From 23a8fbfc74b64e6f698dfe66d2ffdafec2f2cacd Mon Sep 17 00:00:00 2001
From: Age Manning <Age@AgeManning.com>
Date: Wed, 13 Mar 2019 15:37:44 +1100
Subject: [PATCH] Add default topics and initial topic subscription

---
 beacon_node/libp2p/src/behaviour.rs      |  5 +++++
 beacon_node/libp2p/src/network_config.rs |  4 +++-
 beacon_node/libp2p/src/service.rs        | 19 +++++++++++++++++--
 eth2/types/src/lib.rs                    |  2 +-
 4 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/beacon_node/libp2p/src/behaviour.rs b/beacon_node/libp2p/src/behaviour.rs
index be12011dd..be49abb94 100644
--- a/beacon_node/libp2p/src/behaviour.rs
+++ b/beacon_node/libp2p/src/behaviour.rs
@@ -5,6 +5,7 @@ use libp2p::{
     tokio_io::{AsyncRead, AsyncWrite},
     NetworkBehaviour, PeerId,
 };
+use types::Topic;
 
 /// Builds the network behaviour for the libp2p Swarm.
 /// Implements gossipsub message routing.
@@ -57,6 +58,10 @@ impl<TSubstream: AsyncRead + AsyncWrite> Behaviour<TSubstream> {
 }
 
 impl<TSubstream: AsyncRead + AsyncWrite> Behaviour<TSubstream> {
+    pub fn subscribe(&mut self, topic: Topic) -> bool {
+        self.gossipsub.subscribe(topic)
+    }
+
     pub fn send_message(&self, message: String) {
         // TODO: Encode and send via gossipsub
 
diff --git a/beacon_node/libp2p/src/network_config.rs b/beacon_node/libp2p/src/network_config.rs
index ecc36da33..176892bb0 100644
--- a/beacon_node/libp2p/src/network_config.rs
+++ b/beacon_node/libp2p/src/network_config.rs
@@ -2,7 +2,6 @@ use crate::Multiaddr;
 use libp2p::gossipsub::{GossipsubConfig, GossipsubConfigBuilder};
 use libp2p::secio;
 use std::fmt;
-use types::Topic;
 
 #[derive(Clone)]
 /// Network configuration for lighthouse.
@@ -20,6 +19,8 @@ pub struct NetworkConfig {
     pub local_private_key: secio::SecioKeyPair,
     /// Client version
     pub client_version: String,
+    /// List of topics to subscribe to as strings
+    pub topics: Vec<String>,
 }
 
 impl Default for NetworkConfig {
@@ -37,6 +38,7 @@ impl Default for NetworkConfig {
             boot_nodes: Vec::new(),
             local_private_key: secio::SecioKeyPair::secp256k1_generated().unwrap(),
             client_version: version::version(),
+            topics: vec![String::from("beacon_chain")],
         }
     }
 }
diff --git a/beacon_node/libp2p/src/service.rs b/beacon_node/libp2p/src/service.rs
index dceb62511..26154beb6 100644
--- a/beacon_node/libp2p/src/service.rs
+++ b/beacon_node/libp2p/src/service.rs
@@ -12,9 +12,10 @@ use libp2p::core::{
 };
 use libp2p::{core, secio, Transport};
 use libp2p::{PeerId, Swarm};
-use slog::{debug, info, warn};
+use slog::{debug, info, trace, warn};
 use std::io::{Error, ErrorKind};
 use std::time::Duration;
+use types::{Topic, TopicBuilder};
 
 /// The configuration and state of the libp2p components for the beacon node.
 pub struct Service {
@@ -33,7 +34,7 @@ impl Service {
 
         let local_private_key = config.local_private_key;
         let local_peer_id = local_private_key.to_peer_id();
-        debug!(log, "Local peer id: {:?}", local_peer_id);
+        info!(log, "Local peer id: {:?}", local_peer_id);
 
         let mut swarm = {
             // Set up the transport
@@ -67,6 +68,20 @@ impl Service {
             };
         }
 
+        // subscribe to default gossipsub topics
+        let mut subscribed_topics = vec![];
+        for topic in config.topics {
+            let t = TopicBuilder::new(topic.to_string()).build();
+            match swarm.subscribe(t) {
+                true => {
+                    trace!(log, "Subscribed to topic: {:?}", topic);
+                    subscribed_topics.push(topic);
+                }
+                false => warn!(log, "Could not subscribe to topic: {:?}", topic),
+            };
+        }
+        info!(log, "Subscribed to topics: {:?}", subscribed_topics);
+
         Ok(Service {
             local_peer_id,
             swarm,
diff --git a/eth2/types/src/lib.rs b/eth2/types/src/lib.rs
index 47235a15b..2cf61cfec 100644
--- a/eth2/types/src/lib.rs
+++ b/eth2/types/src/lib.rs
@@ -73,6 +73,6 @@ pub type AttesterMap = HashMap<(u64, u64), Vec<usize>>;
 pub type ProposerMap = HashMap<u64, usize>;
 
 pub use bls::{AggregatePublicKey, AggregateSignature, Keypair, PublicKey, Signature};
-pub use libp2p::floodsub::Topic;
+pub use libp2p::floodsub::{Topic, TopicBuilder};
 pub use libp2p::multiaddr;
 pub use libp2p::Multiaddr;