1 //! Utilities that take care of tasks that (1) need to happen periodically to keep Rust-Lightning
2 //! running properly, and (2) either can or should be run in the background. See docs for
3 //! [`BackgroundProcessor`] for more details on the nitty-gritty.
5 #![deny(broken_intra_doc_links)]
9 #[macro_use] extern crate lightning;
12 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
13 use lightning::chain::keysinterface::{Sign, KeysInterface};
14 use lightning::ln::channelmanager::ChannelManager;
15 use lightning::ln::msgs::{ChannelMessageHandler, RoutingMessageHandler};
16 use lightning::ln::peer_handler::{PeerManager, SocketDescriptor};
17 use lightning::util::logger::Logger;
19 use std::sync::atomic::{AtomicBool, Ordering};
21 use std::thread::JoinHandle;
22 use std::time::{Duration, Instant};
24 /// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
25 /// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
26 /// responsibilities are:
27 /// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
28 /// writing it to disk/backups by invoking the callback given to it at startup.
29 /// ChannelManager persistence should be done in the background.
30 /// * Calling `ChannelManager::timer_tick_occurred()` and
31 /// `PeerManager::timer_tick_occurred()` every minute (can be done in the
34 /// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
35 /// then there is a risk of channels force-closing on startup when the manager realizes it's
36 /// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
37 /// for unilateral chain closure fees are at risk.
38 pub struct BackgroundProcessor {
39 stop_thread: Arc<AtomicBool>,
40 /// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
41 /// exits due to an error while persisting.
42 pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
46 const FRESHNESS_TIMER: u64 = 60;
48 const FRESHNESS_TIMER: u64 = 1;
50 impl BackgroundProcessor {
51 /// Start a background thread that takes care of responsibilities enumerated in the top-level
54 /// If `persist_manager` returns an error, then this thread will return said error (and
55 /// `start()` will need to be called again to restart the `BackgroundProcessor`). Users should
56 /// wait on [`thread_handle`]'s `join()` method to be able to tell if and when an error is
57 /// returned, or implement `persist_manager` such that an error is never returned to the
58 /// `BackgroundProcessor`
60 /// `persist_manager` is responsible for writing out the [`ChannelManager`] to disk, and/or
61 /// uploading to one or more backup services. See [`ChannelManager::write`] for writing out a
62 /// [`ChannelManager`]. See [`FilesystemPersister::persist_manager`] for Rust-Lightning's
63 /// provided implementation.
65 /// [`thread_handle`]: BackgroundProcessor::thread_handle
66 /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
67 /// [`ChannelManager::write`]: lightning::ln::channelmanager::ChannelManager#impl-Writeable
68 /// [`FilesystemPersister::persist_manager`]: lightning_persister::FilesystemPersister::persist_manager
69 pub fn start<PM, Signer, M, T, K, F, L, Descriptor: 'static + SocketDescriptor + Send, CM, RM>(
70 persist_channel_manager: PM,
71 channel_manager: Arc<ChannelManager<Signer, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>,
72 peer_manager: Arc<PeerManager<Descriptor, Arc<CM>, Arc<RM>, Arc<L>>>, logger: Arc<L>,
75 Signer: 'static + Sign,
76 M: 'static + chain::Watch<Signer>,
77 T: 'static + BroadcasterInterface,
78 K: 'static + KeysInterface<Signer = Signer>,
79 F: 'static + FeeEstimator,
81 CM: 'static + ChannelMessageHandler,
82 RM: 'static + RoutingMessageHandler,
86 &ChannelManager<Signer, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>,
87 ) -> Result<(), std::io::Error>,
89 let stop_thread = Arc::new(AtomicBool::new(false));
90 let stop_thread_clone = stop_thread.clone();
91 let handle = thread::spawn(move || -> Result<(), std::io::Error> {
92 let mut current_time = Instant::now();
94 peer_manager.process_events();
95 let updates_available =
96 channel_manager.await_persistable_update_timeout(Duration::from_millis(100));
97 if updates_available {
98 persist_channel_manager(&*channel_manager)?;
100 // Exit the loop if the background processor was requested to stop.
101 if stop_thread.load(Ordering::Acquire) == true {
102 log_trace!(logger, "Terminating background processor.");
105 if current_time.elapsed().as_secs() > FRESHNESS_TIMER {
106 log_trace!(logger, "Calling ChannelManager's and PeerManager's timer_tick_occurred");
107 channel_manager.timer_tick_occurred();
108 peer_manager.timer_tick_occurred();
109 current_time = Instant::now();
113 Self { stop_thread: stop_thread_clone, thread_handle: handle }
116 /// Stop `BackgroundProcessor`'s thread.
117 pub fn stop(self) -> Result<(), std::io::Error> {
118 self.stop_thread.store(true, Ordering::Release);
119 self.thread_handle.join().unwrap()
125 use bitcoin::blockdata::constants::genesis_block;
126 use bitcoin::blockdata::transaction::{Transaction, TxOut};
127 use bitcoin::network::constants::Network;
128 use lightning::chain;
129 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
130 use lightning::chain::chainmonitor;
131 use lightning::chain::keysinterface::{Sign, InMemorySigner, KeysInterface, KeysManager};
132 use lightning::chain::transaction::OutPoint;
133 use lightning::get_event_msg;
134 use lightning::ln::channelmanager::{ChainParameters, ChannelManager, SimpleArcChannelManager};
135 use lightning::ln::features::InitFeatures;
136 use lightning::ln::msgs::ChannelMessageHandler;
137 use lightning::ln::peer_handler::{PeerManager, MessageHandler, SocketDescriptor};
138 use lightning::util::config::UserConfig;
139 use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
140 use lightning::util::logger::Logger;
141 use lightning::util::ser::Writeable;
142 use lightning::util::test_utils;
143 use lightning_persister::FilesystemPersister;
145 use std::path::PathBuf;
146 use std::sync::{Arc, Mutex};
147 use std::time::Duration;
148 use super::BackgroundProcessor;
150 #[derive(Clone, Eq, Hash, PartialEq)]
151 struct TestDescriptor{}
152 impl SocketDescriptor for TestDescriptor {
153 fn send_data(&mut self, _data: &[u8], _resume_read: bool) -> usize {
157 fn disconnect_socket(&mut self) {}
160 type ChainMonitor = chainmonitor::ChainMonitor<InMemorySigner, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
163 node: Arc<SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>>,
164 peer_manager: Arc<PeerManager<TestDescriptor, Arc<test_utils::TestChannelMessageHandler>, Arc<test_utils::TestRoutingMessageHandler>, Arc<test_utils::TestLogger>>>,
165 persister: Arc<FilesystemPersister>,
166 logger: Arc<test_utils::TestLogger>,
171 let data_dir = self.persister.get_data_dir();
172 match fs::remove_dir_all(data_dir.clone()) {
173 Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
179 fn get_full_filepath(filepath: String, filename: String) -> String {
180 let mut path = PathBuf::from(filepath);
182 path.to_str().unwrap().to_string()
185 fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
186 let mut nodes = Vec::new();
187 for i in 0..num_nodes {
188 let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
189 let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
190 let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
191 let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
192 let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
193 let seed = [i as u8; 32];
194 let network = Network::Testnet;
195 let genesis_block = genesis_block(network);
196 let now = Duration::from_secs(genesis_block.header.time as u64);
197 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
198 let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
199 let params = ChainParameters {
201 latest_hash: genesis_block.block_hash(),
204 let manager = Arc::new(ChannelManager::new(fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), params));
205 let msg_handler = MessageHandler { chan_handler: Arc::new(test_utils::TestChannelMessageHandler::new()), route_handler: Arc::new(test_utils::TestRoutingMessageHandler::new() )};
206 let peer_manager = Arc::new(PeerManager::new(msg_handler, keys_manager.get_node_secret(), &seed, logger.clone()));
207 let node = Node { node: manager, peer_manager, persister, logger };
213 macro_rules! open_channel {
214 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
215 $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
216 $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
217 $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
218 let events = $node_a.node.get_and_clear_pending_events();
219 assert_eq!(events.len(), 1);
220 let (temporary_channel_id, tx) = match events[0] {
221 Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
222 assert_eq!(*channel_value_satoshis, $channel_value);
223 assert_eq!(user_channel_id, 42);
225 let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
226 value: *channel_value_satoshis, script_pubkey: output_script.clone(),
228 (*temporary_channel_id, tx)
230 _ => panic!("Unexpected event"),
233 $node_a.node.funding_transaction_generated(&temporary_channel_id, tx.clone()).unwrap();
234 $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
235 $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
241 fn test_background_processor() {
242 // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
243 // updates. Also test that when new updates are available, the manager signals that it needs
244 // re-persistence and is successfully re-persisted.
245 let nodes = create_nodes(2, "test_background_processor".to_string());
247 // Initiate the background processors to watch each node.
248 let data_dir = nodes[0].persister.get_data_dir();
249 let callback = move |node: &ChannelManager<InMemorySigner, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
250 let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
252 // Go through the channel creation process until each node should have something persisted.
253 let tx = open_channel!(nodes[0], nodes[1], 100000);
255 macro_rules! check_persisted_data {
256 ($node: expr, $filepath: expr, $expected_bytes: expr) => {
257 match $node.write(&mut $expected_bytes) {
260 match std::fs::read($filepath) {
262 if bytes == $expected_bytes {
272 Err(e) => panic!("Unexpected error: {}", e)
277 // Check that the initial channel manager data is persisted as expected.
278 let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
279 let mut expected_bytes = Vec::new();
280 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
282 if !nodes[0].node.get_persistence_condvar_value() { break }
285 // Force-close the channel.
286 nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
288 // Check that the force-close updates are persisted.
289 let mut expected_bytes = Vec::new();
290 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
292 if !nodes[0].node.get_persistence_condvar_value() { break }
295 assert!(bg_processor.stop().is_ok());
299 fn test_timer_tick_called() {
300 // Test that ChannelManager's and PeerManager's `timer_tick_occurred` is called every
301 // `FRESHNESS_TIMER`.
302 let nodes = create_nodes(1, "test_timer_tick_called".to_string());
303 let data_dir = nodes[0].persister.get_data_dir();
304 let callback = move |node: &ChannelManager<InMemorySigner, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
305 let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
307 let log_entries = nodes[0].logger.lines.lock().unwrap();
308 let desired_log = "Calling ChannelManager's and PeerManager's timer_tick_occurred".to_string();
309 if log_entries.get(&("lightning_background_processor".to_string(), desired_log)).is_some() {
314 assert!(bg_processor.stop().is_ok());
318 fn test_persist_error() {
319 // Test that if we encounter an error during manager persistence, the thread panics.
320 fn persist_manager<Signer, M, T, K, F, L>(_data: &ChannelManager<Signer, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>
321 where Signer: 'static + Sign,
322 M: 'static + chain::Watch<Signer>,
323 T: 'static + BroadcasterInterface,
324 K: 'static + KeysInterface<Signer=Signer>,
325 F: 'static + FeeEstimator,
328 Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
331 let nodes = create_nodes(2, "test_persist_error".to_string());
332 let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
333 open_channel!(nodes[0], nodes[1], 100000);
335 let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");