Implement read receipts (#1528)

* fix conversion from int to string yields a string of one rune, not a string of digits

* Add receipts table to syncapi

* Use StreamingToken as the since value

* Add required method to testEDUProducer

* Make receipt json creation "easier" to read

* Add receipts api to the eduserver

* Add receipts endpoint

* Add eduserver kafka consumer

* Add missing kafka config

* Add passing tests to whitelist

Signed-off-by: Till Faelligen <tfaelligen@gmail.com>

* Fix copy & paste error

* Fix column count error

* Make outbound federation receipts pass

* Make "Inbound federation rejects receipts from wrong remote" pass

* Don't use errors package

* - Add TODO for batching requests
- Rename variable

* Return a better error message

* - Use OutputReceiptEvent instead of InputReceiptEvent as result
- Don't use the errors package for errors
- Defer CloseAndLogIfError to close rows
- Fix Copyright

* Better creation/usage of JoinResponse

* Query all joined rooms instead of just one

* Update gomatrixserverlib

* Add sqlite3 migration

* Add postgres migration

* Ensure required sequence exists before running migrations

* Clarification on comment

* - Fix a bug when creating client receipts
- Use concrete types instead of interface{}

* Remove dead code
Use key for timestamp

* Fix postgres query...

* Remove single purpose struct

* Use key/value directly

* Only apply receipts on initial sync or if edu positions differ,
otherwise we'll be sending the same receipts over and over again.

* Actually update the id, so it is correctly send in syncs

* Set receipt on request to /read_markers

* Fix issue with receipts getting overwritten

* Use fmt.Errorf instead of pkg/errors

* Revert "Add postgres migration"

This reverts commit 722fe5a04628882b787d096942459961db159b06.

* Revert "Add sqlite3 migration"

This reverts commit d113b03f6495a4b8f8bcf158a3d00b510b4240cc.

* Fix selectRoomReceipts query

* Make golangci-lint happy

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

eduserver/input/input.go

@@ -37,6 +37,8 @@ type EDUServerInputAPI struct {
 	OutputTypingEventTopic string
 	// The kafka topic to output new send to device events to.
 	OutputSendToDeviceEventTopic string
+	// The kafka topic to output new receipt events to
+	OutputReceiptEventTopic string
 	// kafka producer
 	Producer sarama.SyncProducer
 	// Internal user query API
@@ -173,3 +175,31 @@ func (t *EDUServerInputAPI) sendToDeviceEvent(ise *api.InputSendToDeviceEvent) e
 
 	return nil
 }
+
+// InputReceiptEvent implements api.EDUServerInputAPI
+// TODO: Intelligently batch requests sent by the same user (e.g wait a few milliseconds before emitting output events)
+func (t *EDUServerInputAPI) InputReceiptEvent(
+	ctx context.Context,
+	request *api.InputReceiptEventRequest,
+	response *api.InputReceiptEventResponse,
+) error {
+	logrus.WithFields(logrus.Fields{}).Infof("Producing to topic '%s'", t.OutputReceiptEventTopic)
+	output := &api.OutputReceiptEvent{
+		UserID:    request.InputReceiptEvent.UserID,
+		RoomID:    request.InputReceiptEvent.RoomID,
+		EventID:   request.InputReceiptEvent.EventID,
+		Type:      request.InputReceiptEvent.Type,
+		Timestamp: request.InputReceiptEvent.Timestamp,
+	}
+	js, err := json.Marshal(output)
+	if err != nil {
+		return err
+	}
+	m := &sarama.ProducerMessage{
+		Topic: t.OutputReceiptEventTopic,
+		Key:   sarama.StringEncoder(request.InputReceiptEvent.RoomID + ":" + request.InputReceiptEvent.UserID),
+		Value: sarama.ByteEncoder(js),
+	}
+	_, _, err = t.Producer.SendMessage(m)
+	return err
+}