Merge remote-tracking branch 'origin/develop' into erikj/generate_presice_thumbnails

26 files changed, 399 insertions, 300 deletions

diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 487be7ce9c..a7f428a96c 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -44,6 +44,11 @@ class Auth(object):
     def check(self, event, auth_events):
         """ Checks if this event is correctly authed.
 
+        Args:
+            event: the event being checked.
+            auth_events (dict: event-key -> event): the existing room state.
+
+
         Returns:
             True if the auth checks pass.
         """
@@ -319,7 +324,7 @@ class Auth(object):
         Returns:
             tuple : of UserID and device string:
                 User ID object of the user making the request
-                Client ID object of the client instance the user is using
+                ClientInfo object of the client instance the user is using
         Raises:
             AuthError if no user by that token exists or the token is invalid.
         """
@@ -352,7 +357,7 @@ class Auth(object):
                 )
                 return
             except KeyError:
-                pass  # normal users won't have this query parameter set
+                pass  # normal users won't have the user_id query parameter set.
 
             user_info = yield self.get_user_by_token(access_token)
             user = user_info["user"]
@@ -521,23 +526,22 @@ class Auth(object):
 
         # Check state_key
         if hasattr(event, "state_key"):
-            if not event.state_key.startswith("_"):
-                if event.state_key.startswith("@"):
-                    if event.state_key != event.user_id:
+            if event.state_key.startswith("@"):
+                if event.state_key != event.user_id:
+                    raise AuthError(
+                        403,
+                        "You are not allowed to set others state"
+                    )
+                else:
+                    sender_domain = UserID.from_string(
+                        event.user_id
+                    ).domain
+
+                    if sender_domain != event.state_key:
                         raise AuthError(
                             403,
                             "You are not allowed to set others state"
                         )
-                    else:
-                        sender_domain = UserID.from_string(
-                            event.user_id
-                        ).domain
-
-                        if sender_domain != event.state_key:
-                            raise AuthError(
-                                403,
-                                "You are not allowed to set others state"
-                            )
 
         return True
 
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 49e27c9e11..f04493f92a 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -657,7 +657,8 @@ def run(hs):
 
     if hs.config.daemonize:
 
-        print hs.config.pid_file
+        if hs.config.print_pidfile:
+            print hs.config.pid_file
 
         daemon = Daemonize(
             app="synapse-homeserver",
diff --git a/synapse/config/_base.py b/synapse/config/_base.py
index d483c67c6a..73f6959959 100644
--- a/synapse/config/_base.py
+++ b/synapse/config/_base.py
@@ -139,11 +139,18 @@ class Config(object):
             help="Generate a config file for the server name"
         )
         config_parser.add_argument(
+            "--generate-keys",
+            action="store_true",
+            help="Generate any missing key files then exit"
+        )
+        config_parser.add_argument(
             "-H", "--server-name",
             help="The server name to generate a config file for"
         )
         config_args, remaining_args = config_parser.parse_known_args(argv)
 
+        generate_keys = config_args.generate_keys
+
         if config_args.generate_config:
             if not config_args.config_path:
                 config_parser.error(
@@ -151,51 +158,40 @@ class Config(object):
                     " generated using \"--generate-config -H SERVER_NAME"
                     " -c CONFIG-FILE\""
                 )
-
-            config_dir_path = os.path.dirname(config_args.config_path[0])
-            config_dir_path = os.path.abspath(config_dir_path)
-
-            server_name = config_args.server_name
-            if not server_name:
-                print "Must specify a server_name to a generate config for."
-                sys.exit(1)
             (config_path,) = config_args.config_path
-            if not os.path.exists(config_dir_path):
-                os.makedirs(config_dir_path)
-            if os.path.exists(config_path):
-                print "Config file %r already exists" % (config_path,)
-                yaml_config = cls.read_config_file(config_path)
-                yaml_name = yaml_config["server_name"]
-                if server_name != yaml_name:
-                    print (
-                        "Config file %r has a different server_name: "
-                        " %r != %r" % (config_path, server_name, yaml_name)
-                    )
+            if not os.path.exists(config_path):
+                config_dir_path = os.path.dirname(config_path)
+                config_dir_path = os.path.abspath(config_dir_path)
+
+                server_name = config_args.server_name
+                if not server_name:
+                    print "Must specify a server_name to a generate config for."
                     sys.exit(1)
-                config_bytes, config = obj.generate_config(
-                    config_dir_path, server_name
+                if not os.path.exists(config_dir_path):
+                    os.makedirs(config_dir_path)
+                with open(config_path, "wb") as config_file:
+                    config_bytes, config = obj.generate_config(
+                        config_dir_path, server_name
+                    )
+                    obj.invoke_all("generate_files", config)
+                    config_file.write(config_bytes)
+                print (
+                    "A config file has been generated in %r for server name"
+                    " %r with corresponding SSL keys and self-signed"
+                    " certificates. Please review this file and customise it"
+                    " to your needs."
+                ) % (config_path, server_name)
+                print (
+                    "If this server name is incorrect, you will need to"
+                    " regenerate the SSL certificates"
                 )
-                config.update(yaml_config)
-                print "Generating any missing keys for %r" % (server_name,)
-                obj.invoke_all("generate_files", config)
                 sys.exit(0)
-            with open(config_path, "wb") as config_file:
-                config_bytes, config = obj.generate_config(
-                    config_dir_path, server_name
-                )
-                obj.invoke_all("generate_files", config)
-                config_file.write(config_bytes)
+            else:
                 print (
-                    "A config file has been generated in %s for server name"
-                    " '%s' with corresponding SSL keys and self-signed"
-                    " certificates. Please review this file and customise it to"
-                    " your needs."
-                ) % (config_path, server_name)
-            print (
-                "If this server name is incorrect, you will need to regenerate"
-                " the SSL certificates"
-            )
-            sys.exit(0)
+                    "Config file %r already exists. Generating any missing key"
+                    " files."
+                ) % (config_path,)
+                generate_keys = True
 
         parser = argparse.ArgumentParser(
             parents=[config_parser],
@@ -213,7 +209,7 @@ class Config(object):
                 " -c CONFIG-FILE\""
             )
 
-        config_dir_path = os.path.dirname(config_args.config_path[0])
+        config_dir_path = os.path.dirname(config_args.config_path[-1])
         config_dir_path = os.path.abspath(config_dir_path)
 
         specified_config = {}
@@ -226,6 +222,10 @@ class Config(object):
         config.pop("log_config")
         config.update(specified_config)
 
+        if generate_keys:
+            obj.invoke_all("generate_files", config)
+            sys.exit(0)
+
         obj.invoke_all("read_config", config)
 
         obj.invoke_all("read_arguments", args)
diff --git a/synapse/config/server.py b/synapse/config/server.py
index f4d4a87103..f9a3b5f15b 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -24,6 +24,7 @@ class ServerConfig(Config):
         self.web_client = config["web_client"]
         self.soft_file_limit = config["soft_file_limit"]
         self.daemonize = config.get("daemonize")
+        self.print_pidfile = config.get("print_pidfile")
         self.use_frozen_dicts = config.get("use_frozen_dicts", True)
 
         self.listeners = config.get("listeners", [])
@@ -208,12 +209,18 @@ class ServerConfig(Config):
             self.manhole = args.manhole
         if args.daemonize is not None:
             self.daemonize = args.daemonize
+        if args.print_pidfile is not None:
+            self.print_pidfile = args.print_pidfile
 
     def add_arguments(self, parser):
         server_group = parser.add_argument_group("server")
         server_group.add_argument("-D", "--daemonize", action='store_true',
                                   default=None,
                                   help="Daemonize the home server")
+        server_group.add_argument("--print-pidfile", action='store_true',
+                                  default=None,
+                                  help="Print the path to the pidfile just"
+                                  " before daemonizing")
         server_group.add_argument("--manhole", metavar="PORT", dest="manhole",
                                   type=int,
                                   help="Turn on the twisted telnet manhole"
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index 6200e10775..c1095708a0 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -44,7 +44,7 @@ class IdentityHandler(BaseHandler):
         http_client = SimpleHttpClient(self.hs)
         # XXX: make this configurable!
         # trustedIdServers = ['matrix.org', 'localhost:8090']
-        trustedIdServers = ['matrix.org']
+        trustedIdServers = ['matrix.org', 'vector.im']
 
         if 'id_server' in creds:
             id_server = creds['id_server']
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index a1288b4252..f81d75017d 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -73,7 +73,8 @@ class RegistrationHandler(BaseHandler):
             localpart : The local part of the user ID to register. If None,
               one will be randomly generated.
             password (str) : The password to assign to this user so they can
-            login again.
+            login again. This can be None which means they cannot login again
+            via a password (e.g. the user is an application service user).
         Returns:
             A tuple of (user_id, access_token).
         Raises:
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index ed47e701e7..854e17a473 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -16,7 +16,7 @@
 
 from twisted.internet import defer, reactor, protocol
 from twisted.internet.error import DNSLookupError
-from twisted.web.client import readBody, _AgentBase, _URI, HTTPConnectionPool
+from twisted.web.client import readBody, HTTPConnectionPool, Agent
 from twisted.web.http_headers import Headers
 from twisted.web._newclient import ResponseDone
 
@@ -55,41 +55,17 @@ incoming_responses_counter = metrics.register_counter(
 )
 
 
-class MatrixFederationHttpAgent(_AgentBase):
-
-    def __init__(self, reactor, pool=None):
-        _AgentBase.__init__(self, reactor, pool)
-
-    def request(self, destination, endpoint, method, path, params, query,
-                headers, body_producer):
-
-        outgoing_requests_counter.inc(method)
-
-        host = b""
-        port = 0
-        fragment = b""
-
-        parsed_URI = _URI(b"http", destination, host, port, path, params,
-                          query, fragment)
-
-        # Set the connection pool key to be the destination.
-        key = destination
-
-        d = self._requestWithEndpoint(key, endpoint, method, parsed_URI,
-                                      headers, body_producer,
-                                      parsed_URI.originForm)
-
-        def _cb(response):
-            incoming_responses_counter.inc(method, response.code)
-            return response
-
-        def _eb(failure):
-            incoming_responses_counter.inc(method, "ERR")
-            return failure
+class MatrixFederationEndpointFactory(object):
+    def __init__(self, hs):
+        self.tls_context_factory = hs.tls_context_factory
 
-        d.addCallbacks(_cb, _eb)
+    def endpointForURI(self, uri):
+        destination = uri.netloc
 
-        return d
+        return matrix_federation_endpoint(
+            reactor, destination, timeout=10,
+            ssl_context_factory=self.tls_context_factory
+        )
 
 
 class MatrixFederationHttpClient(object):
@@ -107,12 +83,18 @@ class MatrixFederationHttpClient(object):
         self.server_name = hs.hostname
         pool = HTTPConnectionPool(reactor)
         pool.maxPersistentPerHost = 10
-        self.agent = MatrixFederationHttpAgent(reactor, pool=pool)
+        self.agent = Agent.usingEndpointFactory(
+            reactor, MatrixFederationEndpointFactory(hs), pool=pool
+        )
         self.clock = hs.get_clock()
         self.version_string = hs.version_string
-
         self._next_id = 1
 
+    def _create_url(self, destination, path_bytes, param_bytes, query_bytes):
+        return urlparse.urlunparse(
+            ("matrix", destination, path_bytes, param_bytes, query_bytes, "")
+        )
+
     @defer.inlineCallbacks
     def _create_request(self, destination, method, path_bytes,
                         body_callback, headers_dict={}, param_bytes=b"",
@@ -123,8 +105,8 @@ class MatrixFederationHttpClient(object):
         headers_dict[b"User-Agent"] = [self.version_string]
         headers_dict[b"Host"] = [destination]
 
-        url_bytes = urlparse.urlunparse(
-            ("", "", path_bytes, param_bytes, query_bytes, "",)
+        url_bytes = self._create_url(
+            destination, path_bytes, param_bytes, query_bytes
         )
 
         txn_id = "%s-O-%s" % (method, self._next_id)
@@ -139,8 +121,8 @@ class MatrixFederationHttpClient(object):
         # (once we have reliable transactions in place)
         retries_left = 5
 
-        endpoint = preserve_context_over_fn(
-            self._getEndpoint, reactor, destination
+        http_url_bytes = urlparse.urlunparse(
+            ("", "", path_bytes, param_bytes, query_bytes, "")
         )
 
         log_result = None
@@ -148,17 +130,14 @@ class MatrixFederationHttpClient(object):
             while True:
                 producer = None
                 if body_callback:
-                    producer = body_callback(method, url_bytes, headers_dict)
+                    producer = body_callback(method, http_url_bytes, headers_dict)
 
                 try:
                     def send_request():
-                        request_deferred = self.agent.request(
-                            destination,
-                            endpoint,
+                        request_deferred = preserve_context_over_fn(
+                            self.agent.request,
                             method,
-                            path_bytes,
-                            param_bytes,
-                            query_bytes,
+                            url_bytes,
                             Headers(headers_dict),
                             producer
                         )
@@ -452,12 +431,6 @@ class MatrixFederationHttpClient(object):
 
         defer.returnValue((length, headers))
 
-    def _getEndpoint(self, reactor, destination):
-        return matrix_federation_endpoint(
-            reactor, destination, timeout=10,
-            ssl_context_factory=self.hs.tls_context_factory
-        )
-
 
 class _ReadBodyToFileProtocol(protocol.Protocol):
     def __init__(self, stream, deferred, max_size):
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index 9233ea3da9..0be9772991 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -18,8 +18,12 @@ from __future__ import absolute_import
 
 import logging
 from resource import getrusage, getpagesize, RUSAGE_SELF
+import functools
 import os
 import stat
+import time
+
+from twisted.internet import reactor
 
 from .metric import (
     CounterMetric, CallbackMetric, DistributionMetric, CacheMetric
@@ -144,3 +148,28 @@ def _process_fds():
     return counts
 
 get_metrics_for("process").register_callback("fds", _process_fds, labels=["type"])
+
+reactor_metrics = get_metrics_for("reactor")
+tick_time = reactor_metrics.register_distribution("tick_time")
+pending_calls_metric = reactor_metrics.register_distribution("pending_calls")
+
+
+def runUntilCurrentTimer(func):
+
+    @functools.wraps(func)
+    def f(*args, **kwargs):
+        pending_calls = len(reactor.getDelayedCalls())
+        start = time.time() * 1000
+        ret = func(*args, **kwargs)
+        end = time.time() * 1000
+        tick_time.inc_by(end - start)
+        pending_calls_metric.inc_by(pending_calls)
+        return ret
+
+    return f
+
+
+if hasattr(reactor, "runUntilCurrent"):
+    # runUntilCurrent is called when we have pending calls. It is called once
+    # per iteratation after fd polling.
+    reactor.runUntilCurrent = runUntilCurrentTimer(reactor.runUntilCurrent)
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 115bee8c41..fa06480ad1 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -19,7 +19,7 @@ logger = logging.getLogger(__name__)
 
 REQUIREMENTS = {
     "syutil>=0.0.7": ["syutil>=0.0.7"],
-    "Twisted==14.0.2": ["twisted==14.0.2"],
+    "Twisted>=15.1.0": ["twisted>=15.1.0"],
     "service_identity>=1.0.0": ["service_identity>=1.0.0"],
     "pyopenssl>=0.14": ["OpenSSL>=0.14"],
     "pyyaml": ["yaml"],
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 0c737d73b8..b5926f9ca6 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -19,7 +19,7 @@ from synapse.api.constants import LoginType
 from synapse.api.errors import SynapseError, Codes
 from synapse.http.servlet import RestServlet
 
-from ._base import client_v2_pattern, parse_request_allow_empty
+from ._base import client_v2_pattern, parse_json_dict_from_request
 
 import logging
 import hmac
@@ -55,30 +55,55 @@ class RegisterRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_POST(self, request):
         yield run_on_reactor()
+        body = parse_json_dict_from_request(request)
 
-        body = parse_request_allow_empty(request)
-        # we do basic sanity checks here because the auth
-        # layer will store these in sessions
+        # we do basic sanity checks here because the auth layer will store these
+        # in sessions. Pull out the username/password provided to us.
+        desired_password = None
         if 'password' in body:
-            if ((not isinstance(body['password'], str) and
-                    not isinstance(body['password'], unicode)) or
+            if (not isinstance(body['password'], basestring) or
                     len(body['password']) > 512):
                 raise SynapseError(400, "Invalid password")
+            desired_password = body["password"]
 
+        desired_username = None
         if 'username' in body:
-            if ((not isinstance(body['username'], str) and
-                    not isinstance(body['username'], unicode)) or
+            if (not isinstance(body['username'], basestring) or
                     len(body['username']) > 512):
                 raise SynapseError(400, "Invalid username")
             desired_username = body['username']
-            yield self.registration_handler.check_username(desired_username)
-
-        is_using_shared_secret = False
-        is_application_server = False
 
-        service = None
+        appservice = None
         if 'access_token' in request.args:
-            service = yield self.auth.get_appservice_by_req(request)
+            appservice = yield self.auth.get_appservice_by_req(request)
+
+        # fork off as soon as possible for ASes and shared secret auth which
+        # have completely different registration flows to normal users
+
+        # == Application Service Registration ==
+        if appservice:
+            result = yield self._do_appservice_registration(
+                desired_username, request.args["access_token"][0]
+            )
+            defer.returnValue((200, result))  # we throw for non 200 responses
+            return
+
+        # == Shared Secret Registration == (e.g. create new user scripts)
+        if 'mac' in body:
+            # FIXME: Should we really be determining if this is shared secret
+            # auth based purely on the 'mac' key?
+            result = yield self._do_shared_secret_registration(
+                desired_username, desired_password, body["mac"]
+            )
+            defer.returnValue((200, result))  # we throw for non 200 responses
+            return
+
+        # == Normal User Registration == (everyone else)
+        if self.hs.config.disable_registration:
+            raise SynapseError(403, "Registration has been disabled")
+
+        if desired_username is not None:
+            yield self.registration_handler.check_username(desired_username)
 
         if self.hs.config.enable_registration_captcha:
             flows = [
@@ -91,39 +116,20 @@ class RegisterRestServlet(RestServlet):
                 [LoginType.EMAIL_IDENTITY]
             ]
 
-        result = None
-        if service:
-            is_application_server = True
-            params = body
-        elif 'mac' in body:
-            # Check registration-specific shared secret auth
-            if 'username' not in body:
-                raise SynapseError(400, "", Codes.MISSING_PARAM)
-            self._check_shared_secret_auth(
-                body['username'], body['mac']
-            )
-            is_using_shared_secret = True
-            params = body
-        else:
-            authed, result, params = yield self.auth_handler.check_auth(
-                flows, body, self.hs.get_ip_from_request(request)
-            )
-
-            if not authed:
-                defer.returnValue((401, result))
-
-        can_register = (
-            not self.hs.config.disable_registration
-            or is_application_server
-            or is_using_shared_secret
+        authed, result, params = yield self.auth_handler.check_auth(
+            flows, body, self.hs.get_ip_from_request(request)
         )
-        if not can_register:
-            raise SynapseError(403, "Registration has been disabled")
 
+        if not authed:
+            defer.returnValue((401, result))
+            return
+
+        # NB: This may be from the auth handler and NOT from the POST
         if 'password' not in params:
-            raise SynapseError(400, "", Codes.MISSING_PARAM)
-        desired_username = params['username'] if 'username' in params else None
-        new_password = params['password']
+            raise SynapseError(400, "Missing password.", Codes.MISSING_PARAM)
+
+        desired_username = params.get("username", None)
+        new_password = params.get("password", None)
 
         (user_id, token) = yield self.registration_handler.register(
             localpart=desired_username,
@@ -156,18 +162,21 @@ class RegisterRestServlet(RestServlet):
             else:
                 logger.info("bind_email not specified: not binding email")
 
-        result = {
-            "user_id": user_id,
-            "access_token": token,
-            "home_server": self.hs.hostname,
-        }
-
+        result = self._create_registration_details(user_id, token)
         defer.returnValue((200, result))
 
     def on_OPTIONS(self, _):
         return 200, {}
 
-    def _check_shared_secret_auth(self, username, mac):
+    @defer.inlineCallbacks
+    def _do_appservice_registration(self, username, as_token):
+        (user_id, token) = yield self.registration_handler.appservice_register(
+            username, as_token
+        )
+        defer.returnValue(self._create_registration_details(user_id, token))
+
+    @defer.inlineCallbacks
+    def _do_shared_secret_registration(self, username, password, mac):
         if not self.hs.config.registration_shared_secret:
             raise SynapseError(400, "Shared secret registration is not enabled")
 
@@ -183,13 +192,23 @@ class RegisterRestServlet(RestServlet):
             digestmod=sha1,
         ).hexdigest()
 
-        if compare_digest(want_mac, got_mac):
-            return True
-        else:
+        if not compare_digest(want_mac, got_mac):
             raise SynapseError(
                 403, "HMAC incorrect",
             )
 
+        (user_id, token) = yield self.registration_handler.register(
+            localpart=username, password=password
+        )
+        defer.returnValue(self._create_registration_details(user_id, token))
+
+    def _create_registration_details(self, user_id, token):
+        return {
+            "user_id": user_id,
+            "access_token": token,
+            "home_server": self.hs.hostname,
+        }
+
 
 def register_servlets(hs, http_server):
     RegisterRestServlet(hs).register(http_server)
diff --git a/synapse/rest/media/v1/base_resource.py b/synapse/rest/media/v1/base_resource.py
index 271cbca2d6..4e21527c3d 100644
--- a/synapse/rest/media/v1/base_resource.py
+++ b/synapse/rest/media/v1/base_resource.py
@@ -298,43 +298,52 @@ class BaseMediaResource(Resource):
             )
             return
 
-        scales = set()
-        crops = set()
-        for r_width, r_height, r_method, r_type in requirements:
-            if r_method == "scale":
-                t_width, t_height = thumbnailer.aspect(r_width, r_height)
-                scales.add((
-                    min(m_width, t_width), min(m_height, t_height), r_type,
+        local_thumbnails = []
+
+        def generate_thumbnails():
+            scales = set()
+            crops = set()
+            for r_width, r_height, r_method, r_type in requirements:
+                if r_method == "scale":
+                    t_width, t_height = thumbnailer.aspect(r_width, r_height)
+                    scales.add((
+                        min(m_width, t_width), min(m_height, t_height), r_type,
+                    ))
+                elif r_method == "crop":
+                    crops.add((r_width, r_height, r_type))
+
+            for t_width, t_height, t_type in scales:
+                t_method = "scale"
+                t_path = self.filepaths.local_media_thumbnail(
+                    media_id, t_width, t_height, t_type, t_method
+                )
+                self._makedirs(t_path)
+                t_len = thumbnailer.scale(t_path, t_width, t_height, t_type)
+
+                local_thumbnails.append((
+                    media_id, t_width, t_height, t_type, t_method, t_len
                 ))
-            elif r_method == "crop":
-                crops.add((r_width, r_height, r_type))
 
-        for t_width, t_height, t_type in scales:
-            t_method = "scale"
-            t_path = self.filepaths.local_media_thumbnail(
-                media_id, t_width, t_height, t_type, t_method
-            )
-            self._makedirs(t_path)
-            t_len = thumbnailer.scale(t_path, t_width, t_height, t_type)
-            yield self.store.store_local_thumbnail(
-                media_id, t_width, t_height, t_type, t_method, t_len
-            )
+            for t_width, t_height, t_type in crops:
+                if (t_width, t_height, t_type) in scales:
+                    # If the aspect ratio of the cropped thumbnail matches a purely
+                    # scaled one then there is no point in calculating a separate
+                    # thumbnail.
+                    continue
+                t_method = "crop"
+                t_path = self.filepaths.local_media_thumbnail(
+                    media_id, t_width, t_height, t_type, t_method
+                )
+                self._makedirs(t_path)
+                t_len = thumbnailer.crop(t_path, t_width, t_height, t_type)
+                local_thumbnails.append((
+                    media_id, t_width, t_height, t_type, t_method, t_len
+                ))
 
-        for t_width, t_height, t_type in crops:
-            if (t_width, t_height, t_type) in scales:
-                # If the aspect ratio of the cropped thumbnail matches a purely
-                # scaled one then there is no point in calculating a separate
-                # thumbnail.
-                continue
-            t_method = "crop"
-            t_path = self.filepaths.local_media_thumbnail(
-                media_id, t_width, t_height, t_type, t_method
-            )
-            self._makedirs(t_path)
-            t_len = thumbnailer.crop(t_path, t_width, t_height, t_type)
-            yield self.store.store_local_thumbnail(
-                media_id, t_width, t_height, t_type, t_method, t_len
-            )
+        yield threads.deferToThread(generate_thumbnails)
+
+        for l in local_thumbnails:
+            yield self.store.store_local_thumbnail(*l)
 
         defer.returnValue({
             "width": m_width,
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index 71d5d92500..c6ce65b4cc 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -99,7 +99,7 @@ class DataStore(RoomMemberStore, RoomStore,
         key = (user.to_string(), access_token, device_id, ip)
 
         try:
-            last_seen = self.client_ip_last_seen.get(*key)
+            last_seen = self.client_ip_last_seen.get(key)
         except KeyError:
             last_seen = None
 
@@ -107,7 +107,7 @@ class DataStore(RoomMemberStore, RoomStore,
         if last_seen is not None and (now - last_seen) < LAST_SEEN_GRANULARITY:
             defer.returnValue(None)
 
-        self.client_ip_last_seen.prefill(*key + (now,))
+        self.client_ip_last_seen.prefill(key, now)
 
         # It's safe not to lock here: a) no unique constraint,
         # b) LAST_SEEN_GRANULARITY makes concurrent updates incredibly unlikely
@@ -354,6 +354,11 @@ def _upgrade_existing_database(cur, current_version, applied_delta_files,
                     )
                 logger.debug("Running script %s", relative_path)
                 module.run_upgrade(cur, database_engine)
+            elif ext == ".pyc":
+                # Sometimes .pyc files turn up anyway even though we've
+                # disabled their generation; e.g. from distribution package
+                # installers. Silently skip it
+                pass
             elif ext == ".sql":
                 # A plain old .sql file, just read and execute it
                 logger.debug("Applying schema %s", relative_path)
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 8f812f0fd7..73eea157a4 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -15,6 +15,7 @@
 import logging
 
 from synapse.api.errors import StoreError
+from synapse.util.async import ObservableDeferred
 from synapse.util.logutils import log_function
 from synapse.util.logcontext import preserve_context_over_fn, LoggingContext
 from synapse.util.lrucache import LruCache
@@ -27,6 +28,7 @@ from twisted.internet import defer
 from collections import namedtuple, OrderedDict
 
 import functools
+import inspect
 import sys
 import time
 import threading
@@ -55,9 +57,12 @@ cache_counter = metrics.register_cache(
 )
 
 
+_CacheSentinel = object()
+
+
 class Cache(object):
 
-    def __init__(self, name, max_entries=1000, keylen=1, lru=False):
+    def __init__(self, name, max_entries=1000, keylen=1, lru=True):
         if lru:
             self.cache = LruCache(max_size=max_entries)
             self.max_entries = None
@@ -81,45 +86,44 @@ class Cache(object):
                     "Cache objects can only be accessed from the main thread"
                 )
 
-    def get(self, *keyargs):
-        if len(keyargs) != self.keylen:
-            raise ValueError("Expected a key to have %d items", self.keylen)
-
-        if keyargs in self.cache:
+    def get(self, key, default=_CacheSentinel):
+        val = self.cache.get(key, _CacheSentinel)
+        if val is not _CacheSentinel:
             cache_counter.inc_hits(self.name)
-            return self.cache[keyargs]
+            return val
 
         cache_counter.inc_misses(self.name)
-        raise KeyError()
 
-    def update(self, sequence, *args):
+        if default is _CacheSentinel:
+            raise KeyError()
+        else:
+            return default
+
+    def update(self, sequence, key, value):
         self.check_thread()
         if self.sequence == sequence:
             # Only update the cache if the caches sequence number matches the
             # number that the cache had before the SELECT was started (SYN-369)
-            self.prefill(*args)
-
-    def prefill(self, *args):  # because I can't  *keyargs, value
-        keyargs = args[:-1]
-        value = args[-1]
-
-        if len(keyargs) != self.keylen:
-            raise ValueError("Expected a key to have %d items", self.keylen)
+            self.prefill(key, value)
 
+    def prefill(self, key, value):
         if self.max_entries is not None:
             while len(self.cache) >= self.max_entries:
                 self.cache.popitem(last=False)
 
-        self.cache[keyargs] = value
+        self.cache[key] = value
 
-    def invalidate(self, *keyargs):
+    def invalidate(self, key):
         self.check_thread()
-        if len(keyargs) != self.keylen:
-            raise ValueError("Expected a key to have %d items", self.keylen)
+        if not isinstance(key, tuple):
+            raise TypeError(
+                "The cache key must be a tuple not %r" % (type(key),)
+            )
+
         # Increment the sequence number so that any SELECT statements that
         # raced with the INSERT don't update the cache (SYN-369)
         self.sequence += 1
-        self.cache.pop(keyargs, None)
+        self.cache.pop(key, None)
 
     def invalidate_all(self):
         self.check_thread()
@@ -130,6 +134,9 @@ class Cache(object):
 class CacheDescriptor(object):
     """ A method decorator that applies a memoizing cache around the function.
 
+    This caches deferreds, rather than the results themselves. Deferreds that
+    fail are removed from the cache.
+
     The function is presumed to take zero or more arguments, which are used in
     a tuple as the key for the cache. Hits are served directly from the cache;
     misses use the function body to generate the value.
@@ -141,58 +148,92 @@ class CacheDescriptor(object):
     which can be used to insert values into the cache specifically, without
     calling the calculation function.
     """
-    def __init__(self, orig, max_entries=1000, num_args=1, lru=False):
+    def __init__(self, orig, max_entries=1000, num_args=1, lru=True,
+                 inlineCallbacks=False):
         self.orig = orig
 
+        if inlineCallbacks:
+            self.function_to_call = defer.inlineCallbacks(orig)
+        else:
+            self.function_to_call = orig
+
         self.max_entries = max_entries
         self.num_args = num_args
         self.lru = lru
 
-    def __get__(self, obj, objtype=None):
-        cache = Cache(
+        self.arg_names = inspect.getargspec(orig).args[1:num_args+1]
+
+        if len(self.arg_names) < self.num_args:
+            raise Exception(
+                "Not enough explicit positional arguments to key off of for %r."
+                " (@cached cannot key off of *args or **kwars)"
+                % (orig.__name__,)
+            )
+
+        self.cache = Cache(
             name=self.orig.__name__,
             max_entries=self.max_entries,
             keylen=self.num_args,
             lru=self.lru,
         )
 
+    def __get__(self, obj, objtype=None):
+
         @functools.wraps(self.orig)
-        @defer.inlineCallbacks
-        def wrapped(*keyargs):
+        def wrapped(*args, **kwargs):
+            arg_dict = inspect.getcallargs(self.orig, obj, *args, **kwargs)
+            cache_key = tuple(arg_dict[arg_nm] for arg_nm in self.arg_names)
             try:
-                cached_result = cache.get(*keyargs[:self.num_args])
+                cached_result_d = self.cache.get(cache_key)
+
+                observer = cached_result_d.observe()
                 if DEBUG_CACHES:
-                    actual_result = yield self.orig(obj, *keyargs)
-                    if actual_result != cached_result:
-                        logger.error(
-                            "Stale cache entry %s%r: cached: %r, actual %r",
-                            self.orig.__name__, keyargs,
-                            cached_result, actual_result,
-                        )
-                        raise ValueError("Stale cache entry")
-                defer.returnValue(cached_result)
+                    @defer.inlineCallbacks
+                    def check_result(cached_result):
+                        actual_result = yield self.function_to_call(obj, *args, **kwargs)
+                        if actual_result != cached_result:
+                            logger.error(
+                                "Stale cache entry %s%r: cached: %r, actual %r",
+                                self.orig.__name__, cache_key,
+                                cached_result, actual_result,
+                            )
+                            raise ValueError("Stale cache entry")
+                        defer.returnValue(cached_result)
+                    observer.addCallback(check_result)
+
+                return observer
             except KeyError:
                 # Get the sequence number of the cache before reading from the
                 # database so that we can tell if the cache is invalidated
                 # while the SELECT is executing (SYN-369)
-                sequence = cache.sequence
+                sequence = self.cache.sequence
+
+                ret = defer.maybeDeferred(
+                    self.function_to_call,
+                    obj, *args, **kwargs
+                )
+
+                def onErr(f):
+                    self.cache.invalidate(cache_key)
+                    return f
 
-                ret = yield self.orig(obj, *keyargs)
+                ret.addErrback(onErr)
 
-                cache.update(sequence, *keyargs[:self.num_args] + (ret,))
+                ret = ObservableDeferred(ret, consumeErrors=True)
+                self.cache.update(sequence, cache_key, ret)
 
-                defer.returnValue(ret)
+                return ret.observe()
 
-        wrapped.invalidate = cache.invalidate
-        wrapped.invalidate_all = cache.invalidate_all
-        wrapped.prefill = cache.prefill
+        wrapped.invalidate = self.cache.invalidate
+        wrapped.invalidate_all = self.cache.invalidate_all
+        wrapped.prefill = self.cache.prefill
 
         obj.__dict__[self.orig.__name__] = wrapped
 
         return wrapped
 
 
-def cached(max_entries=1000, num_args=1, lru=False):
+def cached(max_entries=1000, num_args=1, lru=True):
     return lambda orig: CacheDescriptor(
         orig,
         max_entries=max_entries,
@@ -201,6 +242,16 @@ def cached(max_entries=1000, num_args=1, lru=False):
     )
 
 
+def cachedInlineCallbacks(max_entries=1000, num_args=1, lru=False):
+    return lambda orig: CacheDescriptor(
+        orig,
+        max_entries=max_entries,
+        num_args=num_args,
+        lru=lru,
+        inlineCallbacks=True,
+    )
+
+
 class LoggingTransaction(object):
     """An object that almost-transparently proxies for the 'txn' object
     passed to the constructor. Adds logging and metrics to the .execute()
diff --git a/synapse/storage/directory.py b/synapse/storage/directory.py
index 2b2bdf8615..f3947bbe89 100644
--- a/synapse/storage/directory.py
+++ b/synapse/storage/directory.py
@@ -104,7 +104,7 @@ class DirectoryStore(SQLBaseStore):
                 },
                 desc="create_room_alias_association",
             )
-        self.get_aliases_for_room.invalidate(room_id)
+        self.get_aliases_for_room.invalidate((room_id,))
 
     @defer.inlineCallbacks
     def delete_room_alias(self, room_alias):
@@ -114,7 +114,7 @@ class DirectoryStore(SQLBaseStore):
             room_alias,
         )
 
-        self.get_aliases_for_room.invalidate(room_id)
+        self.get_aliases_for_room.invalidate((room_id,))
         defer.returnValue(room_id)
 
     def _delete_room_alias_txn(self, txn, room_alias):
diff --git a/synapse/storage/event_federation.py b/synapse/storage/event_federation.py
index 45b86c94e8..910b6598a7 100644
--- a/synapse/storage/event_federation.py
+++ b/synapse/storage/event_federation.py
@@ -362,7 +362,7 @@ class EventFederationStore(SQLBaseStore):
 
         for room_id in events_by_room:
             txn.call_after(
-                self.get_latest_event_ids_in_room.invalidate, room_id
+                self.get_latest_event_ids_in_room.invalidate, (room_id,)
             )
 
     def get_backfill_events(self, room_id, event_list, limit):
@@ -505,4 +505,4 @@ class EventFederationStore(SQLBaseStore):
         query = "DELETE FROM event_forward_extremities WHERE room_id = ?"
 
         txn.execute(query, (room_id,))
-        txn.call_after(self.get_latest_event_ids_in_room.invalidate, room_id)
+        txn.call_after(self.get_latest_event_ids_in_room.invalidate, (room_id,))
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index ed7ea38804..5b64918024 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -162,8 +162,8 @@ class EventsStore(SQLBaseStore):
         if current_state:
             txn.call_after(self.get_current_state_for_key.invalidate_all)
             txn.call_after(self.get_rooms_for_user.invalidate_all)
-            txn.call_after(self.get_users_in_room.invalidate, event.room_id)
-            txn.call_after(self.get_joined_hosts_for_room.invalidate, event.room_id)
+            txn.call_after(self.get_users_in_room.invalidate, (event.room_id,))
+            txn.call_after(self.get_joined_hosts_for_room.invalidate, (event.room_id,))
             txn.call_after(self.get_room_name_and_aliases, event.room_id)
 
             self._simple_delete_txn(
@@ -430,13 +430,13 @@ class EventsStore(SQLBaseStore):
                 if not context.rejected:
                     txn.call_after(
                         self.get_current_state_for_key.invalidate,
-                        event.room_id, event.type, event.state_key
-                        )
+                        (event.room_id, event.type, event.state_key,)
+                    )
 
                     if event.type in [EventTypes.Name, EventTypes.Aliases]:
                         txn.call_after(
                             self.get_room_name_and_aliases.invalidate,
-                            event.room_id
+                            (event.room_id,)
                         )
 
                     self._simple_upsert_txn(
@@ -567,8 +567,9 @@ class EventsStore(SQLBaseStore):
     def _invalidate_get_event_cache(self, event_id):
         for check_redacted in (False, True):
             for get_prev_content in (False, True):
-                self._get_event_cache.invalidate(event_id, check_redacted,
-                                                 get_prev_content)
+                self._get_event_cache.invalidate(
+                    (event_id, check_redacted, get_prev_content)
+                )
 
     def _get_event_txn(self, txn, event_id, check_redacted=True,
                        get_prev_content=False, allow_rejected=False):
@@ -589,7 +590,7 @@ class EventsStore(SQLBaseStore):
         for event_id in events:
             try:
                 ret = self._get_event_cache.get(
-                    event_id, check_redacted, get_prev_content
+                    (event_id, check_redacted, get_prev_content,)
                 )
 
                 if allow_rejected or not ret.rejected_reason:
@@ -822,7 +823,7 @@ class EventsStore(SQLBaseStore):
                 ev.unsigned["prev_content"] = prev.get_dict()["content"]
 
         self._get_event_cache.prefill(
-            ev.event_id, check_redacted, get_prev_content, ev
+            (ev.event_id, check_redacted, get_prev_content), ev
         )
 
         defer.returnValue(ev)
@@ -879,7 +880,7 @@ class EventsStore(SQLBaseStore):
                 ev.unsigned["prev_content"] = prev.get_dict()["content"]
 
         self._get_event_cache.prefill(
-            ev.event_id, check_redacted, get_prev_content, ev
+            (ev.event_id, check_redacted, get_prev_content), ev
         )
 
         return ev
diff --git a/synapse/storage/keys.py b/synapse/storage/keys.py
index 940a5f7e08..49b8e37cfd 100644
--- a/synapse/storage/keys.py
+++ b/synapse/storage/keys.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from _base import SQLBaseStore, cached
+from _base import SQLBaseStore, cachedInlineCallbacks
 
 from twisted.internet import defer
 
@@ -71,8 +71,7 @@ class KeyStore(SQLBaseStore):
             desc="store_server_certificate",
         )
 
-    @cached()
-    @defer.inlineCallbacks
+    @cachedInlineCallbacks()
     def get_all_server_verify_keys(self, server_name):
         rows = yield self._simple_select_list(
             table="server_signature_keys",
@@ -132,7 +131,7 @@ class KeyStore(SQLBaseStore):
             desc="store_server_verify_key",
         )
 
-        self.get_all_server_verify_keys.invalidate(server_name)
+        self.get_all_server_verify_keys.invalidate((server_name,))
 
     def store_server_keys_json(self, server_name, key_id, from_server,
                                ts_now_ms, ts_expires_ms, key_json_bytes):
diff --git a/synapse/storage/presence.py b/synapse/storage/presence.py
index fefcf6bce0..576cf670cc 100644
--- a/synapse/storage/presence.py
+++ b/synapse/storage/presence.py
@@ -98,7 +98,7 @@ class PresenceStore(SQLBaseStore):
             updatevalues={"accepted": True},
             desc="set_presence_list_accepted",
         )
-        self.get_presence_list_accepted.invalidate(observer_localpart)
+        self.get_presence_list_accepted.invalidate((observer_localpart,))
         defer.returnValue(result)
 
     def get_presence_list(self, observer_localpart, accepted=None):
@@ -133,4 +133,4 @@ class PresenceStore(SQLBaseStore):
                        "observed_user_id": observed_userid},
             desc="del_presence_list",
         )
-        self.get_presence_list_accepted.invalidate(observer_localpart)
+        self.get_presence_list_accepted.invalidate((observer_localpart,))
diff --git a/synapse/storage/push_rule.py b/synapse/storage/push_rule.py
index 4cac118d17..9b88ca7b39 100644
--- a/synapse/storage/push_rule.py
+++ b/synapse/storage/push_rule.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore, cached
+from ._base import SQLBaseStore, cachedInlineCallbacks
 from twisted.internet import defer
 
 import logging
@@ -23,8 +23,7 @@ logger = logging.getLogger(__name__)
 
 
 class PushRuleStore(SQLBaseStore):
-    @cached()
-    @defer.inlineCallbacks
+    @cachedInlineCallbacks()
     def get_push_rules_for_user(self, user_name):
         rows = yield self._simple_select_list(
             table=PushRuleTable.table_name,
@@ -41,8 +40,7 @@ class PushRuleStore(SQLBaseStore):
 
         defer.returnValue(rows)
 
-    @cached()
-    @defer.inlineCallbacks
+    @cachedInlineCallbacks()
     def get_push_rules_enabled_for_user(self, user_name):
         results = yield self._simple_select_list(
             table=PushRuleEnableTable.table_name,
@@ -153,11 +151,11 @@ class PushRuleStore(SQLBaseStore):
             txn.execute(sql, (user_name, priority_class, new_rule_priority))
 
         txn.call_after(
-            self.get_push_rules_for_user.invalidate, user_name
+            self.get_push_rules_for_user.invalidate, (user_name,)
         )
 
         txn.call_after(
-            self.get_push_rules_enabled_for_user.invalidate, user_name
+            self.get_push_rules_enabled_for_user.invalidate, (user_name,)
         )
 
         self._simple_insert_txn(
@@ -189,10 +187,10 @@ class PushRuleStore(SQLBaseStore):
         new_rule['priority'] = new_prio
 
         txn.call_after(
-            self.get_push_rules_for_user.invalidate, user_name
+            self.get_push_rules_for_user.invalidate, (user_name,)
         )
         txn.call_after(
-            self.get_push_rules_enabled_for_user.invalidate, user_name
+            self.get_push_rules_enabled_for_user.invalidate, (user_name,)
         )
 
         self._simple_insert_txn(
@@ -218,8 +216,8 @@ class PushRuleStore(SQLBaseStore):
             desc="delete_push_rule",
         )
 
-        self.get_push_rules_for_user.invalidate(user_name)
-        self.get_push_rules_enabled_for_user.invalidate(user_name)
+        self.get_push_rules_for_user.invalidate((user_name,))
+        self.get_push_rules_enabled_for_user.invalidate((user_name,))
 
     @defer.inlineCallbacks
     def set_push_rule_enabled(self, user_name, rule_id, enabled):
@@ -240,10 +238,10 @@ class PushRuleStore(SQLBaseStore):
             {'id': new_id},
         )
         txn.call_after(
-            self.get_push_rules_for_user.invalidate, user_name
+            self.get_push_rules_for_user.invalidate, (user_name,)
         )
         txn.call_after(
-            self.get_push_rules_enabled_for_user.invalidate, user_name
+            self.get_push_rules_enabled_for_user.invalidate, (user_name,)
         )
 
 
diff --git a/synapse/storage/receipts.py b/synapse/storage/receipts.py
index 7a6af98d98..b79d6683ca 100644
--- a/synapse/storage/receipts.py
+++ b/synapse/storage/receipts.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore, cached
+from ._base import SQLBaseStore, cachedInlineCallbacks
 
 from twisted.internet import defer
 
@@ -128,8 +128,7 @@ class ReceiptsStore(SQLBaseStore):
     def get_max_receipt_stream_id(self):
         return self._receipts_id_gen.get_max_token(self)
 
-    @cached
-    @defer.inlineCallbacks
+    @cachedInlineCallbacks()
     def get_graph_receipts_for_room(self, room_id):
         """Get receipts for sending to remote servers.
         """
diff --git a/synapse/storage/registration.py b/synapse/storage/registration.py
index 90e2606be2..4eaa088b36 100644
--- a/synapse/storage/registration.py
+++ b/synapse/storage/registration.py
@@ -131,7 +131,7 @@ class RegistrationStore(SQLBaseStore):
             user_id
         )
         for r in rows:
-            self.get_user_by_token.invalidate(r)
+            self.get_user_by_token.invalidate((r,))
 
     @cached()
     def get_user_by_token(self, token):
diff --git a/synapse/storage/room.py b/synapse/storage/room.py
index 4612a8aa83..dd5bc2c8fb 100644
--- a/synapse/storage/room.py
+++ b/synapse/storage/room.py
@@ -17,7 +17,7 @@ from twisted.internet import defer
 
 from synapse.api.errors import StoreError
 
-from ._base import SQLBaseStore, cached
+from ._base import SQLBaseStore, cachedInlineCallbacks
 
 import collections
 import logging
@@ -186,8 +186,7 @@ class RoomStore(SQLBaseStore):
                 }
             )
 
-    @cached()
-    @defer.inlineCallbacks
+    @cachedInlineCallbacks()
     def get_room_name_and_aliases(self, room_id):
         def f(txn):
             sql = (
diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py
index 4db07f6fb4..9f14f38f24 100644
--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@@ -54,9 +54,9 @@ class RoomMemberStore(SQLBaseStore):
         )
 
         for event in events:
-            txn.call_after(self.get_rooms_for_user.invalidate, event.state_key)
-            txn.call_after(self.get_joined_hosts_for_room.invalidate, event.room_id)
-            txn.call_after(self.get_users_in_room.invalidate, event.room_id)
+            txn.call_after(self.get_rooms_for_user.invalidate, (event.state_key,))
+            txn.call_after(self.get_joined_hosts_for_room.invalidate, (event.room_id,))
+            txn.call_after(self.get_users_in_room.invalidate, (event.room_id,))
 
     def get_room_member(self, user_id, room_id):
         """Retrieve the current state of a room member.
@@ -78,7 +78,7 @@ class RoomMemberStore(SQLBaseStore):
             lambda events: events[0] if events else None
         )
 
-    @cached()
+    @cached(max_entries=5000)
     def get_users_in_room(self, room_id):
         def f(txn):
 
@@ -154,7 +154,7 @@ class RoomMemberStore(SQLBaseStore):
             RoomsForUser(**r) for r in self.cursor_to_dict(txn)
         ]
 
-    @cached()
+    @cached(max_entries=5000)
     def get_joined_hosts_for_room(self, room_id):
         return self.runInteraction(
             "get_joined_hosts_for_room",
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index 47bec65497..7ce51b9bdc 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore, cached
+from ._base import SQLBaseStore, cachedInlineCallbacks
 
 from twisted.internet import defer
 
@@ -91,7 +91,6 @@ class StateStore(SQLBaseStore):
 
         defer.returnValue(dict(state_list))
 
-    @cached(num_args=1)
     def _fetch_events_for_group(self, key, events):
         return self._get_events(
             events, get_prev_content=False
@@ -189,8 +188,7 @@ class StateStore(SQLBaseStore):
         events = yield self._get_events(event_ids, get_prev_content=False)
         defer.returnValue(events)
 
-    @cached(num_args=3)
-    @defer.inlineCallbacks
+    @cachedInlineCallbacks(num_args=3)
     def get_current_state_for_key(self, room_id, event_type, state_key):
         def f(txn):
             sql = (
diff --git a/synapse/types.py b/synapse/types.py
index dd1b10d646..e190374cbd 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -178,7 +178,7 @@ class RoomStreamToken(namedtuple("_StreamToken", "topological stream")):
 
     Live tokens start with an "s" followed by the "stream_ordering" id of the
     event it comes after. Historic tokens start with a "t" followed by the
-    "topological_ordering" id of the event it comes after, follewed by "-",
+    "topological_ordering" id of the event it comes after, followed by "-",
     followed by the "stream_ordering" id of the event it comes after.
     """
     __slots__ = []
@@ -211,4 +211,5 @@ class RoomStreamToken(namedtuple("_StreamToken", "topological stream")):
             return "s%d" % (self.stream,)
 
 
+# token_id is the primary key ID of the access token, not the access token itself.
 ClientInfo = namedtuple("ClientInfo", ("device_id", "token_id"))
diff --git a/synapse/util/async.py b/synapse/util/async.py
index 5a1d545c96..7bf2d38bb8 100644
--- a/synapse/util/async.py
+++ b/synapse/util/async.py
@@ -51,7 +51,7 @@ class ObservableDeferred(object):
         object.__setattr__(self, "_observers", set())
 
         def callback(r):
-            self._result = (True, r)
+            object.__setattr__(self, "_result", (True, r))
             while self._observers:
                 try:
                     self._observers.pop().callback(r)
@@ -60,7 +60,7 @@ class ObservableDeferred(object):
             return r
 
         def errback(f):
-            self._result = (False, f)
+            object.__setattr__(self, "_result", (False, f))
             while self._observers:
                 try:
                     self._observers.pop().errback(f)
@@ -97,3 +97,8 @@ class ObservableDeferred(object):
 
     def __setattr__(self, name, value):
         setattr(self._deferred, name, value)
+
+    def __repr__(self):
+        return "<ObservableDeferred object at %s, result=%r, _deferred=%r>" % (
+            id(self), self._result, self._deferred,
+        )