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};
25 /// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
26 /// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
27 /// responsibilities are:
28 /// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
29 /// writing it to disk/backups by invoking the callback given to it at startup.
30 /// ChannelManager persistence should be done in the background.
31 /// * Calling `ChannelManager::timer_tick_occurred()` and
32 /// `PeerManager::timer_tick_occurred()` every minute (can be done in the
35 /// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
36 /// then there is a risk of channels force-closing on startup when the manager realizes it's
37 /// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
38 /// for unilateral chain closure fees are at risk.
39 pub struct BackgroundProcessor {
40 stop_thread: Arc<AtomicBool>,
41 /// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
42 /// exits due to an error while persisting.
43 pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
47 const FRESHNESS_TIMER: u64 = 60;
49 const FRESHNESS_TIMER: u64 = 1;
51 /// Trait which handles persisting a [`ChannelManager`] to disk.
53 /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
54 pub trait ChannelManagerPersister<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
56 M::Target: 'static + chain::Watch<Signer>,
57 T::Target: 'static + BroadcasterInterface,
58 K::Target: 'static + KeysInterface<Signer = Signer>,
59 F::Target: 'static + FeeEstimator,
60 L::Target: 'static + Logger,
62 /// Persist the given [`ChannelManager`] to disk, returning an error if persistence failed
63 /// (which will cause the [`BackgroundProcessor`] which called this method to exit.
65 /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
66 fn persist_manager(&self, channel_manager: &ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error>;
69 impl<Fun, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
70 ChannelManagerPersister<Signer, M, T, K, F, L> for Fun where
71 M::Target: 'static + chain::Watch<Signer>,
72 T::Target: 'static + BroadcasterInterface,
73 K::Target: 'static + KeysInterface<Signer = Signer>,
74 F::Target: 'static + FeeEstimator,
75 L::Target: 'static + Logger,
76 Fun: Fn(&ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error>,
78 fn persist_manager(&self, channel_manager: &ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error> {
83 impl BackgroundProcessor {
84 /// Start a background thread that takes care of responsibilities enumerated in the top-level
87 /// If `persist_manager` returns an error, then this thread will return said error (and
88 /// `start()` will need to be called again to restart the `BackgroundProcessor`). Users should
89 /// wait on [`thread_handle`]'s `join()` method to be able to tell if and when an error is
90 /// returned, or implement `persist_manager` such that an error is never returned to the
91 /// `BackgroundProcessor`
93 /// `persist_manager` is responsible for writing out the [`ChannelManager`] to disk, and/or
94 /// uploading to one or more backup services. See [`ChannelManager::write`] for writing out a
95 /// [`ChannelManager`]. See [`FilesystemPersister::persist_manager`] for Rust-Lightning's
96 /// provided implementation.
98 /// [`thread_handle`]: BackgroundProcessor::thread_handle
99 /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
100 /// [`ChannelManager::write`]: lightning::ln::channelmanager::ChannelManager#impl-Writeable
101 /// [`FilesystemPersister::persist_manager`]: lightning_persister::FilesystemPersister::persist_manager
103 Signer: 'static + Sign,
104 M: 'static + Deref + Send + Sync,
105 T: 'static + Deref + Send + Sync,
106 K: 'static + Deref + Send + Sync,
107 F: 'static + Deref + Send + Sync,
108 L: 'static + Deref + Send + Sync,
109 Descriptor: 'static + SocketDescriptor + Send + Sync,
110 CMH: 'static + Deref + Send + Sync,
111 RMH: 'static + Deref + Send + Sync,
112 CMP: 'static + Send + ChannelManagerPersister<Signer, M, T, K, F, L>,
113 CM: 'static + Deref<Target = ChannelManager<Signer, M, T, K, F, L>> + Send + Sync,
114 PM: 'static + Deref<Target = PeerManager<Descriptor, CMH, RMH, L>> + Send + Sync,
116 (handler: CMP, channel_manager: CM, peer_manager: PM, logger: L) -> Self
118 M::Target: 'static + chain::Watch<Signer>,
119 T::Target: 'static + BroadcasterInterface,
120 K::Target: 'static + KeysInterface<Signer = Signer>,
121 F::Target: 'static + FeeEstimator,
122 L::Target: 'static + Logger,
123 CMH::Target: 'static + ChannelMessageHandler,
124 RMH::Target: 'static + RoutingMessageHandler,
126 let stop_thread = Arc::new(AtomicBool::new(false));
127 let stop_thread_clone = stop_thread.clone();
128 let handle = thread::spawn(move || -> Result<(), std::io::Error> {
129 let mut current_time = Instant::now();
131 peer_manager.process_events();
132 let updates_available =
133 channel_manager.await_persistable_update_timeout(Duration::from_millis(100));
134 if updates_available {
135 handler.persist_manager(&*channel_manager)?;
137 // Exit the loop if the background processor was requested to stop.
138 if stop_thread.load(Ordering::Acquire) == true {
139 log_trace!(logger, "Terminating background processor.");
142 if current_time.elapsed().as_secs() > FRESHNESS_TIMER {
143 log_trace!(logger, "Calling ChannelManager's and PeerManager's timer_tick_occurred");
144 channel_manager.timer_tick_occurred();
145 peer_manager.timer_tick_occurred();
146 current_time = Instant::now();
150 Self { stop_thread: stop_thread_clone, thread_handle: handle }
153 /// Stop `BackgroundProcessor`'s thread.
154 pub fn stop(self) -> Result<(), std::io::Error> {
155 self.stop_thread.store(true, Ordering::Release);
156 self.thread_handle.join().unwrap()
162 use bitcoin::blockdata::constants::genesis_block;
163 use bitcoin::blockdata::transaction::{Transaction, TxOut};
164 use bitcoin::network::constants::Network;
165 use lightning::chain;
166 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
167 use lightning::chain::chainmonitor;
168 use lightning::chain::keysinterface::{Sign, InMemorySigner, KeysInterface, KeysManager};
169 use lightning::chain::transaction::OutPoint;
170 use lightning::get_event_msg;
171 use lightning::ln::channelmanager::{BestBlock, ChainParameters, ChannelManager, SimpleArcChannelManager};
172 use lightning::ln::features::InitFeatures;
173 use lightning::ln::msgs::ChannelMessageHandler;
174 use lightning::ln::peer_handler::{PeerManager, MessageHandler, SocketDescriptor};
175 use lightning::util::config::UserConfig;
176 use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
177 use lightning::util::logger::Logger;
178 use lightning::util::ser::Writeable;
179 use lightning::util::test_utils;
180 use lightning_persister::FilesystemPersister;
182 use std::path::PathBuf;
183 use std::sync::{Arc, Mutex};
184 use std::time::Duration;
185 use super::BackgroundProcessor;
187 #[derive(Clone, Eq, Hash, PartialEq)]
188 struct TestDescriptor{}
189 impl SocketDescriptor for TestDescriptor {
190 fn send_data(&mut self, _data: &[u8], _resume_read: bool) -> usize {
194 fn disconnect_socket(&mut self) {}
197 type ChainMonitor = chainmonitor::ChainMonitor<InMemorySigner, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
200 node: Arc<SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>>,
201 peer_manager: Arc<PeerManager<TestDescriptor, Arc<test_utils::TestChannelMessageHandler>, Arc<test_utils::TestRoutingMessageHandler>, Arc<test_utils::TestLogger>>>,
202 persister: Arc<FilesystemPersister>,
203 logger: Arc<test_utils::TestLogger>,
208 let data_dir = self.persister.get_data_dir();
209 match fs::remove_dir_all(data_dir.clone()) {
210 Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
216 fn get_full_filepath(filepath: String, filename: String) -> String {
217 let mut path = PathBuf::from(filepath);
219 path.to_str().unwrap().to_string()
222 fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
223 let mut nodes = Vec::new();
224 for i in 0..num_nodes {
225 let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
226 let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
227 let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
228 let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
229 let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
230 let seed = [i as u8; 32];
231 let network = Network::Testnet;
232 let now = Duration::from_secs(genesis_block(network).header.time as u64);
233 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
234 let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
235 let params = ChainParameters {
237 best_block: BestBlock::from_genesis(network),
239 let manager = Arc::new(ChannelManager::new(fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), params));
240 let msg_handler = MessageHandler { chan_handler: Arc::new(test_utils::TestChannelMessageHandler::new()), route_handler: Arc::new(test_utils::TestRoutingMessageHandler::new() )};
241 let peer_manager = Arc::new(PeerManager::new(msg_handler, keys_manager.get_node_secret(), &seed, logger.clone()));
242 let node = Node { node: manager, peer_manager, persister, logger };
248 macro_rules! open_channel {
249 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
250 $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
251 $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
252 $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
253 let events = $node_a.node.get_and_clear_pending_events();
254 assert_eq!(events.len(), 1);
255 let (temporary_channel_id, tx) = match events[0] {
256 Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
257 assert_eq!(*channel_value_satoshis, $channel_value);
258 assert_eq!(user_channel_id, 42);
260 let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
261 value: *channel_value_satoshis, script_pubkey: output_script.clone(),
263 (*temporary_channel_id, tx)
265 _ => panic!("Unexpected event"),
268 $node_a.node.funding_transaction_generated(&temporary_channel_id, tx.clone()).unwrap();
269 $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
270 $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
276 fn test_background_processor() {
277 // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
278 // updates. Also test that when new updates are available, the manager signals that it needs
279 // re-persistence and is successfully re-persisted.
280 let nodes = create_nodes(2, "test_background_processor".to_string());
282 // Initiate the background processors to watch each node.
283 let data_dir = nodes[0].persister.get_data_dir();
284 let callback = move |node: &ChannelManager<InMemorySigner, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
285 let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
287 // Go through the channel creation process until each node should have something persisted.
288 let tx = open_channel!(nodes[0], nodes[1], 100000);
290 macro_rules! check_persisted_data {
291 ($node: expr, $filepath: expr, $expected_bytes: expr) => {
292 match $node.write(&mut $expected_bytes) {
295 match std::fs::read($filepath) {
297 if bytes == $expected_bytes {
307 Err(e) => panic!("Unexpected error: {}", e)
312 // Check that the initial channel manager data is persisted as expected.
313 let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
314 let mut expected_bytes = Vec::new();
315 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
317 if !nodes[0].node.get_persistence_condvar_value() { break }
320 // Force-close the channel.
321 nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
323 // Check that the force-close updates are persisted.
324 let mut expected_bytes = Vec::new();
325 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
327 if !nodes[0].node.get_persistence_condvar_value() { break }
330 assert!(bg_processor.stop().is_ok());
334 fn test_timer_tick_called() {
335 // Test that ChannelManager's and PeerManager's `timer_tick_occurred` is called every
336 // `FRESHNESS_TIMER`.
337 let nodes = create_nodes(1, "test_timer_tick_called".to_string());
338 let data_dir = nodes[0].persister.get_data_dir();
339 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);
340 let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
342 let log_entries = nodes[0].logger.lines.lock().unwrap();
343 let desired_log = "Calling ChannelManager's and PeerManager's timer_tick_occurred".to_string();
344 if log_entries.get(&("lightning_background_processor".to_string(), desired_log)).is_some() {
349 assert!(bg_processor.stop().is_ok());
353 fn test_persist_error() {
354 // Test that if we encounter an error during manager persistence, the thread panics.
355 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>
356 where Signer: 'static + Sign,
357 M: 'static + chain::Watch<Signer>,
358 T: 'static + BroadcasterInterface,
359 K: 'static + KeysInterface<Signer=Signer>,
360 F: 'static + FeeEstimator,
363 Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
366 let nodes = create_nodes(2, "test_persist_error".to_string());
367 let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].peer_manager.clone(), nodes[0].logger.clone());
368 open_channel!(nodes[0], nodes[1], 100000);
370 let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");