Send-to-device support (#1072)

* Groundwork for send-to-device messaging

* Update sample config

* Add unstable routing for now

* Send to device consumer in sync API

* Start the send-to-device consumer

* fix indentation in dendrite-config.yaml

* Create send-to-device database tables, other tweaks

* Add some logic for send-to-device messages, add them into sync stream

* Handle incoming send-to-device messages, count them with EDU stream pos

* Undo changes to test

* pq.Array

* Fix sync

* Logging

* Fix a couple of transaction things, fix client API

* Add send-to-device test, hopefully fix bugs

* Comments

* Refactor a bit

* Fix schema

* Fix queries

* Debug logging

* Fix storing and retrieving of send-to-device messages

* Try to avoid database locks

* Update sync position

* Use latest sync position

* Jiggle about sync a bit

* Fix tests

* Break out the retrieval from the update/delete behaviour

* Comments

* nolint on getResponseWithPDUsForCompleteSync

* Try to line up sync tokens again

* Implement wildcard

* Add all send-to-device tests to whitelist, what could possibly go wrong?

* Only care about wildcard when targeted locally

* Deduplicate transactions

* Handle tokens properly, return immediately if waiting send-to-device messages

* Fix sync

* Update sytest-whitelist

* Fix copyright notice (need to do more of this)

* Comments, copyrights

* Return errors from Do, fix dendritejs

* Review comments

* Comments

* Constructor for TransactionWriter

* defletions

* Update gomatrixserverlib, sytest-blacklist

2 files changed, 113 insertions, 0 deletions

diff --git a/syncapi/consumers/eduserver_sendtodevice.go b/syncapi/consumers/eduserver_sendtodevice.go
new file mode 100644
index 00000000..48701803
--- /dev/null
+++ b/syncapi/consumers/eduserver_sendtodevice.go
@@ -0,0 +1,113 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// 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/Shopify/sarama"
+	"github.com/matrix-org/dendrite/eduserver/api"
+	"github.com/matrix-org/dendrite/internal"
+	"github.com/matrix-org/dendrite/internal/config"
+	"github.com/matrix-org/dendrite/syncapi/storage"
+	"github.com/matrix-org/dendrite/syncapi/sync"
+	"github.com/matrix-org/dendrite/syncapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+	log "github.com/sirupsen/logrus"
+)
+
+// OutputSendToDeviceEventConsumer consumes events that originated in the EDU server.
+type OutputSendToDeviceEventConsumer struct {
+	sendToDeviceConsumer *internal.ContinualConsumer
+	db                   storage.Database
+	serverName           gomatrixserverlib.ServerName // our server name
+	notifier             *sync.Notifier
+}
+
+// NewOutputSendToDeviceEventConsumer creates a new OutputSendToDeviceEventConsumer.
+// Call Start() to begin consuming from the EDU server.
+func NewOutputSendToDeviceEventConsumer(
+	cfg *config.Dendrite,
+	kafkaConsumer sarama.Consumer,
+	n *sync.Notifier,
+	store storage.Database,
+) *OutputSendToDeviceEventConsumer {
+
+	consumer := internal.ContinualConsumer{
+		Topic:          string(cfg.Kafka.Topics.OutputSendToDeviceEvent),
+		Consumer:       kafkaConsumer,
+		PartitionStore: store,
+	}
+
+	s := &OutputSendToDeviceEventConsumer{
+		sendToDeviceConsumer: &consumer,
+		db:                   store,
+		serverName:           cfg.Matrix.ServerName,
+		notifier:             n,
+	}
+
+	consumer.ProcessMessage = s.onMessage
+
+	return s
+}
+
+// Start consuming from EDU api
+func (s *OutputSendToDeviceEventConsumer) Start() error {
+	return s.sendToDeviceConsumer.Start()
+}
+
+func (s *OutputSendToDeviceEventConsumer) onMessage(msg *sarama.ConsumerMessage) error {
+	var output api.OutputSendToDeviceEvent
+	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("EDU server output log: message parse failure")
+		return err
+	}
+
+	_, domain, err := gomatrixserverlib.SplitID('@', output.UserID)
+	if err != nil {
+		return err
+	}
+	if domain != s.serverName {
+		return nil
+	}
+
+	util.GetLogger(context.TODO()).WithFields(log.Fields{
+		"sender":     output.Sender,
+		"user_id":    output.UserID,
+		"device_id":  output.DeviceID,
+		"event_type": output.Type,
+	}).Info("sync API received send-to-device event from EDU server")
+
+	streamPos := s.db.AddSendToDevice()
+
+	_, err = s.db.StoreNewSendForDeviceMessage(
+		context.TODO(), streamPos, output.UserID, output.DeviceID, output.SendToDeviceEvent,
+	)
+	if err != nil {
+		log.WithError(err).Errorf("failed to store send-to-device message")
+		return err
+	}
+
+	s.notifier.OnNewSendToDevice(
+		output.UserID,
+		[]string{output.DeviceID},
+		types.NewStreamToken(0, streamPos),
+	)
+
+	return nil
+}
diff --git a/syncapi/consumers/eduserver.go b/syncapi/consumers/eduserver_typing.go
index 12b1efbc..12b1efbc 100644
--- a/syncapi/consumers/eduserver.go
+++ b/syncapi/consumers/eduserver_typing.go