Allow bootstrapper to scrape libp2p address

beacon_node/network/src/service.rs

@@ -5,7 +5,7 @@ use beacon_chain::{BeaconChain, BeaconChainTypes};
 use core::marker::PhantomData;
 use eth2_libp2p::Service as LibP2PService;
 use eth2_libp2p::Topic;
-use eth2_libp2p::{Enr, Libp2pEvent, PeerId};
+use eth2_libp2p::{Enr, Libp2pEvent, Multiaddr, PeerId, Swarm};
 use eth2_libp2p::{PubsubMessage, RPCEvent};
 use futures::prelude::*;
 use futures::Stream;
@@ -64,6 +64,8 @@ impl<T: BeaconChainTypes + 'static> Service<T> {
         Ok((Arc::new(network_service), network_send))
     }
 
+    /// Returns the local ENR from the underlying Discv5 behaviour that external peers may connect
+    /// to.
     pub fn local_enr(&self) -> Enr {
         self.libp2p_service
             .lock()
@@ -73,10 +75,19 @@ impl<T: BeaconChainTypes + 'static> Service<T> {
             .clone()
     }
 
+    /// Returns the list of `Multiaddr` that the underlying libp2p instance is listening on.
+    pub fn listen_multiaddrs(&self) -> Vec<Multiaddr> {
+        Swarm::listeners(&self.libp2p_service.lock().swarm)
+            .cloned()
+            .collect()
+    }
+
+    /// Returns the number of libp2p connected peers.
     pub fn connected_peers(&self) -> usize {
         self.libp2p_service.lock().swarm.connected_peers()
     }
 
+    /// Returns the set of `PeerId` that are connected via libp2p.
     pub fn connected_peer_set(&self) -> Vec<PeerId> {
         self.libp2p_service
             .lock()
@@ -88,6 +99,7 @@ impl<T: BeaconChainTypes + 'static> Service<T> {
             .collect()
     }
 
+    /// Provides a reference to the underlying libp2p service.
     pub fn libp2p_service(&self) -> Arc<Mutex<LibP2PService>> {
         self.libp2p_service.clone()
     }