Implement ExtraPublicRoomsProvider for p2p demos (#1180)

* Change API and rename to ExtraPublicRoomsProvider

* Make dendritejs work again

* Maybe make libp2p demo work again

* Linting

cmd/dendrite-demo-libp2p/main.go

@@ -1,6 +1,4 @@
-// Copyright 2017 Vector Creations Ltd
-// Copyright 2018 New Vector Ltd
-// Copyright 2019-2020 The Matrix.org Foundation C.I.C.
+// 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.
@@ -162,13 +160,12 @@ func main() {
 		&base.Base, federation, rsAPI, keyRing,
 	)
 	rsAPI.SetFederationSenderAPI(fsAPI)
-	/* TODO:
-	publicRoomsDB, err := storage.NewPublicRoomsServerDatabaseWithPubSub(string(base.Base.Cfg.Database.PublicRoomsAPI), base.LibP2PPubsub, cfg.Matrix.ServerName)
-	if err != nil {
-		logrus.WithError(err).Panicf("failed to connect to public rooms db")
-	}
-	*/
 	stateAPI := currentstateserver.NewInternalAPI(base.Base.Cfg, base.Base.KafkaConsumer)
+	provider := newPublicRoomsProvider(base.LibP2PPubsub, rsAPI, stateAPI)
+	err = provider.Start()
+	if err != nil {
+		panic("failed to create new public rooms provider: " + err.Error())
+	}
 
 	monolith := setup.Monolith{
 		Config:        base.Base.Cfg,
@@ -180,13 +177,14 @@ func main() {
 		KafkaConsumer: base.Base.KafkaConsumer,
 		KafkaProducer: base.Base.KafkaProducer,
 
-		AppserviceAPI:       asAPI,
-		EDUInternalAPI:      eduInputAPI,
-		FederationSenderAPI: fsAPI,
-		RoomserverAPI:       rsAPI,
-		ServerKeyAPI:        serverKeyAPI,
-		StateAPI:            stateAPI,
-		UserAPI:             userAPI,
+		AppserviceAPI:          asAPI,
+		EDUInternalAPI:         eduInputAPI,
+		FederationSenderAPI:    fsAPI,
+		RoomserverAPI:          rsAPI,
+		ServerKeyAPI:           serverKeyAPI,
+		StateAPI:               stateAPI,
+		UserAPI:                userAPI,
+		ExtPublicRoomsProvider: provider,
 	}
 	monolith.AddAllPublicRoutes(base.Base.PublicAPIMux)
 

cmd/dendrite-demo-libp2p/publicrooms.go

@@ -0,0 +1,156 @@
+// 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 main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	currentstateAPI "github.com/matrix-org/dendrite/currentstateserver/api"
+	roomserverAPI "github.com/matrix-org/dendrite/roomserver/api"
+
+	pubsub "github.com/libp2p/go-libp2p-pubsub"
+	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
+)
+
+const MaintenanceInterval = time.Second * 10
+
+type discoveredRoom struct {
+	time time.Time
+	room gomatrixserverlib.PublicRoom
+}
+
+type publicRoomsProvider struct {
+	pubsub           *pubsub.PubSub
+	topic            *pubsub.Topic
+	subscription     *pubsub.Subscription
+	foundRooms       map[string]discoveredRoom // additional rooms we have learned about from the DHT
+	foundRoomsMutex  sync.RWMutex              // protects foundRooms
+	maintenanceTimer *time.Timer               //
+	roomsAdvertised  atomic.Value              // stores int
+	rsAPI            roomserverAPI.RoomserverInternalAPI
+	stateAPI         currentstateAPI.CurrentStateInternalAPI
+}
+
+func newPublicRoomsProvider(ps *pubsub.PubSub, rsAPI roomserverAPI.RoomserverInternalAPI, stateAPI currentstateAPI.CurrentStateInternalAPI) *publicRoomsProvider {
+	return &publicRoomsProvider{
+		foundRooms: make(map[string]discoveredRoom),
+		pubsub:     ps,
+		rsAPI:      rsAPI,
+		stateAPI:   stateAPI,
+	}
+}
+
+func (p *publicRoomsProvider) Start() error {
+	if topic, err := p.pubsub.Join("/matrix/publicRooms"); err != nil {
+		return err
+	} else if sub, err := topic.Subscribe(); err == nil {
+		p.topic = topic
+		p.subscription = sub
+		go p.MaintenanceTimer()
+		go p.FindRooms()
+		p.roomsAdvertised.Store(0)
+	} else {
+		return err
+	}
+	return nil
+}
+
+func (p *publicRoomsProvider) MaintenanceTimer() {
+	if p.maintenanceTimer != nil && !p.maintenanceTimer.Stop() {
+		<-p.maintenanceTimer.C
+	}
+	p.Interval()
+}
+
+func (p *publicRoomsProvider) Interval() {
+	p.foundRoomsMutex.Lock()
+	for k, v := range p.foundRooms {
+		if time.Since(v.time) > time.Minute {
+			delete(p.foundRooms, k)
+		}
+	}
+	p.foundRoomsMutex.Unlock()
+	if err := p.AdvertiseRooms(); err != nil {
+		fmt.Println("Failed to advertise room in DHT:", err)
+	}
+	p.foundRoomsMutex.RLock()
+	defer p.foundRoomsMutex.RUnlock()
+	fmt.Println("Found", len(p.foundRooms), "room(s), advertised", p.roomsAdvertised.Load(), "room(s)")
+	p.maintenanceTimer = time.AfterFunc(MaintenanceInterval, p.Interval)
+}
+
+func (p *publicRoomsProvider) AdvertiseRooms() error {
+	ctx := context.Background()
+	var queryRes roomserverAPI.QueryPublishedRoomsResponse
+	// Query published rooms on our server. This will not invoke clientapi.ExtraPublicRoomsProvider
+	err := p.rsAPI.QueryPublishedRooms(ctx, &roomserverAPI.QueryPublishedRoomsRequest{}, &queryRes)
+	if err != nil {
+		util.GetLogger(ctx).WithError(err).Error("QueryPublishedRooms failed")
+		return err
+	}
+	ourRooms, err := currentstateAPI.PopulatePublicRooms(ctx, queryRes.RoomIDs, p.stateAPI)
+	if err != nil {
+		util.GetLogger(ctx).WithError(err).Error("PopulatePublicRooms failed")
+		return err
+	}
+	advertised := 0
+	for _, room := range ourRooms {
+		if j, err := json.Marshal(room); err == nil {
+			if err := p.topic.Publish(context.TODO(), j); err != nil {
+				fmt.Println("Failed to publish public room:", err)
+			} else {
+				advertised++
+			}
+		}
+	}
+
+	p.roomsAdvertised.Store(advertised)
+	return nil
+}
+
+func (p *publicRoomsProvider) FindRooms() {
+	for {
+		msg, err := p.subscription.Next(context.Background())
+		if err != nil {
+			continue
+		}
+		received := discoveredRoom{
+			time: time.Now(),
+		}
+		if err := json.Unmarshal(msg.Data, &received.room); err != nil {
+			fmt.Println("Unmarshal error:", err)
+			continue
+		}
+		fmt.Printf("received %+v \n", received)
+		p.foundRoomsMutex.Lock()
+		p.foundRooms[received.room.RoomID] = received
+		p.foundRoomsMutex.Unlock()
+	}
+}
+
+func (p *publicRoomsProvider) Rooms() (rooms []gomatrixserverlib.PublicRoom) {
+	p.foundRoomsMutex.RLock()
+	defer p.foundRoomsMutex.RUnlock()
+	for _, dr := range p.foundRooms {
+		rooms = append(rooms, dr.room)
+	}
+	return
+}

cmd/dendritejs/main.go

@@ -211,7 +211,7 @@ func main() {
 	)
 	fedSenderAPI := federationsender.NewInternalAPI(base, federation, rsAPI, &keyRing)
 	rsAPI.SetFederationSenderAPI(fedSenderAPI)
-	p2pPublicRoomProvider := NewLibP2PPublicRoomsProvider(node, fedSenderAPI)
+	p2pPublicRoomProvider := NewLibP2PPublicRoomsProvider(node, fedSenderAPI, federation)
 
 	stateAPI := currentstateserver.NewInternalAPI(base.Cfg, base.KafkaConsumer)
 

cmd/dendritejs/publicrooms.go

@@ -18,22 +18,29 @@ package main
 
 import (
 	"context"
+	"sync"
+	"time"
 
 	"github.com/matrix-org/dendrite/federationsender/api"
 	go_http_js_libp2p "github.com/matrix-org/go-http-js-libp2p"
 	"github.com/matrix-org/gomatrixserverlib"
+	"github.com/matrix-org/util"
 )
 
 type libp2pPublicRoomsProvider struct {
 	node      *go_http_js_libp2p.P2pLocalNode
 	providers []go_http_js_libp2p.PeerInfo
 	fedSender api.FederationSenderInternalAPI
+	fedClient *gomatrixserverlib.FederationClient
 }
 
-func NewLibP2PPublicRoomsProvider(node *go_http_js_libp2p.P2pLocalNode, fedSender api.FederationSenderInternalAPI) *libp2pPublicRoomsProvider {
+func NewLibP2PPublicRoomsProvider(
+	node *go_http_js_libp2p.P2pLocalNode, fedSender api.FederationSenderInternalAPI, fedClient *gomatrixserverlib.FederationClient,
+) *libp2pPublicRoomsProvider {
 	p := &libp2pPublicRoomsProvider{
 		node:      node,
 		fedSender: fedSender,
+		fedClient: fedClient,
 	}
 	node.RegisterFoundProviders(p.foundProviders)
 	return p
@@ -62,10 +69,86 @@ func (p *libp2pPublicRoomsProvider) foundProviders(peerInfos []go_http_js_libp2p
 	p.providers = peerInfos
 }
 
-func (p *libp2pPublicRoomsProvider) Homeservers() []string {
+func (p *libp2pPublicRoomsProvider) Rooms() []gomatrixserverlib.PublicRoom {
+	return bulkFetchPublicRoomsFromServers(context.Background(), p.fedClient, p.homeservers())
+}
+
+func (p *libp2pPublicRoomsProvider) homeservers() []string {
 	result := make([]string, len(p.providers))
 	for i := range p.providers {
 		result[i] = p.providers[i].Id
 	}
 	return result
 }
+
+// bulkFetchPublicRoomsFromServers fetches public rooms from the list of homeservers.
+// Returns a list of public rooms.
+func bulkFetchPublicRoomsFromServers(
+	ctx context.Context, fedClient *gomatrixserverlib.FederationClient, homeservers []string,
+) (publicRooms []gomatrixserverlib.PublicRoom) {
+	limit := 200
+	// follow pipeline semantics, see https://blog.golang.org/pipelines for more info.
+	// goroutines send rooms to this channel
+	roomCh := make(chan gomatrixserverlib.PublicRoom, int(limit))
+	// signalling channel to tell goroutines to stop sending rooms and quit
+	done := make(chan bool)
+	// signalling to say when we can close the room channel
+	var wg sync.WaitGroup
+	wg.Add(len(homeservers))
+	// concurrently query for public rooms
+	for _, hs := range homeservers {
+		go func(homeserverDomain string) {
+			defer wg.Done()
+			util.GetLogger(ctx).WithField("hs", homeserverDomain).Info("Querying HS for public rooms")
+			fres, err := fedClient.GetPublicRooms(ctx, gomatrixserverlib.ServerName(homeserverDomain), int(limit), "", false, "")
+			if err != nil {
+				util.GetLogger(ctx).WithError(err).WithField("hs", homeserverDomain).Warn(
+					"bulkFetchPublicRoomsFromServers: failed to query hs",
+				)
+				return
+			}
+			for _, room := range fres.Chunk {
+				// atomically send a room or stop
+				select {
+				case roomCh <- room:
+				case <-done:
+					util.GetLogger(ctx).WithError(err).WithField("hs", homeserverDomain).Info("Interrupted whilst sending rooms")
+					return
+				}
+			}
+		}(hs)
+	}
+
+	// Close the room channel when the goroutines have quit so we don't leak, but don't let it stop the in-flight request.
+	// This also allows the request to fail fast if all HSes experience errors as it will cause the room channel to be
+	// closed.
+	go func() {
+		wg.Wait()
+		util.GetLogger(ctx).Info("Cleaning up resources")
+		close(roomCh)
+	}()
+
+	// fan-in results with timeout. We stop when we reach the limit.
+FanIn:
+	for len(publicRooms) < int(limit) || limit == 0 {
+		// add a room or timeout
+		select {
+		case room, ok := <-roomCh:
+			if !ok {
+				util.GetLogger(ctx).Info("All homeservers have been queried, returning results.")
+				break FanIn
+			}
+			publicRooms = append(publicRooms, room)
+		case <-time.After(15 * time.Second): // we've waited long enough, let's tell the client what we got.
+			util.GetLogger(ctx).Info("Waited 15s for federated public rooms, returning early")
+			break FanIn
+		case <-ctx.Done(): // the client hung up on us, let's stop.
+			util.GetLogger(ctx).Info("Client hung up, returning early")
+			break FanIn
+		}
+	}
+	// tell goroutines to stop
+	close(done)
+
+	return publicRooms
+}