Send device list updates to servers (outbound only) (#1237)

* Add QueryDeviceMessages to serve up device keys and stream IDs

* Consume key change events in fedsender

Don't yet send them to destinations as we haven't worked them out yet

* Send device list updates to all required servers

* Glue it all together

federationsender/consumers/keychange.go

@@ -0,0 +1,135 @@
+// 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.
+
+package consumers
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/Shopify/sarama"
+	stateapi "github.com/matrix-org/dendrite/currentstateserver/api"
+	"github.com/matrix-org/dendrite/federationsender/queue"
+	"github.com/matrix-org/dendrite/federationsender/storage"
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/config"
+	"github.com/matrix-org/dendrite/keyserver/api"
+	"github.com/matrix-org/gomatrixserverlib"
+	log "github.com/sirupsen/logrus"
+)
+
+// KeyChangeConsumer consumes events that originate in key server.
+type KeyChangeConsumer struct {
+	consumer   *internal.ContinualConsumer
+	db         storage.Database
+	queues     *queue.OutgoingQueues
+	serverName gomatrixserverlib.ServerName
+	stateAPI   stateapi.CurrentStateInternalAPI
+}
+
+// NewKeyChangeConsumer creates a new KeyChangeConsumer. Call Start() to begin consuming from key servers.
+func NewKeyChangeConsumer(
+	cfg *config.Dendrite,
+	kafkaConsumer sarama.Consumer,
+	queues *queue.OutgoingQueues,
+	store storage.Database,
+	stateAPI stateapi.CurrentStateInternalAPI,
+) *KeyChangeConsumer {
+	c := &KeyChangeConsumer{
+		consumer: &internal.ContinualConsumer{
+			Topic:          string(cfg.Kafka.Topics.OutputKeyChangeEvent),
+			Consumer:       kafkaConsumer,
+			PartitionStore: store,
+		},
+		queues:     queues,
+		db:         store,
+		serverName: cfg.Matrix.ServerName,
+		stateAPI:   stateAPI,
+	}
+	c.consumer.ProcessMessage = c.onMessage
+
+	return c
+}
+
+// Start consuming from key servers
+func (t *KeyChangeConsumer) Start() error {
+	if err := t.consumer.Start(); err != nil {
+		return fmt.Errorf("t.consumer.Start: %w", err)
+	}
+	return nil
+}
+
+// onMessage is called in response to a message received on the
+// key change events topic from the key server.
+func (t *KeyChangeConsumer) onMessage(msg *sarama.ConsumerMessage) error {
+	var m api.DeviceMessage
+	if err := json.Unmarshal(msg.Value, &m); err != nil {
+		log.WithError(err).Errorf("failed to read device message from key change topic")
+		return nil
+	}
+	logger := log.WithField("user_id", m.UserID)
+
+	// only send key change events which originated from us
+	_, originServerName, err := gomatrixserverlib.SplitID('@', m.UserID)
+	if err != nil {
+		logger.WithError(err).Error("Failed to extract domain from key change event")
+		return nil
+	}
+	if originServerName != t.serverName {
+		return nil
+	}
+
+	var queryRes stateapi.QueryRoomsForUserResponse
+	err = t.stateAPI.QueryRoomsForUser(context.Background(), &stateapi.QueryRoomsForUserRequest{
+		UserID:         m.UserID,
+		WantMembership: "join",
+	}, &queryRes)
+	if err != nil {
+		logger.WithError(err).Error("failed to calculate joined rooms for user")
+		return nil
+	}
+	// send this key change to all servers who share rooms with this user.
+	destinations, err := t.db.GetJoinedHostsForRooms(context.Background(), queryRes.RoomIDs)
+	if err != nil {
+		logger.WithError(err).Error("failed to calculate joined hosts for rooms user is in")
+		return nil
+	}
+
+	// Pack the EDU and marshal it
+	edu := &gomatrixserverlib.EDU{
+		Type:   gomatrixserverlib.MDeviceListUpdate,
+		Origin: string(t.serverName),
+	}
+	event := gomatrixserverlib.DeviceListUpdateEvent{
+		UserID:            m.UserID,
+		DeviceID:          m.DeviceID,
+		DeviceDisplayName: m.DisplayName,
+		StreamID:          m.StreamID,
+		PrevID:            prevID(m.StreamID),
+		Deleted:           len(m.KeyJSON) == 0,
+		Keys:              m.KeyJSON,
+	}
+	if edu.Content, err = json.Marshal(event); err != nil {
+		return err
+	}
+
+	log.Infof("Sending device list update message to %q", destinations)
+	return t.queues.SendEDU(edu, t.serverName, destinations)
+}
+
+func prevID(streamID int) []int {
+	if streamID <= 1 {
+		return nil
+	}
+	return []int{streamID - 1}
+}