feat(rz): emit NewExternalAddrOfPeer when discovering peers

- Resolves #5105

Pull-Request: #5138.

Author: dariusc93

Cargo.lock

@@ -98,7 +98,7 @@ libp2p-plaintext = { version = "0.43.0", path = "transports/plaintext" }
 libp2p-pnet = { version = "0.26.0", path = "transports/pnet" }
 libp2p-quic = { version = "0.12.1", path = "transports/quic" }
 libp2p-relay = { version = "0.20.0", path = "protocols/relay" }
-libp2p-rendezvous = { version = "0.16.0", path = "protocols/rendezvous" }
+libp2p-rendezvous = { version = "0.16.1", path = "protocols/rendezvous" }
 libp2p-request-response = { version = "0.28.1", path = "protocols/request-response" }
 libp2p-server = { version = "0.12.7", path = "misc/server" }
 libp2p-stream = { version = "0.3.0-alpha", path = "protocols/stream" }

Cargo.toml

@@ -1,3 +1,7 @@
+## 0.16.1 
+- Emit `ToSwarm::NewExternalAddrOfPeer` for newly discovered peers.
+  See [PR 5138](https://github.com/libp2p/rust-libp2p/pull/5138).
+
 ## 0.16.0
 
 - Update to `libp2p-request-response` `v0.28.0`.

protocols/rendezvous/CHANGELOG.md

@@ -3,7 +3,7 @@ name = "libp2p-rendezvous"
 edition.workspace = true
 rust-version = { workspace = true }
 description = "Rendezvous protocol for libp2p"
-version = "0.16.0"
+version = "0.16.1"
 authors = ["The COMIT guys <[email protected]>"]
 license = "MIT"
 repository = "https://github.com/libp2p/rust-libp2p"

protocols/rendezvous/Cargo.toml

@@ -19,7 +19,7 @@
 // DEALINGS IN THE SOFTWARE.
 
 use std::{
-    collections::HashMap,
+    collections::{HashMap, VecDeque},
     iter,
     task::{Context, Poll},
     time::Duration,
@@ -42,6 +42,8 @@ use crate::codec::{
 };
 
 pub struct Behaviour {
+    events: VecDeque<ToSwarm<<Self as NetworkBehaviour>::ToSwarm, THandlerInEvent<Self>>>,
+
     inner: libp2p_request_response::Behaviour<crate::codec::Codec>,
 
     keypair: Keypair,
@@ -68,6 +70,7 @@ impl Behaviour {
     /// Create a new instance of the rendezvous [`NetworkBehaviour`].
     pub fn new(keypair: Keypair) -> Self {
         Self {
+            events: Default::default(),
             inner: libp2p_request_response::Behaviour::with_codec(
                 crate::codec::Codec::default(),
                 iter::once((crate::PROTOCOL_IDENT, ProtocolSupport::Outbound)),
@@ -258,8 +261,11 @@ impl NetworkBehaviour for Behaviour {
         cx: &mut Context<'_>,
     ) -> Poll<ToSwarm<Self::ToSwarm, THandlerInEvent<Self>>> {
         use libp2p_request_response as req_res;
-
         loop {
+            if let Some(event) = self.events.pop_front() {
+                return Poll::Ready(event);
+            }
+
             match self.inner.poll(cx) {
                 Poll::Ready(ToSwarm::GenerateEvent(req_res::Event::Message {
                     message:
@@ -400,6 +406,27 @@ impl Behaviour {
             DiscoverResponse(Ok((registrations, cookie))) => {
                 if let Some((rendezvous_node, _ns)) = self.waiting_for_discovery.remove(request_id)
                 {
+                    self.events
+                        .extend(registrations.iter().flat_map(|registration| {
+                            let peer_id = registration.record.peer_id();
+                            registration
+                                .record
+                                .addresses()
+                                .iter()
+                                .filter(|addr| {
+                                    !self.discovered_peers.iter().any(
+                                        |((discovered_peer_id, _), addrs)| {
+                                            *discovered_peer_id == peer_id && addrs.contains(addr)
+                                        },
+                                    )
+                                })
+                                .map(|address| ToSwarm::NewExternalAddrOfPeer {
+                                    peer_id,
+                                    address: address.clone(),
+                                })
+                                .collect::<Vec<_>>()
+                        }));
+
                     self.discovered_peers
                         .extend(registrations.iter().map(|registration| {
                             let peer_id = registration.record.peer_id();

protocols/rendezvous/src/client.rs

@@ -384,6 +384,7 @@ async fn registration_on_clients_expire() {
         new_server_with_connected_clients(rendezvous::server::Config::default().with_min_ttl(1))
             .await;
 
+    let alice_peer_id = *alice.local_peer_id();
     let roberts_peer_id = *robert.local_peer_id();
     tokio::spawn(robert.loop_on_next());
 
@@ -406,6 +407,16 @@ async fn registration_on_clients_expire() {
         event => panic!("Unexpected event: {event:?}"),
     }
 
+    match bob.next_swarm_event().await {
+        SwarmEvent::NewExternalAddrOfPeer {
+            peer_id: discovered_peer_id,
+            ..
+        } => {
+            assert_eq!(discovered_peer_id, alice_peer_id);
+        }
+        event => panic!("Unexpected event: {event:?}"),
+    }
+
     tokio::time::sleep(Duration::from_secs(registration_ttl + 1)).await;
 
     let event = bob.select_next_some().await;