Merge pull request #1074 from matrix-org/markjh/direct_to_device_federation

Send device messages over federation

synapse/federation/federation_client.py

@@ -137,6 +137,12 @@ class FederationClient(FederationBase):
         self._transaction_queue.enqueue_edu(edu)
         return defer.succeed(None)
 
+    @log_function
+    def send_device_messages(self, destination):
+        """Sends the device messages in the local database to the remote
+        destination"""
+        self._transaction_queue.enqueue_device_messages(destination)
+
     @log_function
     def send_failure(self, failure, destination):
         self._transaction_queue.enqueue_failure(failure, destination)

synapse/federation/federation_server.py

@@ -188,7 +188,7 @@ class FederationServer(FederationBase):
             except SynapseError as e:
                 logger.info("Failed to handle edu %r: %r", edu_type, e)
             except Exception as e:
-                logger.exception("Failed to handle edu %r", edu_type, e)
+                logger.exception("Failed to handle edu %r", edu_type)
         else:
             logger.warn("Received EDU of type %s with no handler", edu_type)
 

synapse/federation/transaction_queue.py

@@ -17,7 +17,7 @@
 from twisted.internet import defer
 
 from .persistence import TransactionActions
-from .units import Transaction
+from .units import Transaction, Edu
 
 from synapse.api.errors import HttpResponseException
 from synapse.util.async import run_on_reactor
@@ -81,6 +81,8 @@ class TransactionQueue(object):
         # destination -> list of tuple(failure, deferred)
         self.pending_failures_by_dest = {}
 
+        self.last_device_stream_id_by_dest = {}
+
         # HACK to get unique tx id
         self._next_txn_id = int(self.clock.time_msec())
 
@@ -155,6 +157,17 @@ class TransactionQueue(object):
             self._attempt_new_transaction, destination
         )
 
+    def enqueue_device_messages(self, destination):
+        if destination == self.server_name or destination == "localhost":
+            return
+
+        if not self.can_send_to(destination):
+            return
+
+        preserve_context_over_fn(
+            self._attempt_new_transaction, destination
+        )
+
     @defer.inlineCallbacks
     def _attempt_new_transaction(self, destination):
         yield run_on_reactor()
@@ -175,6 +188,12 @@ class TransactionQueue(object):
             pending_edus = self.pending_edus_by_dest.pop(destination, [])
             pending_failures = self.pending_failures_by_dest.pop(destination, [])
 
+            device_message_edus, device_stream_id = (
+                yield self._get_new_device_messages(destination)
+            )
+
+            pending_edus.extend(device_message_edus)
+
             if pending_pdus:
                 logger.debug("TX [%s] len(pending_pdus_by_dest[dest]) = %d",
                              destination, len(pending_pdus))
@@ -184,13 +203,34 @@ class TransactionQueue(object):
                 return
 
             yield self._send_new_transaction(
-                destination, pending_pdus, pending_edus, pending_failures
+                destination, pending_pdus, pending_edus, pending_failures,
+                device_stream_id,
+                should_delete_from_device_stream=bool(device_message_edus)
             )
 
+    @defer.inlineCallbacks
+    def _get_new_device_messages(self, destination):
+        last_device_stream_id = self.last_device_stream_id_by_dest.get(destination, 0)
+        to_device_stream_id = self.store.get_to_device_stream_token()
+        contents, stream_id = yield self.store.get_new_device_msgs_for_remote(
+            destination, last_device_stream_id, to_device_stream_id
+        )
+        edus = [
+            Edu(
+                origin=self.server_name,
+                destination=destination,
+                edu_type="m.direct_to_device",
+                content=content,
+            )
+            for content in contents
+        ]
+        defer.returnValue((edus, stream_id))
+
     @measure_func("_send_new_transaction")
     @defer.inlineCallbacks
     def _send_new_transaction(self, destination, pending_pdus, pending_edus,
-                              pending_failures):
+                              pending_failures, device_stream_id,
+                              should_delete_from_device_stream):
 
             # Sort based on the order field
             pending_pdus.sort(key=lambda t: t[1])
@@ -215,9 +255,9 @@ class TransactionQueue(object):
                     "TX [%s] {%s} Attempting new transaction"
                     " (pdus: %d, edus: %d, failures: %d)",
                     destination, txn_id,
-                    len(pending_pdus),
-                    len(pending_edus),
-                    len(pending_failures)
+                    len(pdus),
+                    len(edus),
+                    len(failures)
                 )
 
                 logger.debug("TX [%s] Persisting transaction...", destination)
@@ -242,9 +282,9 @@ class TransactionQueue(object):
                     " (PDUs: %d, EDUs: %d, failures: %d)",
                     destination, txn_id,
                     transaction.transaction_id,
-                    len(pending_pdus),
-                    len(pending_edus),
-                    len(pending_failures),
+                    len(pdus),
+                    len(edus),
+                    len(failures),
                 )
 
                 with limiter:
@@ -299,6 +339,13 @@ class TransactionQueue(object):
                         logger.info(
                             "Failed to send event %s to %s", p.event_id, destination
                         )
+                else:
+                    # Remove the acknowledged device messages from the database
+                    if should_delete_from_device_stream:
+                        yield self.store.delete_device_msgs_for_remote(
+                            destination, device_stream_id
+                        )
+                    self.last_device_stream_id_by_dest[destination] = device_stream_id
             except NotRetryingDestination:
                 logger.info(
                     "TX [%s] not ready for retry yet - "

synapse/handlers/devicemessage.py

@@ -0,0 +1,117 @@
+# -*- coding: utf-8 -*-
+# Copyright 2016 OpenMarket 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 twisted.internet import defer
+
+from synapse.types import get_domain_from_id
+from synapse.util.stringutils import random_string
+
+
+logger = logging.getLogger(__name__)
+
+
+class DeviceMessageHandler(object):
+
+    def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer): server
+        """
+        self.store = hs.get_datastore()
+        self.notifier = hs.get_notifier()
+        self.is_mine_id = hs.is_mine_id
+        self.federation = hs.get_replication_layer()
+
+        self.federation.register_edu_handler(
+            "m.direct_to_device", self.on_direct_to_device_edu
+        )
+
+    @defer.inlineCallbacks
+    def on_direct_to_device_edu(self, origin, content):
+        local_messages = {}
+        sender_user_id = content["sender"]
+        if origin != get_domain_from_id(sender_user_id):
+            logger.warn(
+                "Dropping device message from %r with spoofed sender %r",
+                origin, sender_user_id
+            )
+        message_type = content["type"]
+        message_id = content["message_id"]
+        for user_id, by_device in content["messages"].items():
+            messages_by_device = {
+                device_id: {
+                    "content": message_content,
+                    "type": message_type,
+                    "sender": sender_user_id,
+                }
+                for device_id, message_content in by_device.items()
+            }
+            if messages_by_device:
+                local_messages[user_id] = messages_by_device
+
+        stream_id = yield self.store.add_messages_from_remote_to_device_inbox(
+            origin, message_id, local_messages
+        )
+
+        self.notifier.on_new_event(
+            "to_device_key", stream_id, users=local_messages.keys()
+        )
+
+    @defer.inlineCallbacks
+    def send_device_message(self, sender_user_id, message_type, messages):
+
+        local_messages = {}
+        remote_messages = {}
+        for user_id, by_device in messages.items():
+            if self.is_mine_id(user_id):
+                messages_by_device = {
+                    device_id: {
+                        "content": message_content,
+                        "type": message_type,
+                        "sender": sender_user_id,
+                    }
+                    for device_id, message_content in by_device.items()
+                }
+                if messages_by_device:
+                    local_messages[user_id] = messages_by_device
+            else:
+                destination = get_domain_from_id(user_id)
+                remote_messages.setdefault(destination, {})[user_id] = by_device
+
+        message_id = random_string(16)
+
+        remote_edu_contents = {}
+        for destination, messages in remote_messages.items():
+            remote_edu_contents[destination] = {
+                "messages": messages,
+                "sender": sender_user_id,
+                "type": message_type,
+                "message_id": message_id,
+            }
+
+        stream_id = yield self.store.add_messages_to_device_inbox(
+            local_messages, remote_edu_contents
+        )
+
+        self.notifier.on_new_event(
+            "to_device_key", stream_id, users=local_messages.keys()
+        )
+
+        for destination in remote_messages.keys():
+            # Enqueue a new federation transaction to send the new
+            # device messages to each remote destination.
+            self.federation.send_device_messages(destination)

synapse/replication/slave/storage/deviceinbox.py

@@ -16,6 +16,7 @@
 from ._base import BaseSlavedStore
 from ._slaved_id_tracker import SlavedIdTracker
 from synapse.storage import DataStore
+from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 
 class SlavedDeviceInboxStore(BaseSlavedStore):
@@ -24,6 +25,10 @@ class SlavedDeviceInboxStore(BaseSlavedStore):
         self._device_inbox_id_gen = SlavedIdTracker(
             db_conn, "device_inbox", "stream_id",
         )
+        self._device_inbox_stream_cache = StreamChangeCache(
+            "DeviceInboxStreamChangeCache",
+            self._device_inbox_id_gen.get_current_token()
+        )
 
     get_to_device_stream_token = DataStore.get_to_device_stream_token.__func__
     get_new_messages_for_device = DataStore.get_new_messages_for_device.__func__
@@ -38,5 +43,11 @@ class SlavedDeviceInboxStore(BaseSlavedStore):
         stream = result.get("to_device")
         if stream:
             self._device_inbox_id_gen.advance(int(stream["position"]))
+            for row in stream["rows"]:
+                stream_id = row[0]
+                user_id = row[1]
+                self._device_inbox_stream_cache.entity_has_changed(
+                    user_id, stream_id
+                )
 
         return super(SlavedDeviceInboxStore, self).process_replication(result)

synapse/rest/client/v2_alpha/sendtodevice.py

@@ -16,10 +16,11 @@
 import logging
 
 from twisted.internet import defer
-from synapse.http.servlet import parse_json_object_from_request
 
 from synapse.http import servlet
+from synapse.http.servlet import parse_json_object_from_request
 from synapse.rest.client.v1.transactions import HttpTransactionStore
+
 from ._base import client_v2_patterns
 
 logger = logging.getLogger(__name__)
@@ -39,10 +40,8 @@ class SendToDeviceRestServlet(servlet.RestServlet):
         super(SendToDeviceRestServlet, self).__init__()
         self.hs = hs
         self.auth = hs.get_auth()
-        self.store = hs.get_datastore()
-        self.notifier = hs.get_notifier()
-        self.is_mine_id = hs.is_mine_id
         self.txns = HttpTransactionStore()
+        self.device_message_handler = hs.get_device_message_handler()
 
     @defer.inlineCallbacks
     def on_PUT(self, request, message_type, txn_id):
@@ -57,28 +56,10 @@ class SendToDeviceRestServlet(servlet.RestServlet):
 
         content = parse_json_object_from_request(request)
 
-        # TODO: Prod the notifier to wake up sync streams.
-        # TODO: Implement replication for the messages.
-        # TODO: Send the messages to remote servers if needed.
+        sender_user_id = requester.user.to_string()
 
-        local_messages = {}
-        for user_id, by_device in content["messages"].items():
-            if self.is_mine_id(user_id):
-                messages_by_device = {
-                    device_id: {
-                        "content": message_content,
-                        "type": message_type,
-                        "sender": requester.user.to_string(),
-                    }
-                    for device_id, message_content in by_device.items()
-                }
-                if messages_by_device:
-                    local_messages[user_id] = messages_by_device
-
-        stream_id = yield self.store.add_messages_to_device_inbox(local_messages)
-
-        self.notifier.on_new_event(
-            "to_device_key", stream_id, users=local_messages.keys()
+        yield self.device_message_handler.send_device_message(
+            sender_user_id, message_type, content["messages"]
         )
 
         response = (200, {})

synapse/server.py

@@ -35,6 +35,7 @@ from synapse.federation import initialize_http_replication
 from synapse.handlers import Handlers
 from synapse.handlers.appservice import ApplicationServicesHandler
 from synapse.handlers.auth import AuthHandler
+from synapse.handlers.devicemessage import DeviceMessageHandler
 from synapse.handlers.device import DeviceHandler
 from synapse.handlers.e2e_keys import E2eKeysHandler
 from synapse.handlers.presence import PresenceHandler
@@ -100,6 +101,7 @@ class HomeServer(object):
         'application_service_api',
         'application_service_scheduler',
         'application_service_handler',
+        'device_message_handler',
         'notifier',
         'distributor',
         'client_resource',
@@ -205,6 +207,9 @@ class HomeServer(object):
     def build_device_handler(self):
         return DeviceHandler(self)
 
+    def build_device_message_handler(self):
+        return DeviceMessageHandler(self)
+
     def build_e2e_keys_handler(self):
         return E2eKeysHandler(self)
 

synapse/storage/__init__.py

@@ -182,6 +182,30 @@ class DataStore(RoomMemberStore, RoomStore,
             prefilled_cache=push_rules_prefill,
         )
 
+        max_device_inbox_id = self._device_inbox_id_gen.get_current_token()
+        device_inbox_prefill, min_device_inbox_id = self._get_cache_dict(
+            db_conn, "device_inbox",
+            entity_column="user_id",
+            stream_column="stream_id",
+            max_value=max_device_inbox_id
+        )
+        self._device_inbox_stream_cache = StreamChangeCache(
+            "DeviceInboxStreamChangeCache", min_device_inbox_id,
+            prefilled_cache=device_inbox_prefill,
+        )
+        # The federation outbox and the local device inbox uses the same
+        # stream_id generator.
+        device_outbox_prefill, min_device_outbox_id = self._get_cache_dict(
+            db_conn, "device_federation_outbox",
+            entity_column="destination",
+            stream_column="stream_id",
+            max_value=max_device_inbox_id,
+        )
+        self._device_federation_outbox_stream_cache = StreamChangeCache(
+            "DeviceFederationOutboxStreamChangeCache", min_device_outbox_id,
+            prefilled_cache=device_outbox_prefill,
+        )
+
         cur = LoggingTransaction(
             db_conn.cursor(),
             name="_find_stream_orderings_for_times_txn",

synapse/storage/deviceinbox.py

@@ -27,19 +27,112 @@ logger = logging.getLogger(__name__)
 class DeviceInboxStore(SQLBaseStore):
 
     @defer.inlineCallbacks
-    def add_messages_to_device_inbox(self, messages_by_user_then_device):
-        """
+    def add_messages_to_device_inbox(self, local_messages_by_user_then_device,
+                                     remote_messages_by_destination):
+        """Used to send messages from this server.
+
         Args:
-            messages_by_user_and_device(dict):
+            sender_user_id(str): The ID of the user sending these messages.
+            local_messages_by_user_and_device(dict):
                 Dictionary of user_id to device_id to message.
+            remote_messages_by_destination(dict):
+                Dictionary of destination server_name to the EDU JSON to send.
         Returns:
             A deferred stream_id that resolves when the messages have been
             inserted.
         """
 
-        def select_devices_txn(txn, user_id, devices):
-            if not devices:
-                return []
+        def add_messages_txn(txn, now_ms, stream_id):
+            # Add the local messages directly to the local inbox.
+            self._add_messages_to_local_device_inbox_txn(
+                txn, stream_id, local_messages_by_user_then_device
+            )
+
+            # Add the remote messages to the federation outbox.
+            # We'll send them to a remote server when we next send a
+            # federation transaction to that destination.
+            sql = (
+                "INSERT INTO device_federation_outbox"
+                " (destination, stream_id, queued_ts, messages_json)"
+                " VALUES (?,?,?,?)"
+            )
+            rows = []
+            for destination, edu in remote_messages_by_destination.items():
+                edu_json = ujson.dumps(edu)
+                rows.append((destination, stream_id, now_ms, edu_json))
+            txn.executemany(sql, rows)
+
+        with self._device_inbox_id_gen.get_next() as stream_id:
+            now_ms = self.clock.time_msec()
+            yield self.runInteraction(
+                "add_messages_to_device_inbox",
+                add_messages_txn,
+                now_ms,
+                stream_id,
+            )
+            for user_id in local_messages_by_user_then_device.keys():
+                self._device_inbox_stream_cache.entity_has_changed(
+                    user_id, stream_id
+                )
+            for destination in remote_messages_by_destination.keys():
+                self._device_federation_outbox_stream_cache.entity_has_changed(
+                    destination, stream_id
+                )
+
+        defer.returnValue(self._device_inbox_id_gen.get_current_token())
+
+    @defer.inlineCallbacks
+    def add_messages_from_remote_to_device_inbox(
+        self, origin, message_id, local_messages_by_user_then_device
+    ):
+        def add_messages_txn(txn, now_ms, stream_id):
+            # Check if we've already inserted a matching message_id for that
+            # origin. This can happen if the origin doesn't receive our
+            # acknowledgement from the first time we received the message.
+            already_inserted = self._simple_select_one_txn(
+                txn, table="device_federation_inbox",
+                keyvalues={"origin": origin, "message_id": message_id},
+                retcols=("message_id",),
+                allow_none=True,
+            )
+            if already_inserted is not None:
+                return
+
+            # Add an entry for this message_id so that we know we've processed
+            # it.
+            self._simple_insert_txn(
+                txn, table="device_federation_inbox",
+                values={
+                    "origin": origin,
+                    "message_id": message_id,
+                    "received_ts": now_ms,
+                },
+            )
+
+            # Add the messages to the approriate local device inboxes so that
+            # they'll be sent to the devices when they next sync.
+            self._add_messages_to_local_device_inbox_txn(
+                txn, stream_id, local_messages_by_user_then_device
+            )
+
+        with self._device_inbox_id_gen.get_next() as stream_id:
+            now_ms = self.clock.time_msec()
+            yield self.runInteraction(
+                "add_messages_from_remote_to_device_inbox",
+                add_messages_txn,
+                now_ms,
+                stream_id,
+            )
+            for user_id in local_messages_by_user_then_device.keys():
+                self._device_inbox_stream_cache.entity_has_changed(
+                    user_id, stream_id
+                )
+
+    def _add_messages_to_local_device_inbox_txn(self, txn, stream_id,
+                                                messages_by_user_then_device):
+        local_users_and_devices = set()
+        for user_id, messages_by_device in messages_by_user_then_device.items():
+            devices = messages_by_device.keys()
             sql = (
                 "SELECT user_id, device_id FROM devices"
                 " WHERE user_id = ? AND device_id IN ("
@@ -48,16 +141,8 @@ class DeviceInboxStore(SQLBaseStore):
             )
             # TODO: Maybe this needs to be done in batches if there are
             # too many local devices for a given user.
-            args = [user_id] + devices
-            txn.execute(sql, args)
-            return [tuple(row) for row in txn.fetchall()]
-
-        def add_messages_to_device_inbox_txn(txn, stream_id):
-            local_users_and_devices = set()
-            for user_id, messages_by_device in messages_by_user_then_device.items():
-                local_users_and_devices.update(
-                    select_devices_txn(txn, user_id, messages_by_device.keys())
-                )
+            txn.execute(sql, [user_id] + devices)
+            local_users_and_devices.update(map(tuple, txn.fetchall()))
 
         sql = (
             "INSERT INTO device_inbox"
@@ -75,15 +160,6 @@ class DeviceInboxStore(SQLBaseStore):
 
         txn.executemany(sql, rows)
 
-        with self._device_inbox_id_gen.get_next() as stream_id:
-            yield self.runInteraction(
-                "add_messages_to_device_inbox",
-                add_messages_to_device_inbox_txn,
-                stream_id
-            )
-
-        defer.returnValue(self._device_inbox_id_gen.get_current_token())
-
     def get_new_messages_for_device(
         self, user_id, device_id, last_stream_id, current_stream_id, limit=100
     ):
@@ -97,6 +173,12 @@ class DeviceInboxStore(SQLBaseStore):
             Deferred ([dict], int): List of messages for the device and where
                 in the stream the messages got to.
         """
+        has_changed = self._device_inbox_stream_cache.has_entity_changed(
+            user_id, last_stream_id
+        )
+        if not has_changed:
+            return defer.succeed(([], current_stream_id))
+
         def get_new_messages_for_device_txn(txn):
             sql = (
                 "SELECT stream_id, message_json FROM device_inbox"
@@ -182,3 +264,71 @@ class DeviceInboxStore(SQLBaseStore):
 
     def get_to_device_stream_token(self):
         return self._device_inbox_id_gen.get_current_token()
+
+    def get_new_device_msgs_for_remote(
+        self, destination, last_stream_id, current_stream_id, limit=100
+    ):
+        """
+        Args:
+            destination(str): The name of the remote server.
+            last_stream_id(int): The last position of the device message stream
+                that the server sent up to.
+            current_stream_id(int): The current position of the device
+                message stream.
+        Returns:
+            Deferred ([dict], int): List of messages for the device and where
+                in the stream the messages got to.
+        """
+
+        has_changed = self._device_federation_outbox_stream_cache.has_entity_changed(
+            destination, last_stream_id
+        )
+        if not has_changed:
+            return defer.succeed(([], current_stream_id))
+
+        def get_new_messages_for_remote_destination_txn(txn):
+            sql = (
+                "SELECT stream_id, messages_json FROM device_federation_outbox"
+                " WHERE destination = ?"
+                " AND ? < stream_id AND stream_id <= ?"
+                " ORDER BY stream_id ASC"
+                " LIMIT ?"
+            )
+            txn.execute(sql, (
+                destination, last_stream_id, current_stream_id, limit
+            ))
+            messages = []
+            for row in txn.fetchall():
+                stream_pos = row[0]
+                messages.append(ujson.loads(row[1]))
+            if len(messages) < limit:
+                stream_pos = current_stream_id
+            return (messages, stream_pos)
+
+        return self.runInteraction(
+            "get_new_device_msgs_for_remote",
+            get_new_messages_for_remote_destination_txn,
+        )
+
+    def delete_device_msgs_for_remote(self, destination, up_to_stream_id):
+        """Used to delete messages when the remote destination acknowledges
+        their receipt.
+
+        Args:
+            destination(str): The destination server_name
+            up_to_stream_id(int): Where to delete messages up to.
+        Returns:
+            A deferred that resolves when the messages have been deleted.
+        """
+        def delete_messages_for_remote_destination_txn(txn):
+            sql = (
+                "DELETE FROM device_federation_outbox"
+                " WHERE destination = ?"
+                " AND stream_id <= ?"
+            )
+            txn.execute(sql, (destination, up_to_stream_id))
+
+        return self.runInteraction(
+            "delete_device_msgs_for_remote",
+            delete_messages_for_remote_destination_txn
+        )

synapse/storage/schema/delta/34/device_outbox.sql

@@ -0,0 +1,36 @@
+/* Copyright 2016 OpenMarket 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.
+ */
+
+CREATE TABLE device_federation_outbox (
+    destination TEXT NOT NULL,
+    stream_id BIGINT NOT NULL,
+    queued_ts BIGINT NOT NULL,
+    messages_json TEXT NOT NULL
+);
+
+
+CREATE INDEX device_federation_outbox_destination_id
+    ON device_federation_outbox(destination, stream_id);
+
+
+CREATE TABLE device_federation_inbox (
+    origin TEXT NOT NULL,
+    message_id TEXT NOT NULL,
+    received_ts BIGINT NOT NULL
+);
+
+
+CREATE INDEX device_federation_inbox_sender_id
+    ON device_federation_inbox(origin, message_id);

tests/handlers/test_typing.py

@@ -121,6 +121,14 @@ class TypingNotificationsTestCase(unittest.TestCase):
 
         self.auth.check_joined_room = check_joined_room
 
+        self.datastore.get_to_device_stream_token = lambda: 0
+        self.datastore.get_new_device_msgs_for_remote = (
+            lambda *args, **kargs: ([], 0)
+        )
+        self.datastore.delete_device_msgs_for_remote = (
+            lambda *args, **kargs: None
+        )
+
         # Some local users to test with
         self.u_apple = UserID.from_string("@apple:test")
         self.u_banana = UserID.from_string("@banana:test")