Add Queryer and Inputer and factor out more RSAPI stuff (#1382)

* Add Queryer and use embedded structs

* Add Inputer and factor out more RS API stuff

This neatly splits up the RS API based on the functionality it provides,
whilst providing a useful place for code sharing via the `helpers` package.

roomserver/internal/input/input.go

@@ -0,0 +1,91 @@
+// 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 input contains the code processes new room events
+package input
+
+import (
+	"context"
+	"encoding/json"
+	"sync"
+
+	"github.com/Shopify/sarama"
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/dendrite/roomserver/storage"
+	"github.com/matrix-org/gomatrixserverlib"
+	log "github.com/sirupsen/logrus"
+)
+
+type Inputer struct {
+	DB                   storage.Database
+	Producer             sarama.SyncProducer
+	ServerName           gomatrixserverlib.ServerName
+	OutputRoomEventTopic string
+
+	mutexes sync.Map // room ID -> *sync.Mutex, protects calls to processRoomEvent
+}
+
+// WriteOutputEvents implements OutputRoomEventWriter
+func (r *Inputer) WriteOutputEvents(roomID string, updates []api.OutputEvent) error {
+	messages := make([]*sarama.ProducerMessage, len(updates))
+	for i := range updates {
+		value, err := json.Marshal(updates[i])
+		if err != nil {
+			return err
+		}
+		logger := log.WithFields(log.Fields{
+			"room_id": roomID,
+			"type":    updates[i].Type,
+		})
+		if updates[i].NewRoomEvent != nil {
+			logger = logger.WithFields(log.Fields{
+				"event_type":     updates[i].NewRoomEvent.Event.Type(),
+				"event_id":       updates[i].NewRoomEvent.Event.EventID(),
+				"adds_state":     len(updates[i].NewRoomEvent.AddsStateEventIDs),
+				"removes_state":  len(updates[i].NewRoomEvent.RemovesStateEventIDs),
+				"send_as_server": updates[i].NewRoomEvent.SendAsServer,
+				"sender":         updates[i].NewRoomEvent.Event.Sender(),
+			})
+		}
+		logger.Infof("Producing to topic '%s'", r.OutputRoomEventTopic)
+		messages[i] = &sarama.ProducerMessage{
+			Topic: r.OutputRoomEventTopic,
+			Key:   sarama.StringEncoder(roomID),
+			Value: sarama.ByteEncoder(value),
+		}
+	}
+	return r.Producer.SendMessages(messages)
+}
+
+// InputRoomEvents implements api.RoomserverInternalAPI
+func (r *Inputer) InputRoomEvents(
+	ctx context.Context,
+	request *api.InputRoomEventsRequest,
+	response *api.InputRoomEventsResponse,
+) (err error) {
+	for i, e := range request.InputRoomEvents {
+		roomID := "global"
+		if r.DB.SupportsConcurrentRoomInputs() {
+			roomID = e.Event.RoomID()
+		}
+		mutex, _ := r.mutexes.LoadOrStore(roomID, &sync.Mutex{})
+		mutex.(*sync.Mutex).Lock()
+		if response.EventID, err = r.processRoomEvent(ctx, request.InputRoomEvents[i]); err != nil {
+			mutex.(*sync.Mutex).Unlock()
+			return err
+		}
+		mutex.(*sync.Mutex).Unlock()
+	}
+	return nil
+}