never gets populated), so we add our own caching layer here.
 
     Args:
-        service_name (unicode|bytes): record to look up
         dns_client (twisted.internet.interfaces.IResolver): twisted resolver impl
         cache (dict): cache object
-        clock (object): clock implementation. must provide a time() method.
+        get_time (callable): clock implementation. Should return seconds since the epoch
+    """
+    def __init__(self, dns_client=client, cache=SERVER_CACHE, get_time=time.time):
+        self._dns_client = dns_client
+        self._cache = cache
+        self._get_time = get_time
+
+    @defer.inlineCallbacks
+    def resolve_service(self, service_name):
+        """Look up a SRV record
+
+        Args:
+            service_name (bytes): record to look up
 
         Returns:
-        Deferred[list[Server]]: a list of the SRV records, or an empty list if none found
+            Deferred[list[Server]]:
+                a list of the SRV records, or an empty list if none found
         """
-    # TODO: the dns client handles both unicode names (encoding via idna) and pre-encoded
+        now = int(self._get_time())
-    # byteses; however they will obviously end up as separate entries in the cache. We
+
-    # should pick one form and stick with it.
+        if not isinstance(service_name, bytes):
-    cache_entry = cache.get(service_name, None)
+            raise TypeError("%r is not a byte string" % (service_name,))
+
+        cache_entry = self._cache.get(service_name, None)
         if cache_entry:
-        if all(s.expires > int(clock.time()) for s in cache_entry):
+            if all(s.expires > now for s in cache_entry):
                 servers = list(cache_entry)
                 defer.returnValue(servers)
 
         try:
             answers, _, _ = yield make_deferred_yieldable(
-            dns_client.lookupService(service_name),
+                self._dns_client.lookupService(service_name),
             )
         except DNSNameError:
             # TODO: cache this. We can get the SOA out of the exception, and use
@@ -87,7 +133,7 @@ def resolve_service(service_name, dns_client=client, cache=SERVER_CACHE, clock=t
         except DomainError as e:
             # We failed to resolve the name (other than a NameError)
             # Try something in the cache, else rereaise
-        cache_entry = cache.get(service_name, None)
+            cache_entry = self._cache.get(service_name, None)
             if cache_entry:
                 logger.warn(
                     "Failed to resolve %r, falling back to cache. %r",
@@ -116,9 +162,8 @@ def resolve_service(service_name, dns_client=client, cache=SERVER_CACHE, clock=t
                 port=payload.port,
                 priority=payload.priority,
                 weight=payload.weight,
-            expires=int(clock.time()) + answer.ttl,
+                expires=now + answer.ttl,
             ))
 
-    servers.sort()  # FIXME: get rid of this (it's broken by the attrs change)
+        self._cache[service_name] = list(servers)
-    cache[service_name] = list(servers)
         defer.returnValue(servers)

synapse/http/matrixfederationclient.py

@@ -32,7 +32,7 @@ from twisted.internet import defer, protocol
 from twisted.internet.error import DNSLookupError
 from twisted.internet.task import _EPSILON, Cooperator
 from twisted.web._newclient import ResponseDone
-from twisted.web.client import Agent, FileBodyProducer, HTTPConnectionPool
+from twisted.web.client import FileBodyProducer
 from twisted.web.http_headers import Headers
 
 import synapse.metrics
@@ -44,7 +44,7 @@ from synapse.api.errors import (
     RequestSendFailed,
     SynapseError,
 )
-from synapse.http.endpoint import matrix_federation_endpoint
+from synapse.http.federation.matrix_federation_agent import MatrixFederationAgent
 from synapse.util.async_helpers import timeout_deferred
 from synapse.util.logcontext import make_deferred_yieldable
 from synapse.util.metrics import Measure
@@ -66,20 +66,6 @@ else:
     MAXINT = sys.maxint
 
 
-class MatrixFederationEndpointFactory(object):
-    def __init__(self, hs):
-        self.reactor = hs.get_reactor()
-        self.tls_client_options_factory = hs.tls_client_options_factory
-
-    def endpointForURI(self, uri):
-        destination = uri.netloc.decode('ascii')
-
-        return matrix_federation_endpoint(
-            self.reactor, destination, timeout=10,
-            tls_client_options_factory=self.tls_client_options_factory
-        )
-
-
 _next_id = 1
 
 
@@ -187,12 +173,10 @@ class MatrixFederationHttpClient(object):
         self.signing_key = hs.config.signing_key[0]
         self.server_name = hs.hostname
         reactor = hs.get_reactor()
-        pool = HTTPConnectionPool(reactor)
+
-        pool.retryAutomatically = False
+        self.agent = MatrixFederationAgent(
-        pool.maxPersistentPerHost = 5
+            hs.get_reactor(),
-        pool.cachedConnectionTimeout = 2 * 60
+            hs.tls_client_options_factory,
-        self.agent = Agent.usingEndpointFactory(
-            reactor, MatrixFederationEndpointFactory(hs), pool=pool
         )
         self.clock = hs.get_clock()
         self._store = hs.get_datastore()
@@ -316,9 +300,9 @@ class MatrixFederationHttpClient(object):
                     headers_dict[b"Authorization"] = auth_headers
 
                     logger.info(
-                        "{%s} [%s] Sending request: %s %s",
+                        "{%s} [%s] Sending request: %s %s; timeout %fs",
                         request.txn_id, request.destination, request.method,
-                        url_str,
+                        url_str, _sec_timeout,
                     )
 
                     try:
@@ -338,12 +322,11 @@ class MatrixFederationHttpClient(object):
                                 reactor=self.hs.get_reactor(),
                             )
 
-                            response = yield make_deferred_yieldable(
+                            response = yield request_deferred
-                                request_deferred,
-                            )
                     except DNSLookupError as e:
                         raise_from(RequestSendFailed(e, can_retry=retry_on_dns_fail), e)
                     except Exception as e:
+                        logger.info("Failed to send request: %s", e)
                         raise_from(RequestSendFailed(e, can_retry=True), e)
 
                     logger.info(

synapse/python_dependencies.py

@@ -79,6 +79,10 @@ CONDITIONAL_REQUIREMENTS = {
     # ConsentResource uses select_autoescape, which arrived in jinja 2.9
     "resources.consent": ["Jinja2>=2.9"],
 
+    # ACME support is required to provision TLS certificates from authorities
+    # that use the protocol, such as Let's Encrypt.
+    "acme": ["txacme>=0.9.2"],
+
     "saml2": ["pysaml2>=4.5.0"],
     "url_preview": ["lxml>=3.5.0"],
     "test": ["mock>=2.0"],

synapse/server.py

@@ -46,6 +46,7 @@ from synapse.federation.transport.client import TransportLayerClient
 from synapse.groups.attestations import GroupAttestationSigning, GroupAttestionRenewer
 from synapse.groups.groups_server import GroupsServerHandler
 from synapse.handlers import Handlers
+from synapse.handlers.acme import AcmeHandler
 from synapse.handlers.appservice import ApplicationServicesHandler
 from synapse.handlers.auth import AuthHandler, MacaroonGenerator
 from synapse.handlers.deactivate_account import DeactivateAccountHandler
@@ -129,6 +130,7 @@ class HomeServer(object):
         'sync_handler',
         'typing_handler',
         'room_list_handler',
+        'acme_handler',
         'auth_handler',
         'device_handler',
         'e2e_keys_handler',
@@ -310,6 +312,9 @@ class HomeServer(object):
     def build_e2e_room_keys_handler(self):
         return E2eRoomKeysHandler(self)
 
+    def build_acme_handler(self):
+        return AcmeHandler(self)
+
     def build_application_service_api(self):
         return ApplicationServiceApi(self)
 

synapse/storage/client_ips.py

@@ -143,6 +143,11 @@ class ClientIpStore(background_updates.BackgroundUpdateStore):
         # If it returns None, then we're processing the last batch
         last = end_last_seen is None
 
+        logger.info(
+            "Scanning for duplicate 'user_ips' rows in range: %s <= last_seen < %s",
+            begin_last_seen, end_last_seen,
+        )
+
         def remove(txn):
             # This works by looking at all entries in the given time span, and
             # then for each (user_id, access_token, ip) tuple in that range
@@ -170,7 +175,6 @@ class ClientIpStore(background_updates.BackgroundUpdateStore):
                     SELECT user_id, access_token, ip
                     FROM user_ips
                     WHERE {}
-                    ORDER BY last_seen
                 ) c
                 INNER JOIN user_ips USING (user_id, access_token, ip)
                 GROUP BY user_id, access_token, ip

tests/http/federation/test_matrix_federation_agent.py

@@ -0,0 +1,183 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 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 logging
+
+from mock import Mock
+
+import treq
+
+from twisted.internet import defer
+from twisted.internet.protocol import Factory
+from twisted.protocols.tls import TLSMemoryBIOFactory
+from twisted.test.ssl_helpers import ServerTLSContext
+from twisted.web.http import HTTPChannel
+
+from synapse.crypto.context_factory import ClientTLSOptionsFactory
+from synapse.http.federation.matrix_federation_agent import MatrixFederationAgent
+from synapse.util.logcontext import LoggingContext
+
+from tests.server import FakeTransport, ThreadedMemoryReactorClock
+from tests.unittest import TestCase
+
+logger = logging.getLogger(__name__)
+
+
+class MatrixFederationAgentTests(TestCase):
+    def setUp(self):
+        self.reactor = ThreadedMemoryReactorClock()
+
+        self.mock_resolver = Mock()
+
+        self.agent = MatrixFederationAgent(
+            reactor=self.reactor,
+            tls_client_options_factory=ClientTLSOptionsFactory(None),
+            _srv_resolver=self.mock_resolver,
+        )
+
+    def _make_connection(self, client_factory):
+        """Builds a test server, and completes the outgoing client connection
+
+        Returns:
+            HTTPChannel: the test server
+        """
+
+        # build the test server
+        server_tls_protocol = _build_test_server()
+
+        # now, tell the client protocol factory to build the client protocol (it will be a
+        # _WrappingProtocol, around a TLSMemoryBIOProtocol, around an
+        # HTTP11ClientProtocol) and wire the output of said protocol up to the server via
+        # a FakeTransport.
+        #
+        # Normally this would be done by the TCP socket code in Twisted, but we are
+        # stubbing that out here.
+        client_protocol = client_factory.buildProtocol(None)
+        client_protocol.makeConnection(FakeTransport(server_tls_protocol, self.reactor))
+
+        # tell the server tls protocol to send its stuff back to the client, too
+        server_tls_protocol.makeConnection(FakeTransport(client_protocol, self.reactor))
+
+        # finally, give the reactor a pump to get the TLS juices flowing.
+        self.reactor.pump((0.1,))
+
+        # fish the test server back out of the server-side TLS protocol.
+        return server_tls_protocol.wrappedProtocol
+
+    @defer.inlineCallbacks
+    def _make_get_request(self, uri):
+        """
+        Sends a simple GET request via the agent, and checks its logcontext management
+        """
+        with LoggingContext("one") as context:
+            fetch_d = self.agent.request(b'GET', uri)
+
+            # Nothing happened yet
+            self.assertNoResult(fetch_d)
+
+            # should have reset logcontext to the sentinel
+            _check_logcontext(LoggingContext.sentinel)
+
+            try:
+                fetch_res = yield fetch_d
+                defer.returnValue(fetch_res)
+            finally:
+                _check_logcontext(context)
+
+    def test_get(self):
+        """
+        happy-path test of a GET request
+        """
+        self.reactor.lookups["testserv"] = "1.2.3.4"
+        test_d = self._make_get_request(b"matrix://testserv:8448/foo/bar")
+
+        # Nothing happened yet
+        self.assertNoResult(test_d)
+
+        # Make sure treq is trying to connect
+        clients = self.reactor.tcpClients
+        self.assertEqual(len(clients), 1)
+        (host, port, client_factory, _timeout, _bindAddress) = clients[0]
+        self.assertEqual(host, '1.2.3.4')
+        self.assertEqual(port, 8448)
+
+        # make a test server, and wire up the client
+        http_server = self._make_connection(client_factory)
+
+        self.assertEqual(len(http_server.requests), 1)
+        request = http_server.requests[0]
+        self.assertEqual(request.method, b'GET')
+        self.assertEqual(request.path, b'/foo/bar')
+        self.assertEqual(
+            request.requestHeaders.getRawHeaders(b'host'),
+            [b'testserv:8448']
+        )
+        content = request.content.read()
+        self.assertEqual(content, b'')
+
+        # Deferred is still without a result
+        self.assertNoResult(test_d)
+
+        # send the headers
+        request.responseHeaders.setRawHeaders(b'Content-Type', [b'application/json'])
+        request.write('')
+
+        self.reactor.pump((0.1,))
+
+        response = self.successResultOf(test_d)
+
+        # that should give us a Response object
+        self.assertEqual(response.code, 200)
+
+        # Send the body
+        request.write('{ "a": 1 }'.encode('ascii'))
+        request.finish()
+
+        self.reactor.pump((0.1,))
+
+        # check it can be read
+        json = self.successResultOf(treq.json_content(response))
+        self.assertEqual(json, {"a": 1})
+
+
+def _check_logcontext(context):
+    current = LoggingContext.current_context()
+    if current is not context:
+        raise AssertionError(
+            "Expected logcontext %s but was %s" % (context, current),
+        )
+
+
+def _build_test_server():
+    """Construct a test server
+
+    This builds an HTTP channel, wrapped with a TLSMemoryBIOProtocol
+
+    Returns:
+        TLSMemoryBIOProtocol
+    """
+    server_factory = Factory.forProtocol(HTTPChannel)
+    # Request.finish expects the factory to have a 'log' method.
+    server_factory.log = _log_request
+
+    server_tls_factory = TLSMemoryBIOFactory(
+        ServerTLSContext(), isClient=False, wrappedFactory=server_factory,
+    )
+
+    return server_tls_factory.buildProtocol(None)
+
+
+def _log_request(request):
+    """Implements Factory.log, which is expected by Request.finish"""
+    logger.info("Completed request %s", request)

tests/http/federation/test_srv_resolver.py

@@ -21,7 +21,7 @@ from twisted.internet.defer import Deferred
 from twisted.internet.error import ConnectError
 from twisted.names import dns, error
 
-from synapse.http.federation.srv_resolver import resolve_service
+from synapse.http.federation.srv_resolver import SrvResolver
 from synapse.util.logcontext import LoggingContext
 
 from tests import unittest
@@ -43,13 +43,13 @@ class SrvResolverTestCase(unittest.TestCase):
         dns_client_mock.lookupService.return_value = result_deferred
 
         cache = {}
+        resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
 
         @defer.inlineCallbacks
         def do_lookup():
+
             with LoggingContext("one") as ctx:
-                resolve_d = resolve_service(
+                resolve_d = resolver.resolve_service(service_name)
-                    service_name, dns_client=dns_client_mock, cache=cache
-                )
 
                 self.assertNoResult(resolve_d)
 
@@ -83,16 +83,15 @@ class SrvResolverTestCase(unittest.TestCase):
         dns_client_mock = Mock()
         dns_client_mock.lookupService.return_value = defer.fail(error.DNSServerError())
 
-        service_name = "test_service.example.com"
+        service_name = b"test_service.example.com"
 
         entry = Mock(spec_set=["expires"])
         entry.expires = 0
 
         cache = {service_name: [entry]}
+        resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
 
-        servers = yield resolve_service(
+        servers = yield resolver.resolve_service(service_name)
-            service_name, dns_client=dns_client_mock, cache=cache
-        )
 
         dns_client_mock.lookupService.assert_called_once_with(service_name)
 
@@ -106,17 +105,18 @@ class SrvResolverTestCase(unittest.TestCase):
         dns_client_mock = Mock(spec_set=['lookupService'])
         dns_client_mock.lookupService = Mock(spec_set=[])
 
-        service_name = "test_service.example.com"
+        service_name = b"test_service.example.com"
 
         entry = Mock(spec_set=["expires"])
         entry.expires = 999999999
 
         cache = {service_name: [entry]}
-
+        resolver = SrvResolver(
-        servers = yield resolve_service(
+            dns_client=dns_client_mock, cache=cache, get_time=clock.time,
-            service_name, dns_client=dns_client_mock, cache=cache, clock=clock
         )
 
+        servers = yield resolver.resolve_service(service_name)
+
         self.assertFalse(dns_client_mock.lookupService.called)
 
         self.assertEquals(len(servers), 1)
@@ -128,12 +128,13 @@ class SrvResolverTestCase(unittest.TestCase):
 
         dns_client_mock.lookupService.return_value = defer.fail(error.DNSServerError())
 
-        service_name = "test_service.example.com"
+        service_name = b"test_service.example.com"
 
         cache = {}
+        resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
 
         with self.assertRaises(error.DNSServerError):
-            yield resolve_service(service_name, dns_client=dns_client_mock, cache=cache)
+            yield resolver.resolve_service(service_name)
 
     @defer.inlineCallbacks
     def test_name_error(self):
@@ -141,13 +142,12 @@ class SrvResolverTestCase(unittest.TestCase):
 
         dns_client_mock.lookupService.return_value = defer.fail(error.DNSNameError())
 
-        service_name = "test_service.example.com"
+        service_name = b"test_service.example.com"
 
         cache = {}
+        resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
 
-        servers = yield resolve_service(
+        servers = yield resolver.resolve_service(service_name)
-            service_name, dns_client=dns_client_mock, cache=cache
-        )
 
         self.assertEquals(len(servers), 0)
         self.assertEquals(len(cache), 0)
@@ -162,10 +162,9 @@ class SrvResolverTestCase(unittest.TestCase):
         dns_client_mock = Mock()
         dns_client_mock.lookupService.return_value = lookup_deferred
         cache = {}
+        resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
 
-        resolve_d = resolve_service(
+        resolve_d = resolver.resolve_service(service_name)
-            service_name, dns_client=dns_client_mock, cache=cache
-        )
         self.assertNoResult(resolve_d)
 
         # returning a single "." should make the lookup fail with a ConenctError
@@ -187,10 +186,9 @@ class SrvResolverTestCase(unittest.TestCase):
         dns_client_mock = Mock()
         dns_client_mock.lookupService.return_value = lookup_deferred
         cache = {}
+        resolver = SrvResolver(dns_client=dns_client_mock, cache=cache)
 
-        resolve_d = resolve_service(
+        resolve_d = resolver.resolve_service(service_name)
-            service_name, dns_client=dns_client_mock, cache=cache
-        )
         self.assertNoResult(resolve_d)
 
         lookup_deferred.callback((

tests/http/test_fedclient.py

@@ -15,6 +15,7 @@
 
 from mock import Mock
 
+from twisted.internet import defer
 from twisted.internet.defer import TimeoutError
 from twisted.internet.error import ConnectingCancelledError, DNSLookupError
 from twisted.test.proto_helpers import StringTransport
@@ -26,11 +27,20 @@ from synapse.http.matrixfederationclient import (
     MatrixFederationHttpClient,
     MatrixFederationRequest,
 )
+from synapse.util.logcontext import LoggingContext
 
 from tests.server import FakeTransport
 from tests.unittest import HomeserverTestCase
 
 
+def check_logcontext(context):
+    current = LoggingContext.current_context()
+    if current is not context:
+        raise AssertionError(
+            "Expected logcontext %s but was %s" % (context, current),
+        )
+
+
 class FederationClientTests(HomeserverTestCase):
     def make_homeserver(self, reactor, clock):
 
@@ -43,6 +53,70 @@ class FederationClientTests(HomeserverTestCase):
         self.cl = MatrixFederationHttpClient(self.hs)
         self.reactor.lookups["testserv"] = "1.2.3.4"
 
+    def test_client_get(self):
+        """
+        happy-path test of a GET request
+        """
+        @defer.inlineCallbacks
+        def do_request():
+            with LoggingContext("one") as context:
+                fetch_d = self.cl.get_json("testserv:8008", "foo/bar")
+
+                # Nothing happened yet
+                self.assertNoResult(fetch_d)
+
+                # should have reset logcontext to the sentinel
+                check_logcontext(LoggingContext.sentinel)
+
+                try:
+                    fetch_res = yield fetch_d
+                    defer.returnValue(fetch_res)
+                finally:
+                    check_logcontext(context)
+
+        test_d = do_request()
+
+        self.pump()
+
+        # Nothing happened yet
+        self.assertNoResult(test_d)
+
+        # Make sure treq is trying to connect
+        clients = self.reactor.tcpClients
+        self.assertEqual(len(clients), 1)
+        (host, port, factory, _timeout, _bindAddress) = clients[0]
+        self.assertEqual(host, '1.2.3.4')
+        self.assertEqual(port, 8008)
+
+        # complete the connection and wire it up to a fake transport
+        protocol = factory.buildProtocol(None)
+        transport = StringTransport()
+        protocol.makeConnection(transport)
+
+        # that should have made it send the request to the transport
+        self.assertRegex(transport.value(), b"^GET /foo/bar")
+
+        # Deferred is still without a result
+        self.assertNoResult(test_d)
+
+        # Send it the HTTP response
+        res_json = '{ "a": 1 }'.encode('ascii')
+        protocol.dataReceived(
+            b"HTTP/1.1 200 OK\r\n"
+            b"Server: Fake\r\n"
+            b"Content-Type: application/json\r\n"
+            b"Content-Length: %i\r\n"
+            b"\r\n"
+            b"%s" % (len(res_json), res_json)
+        )
+
+        self.pump()
+
+        res = self.successResultOf(test_d)
+
+        # check the response is as expected
+        self.assertEqual(res, {"a": 1})
+
     def test_dns_error(self):
         """
         If the DNS lookup returns an error, it will bubble up.
@@ -54,6 +128,28 @@ class FederationClientTests(HomeserverTestCase):
         self.assertIsInstance(f.value, RequestSendFailed)
         self.assertIsInstance(f.value.inner_exception, DNSLookupError)
 
+    def test_client_connection_refused(self):
+        d = self.cl.get_json("testserv:8008", "foo/bar", timeout=10000)
+
+        self.pump()
+
+        # Nothing happened yet
+        self.assertNoResult(d)
+
+        clients = self.reactor.tcpClients
+        self.assertEqual(len(clients), 1)
+        (host, port, factory, _timeout, _bindAddress) = clients[0]
+        self.assertEqual(host, '1.2.3.4')
+        self.assertEqual(port, 8008)
+        e = Exception("go away")
+        factory.clientConnectionFailed(None, e)
+        self.pump(0.5)
+
+        f = self.failureResultOf(d)
+
+        self.assertIsInstance(f.value, RequestSendFailed)
+        self.assertIs(f.value.inner_exception, e)
+
     def test_client_never_connect(self):
         """
         If the HTTP request is not connected and is timed out, it'll give a

tests/server.py

@@ -1,4 +1,5 @@
 import json
+import logging
 from io import BytesIO
 
 from six import text_type
@@ -22,6 +23,8 @@ from synapse.util import Clock
 
 from tests.utils import setup_test_homeserver as _sth
 
+logger = logging.getLogger(__name__)
+
 
 class TimedOutException(Exception):
     """
@@ -339,7 +342,7 @@ def get_clock():
     return (clock, hs_clock)
 
 
-@attr.s
+@attr.s(cmp=False)
 class FakeTransport(object):
     """
     A twisted.internet.interfaces.ITransport implementation which sends all its data
@@ -414,6 +417,11 @@ class FakeTransport(object):
         self.buffer = self.buffer + byt
 
         def _write():
+            if not self.buffer:
+                # nothing to do. Don't write empty buffers: it upsets the
+                # TLSMemoryBIOProtocol
+                return
+
             if getattr(self.other, "transport") is not None:
                 self.other.dataReceived(self.buffer)
                 self.buffer = b""
@@ -421,7 +429,10 @@ class FakeTransport(object):
 
             self._reactor.callLater(0.0, _write)
 
-        _write()
+        # always actually do the write asynchronously. Some protocols (notably the
+        # TLSMemoryBIOProtocol) get very confused if a read comes back while they are
+        # still doing a write. Doing a callLater here breaks the cycle.
+        self._reactor.callLater(0.0, _write)
 
     def writeSequence(self, seq):
         for x in seq: