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::chainmonitor::ChainMonitor;
14 use lightning::chain::channelmonitor;
15 use lightning::chain::keysinterface::{Sign, KeysInterface};
16 use lightning::ln::channelmanager::ChannelManager;
17 use lightning::ln::msgs::{ChannelMessageHandler, RoutingMessageHandler};
18 use lightning::ln::peer_handler::{PeerManager, SocketDescriptor};
19 use lightning::util::events::{EventHandler, EventsProvider};
20 use lightning::util::logger::Logger;
22 use std::sync::atomic::{AtomicBool, Ordering};
24 use std::thread::JoinHandle;
25 use std::time::{Duration, Instant};
28 /// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
29 /// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
30 /// responsibilities are:
31 /// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
32 /// writing it to disk/backups by invoking the callback given to it at startup.
33 /// ChannelManager persistence should be done in the background.
34 /// * Calling `ChannelManager::timer_tick_occurred()` and
35 /// `PeerManager::timer_tick_occurred()` every minute (can be done in the
38 /// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
39 /// then there is a risk of channels force-closing on startup when the manager realizes it's
40 /// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
41 /// for unilateral chain closure fees are at risk.
42 pub struct BackgroundProcessor {
43 stop_thread: Arc<AtomicBool>,
44 /// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
45 /// exits due to an error while persisting.
46 pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
50 const FRESHNESS_TIMER: u64 = 60;
52 const FRESHNESS_TIMER: u64 = 1;
54 /// Trait which handles persisting a [`ChannelManager`] to disk.
56 /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
57 pub trait ChannelManagerPersister<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
59 M::Target: 'static + chain::Watch<Signer>,
60 T::Target: 'static + BroadcasterInterface,
61 K::Target: 'static + KeysInterface<Signer = Signer>,
62 F::Target: 'static + FeeEstimator,
63 L::Target: 'static + Logger,
65 /// Persist the given [`ChannelManager`] to disk, returning an error if persistence failed
66 /// (which will cause the [`BackgroundProcessor`] which called this method to exit.
68 /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
69 fn persist_manager(&self, channel_manager: &ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error>;
72 impl<Fun, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
73 ChannelManagerPersister<Signer, M, T, K, F, L> for Fun where
74 M::Target: 'static + chain::Watch<Signer>,
75 T::Target: 'static + BroadcasterInterface,
76 K::Target: 'static + KeysInterface<Signer = Signer>,
77 F::Target: 'static + FeeEstimator,
78 L::Target: 'static + Logger,
79 Fun: Fn(&ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error>,
81 fn persist_manager(&self, channel_manager: &ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error> {
86 impl BackgroundProcessor {
87 /// Start a background thread that takes care of responsibilities enumerated in the top-level
90 /// If `persist_manager` returns an error, then this thread will return said error (and
91 /// `start()` will need to be called again to restart the `BackgroundProcessor`). Users should
92 /// wait on [`thread_handle`]'s `join()` method to be able to tell if and when an error is
93 /// returned, or implement `persist_manager` such that an error is never returned to the
94 /// `BackgroundProcessor`
96 /// `persist_manager` is responsible for writing out the [`ChannelManager`] to disk, and/or
97 /// uploading to one or more backup services. See [`ChannelManager::write`] for writing out a
98 /// [`ChannelManager`]. See [`FilesystemPersister::persist_manager`] for Rust-Lightning's
99 /// provided implementation.
101 /// [`thread_handle`]: BackgroundProcessor::thread_handle
102 /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
103 /// [`ChannelManager::write`]: lightning::ln::channelmanager::ChannelManager#impl-Writeable
104 /// [`FilesystemPersister::persist_manager`]: lightning_persister::FilesystemPersister::persist_manager
106 Signer: 'static + Sign,
107 CF: 'static + Deref + Send + Sync,
108 CW: 'static + Deref + Send + Sync,
109 T: 'static + Deref + Send + Sync,
110 K: 'static + Deref + Send + Sync,
111 F: 'static + Deref + Send + Sync,
112 L: 'static + Deref + Send + Sync,
113 P: 'static + Deref + Send + Sync,
114 Descriptor: 'static + SocketDescriptor + Send + Sync,
115 CMH: 'static + Deref + Send + Sync,
116 RMH: 'static + Deref + Send + Sync,
117 EH: 'static + EventHandler + Send + Sync,
118 CMP: 'static + Send + ChannelManagerPersister<Signer, CW, T, K, F, L>,
119 M: 'static + Deref<Target = ChainMonitor<Signer, CF, T, F, L, P>> + Send + Sync,
120 CM: 'static + Deref<Target = ChannelManager<Signer, CW, T, K, F, L>> + Send + Sync,
121 PM: 'static + Deref<Target = PeerManager<Descriptor, CMH, RMH, L>> + Send + Sync,
123 (persister: CMP, event_handler: EH, chain_monitor: M, channel_manager: CM, peer_manager: PM, logger: L) -> Self
125 CF::Target: 'static + chain::Filter,
126 CW::Target: 'static + chain::Watch<Signer>,
127 T::Target: 'static + BroadcasterInterface,
128 K::Target: 'static + KeysInterface<Signer = Signer>,
129 F::Target: 'static + FeeEstimator,
130 L::Target: 'static + Logger,
131 P::Target: 'static + channelmonitor::Persist<Signer>,
132 CMH::Target: 'static + ChannelMessageHandler,
133 RMH::Target: 'static + RoutingMessageHandler,
135 let stop_thread = Arc::new(AtomicBool::new(false));
136 let stop_thread_clone = stop_thread.clone();
137 let handle = thread::spawn(move || -> Result<(), std::io::Error> {
138 let mut current_time = Instant::now();
140 peer_manager.process_events();
141 channel_manager.process_pending_events(&event_handler);
142 chain_monitor.process_pending_events(&event_handler);
143 let updates_available =
144 channel_manager.await_persistable_update_timeout(Duration::from_millis(100));
145 if updates_available {
146 persister.persist_manager(&*channel_manager)?;
148 // Exit the loop if the background processor was requested to stop.
149 if stop_thread.load(Ordering::Acquire) == true {
150 log_trace!(logger, "Terminating background processor.");
153 if current_time.elapsed().as_secs() > FRESHNESS_TIMER {
154 log_trace!(logger, "Calling ChannelManager's and PeerManager's timer_tick_occurred");
155 channel_manager.timer_tick_occurred();
156 peer_manager.timer_tick_occurred();
157 current_time = Instant::now();
161 Self { stop_thread: stop_thread_clone, thread_handle: handle }
164 /// Stop `BackgroundProcessor`'s thread.
165 pub fn stop(self) -> Result<(), std::io::Error> {
166 self.stop_thread.store(true, Ordering::Release);
167 self.thread_handle.join().unwrap()
173 use bitcoin::blockdata::block::BlockHeader;
174 use bitcoin::blockdata::constants::genesis_block;
175 use bitcoin::blockdata::transaction::{Transaction, TxOut};
176 use bitcoin::network::constants::Network;
177 use lightning::chain::Confirm;
178 use lightning::chain::chainmonitor;
179 use lightning::chain::channelmonitor::ANTI_REORG_DELAY;
180 use lightning::chain::keysinterface::{InMemorySigner, KeysInterface, KeysManager};
181 use lightning::chain::transaction::OutPoint;
182 use lightning::get_event_msg;
183 use lightning::ln::channelmanager::{BestBlock, ChainParameters, ChannelManager, SimpleArcChannelManager};
184 use lightning::ln::features::InitFeatures;
185 use lightning::ln::msgs::ChannelMessageHandler;
186 use lightning::ln::peer_handler::{PeerManager, MessageHandler, SocketDescriptor};
187 use lightning::util::config::UserConfig;
188 use lightning::util::events::{Event, MessageSendEventsProvider, MessageSendEvent};
189 use lightning::util::ser::Writeable;
190 use lightning::util::test_utils;
191 use lightning_persister::FilesystemPersister;
193 use std::path::PathBuf;
194 use std::sync::{Arc, Mutex};
195 use std::time::Duration;
196 use super::{BackgroundProcessor, FRESHNESS_TIMER};
198 const EVENT_DEADLINE: u64 = 5 * FRESHNESS_TIMER;
200 #[derive(Clone, Eq, Hash, PartialEq)]
201 struct TestDescriptor{}
202 impl SocketDescriptor for TestDescriptor {
203 fn send_data(&mut self, _data: &[u8], _resume_read: bool) -> usize {
207 fn disconnect_socket(&mut self) {}
210 type ChainMonitor = chainmonitor::ChainMonitor<InMemorySigner, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
213 node: Arc<SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>>,
214 peer_manager: Arc<PeerManager<TestDescriptor, Arc<test_utils::TestChannelMessageHandler>, Arc<test_utils::TestRoutingMessageHandler>, Arc<test_utils::TestLogger>>>,
215 chain_monitor: Arc<ChainMonitor>,
216 persister: Arc<FilesystemPersister>,
217 tx_broadcaster: Arc<test_utils::TestBroadcaster>,
218 logger: Arc<test_utils::TestLogger>,
219 best_block: BestBlock,
224 let data_dir = self.persister.get_data_dir();
225 match fs::remove_dir_all(data_dir.clone()) {
226 Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
232 fn get_full_filepath(filepath: String, filename: String) -> String {
233 let mut path = PathBuf::from(filepath);
235 path.to_str().unwrap().to_string()
238 fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
239 let mut nodes = Vec::new();
240 for i in 0..num_nodes {
241 let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new()), blocks: Arc::new(Mutex::new(Vec::new()))});
242 let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
243 let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
244 let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
245 let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
246 let seed = [i as u8; 32];
247 let network = Network::Testnet;
248 let now = Duration::from_secs(genesis_block(network).header.time as u64);
249 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
250 let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
251 let best_block = BestBlock::from_genesis(network);
252 let params = ChainParameters { network, best_block };
253 let manager = Arc::new(ChannelManager::new(fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster.clone(), logger.clone(), keys_manager.clone(), UserConfig::default(), params));
254 let msg_handler = MessageHandler { chan_handler: Arc::new(test_utils::TestChannelMessageHandler::new()), route_handler: Arc::new(test_utils::TestRoutingMessageHandler::new() )};
255 let peer_manager = Arc::new(PeerManager::new(msg_handler, keys_manager.get_node_secret(), &seed, logger.clone()));
256 let node = Node { node: manager, peer_manager, chain_monitor, persister, tx_broadcaster, logger, best_block };
262 macro_rules! open_channel {
263 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
264 begin_open_channel!($node_a, $node_b, $channel_value);
265 let events = $node_a.node.get_and_clear_pending_events();
266 assert_eq!(events.len(), 1);
267 let (temporary_channel_id, tx) = handle_funding_generation_ready!(events[0], $channel_value);
268 end_open_channel!($node_a, $node_b, temporary_channel_id, tx);
273 macro_rules! begin_open_channel {
274 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
275 $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
276 $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
277 $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
281 macro_rules! handle_funding_generation_ready {
282 ($event: expr, $channel_value: expr) => {{
284 Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
285 assert_eq!(*channel_value_satoshis, $channel_value);
286 assert_eq!(user_channel_id, 42);
288 let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
289 value: *channel_value_satoshis, script_pubkey: output_script.clone(),
291 (*temporary_channel_id, tx)
293 _ => panic!("Unexpected event"),
298 macro_rules! end_open_channel {
299 ($node_a: expr, $node_b: expr, $temporary_channel_id: expr, $tx: expr) => {{
300 $node_a.node.funding_transaction_generated(&$temporary_channel_id, $tx.clone()).unwrap();
301 $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
302 $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
306 fn confirm_transaction(node: &mut Node, tx: &Transaction) {
307 for i in 1..=ANTI_REORG_DELAY {
308 let prev_blockhash = node.best_block.block_hash();
309 let height = node.best_block.height() + 1;
310 let header = BlockHeader { version: 0x20000000, prev_blockhash, merkle_root: Default::default(), time: height, bits: 42, nonce: 42 };
311 let txdata = vec![(0, tx)];
312 node.best_block = BestBlock::new(header.block_hash(), height);
315 node.node.transactions_confirmed(&header, &txdata, height);
316 node.chain_monitor.transactions_confirmed(&header, &txdata, height);
318 ANTI_REORG_DELAY => {
319 node.node.best_block_updated(&header, height);
320 node.chain_monitor.best_block_updated(&header, height);
328 fn test_background_processor() {
329 // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
330 // updates. Also test that when new updates are available, the manager signals that it needs
331 // re-persistence and is successfully re-persisted.
332 let nodes = create_nodes(2, "test_background_processor".to_string());
334 // Go through the channel creation process so that each node has something to persist. Since
335 // open_channel consumes events, it must complete before starting BackgroundProcessor to
336 // avoid a race with processing events.
337 let tx = open_channel!(nodes[0], nodes[1], 100000);
339 // Initiate the background processors to watch each node.
340 let data_dir = nodes[0].persister.get_data_dir();
341 let persister = 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);
342 let event_handler = |_| {};
343 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
345 macro_rules! check_persisted_data {
346 ($node: expr, $filepath: expr, $expected_bytes: expr) => {
347 match $node.write(&mut $expected_bytes) {
350 match std::fs::read($filepath) {
352 if bytes == $expected_bytes {
362 Err(e) => panic!("Unexpected error: {}", e)
367 // Check that the initial channel manager data is persisted as expected.
368 let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
369 let mut expected_bytes = Vec::new();
370 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
372 if !nodes[0].node.get_persistence_condvar_value() { break }
375 // Force-close the channel.
376 nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
378 // Check that the force-close updates are persisted.
379 let mut expected_bytes = Vec::new();
380 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
382 if !nodes[0].node.get_persistence_condvar_value() { break }
385 assert!(bg_processor.stop().is_ok());
389 fn test_timer_tick_called() {
390 // Test that ChannelManager's and PeerManager's `timer_tick_occurred` is called every
391 // `FRESHNESS_TIMER`.
392 let nodes = create_nodes(1, "test_timer_tick_called".to_string());
393 let data_dir = nodes[0].persister.get_data_dir();
394 let persister = 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);
395 let event_handler = |_| {};
396 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
398 let log_entries = nodes[0].logger.lines.lock().unwrap();
399 let desired_log = "Calling ChannelManager's and PeerManager's timer_tick_occurred".to_string();
400 if log_entries.get(&("lightning_background_processor".to_string(), desired_log)).is_some() {
405 assert!(bg_processor.stop().is_ok());
409 fn test_persist_error() {
410 // Test that if we encounter an error during manager persistence, the thread panics.
411 let nodes = create_nodes(2, "test_persist_error".to_string());
412 open_channel!(nodes[0], nodes[1], 100000);
414 let persister = |_: &_| Err(std::io::Error::new(std::io::ErrorKind::Other, "test"));
415 let event_handler = |_| {};
416 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
417 let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");
421 fn test_background_event_handling() {
422 let mut nodes = create_nodes(2, "test_background_event_handling".to_string());
423 let channel_value = 100000;
424 let data_dir = nodes[0].persister.get_data_dir();
425 let persister = move |node: &_| FilesystemPersister::persist_manager(data_dir.clone(), node);
427 // Set up a background event handler for FundingGenerationReady events.
428 let (sender, receiver) = std::sync::mpsc::sync_channel(1);
429 let event_handler = move |event| {
430 sender.send(handle_funding_generation_ready!(event, channel_value)).unwrap();
432 let bg_processor = BackgroundProcessor::start(persister.clone(), event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
434 // Open a channel and check that the FundingGenerationReady event was handled.
435 begin_open_channel!(nodes[0], nodes[1], channel_value);
436 let (temporary_channel_id, funding_tx) = receiver
437 .recv_timeout(Duration::from_secs(EVENT_DEADLINE))
438 .expect("FundingGenerationReady not handled within deadline");
439 end_open_channel!(nodes[0], nodes[1], temporary_channel_id, funding_tx);
441 // Confirm the funding transaction.
442 confirm_transaction(&mut nodes[0], &funding_tx);
443 confirm_transaction(&mut nodes[1], &funding_tx);
444 nodes[0].node.handle_funding_locked(&nodes[1].node.get_our_node_id(), &get_event_msg!(nodes[1], MessageSendEvent::SendFundingLocked, nodes[0].node.get_our_node_id()));
445 nodes[1].node.handle_funding_locked(&nodes[0].node.get_our_node_id(), &get_event_msg!(nodes[0], MessageSendEvent::SendFundingLocked, nodes[1].node.get_our_node_id()));
447 assert!(bg_processor.stop().is_ok());
449 // Set up a background event handler for SpendableOutputs events.
450 let (sender, receiver) = std::sync::mpsc::sync_channel(1);
451 let event_handler = move |event| sender.send(event).unwrap();
452 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
454 // Force close the channel and check that the SpendableOutputs event was handled.
455 nodes[0].node.force_close_channel(&nodes[0].node.list_channels()[0].channel_id).unwrap();
456 let commitment_tx = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().pop().unwrap();
457 confirm_transaction(&mut nodes[0], &commitment_tx);
459 .recv_timeout(Duration::from_secs(EVENT_DEADLINE))
460 .expect("SpendableOutputs not handled within deadline");
462 Event::SpendableOutputs { .. } => {},
463 _ => panic!("Unexpected event: {:?}", event),
466 assert!(bg_processor.stop().is_ok());