fix: add filter option for advertise

Signed-off-by: gfanton <8671905+gfanton@users.noreply.github.com>

client.go

@@ -40,14 +40,18 @@ type RendezvousClient interface {
 	DiscoverSubscribe(ctx context.Context, ns string) (<-chan peer.AddrInfo, error)
 }
 
-func NewRendezvousPoint(host host.Host, p peer.ID) RendezvousPoint {
+func NewRendezvousPoint(host host.Host, p peer.ID, opts ...RendezvousPointOption) RendezvousPoint {
+	cfg := defaultRendezvousPointConfig
+	cfg.apply(opts...)
 	return &rendezvousPoint{
+		addrFactory: cfg.AddrsFactory,
 		host:        host,
 		p:           p,
 	}
 }
 
 type rendezvousPoint struct {
+	addrFactory AddrsFactory
 	host        host.Host
 	p           peer.ID
 }
@@ -75,7 +79,13 @@ func (rp *rendezvousPoint) Register(ctx context.Context, ns string, ttl int) (ti
 	r := ggio.NewDelimitedReader(s, inet.MessageSizeMax)
 	w := ggio.NewDelimitedWriter(s)
 
-	req := newRegisterMessage(ns, peer.AddrInfo{ID: rp.host.ID(), Addrs: rp.host.Addrs()}, ttl)
+	addrs := rp.addrFactory(rp.host.Addrs())
+	if len(addrs) == 0 {
+		return 0, fmt.Errorf("no addrs available to advertise: %s", ns)
+	}
+
+	log.Debugf("advertising on `%s` with: %v", ns, addrs)
+	req := newRegisterMessage(ns, peer.AddrInfo{ID: rp.host.ID(), Addrs: addrs}, ttl)
 	err = w.WriteMsg(req)
 	if err != nil {
 		return 0, err
@@ -88,7 +98,7 @@ func (rp *rendezvousPoint) Register(ctx context.Context, ns string, ttl int) (ti
 	}
 
 	if res.GetType() != pb.Message_REGISTER_RESPONSE {
-		return 0, fmt.Errorf("Unexpected response: %s", res.GetType().String())
+		return 0, fmt.Errorf("unexpected response: %s", res.GetType().String())
 	}
 
 	response := res.GetRegisterResponse()

options.go

@@ -0,0 +1,32 @@
+package rendezvous
+
+import (
+	ma "github.com/multiformats/go-multiaddr"
+)
+
+type RendezvousPointOption func(cfg *rendezvousPointConfig)
+
+type AddrsFactory func(addrs []ma.Multiaddr) []ma.Multiaddr
+
+var DefaultAddrFactory = func(addrs []ma.Multiaddr) []ma.Multiaddr { return addrs }
+
+var defaultRendezvousPointConfig = rendezvousPointConfig{
+	AddrsFactory: DefaultAddrFactory,
+}
+
+type rendezvousPointConfig struct {
+	AddrsFactory AddrsFactory
+}
+
+func (cfg *rendezvousPointConfig) apply(opts ...RendezvousPointOption) {
+	for _, opt := range opts {
+		opt(cfg)
+	}
+}
+
+// AddrsFactory configures libp2p to use the given address factory.
+func ClientWithAddrsFactory(factory AddrsFactory) RendezvousPointOption {
+	return func(cfg *rendezvousPointConfig) {
+		cfg.AddrsFactory = factory
+	}
+}