Fix caching devices for remote servers in worker.

When the `/keys/query` API is hit on client_reader worker Synapse may
decide that it needs to resync some remote deivces. Usually this happens
on master, and then gets cached. However, that fails on workers and so
it falls back to fetching devices from remotes directly, which may in
turn fail if the remote is down.

2 files changed, 78 insertions, 1 deletions

diff --git a/synapse/replication/http/__init__.py b/synapse/replication/http/__init__.py
index 81b85352b1..28dbc6fcba 100644
--- a/synapse/replication/http/__init__.py
+++ b/synapse/replication/http/__init__.py
@@ -14,7 +14,14 @@
 # limitations under the License.
 
 from synapse.http.server import JsonResource
-from synapse.replication.http import federation, login, membership, register, send_event
+from synapse.replication.http import (
+    devices,
+    federation,
+    login,
+    membership,
+    register,
+    send_event,
+)
 
 REPLICATION_PREFIX = "/_synapse/replication"
 
@@ -30,3 +37,4 @@ class ReplicationRestResource(JsonResource):
         federation.register_servlets(hs, self)
         login.register_servlets(hs, self)
         register.register_servlets(hs, self)
+        devices.register_servlets(hs, self)
diff --git a/synapse/replication/http/devices.py b/synapse/replication/http/devices.py
new file mode 100644
index 0000000000..795ca7b65e
--- /dev/null
+++ b/synapse/replication/http/devices.py
@@ -0,0 +1,69 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 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 synapse.replication.http._base import ReplicationEndpoint
+
+logger = logging.getLogger(__name__)
+
+
+class ReplicationUserDevicesResyncRestServlet(ReplicationEndpoint):
+    """Notifies that a user has joined or left the room
+
+    Request format:
+
+        POST /_synapse/replication/user_device_resync/:user_id
+
+        {}
+
+    Response is equivalent to ` /_matrix/federation/v1/user/devices/:user_id`
+    response, e.g.:
+
+        {
+            "user_id": "@alice:example.org",
+            "devices": [
+                {
+                    "device_id": "JLAFKJWSCS",
+                    "keys": { ... },
+                    "device_display_name": "Alice's Mobile Phone"
+                }
+            ]
+        }
+    """
+
+    NAME = "user_device_resync"
+    PATH_ARGS = ("user_id",)
+    CACHE = False
+
+    def __init__(self, hs):
+        super(ReplicationUserDevicesResyncRestServlet, self).__init__(hs)
+
+        self.device_list_updater = hs.get_device_handler().device_list_updater
+        self.store = hs.get_datastore()
+        self.clock = hs.get_clock()
+
+    @staticmethod
+    def _serialize_payload(user_id):
+        return {}
+
+    async def _handle_request(self, request, user_id):
+        user_devices = await self.device_list_updater.user_device_resync(user_id)
+
+        return 200, user_devices
+
+
+def register_servlets(hs, http_server):
+    ReplicationUserDevicesResyncRestServlet(hs).register(http_server)