use go module for dependencies (#594)

clientapi/consumers/roomserver.go

@@ -0,0 +1,144 @@
+// Copyright 2017 Vector Creations 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.
+
+package consumers
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/matrix-org/dendrite/clientapi/auth/storage/accounts"
+	"github.com/matrix-org/dendrite/common"
+	"github.com/matrix-org/dendrite/common/config"
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/gomatrixserverlib"
+
+	log "github.com/sirupsen/logrus"
+	sarama "gopkg.in/Shopify/sarama.v1"
+)
+
+// OutputRoomEventConsumer consumes events that originated in the room server.
+type OutputRoomEventConsumer struct {
+	roomServerConsumer *common.ContinualConsumer
+	db                 *accounts.Database
+	query              api.RoomserverQueryAPI
+	serverName         string
+}
+
+// NewOutputRoomEventConsumer creates a new OutputRoomEventConsumer. Call Start() to begin consuming from room servers.
+func NewOutputRoomEventConsumer(
+	cfg *config.Dendrite,
+	kafkaConsumer sarama.Consumer,
+	store *accounts.Database,
+	queryAPI api.RoomserverQueryAPI,
+) *OutputRoomEventConsumer {
+
+	consumer := common.ContinualConsumer{
+		Topic:          string(cfg.Kafka.Topics.OutputRoomEvent),
+		Consumer:       kafkaConsumer,
+		PartitionStore: store,
+	}
+	s := &OutputRoomEventConsumer{
+		roomServerConsumer: &consumer,
+		db:                 store,
+		query:              queryAPI,
+		serverName:         string(cfg.Matrix.ServerName),
+	}
+	consumer.ProcessMessage = s.onMessage
+
+	return s
+}
+
+// Start consuming from room servers
+func (s *OutputRoomEventConsumer) Start() error {
+	return s.roomServerConsumer.Start()
+}
+
+// onMessage is called when the sync server receives a new event from the room server output log.
+// It is not safe for this function to be called from multiple goroutines, or else the
+// sync stream position may race and be incorrectly calculated.
+func (s *OutputRoomEventConsumer) onMessage(msg *sarama.ConsumerMessage) error {
+	// Parse out the event JSON
+	var output api.OutputEvent
+	if err := json.Unmarshal(msg.Value, &output); err != nil {
+		// If the message was invalid, log it and move on to the next message in the stream
+		log.WithError(err).Errorf("roomserver output log: message parse failure")
+		return nil
+	}
+
+	if output.Type != api.OutputTypeNewRoomEvent {
+		log.WithField("type", output.Type).Debug(
+			"roomserver output log: ignoring unknown output type",
+		)
+		return nil
+	}
+
+	ev := output.NewRoomEvent.Event
+	log.WithFields(log.Fields{
+		"event_id": ev.EventID(),
+		"room_id":  ev.RoomID(),
+		"type":     ev.Type(),
+	}).Info("received event from roomserver")
+
+	events, err := s.lookupStateEvents(output.NewRoomEvent.AddsStateEventIDs, ev)
+	if err != nil {
+		return err
+	}
+
+	return s.db.UpdateMemberships(context.TODO(), events, output.NewRoomEvent.RemovesStateEventIDs)
+}
+
+// lookupStateEvents looks up the state events that are added by a new event.
+func (s *OutputRoomEventConsumer) lookupStateEvents(
+	addsStateEventIDs []string, event gomatrixserverlib.Event,
+) ([]gomatrixserverlib.Event, error) {
+	// Fast path if there aren't any new state events.
+	if len(addsStateEventIDs) == 0 {
+		// If the event is a membership update (e.g. for a profile update), it won't
+		// show up in AddsStateEventIDs, so we need to add it manually
+		if event.Type() == "m.room.member" {
+			return []gomatrixserverlib.Event{event}, nil
+		}
+		return nil, nil
+	}
+
+	// Fast path if the only state event added is the event itself.
+	if len(addsStateEventIDs) == 1 && addsStateEventIDs[0] == event.EventID() {
+		return []gomatrixserverlib.Event{event}, nil
+	}
+
+	result := []gomatrixserverlib.Event{}
+	missing := []string{}
+	for _, id := range addsStateEventIDs {
+		// Append the current event in the results if its ID is in the events list
+		if id == event.EventID() {
+			result = append(result, event)
+		} else {
+			// If the event isn't the current one, add it to the list of events
+			// to retrieve from the roomserver
+			missing = append(missing, id)
+		}
+	}
+
+	// Request the missing events from the roomserver
+	eventReq := api.QueryEventsByIDRequest{EventIDs: missing}
+	var eventResp api.QueryEventsByIDResponse
+	if err := s.query.QueryEventsByID(context.TODO(), &eventReq, &eventResp); err != nil {
+		return nil, err
+	}
+
+	result = append(result, eventResp.Events...)
+
+	return result, nil
+}