Lighthouse bootnode (#1265)

* Initial bootnode structure

* Add boot_node subcommand

* Add bootnode subcommand

* fmt corrections

* Extend help message

* Move boot_node crate

* Update discv5 dep

* Improve logging and boot-node logging

Co-authored-by: Paul Hauner <paul@paulhauner.com>

boot_node/src/server.rs

@@ -0,0 +1,89 @@
+//! The main bootnode server execution.
+
+use super::BootNodeConfig;
+use discv5::{Discv5, Discv5ConfigBuilder, Discv5Event};
+use eth2_libp2p::EnrExt;
+use futures::prelude::*;
+use slog::info;
+
+pub async fn run(config: BootNodeConfig, log: slog::Logger) {
+    // Print out useful information about the generated ENR
+
+    let enr_socket = config.local_enr.udp_socket().expect("Enr has a UDP socket");
+    info!(log, "Configuration parameters"; "listening_address" => format!("{}:{}", config.listen_socket.ip(), config.listen_socket.port()), "broadcast_address" => format!("{}:{}",enr_socket.ip(), enr_socket.port()));
+
+    info!(log, "Identity established"; "peer_id" => config.local_enr.peer_id().to_string(), "node_id" => config.local_enr.node_id().to_string());
+
+    // build the contactable multiaddr list, adding the p2p protocol
+    info!(log, "Contact information"; "enr" => config.local_enr.to_base64());
+    info!(log, "Contact information"; "multiaddrs" => format!("{:?}", config.local_enr.multiaddr_p2p()));
+
+    // Build the discv5 server
+
+    // default configuration with packet filtering
+
+    let discv5_config = {
+        let mut builder = Discv5ConfigBuilder::new();
+        builder.enable_packet_filter();
+        if !config.auto_update {
+            builder.disable_enr_update();
+        }
+        builder.build()
+    };
+
+    // construct the discv5 server
+    let mut discv5 = Discv5::new(config.local_enr, config.local_key, discv5_config).unwrap();
+
+    // If there are any bootnodes add them to the routing table
+    for enr in config.boot_nodes {
+        info!(log, "Adding bootnode"; "address" => format!("{:?}", enr.udp_socket()), "peer_id" => enr.peer_id().to_string(), "node_id" => enr.node_id().to_string());
+        if let Err(e) = discv5.add_enr(enr) {
+            slog::warn!(log, "Failed adding ENR"; "error" => e.to_string());
+        }
+    }
+
+    // start the server
+    discv5.start(config.listen_socket);
+
+    // if there are peers in the local routing table, establish a session by running a query
+    if !discv5.table_entries_id().is_empty() {
+        info!(log, "Executing bootstrap query...");
+        let _ = discv5.find_node(discv5::enr::NodeId::random()).await;
+    }
+
+    // respond with metrics every 10 seconds
+    let mut metric_interval = tokio::time::interval(tokio::time::Duration::from_secs(10));
+
+    // get an event stream
+    let mut event_stream = match discv5.event_stream().await {
+        Ok(stream) => stream,
+        Err(e) => {
+            slog::crit!(log, "Failed to obtain event stream"; "error" => e.to_string());
+            return;
+        }
+    };
+
+    // listen for events
+    loop {
+        tokio::select! {
+            _ = metric_interval.next() => {
+                // display server metrics
+                let metrics = discv5.metrics();
+                info!(log, "Server metrics"; "connected_peers" => discv5.connected_peers(), "active_sessions" => metrics.active_sessions, "requests/s" => format!("{:.2}", metrics.unsolicited_requests_per_second));
+            }
+            Some(event) = event_stream.recv() => {
+                match event {
+                    Discv5Event::Discovered(_enr) => {
+                        // An ENR has bee obtained by the server
+                        // Ignore these events here
+                    }
+                    Discv5Event::EnrAdded { .. } => {}     // Ignore
+                    Discv5Event::NodeInserted { .. } => {} // Ignore
+                    Discv5Event::SocketUpdated(socket_addr) => {
+                        info!(log, "External socket address updated"; "socket_addr" => format!("{:?}", socket_addr));
+                    }
+                }
+            }
+        }
+    }
+}