Hidden participants (#65)

Enables hidden recording and/or forwarding participants

cmd/server/commands.go

@@ -103,6 +103,11 @@ func createToken(c *cli.Context) error {
 		RoomJoin: true,
 		Room:     room,
 	}
+	if c.Bool("recorder") {
+		grant.Hidden = true
+		grant.CanSubscribe = true
+	}
+
 	at := auth.NewAccessToken(apiKey, apiSecret).
 		AddGrant(grant).
 		SetIdentity(identity).

cmd/server/main.go

@@ -118,6 +118,11 @@ func main() {
 						Usage:    "identity of participant that holds the token",
 						Required: true,
 					},
+					&cli.BoolFlag{
+						Name:     "recorder",
+						Usage:    "creates a hidden participant that can only subscribe",
+						Required: false,
+					},
 				},
 			},
 		},

go.mod

@@ -11,7 +11,7 @@ require (
 	github.com/google/wire v0.5.0
 	github.com/gorilla/websocket v1.4.2
 	github.com/jxskiss/base62 v0.0.0-20191017122030-4f11678b909b
-	github.com/livekit/protocol v0.5.6
+	github.com/livekit/protocol v0.5.8
 	github.com/magefile/mage v1.11.0
 	github.com/maxbrunsfeld/counterfeiter/v6 v6.3.0
 	github.com/mitchellh/go-homedir v1.1.0

go.sum

@@ -237,8 +237,8 @@ github.com/lithammer/shortuuid/v3 v3.0.6 h1:pr15YQyvhiSX/qPxncFtqk+v4xLEpOZObbsY
 github.com/lithammer/shortuuid/v3 v3.0.6/go.mod h1:vMk8ke37EmiewwolSO1NLW8vP4ZaKlRuDIi8tWWmAts=
 github.com/livekit/ion-sfu v1.20.3 h1:1xfWnbg3tgXHLQWDaRQvuD/DtIOp72hAHDaDutP/i6M=
 github.com/livekit/ion-sfu v1.20.3/go.mod h1:dEdOG4KSqIftr5HxxqciNKBIdu0v3OD0ZYL7A3J09KA=
-github.com/livekit/protocol v0.5.6 h1:vMUjYvJH2TD/WIjrXtG6aQl5fFrIj0/ZgIctQqmmwro=
-github.com/livekit/protocol v0.5.6/go.mod h1:wo3CGfYB7XMF8GoVJAfTARrYSP/ombi+sbLl6AYdKP0=
+github.com/livekit/protocol v0.5.8 h1:gcHZ1afxtmYrs8TvL1HqlRDFrF7SjnTbxCNWZGM5kik=
+github.com/livekit/protocol v0.5.8/go.mod h1:wo3CGfYB7XMF8GoVJAfTARrYSP/ombi+sbLl6AYdKP0=
 github.com/lucsky/cuid v1.0.2 h1:z4XlExeoderxoPj2/dxKOyPxe9RCOu7yNq9/XWxIUMQ=
 github.com/lucsky/cuid v1.0.2/go.mod h1:QaaJqckboimOmhRSJXSx/+IT+VTfxfPGSo/6mfgUfmE=
 github.com/lyft/protoc-gen-validate v0.0.13/go.mod h1:XbGvPuh87YZc5TdIa2/I4pLk0QoUACkjt2znoq26NVQ=

pkg/routing/interfaces.go

@@ -31,6 +31,7 @@ type ParticipantInit struct {
 	ProtocolVersion int32
 	UsePlanB        bool
 	AutoSubscribe   bool
+	Hidden          bool
 }
 
 type NewParticipantCallback func(roomName string, pi ParticipantInit, requestSource MessageSource, responseSink MessageSink)

pkg/rtc/helper_test.go

@@ -1,20 +1,22 @@
 package rtc_test
 
 import (
+	"github.com/livekit/protocol/utils"
+
 	"github.com/livekit/livekit-server/pkg/rtc/types"
 	"github.com/livekit/livekit-server/pkg/rtc/types/typesfakes"
 	livekit "github.com/livekit/livekit-server/proto"
-	"github.com/livekit/protocol/utils"
 )
 
-func newMockParticipant(identity string, protocol types.ProtocolVersion) *typesfakes.FakeParticipant {
+func newMockParticipant(identity string, protocol types.ProtocolVersion, hidden bool) *typesfakes.FakeParticipant {
 	p := &typesfakes.FakeParticipant{}
 	p.IDReturns(utils.NewGuid(utils.ParticipantPrefix))
 	p.IdentityReturns(identity)
 	p.StateReturns(livekit.ParticipantInfo_JOINED)
 	p.ProtocolVersionReturns(protocol)
 	p.CanSubscribeReturns(true)
-	p.CanPublishReturns(true)
+	p.CanPublishReturns(!hidden)
+	p.HiddenReturns(hidden)
 
 	p.SetMetadataStub = func(m string) {
 		var f func(participant types.Participant)

pkg/rtc/participant.go

@@ -39,6 +39,7 @@ type ParticipantParams struct {
 	Stats           *RoomStatsReporter
 	ThrottleConfig  config.PLIThrottleConfig
 	EnabledCodecs   []*livekit.Codec
+	Hidden          bool
 }
 
 type ParticipantImpl struct {
@@ -195,6 +196,7 @@ func (p *ParticipantImpl) ToProto() *livekit.ParticipantInfo {
 		Metadata: p.metadata,
 		State:    p.State(),
 		JoinedAt: p.ConnectedAt().Unix(),
+		Hidden:   p.Hidden(),
 	}
 
 	p.lock.RLock()
@@ -583,6 +585,10 @@ func (p *ParticipantImpl) CanSubscribe() bool {
 	return p.permission == nil || p.permission.CanSubscribe
 }
 
+func (p *ParticipantImpl) Hidden() bool {
+	return p.params.Hidden
+}
+
 func (p *ParticipantImpl) SubscriberPC() *webrtc.PeerConnection {
 	return p.subscriber.pc
 }

pkg/rtc/room.go

@@ -199,7 +199,7 @@ func (r *Room) Join(participant types.Participant, opts *ParticipantOptions) err
 	// gather other participants and send join response
 	otherParticipants := make([]types.Participant, 0, len(r.participants))
 	for _, p := range r.participants {
-		if p.ID() != participant.ID() {
+		if p.ID() != participant.ID() && !p.Hidden() {
 			otherParticipants = append(otherParticipants, p)
 		}
 	}
@@ -295,10 +295,15 @@ func (r *Room) CloseIfEmpty() {
 	}
 
 	r.lock.RLock()
-	numParticipants := len(r.participants)
+	visibleParticipants := 0
+	for _, p := range r.participants {
+		if !p.Hidden() {
+			visibleParticipants++
+		}
+	}
 	r.lock.RUnlock()
 
-	if numParticipants > 0 {
+	if visibleParticipants > 0 {
 		return
 	}
 
@@ -472,6 +477,19 @@ func (r *Room) subscribeToExistingTracks(p types.Participant) {
 
 // broadcast an update about participant p
 func (r *Room) broadcastParticipantState(p types.Participant, skipSource bool) {
+	if p.Hidden() {
+		if !skipSource {
+			// send update only to hidden participant
+			updates := ToProtoParticipants([]types.Participant{p})
+			err := p.SendParticipantUpdate(updates)
+			if err != nil {
+				logger.Errorw("could not send update to participant", err,
+					"participant", p.Identity(), "pID", p.ID())
+			}
+		}
+		return
+	}
+
 	updates := ToProtoParticipants([]types.Participant{p})
 	participants := r.GetParticipants()
 	for _, op := range participants {

pkg/rtc/room_test.go

@@ -5,9 +5,10 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/require"
+
 	"github.com/livekit/livekit-server/pkg/config"
 	"github.com/livekit/livekit-server/pkg/testutils"
-	"github.com/stretchr/testify/require"
 
 	"github.com/livekit/livekit-server/pkg/logger"
 	"github.com/livekit/livekit-server/pkg/rtc"
@@ -59,7 +60,7 @@ func TestJoinedState(t *testing.T) {
 func TestRoomJoin(t *testing.T) {
 	t.Run("joining returns existing participant data", func(t *testing.T) {
 		rm := newRoomWithParticipants(t, testRoomOpts{num: numParticipants})
-		pNew := newMockParticipant("new", types.DefaultProtocol)
+		pNew := newMockParticipant("new", types.DefaultProtocol, false)
 
 		rm.Join(pNew, nil)
 
@@ -74,7 +75,7 @@ func TestRoomJoin(t *testing.T) {
 	t.Run("subscribe to existing channels upon join", func(t *testing.T) {
 		numExisting := 3
 		rm := newRoomWithParticipants(t, testRoomOpts{num: numExisting})
-		p := newMockParticipant("new", types.DefaultProtocol)
+		p := newMockParticipant("new", types.DefaultProtocol, false)
 
 		err := rm.Join(p, &rtc.ParticipantOptions{AutoSubscribe: true})
 		require.NoError(t, err)
@@ -128,7 +129,7 @@ func TestRoomJoin(t *testing.T) {
 	t.Run("cannot exceed max participants", func(t *testing.T) {
 		rm := newRoomWithParticipants(t, testRoomOpts{num: 1})
 		rm.Room.MaxParticipants = 1
-		p := newMockParticipant("second", types.ProtocolVersion(0))
+		p := newMockParticipant("second", types.ProtocolVersion(0), false)
 
 		err := rm.Join(p, nil)
 		require.Equal(t, rtc.ErrMaxParticipantsExceeded, err)
@@ -455,8 +456,50 @@ func TestDataChannel(t *testing.T) {
 	})
 }
 
+func TestHiddenParticipants(t *testing.T) {
+	t.Run("other participants don't receive hidden updates", func(t *testing.T) {
+		rm := newRoomWithParticipants(t, testRoomOpts{num: 2, numHidden: 1})
+		defer rm.Close()
+
+		pNew := newMockParticipant("new", types.DefaultProtocol, false)
+		rm.Join(pNew, nil)
+
+		// expect new participant to get a JoinReply
+		info, participants, iceServers := pNew.SendJoinResponseArgsForCall(0)
+		require.Equal(t, info.Sid, rm.Room.Sid)
+		require.Len(t, participants, 2)
+		require.Len(t, rm.GetParticipants(), 4)
+		require.NotEmpty(t, iceServers)
+	})
+
+	t.Run("hidden participant subscribes to tracks", func(t *testing.T) {
+		rm := newRoomWithParticipants(t, testRoomOpts{num: 2, numHidden: 1})
+		p := newMockParticipant("new", types.DefaultProtocol, false)
+
+		err := rm.Join(p, &rtc.ParticipantOptions{AutoSubscribe: true})
+		require.NoError(t, err)
+
+		stateChangeCB := p.OnStateChangeArgsForCall(0)
+		require.NotNil(t, stateChangeCB)
+		p.StateReturns(livekit.ParticipantInfo_ACTIVE)
+		stateChangeCB(p, livekit.ParticipantInfo_JOINED)
+
+		// it should become a subscriber when connectivity changes
+		for _, op := range rm.GetParticipants() {
+			if p == op {
+				continue
+			}
+			mockP := op.(*typesfakes.FakeParticipant)
+			require.NotZero(t, mockP.AddSubscriberCallCount())
+			// last call should be to add the newest participant
+			require.Equal(t, p, mockP.AddSubscriberArgsForCall(mockP.AddSubscriberCallCount()-1))
+		}
+	})
+}
+
 type testRoomOpts struct {
 	num                  int
+	numHidden            int
 	protocol             types.ProtocolVersion
 	audioSmoothIntervals uint32
 }
@@ -477,9 +520,9 @@ func newRoomWithParticipants(t *testing.T, opts testRoomOpts) *rtc.Room {
 			SmoothIntervals: opts.audioSmoothIntervals,
 		},
 	)
-	for i := 0; i < opts.num; i++ {
+	for i := 0; i < opts.num+opts.numHidden; i++ {
 		identity := fmt.Sprintf("p%d", i)
-		participant := newMockParticipant(identity, opts.protocol)
+		participant := newMockParticipant(identity, opts.protocol, i >= opts.num)
 		err := rm.Join(participant, &rtc.ParticipantOptions{AutoSubscribe: true})
 		participant.StateReturns(livekit.ParticipantInfo_ACTIVE)
 		require.NoError(t, err)

pkg/rtc/types/interfaces.go

@@ -57,6 +57,7 @@ type Participant interface {
 
 	CanPublish() bool
 	CanSubscribe() bool
+	Hidden() bool
 
 	Start()
 	Close() error

pkg/rtc/types/typesfakes/fake_participant.go

@@ -165,6 +165,16 @@ type FakeParticipant struct {
 		result1 webrtc.SessionDescription
 		result2 error
 	}
+	HiddenStub        func() bool
+	hiddenMutex       sync.RWMutex
+	hiddenArgsForCall []struct {
+	}
+	hiddenReturns struct {
+		result1 bool
+	}
+	hiddenReturnsOnCall map[int]struct {
+		result1 bool
+	}
 	ICERestartStub        func() error
 	iCERestartMutex       sync.RWMutex
 	iCERestartArgsForCall []struct {
@@ -1191,6 +1201,59 @@ func (fake *FakeParticipant) HandleOfferReturnsOnCall(i int, result1 webrtc.Sess
 	}{result1, result2}
 }
 
+func (fake *FakeParticipant) Hidden() bool {
+	fake.hiddenMutex.Lock()
+	ret, specificReturn := fake.hiddenReturnsOnCall[len(fake.hiddenArgsForCall)]
+	fake.hiddenArgsForCall = append(fake.hiddenArgsForCall, struct {
+	}{})
+	stub := fake.HiddenStub
+	fakeReturns := fake.hiddenReturns
+	fake.recordInvocation("Hidden", []interface{}{})
+	fake.hiddenMutex.Unlock()
+	if stub != nil {
+		return stub()
+	}
+	if specificReturn {
+		return ret.result1
+	}
+	return fakeReturns.result1
+}
+
+func (fake *FakeParticipant) HiddenCallCount() int {
+	fake.hiddenMutex.RLock()
+	defer fake.hiddenMutex.RUnlock()
+	return len(fake.hiddenArgsForCall)
+}
+
+func (fake *FakeParticipant) HiddenCalls(stub func() bool) {
+	fake.hiddenMutex.Lock()
+	defer fake.hiddenMutex.Unlock()
+	fake.HiddenStub = stub
+}
+
+func (fake *FakeParticipant) HiddenReturns(result1 bool) {
+	fake.hiddenMutex.Lock()
+	defer fake.hiddenMutex.Unlock()
+	fake.HiddenStub = nil
+	fake.hiddenReturns = struct {
+		result1 bool
+	}{result1}
+}
+
+func (fake *FakeParticipant) HiddenReturnsOnCall(i int, result1 bool) {
+	fake.hiddenMutex.Lock()
+	defer fake.hiddenMutex.Unlock()
+	fake.HiddenStub = nil
+	if fake.hiddenReturnsOnCall == nil {
+		fake.hiddenReturnsOnCall = make(map[int]struct {
+			result1 bool
+		})
+	}
+	fake.hiddenReturnsOnCall[i] = struct {
+		result1 bool
+	}{result1}
+}
+
 func (fake *FakeParticipant) ICERestart() error {
 	fake.iCERestartMutex.Lock()
 	ret, specificReturn := fake.iCERestartReturnsOnCall[len(fake.iCERestartArgsForCall)]
@@ -2507,6 +2570,8 @@ func (fake *FakeParticipant) Invocations() map[string][][]interface{} {
 	defer fake.handleAnswerMutex.RUnlock()
 	fake.handleOfferMutex.RLock()
 	defer fake.handleOfferMutex.RUnlock()
+	fake.hiddenMutex.RLock()
+	defer fake.hiddenMutex.RUnlock()
 	fake.iCERestartMutex.RLock()
 	defer fake.iCERestartMutex.RUnlock()
 	fake.iDMutex.RLock()

pkg/service/redisroomstore_test.go

@@ -6,9 +6,10 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/require"
+
 	"github.com/livekit/livekit-server/pkg/service"
 	livekit "github.com/livekit/livekit-server/proto"
-	"github.com/stretchr/testify/require"
 )
 
 func TestParticipantPersistence(t *testing.T) {

pkg/service/roommanager.go

@@ -291,6 +291,7 @@ func (r *RoomManager) StartSession(roomName string, pi routing.ParticipantInit,
 		Stats:           room.GetStatsReporter(),
 		ThrottleConfig:  r.config.RTC.PLIThrottle,
 		EnabledCodecs:   room.Room.EnabledCodecs,
+		Hidden:          pi.Hidden,
 	})
 	if err != nil {
 		logger.Errorw("could not create participant", err)

pkg/service/rtcservice.go

@@ -81,6 +81,7 @@ func (s *RTCService) validate(r *http.Request) (string, routing.ParticipantInit,
 		UsePlanB:      boolValue(planBParam),
 		AutoSubscribe: true,
 		Metadata:      claims.Metadata,
+		Hidden:        claims.Video.Hidden,
 	}
 	if autoSubParam != "" {
 		pi.AutoSubscribe = boolValue(autoSubParam)