Persist network graph

diff --git a/src/disk.rs b/src/disk.rs
index 827cb7e9e79326f6a3b8ae5022748267c07bf72a..2c1834a6f0b7ac92caec7c712a659dd25786c718 100644 (file)
--- a/src/disk.rs
+++ b/src/disk.rs
@@ -1,11 +1,13 @@
 use crate::cli;
 use bitcoin::secp256k1::key::PublicKey;
+use bitcoin::BlockHash;
+use lightning::routing::network_graph::NetworkGraph;
 use lightning::util::logger::{Logger, Record};
-use lightning::util::ser::Writer;
+use lightning::util::ser::{Readable, Writeable, Writer};
 use std::collections::HashMap;
 use std::fs;
 use std::fs::File;
-use std::io::{BufRead, BufReader};
+use std::io::{BufRead, BufReader, BufWriter};
 use std::net::SocketAddr;
 use std::path::Path;
 use time::OffsetDateTime;
@@ -65,3 +67,25 @@ pub(crate) fn read_channel_peer_data(
        }
        Ok(peer_data)
 }
+
+pub(crate) fn persist_network(path: &Path, network_graph: &NetworkGraph) -> std::io::Result<()> {
+       let mut tmp_path = path.to_path_buf().into_os_string();
+       tmp_path.push(".tmp");
+       let file = fs::OpenOptions::new().write(true).create(true).open(&tmp_path)?;
+       let write_res = network_graph.write(&mut BufWriter::new(file));
+       if let Err(e) = write_res.and_then(|_| fs::rename(&tmp_path, path)) {
+               let _ = fs::remove_file(&tmp_path);
+               Err(e)
+       } else {
+               Ok(())
+       }
+}
+
+pub(crate) fn read_network(path: &Path, genesis_hash: BlockHash) -> NetworkGraph {
+       if let Ok(file) = File::open(path) {
+               if let Ok(graph) = NetworkGraph::read(&mut BufReader::new(file)) {
+                       return graph;
+               }
+       }
+       NetworkGraph::new(genesis_hash)
+}

diff --git a/src/main.rs b/src/main.rs
index 892fd0ebe3b55ddce50c8a9222283bc73169787d..cba93f6a7f28e9c3d22a68aad98c210edce1874a 100644 (file)
--- a/src/main.rs
+++ b/src/main.rs
@@ -426,13 +426,33 @@ async fn start_ldk() {
        }
 
        // Step 11: Optional: Initialize the NetGraphMsgHandler
-       // XXX persist routing data
        let genesis = genesis_block(args.network).header.block_hash();
-       let router = Arc::new(NetGraphMsgHandler::new(
-               genesis,
+       let network_graph_path = format!("{}/network_graph", ldk_data_dir.clone());
+       let network_graph = disk::read_network(Path::new(&network_graph_path), genesis);
+       let router = Arc::new(NetGraphMsgHandler::from_net_graph(
                None::<Arc<dyn chain::Access + Send + Sync>>,
                logger.clone(),
+               network_graph,
        ));
+       let router_persist = Arc::clone(&router);
+       tokio::spawn(async move {
+               let mut interval = tokio::time::interval(Duration::from_secs(600));
+               loop {
+                       interval.tick().await;
+                       if disk::persist_network(
+                               Path::new(&network_graph_path),
+                               &*router_persist.network_graph.read().unwrap(),
+                       )
+                       .is_err()
+                       {
+                               // Persistence errors here are non-fatal as we can just fetch the routing graph
+                               // again later, but they may indicate a disk error which could be fatal elsewhere.
+                               eprintln!(
+                                       "Warning: Failed to persist network graph, check your disk and permissions"
+                               );
+                       }
+               }
+       });
 
        // Step 12: Initialize the PeerManager
        let channel_manager: Arc<ChannelManager> = Arc::new(channel_manager);