fix: autorelay: treat static relays as just another peer source

p2p/host/autorelay/autorelay_test.go

@@ -456,3 +456,37 @@ func TestIncorrectInit(t *testing.T) {
 	}()
 	_ = newPrivateNode(t)
 }
+
+func TestReconnectToStaticRelays(t *testing.T) {
+	cl := clock.NewMock()
+	var staticRelays []peer.AddrInfo
+	const numStaticRelays = 1
+	relays := make([]host.Host, 0, numStaticRelays)
+	for i := 0; i < numStaticRelays; i++ {
+		r := newRelay(t)
+		t.Cleanup(func() { r.Close() })
+		relays = append(relays, r)
+		staticRelays = append(staticRelays, peer.AddrInfo{ID: r.ID(), Addrs: r.Addrs()})
+	}
+
+	h := newPrivateNode(t,
+		autorelay.WithStaticRelays(staticRelays),
+		autorelay.WithClock(cl),
+	)
+
+	defer h.Close()
+
+	cl.Add(time.Minute)
+	require.Eventually(t, func() bool { return numRelays(h) == 1 }, 10*time.Second, 50*time.Millisecond)
+
+	relaysInUse := usedRelays(h)
+	oldRelay := relaysInUse[0]
+	for _, r := range relays {
+		if r.ID() == oldRelay {
+			r.Network().ClosePeer(h.ID())
+		}
+	}
+
+	cl.Add(time.Hour)
+	require.Eventually(t, func() bool { return numRelays(h) == 1 }, 10*time.Second, 100*time.Millisecond)
+}

p2p/host/autorelay/options.go

@@ -15,8 +15,7 @@ type config struct {
 	clock      clock.Clock
 	peerSource func(ctx context.Context, num int) <-chan peer.AddrInfo
 	// minimum interval used to call the peerSource callback
-	minInterval  time.Duration
-	staticRelays []peer.AddrInfo
+	minInterval time.Duration
 	// see WithMinCandidates
 	minCandidates int
 	// see WithMaxCandidates
@@ -45,8 +44,7 @@ var defaultConfig = config{
 }
 
 var (
-	errStaticRelaysMinCandidates = errors.New("cannot use WithMinCandidates and WithStaticRelays")
-	errStaticRelaysPeerSource    = errors.New("cannot use WithPeerSource and WithStaticRelays")
+	errAlreadyHavePeerSource = errors.New("can only use a single WithPeerSource or WithStaticRelays")
 )
 
 // DefaultRelays are the known PL-operated v1 relays; will be decommissioned in 2022.
@@ -75,17 +73,26 @@ type Option func(*config) error
 
 func WithStaticRelays(static []peer.AddrInfo) Option {
 	return func(c *config) error {
-		if c.setMinCandidates {
-			return errStaticRelaysMinCandidates
-		}
 		if c.peerSource != nil {
-			return errStaticRelaysPeerSource
-		}
-		if len(c.staticRelays) > 0 {
-			return errors.New("can't set static relays, static relays already configured")
+			return errAlreadyHavePeerSource
 		}
-		c.minCandidates = len(static)
-		c.staticRelays = static
+
+		WithPeerSource(func(ctx context.Context, numPeers int) <-chan peer.AddrInfo {
+			if len(static) < numPeers {
+				numPeers = len(static)
+			}
+			c := make(chan peer.AddrInfo, numPeers)
+			defer close(c)
+
+			for i := 0; i < numPeers; i++ {
+				c <- static[i]
+			}
+			return c
+		}, 30*time.Second)(c)
+		WithMinCandidates(len(static))(c)
+		WithMaxCandidates(len(static))(c)
+		WithNumRelays(len(static))(c)
+
 		return nil
 	}
 }
@@ -107,8 +114,8 @@ func WithDefaultStaticRelays() Option {
 // If the channel is canceled you MUST close the output channel at some point.
 func WithPeerSource(f func(ctx context.Context, numPeers int) <-chan peer.AddrInfo, minInterval time.Duration) Option {
 	return func(c *config) error {
-		if len(c.staticRelays) > 0 {
-			return errStaticRelaysPeerSource
+		if c.peerSource != nil {
+			return errAlreadyHavePeerSource
 		}
 		c.peerSource = f
 		c.minInterval = minInterval
@@ -140,9 +147,6 @@ func WithMaxCandidates(n int) Option {
 // This is to make sure that we don't just randomly connect to the first candidate that we discover.
 func WithMinCandidates(n int) Option {
 	return func(c *config) error {
-		if len(c.staticRelays) > 0 {
-			return errStaticRelaysMinCandidates
-		}
 		if n > c.maxCandidates {
 			n = c.maxCandidates
 		}

p2p/host/autorelay/relay_finder.go

@@ -83,7 +83,7 @@ type relayFinder struct {
 }
 
 func newRelayFinder(host *basic.BasicHost, peerSource func(context.Context, int) <-chan peer.AddrInfo, conf *config) *relayFinder {
-	if peerSource == nil && len(conf.staticRelays) == 0 {
+	if peerSource == nil {
 		panic("Can not create a new relayFinder. Need a Peer Source fn or a list of static relays. Refer to the documentation around `libp2p.EnableAutoRelay`")
 	}
 
@@ -103,19 +103,11 @@ func newRelayFinder(host *basic.BasicHost, peerSource func(context.Context, int)
 }
 
 func (rf *relayFinder) background(ctx context.Context) {
-	if rf.usesStaticRelay() {
-		rf.refCount.Add(1)
-		go func() {
-			defer rf.refCount.Done()
-			rf.handleStaticRelays(ctx)
-		}()
-	} else {
-		rf.refCount.Add(1)
-		go func() {
-			defer rf.refCount.Done()
-			rf.findNodes(ctx)
-		}()
-	}
+	rf.refCount.Add(1)
+	go func() {
+		defer rf.refCount.Done()
+		rf.findNodes(ctx)
+	}()
 
 	rf.refCount.Add(1)
 	go func() {
@@ -274,23 +266,6 @@ func (rf *relayFinder) findNodes(ctx context.Context) {
 	}
 }
 
-func (rf *relayFinder) handleStaticRelays(ctx context.Context) {
-	sem := make(chan struct{}, 4)
-	var wg sync.WaitGroup
-	wg.Add(len(rf.conf.staticRelays))
-	for _, pi := range rf.conf.staticRelays {
-		sem <- struct{}{}
-		go func(pi peer.AddrInfo) {
-			defer wg.Done()
-			defer func() { <-sem }()
-			rf.handleNewNode(ctx, pi)
-		}(pi)
-	}
-	wg.Wait()
-	log.Debug("processed all static relays")
-	rf.notifyNewCandidate()
-}
-
 func (rf *relayFinder) notifyMaybeConnectToRelay() {
 	select {
 	case rf.maybeConnectToRelayTrigger <- struct{}{}:
@@ -450,7 +425,7 @@ func (rf *relayFinder) maybeConnectToRelay(ctx context.Context) {
 	}
 
 	rf.candidateMx.Lock()
-	if !rf.usesStaticRelay() && len(rf.relays) == 0 && len(rf.candidates) < rf.conf.minCandidates && rf.conf.clock.Since(rf.bootTime) < rf.conf.bootDelay {
+	if len(rf.relays) == 0 && len(rf.candidates) < rf.conf.minCandidates && rf.conf.clock.Since(rf.bootTime) < rf.conf.bootDelay {
 		// During the startup phase, we don't want to connect to the first candidate that we find.
 		// Instead, we wait until we've found at least minCandidates, and then select the best of those.
 		// However, if that takes too long (longer than bootDelay), we still go ahead.
@@ -643,10 +618,6 @@ func (rf *relayFinder) relayAddrs(addrs []ma.Multiaddr) []ma.Multiaddr {
 	return raddrs
 }
 
-func (rf *relayFinder) usesStaticRelay() bool {
-	return len(rf.conf.staticRelays) > 0
-}
-
 func (rf *relayFinder) Start() error {
 	rf.ctxCancelMx.Lock()
 	defer rf.ctxCancelMx.Unlock()