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::util::logger::Logger;
17 use std::sync::atomic::{AtomicBool, Ordering};
19 use std::thread::JoinHandle;
20 use std::time::{Duration, Instant};
22 /// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
23 /// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
24 /// responsibilities are:
25 /// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
26 /// writing it to disk/backups by invoking the callback given to it at startup.
27 /// ChannelManager persistence should be done in the background.
28 /// * Calling `ChannelManager::timer_chan_freshness_every_min()` every minute (can be done in the
31 /// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
32 /// then there is a risk of channels force-closing on startup when the manager realizes it's
33 /// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
34 /// for unilateral chain closure fees are at risk.
35 pub struct BackgroundProcessor {
36 stop_thread: Arc<AtomicBool>,
37 /// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
38 /// exits due to an error while persisting.
39 pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
43 const CHAN_FRESHNESS_TIMER: u64 = 60;
45 const CHAN_FRESHNESS_TIMER: u64 = 1;
47 impl BackgroundProcessor {
48 /// Start a background thread that takes care of responsibilities enumerated in the top-level
51 /// If `persist_manager` returns an error, then this thread will return said error (and `start()`
52 /// will need to be called again to restart the `BackgroundProcessor`). Users should wait on
53 /// [`thread_handle`]'s `join()` method to be able to tell if and when an error is returned, or
54 /// implement `persist_manager` such that an error is never returned to the `BackgroundProcessor`
56 /// `persist_manager` is responsible for writing out the `ChannelManager` to disk, and/or uploading
57 /// to one or more backup services. See [`ChannelManager::write`] for writing out a `ChannelManager`.
58 /// See [`FilesystemPersister::persist_manager`] for Rust-Lightning's provided implementation.
60 /// [`thread_handle`]: struct.BackgroundProcessor.html#structfield.thread_handle
61 /// [`ChannelManager::write`]: ../lightning/ln/channelmanager/struct.ChannelManager.html#method.write
62 /// [`FilesystemPersister::persist_manager`]: ../lightning_persister/struct.FilesystemPersister.html#impl
63 pub fn start<PM, Signer, M, T, K, F, L>(persist_manager: PM, manager: Arc<ChannelManager<Signer, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>, logger: Arc<L>) -> Self
64 where Signer: 'static + Sign,
65 M: 'static + chain::Watch<Signer>,
66 T: 'static + BroadcasterInterface,
67 K: 'static + KeysInterface<Signer=Signer>,
68 F: 'static + FeeEstimator,
70 PM: 'static + Send + Fn(&ChannelManager<Signer, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>,
72 let stop_thread = Arc::new(AtomicBool::new(false));
73 let stop_thread_clone = stop_thread.clone();
74 let handle = thread::spawn(move || -> Result<(), std::io::Error> {
75 let mut current_time = Instant::now();
77 let updates_available = manager.await_persistable_update_timeout(Duration::from_millis(100));
78 if updates_available {
79 persist_manager(&*manager)?;
81 // Exit the loop if the background processor was requested to stop.
82 if stop_thread.load(Ordering::Acquire) == true {
83 log_trace!(logger, "Terminating background processor.");
86 if current_time.elapsed().as_secs() > CHAN_FRESHNESS_TIMER {
87 log_trace!(logger, "Calling manager's timer_chan_freshness_every_min");
88 manager.timer_chan_freshness_every_min();
89 current_time = Instant::now();
94 stop_thread: stop_thread_clone,
95 thread_handle: handle,
99 /// Stop `BackgroundProcessor`'s thread.
100 pub fn stop(self) -> Result<(), std::io::Error> {
101 self.stop_thread.store(true, Ordering::Release);
102 self.thread_handle.join().unwrap()
108 use bitcoin::blockdata::constants::genesis_block;
109 use bitcoin::blockdata::transaction::{Transaction, TxOut};
110 use bitcoin::network::constants::Network;
111 use lightning::chain;
112 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
113 use lightning::chain::chainmonitor;
114 use lightning::chain::keysinterface::{Sign, InMemorySigner, KeysInterface, KeysManager};
115 use lightning::chain::transaction::OutPoint;
116 use lightning::get_event_msg;
117 use lightning::ln::channelmanager::{ChainParameters, ChannelManager, SimpleArcChannelManager};
118 use lightning::ln::features::InitFeatures;
119 use lightning::ln::msgs::ChannelMessageHandler;
120 use lightning::util::config::UserConfig;
121 use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
122 use lightning::util::logger::Logger;
123 use lightning::util::ser::Writeable;
124 use lightning::util::test_utils;
125 use lightning_persister::FilesystemPersister;
127 use std::path::PathBuf;
128 use std::sync::{Arc, Mutex};
129 use std::time::Duration;
130 use super::BackgroundProcessor;
132 type ChainMonitor = chainmonitor::ChainMonitor<InMemorySigner, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
135 node: Arc<SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>>,
136 persister: Arc<FilesystemPersister>,
137 logger: Arc<test_utils::TestLogger>,
142 let data_dir = self.persister.get_data_dir();
143 match fs::remove_dir_all(data_dir.clone()) {
144 Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
150 fn get_full_filepath(filepath: String, filename: String) -> String {
151 let mut path = PathBuf::from(filepath);
153 path.to_str().unwrap().to_string()
156 fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
157 let mut nodes = Vec::new();
158 for i in 0..num_nodes {
159 let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
160 let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
161 let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
162 let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
163 let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
164 let seed = [i as u8; 32];
165 let network = Network::Testnet;
166 let genesis_block = genesis_block(network);
167 let now = Duration::from_secs(genesis_block.header.time as u64);
168 let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
169 let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
170 let params = ChainParameters {
172 latest_hash: genesis_block.block_hash(),
175 let manager = Arc::new(ChannelManager::new(fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), params));
176 let node = Node { node: manager, persister, logger };
182 macro_rules! open_channel {
183 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
184 $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
185 $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
186 $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
187 let events = $node_a.node.get_and_clear_pending_events();
188 assert_eq!(events.len(), 1);
189 let (temporary_channel_id, tx, funding_output) = match events[0] {
190 Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
191 assert_eq!(*channel_value_satoshis, $channel_value);
192 assert_eq!(user_channel_id, 42);
194 let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
195 value: *channel_value_satoshis, script_pubkey: output_script.clone(),
197 let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
198 (*temporary_channel_id, tx, funding_outpoint)
200 _ => panic!("Unexpected event"),
203 $node_a.node.funding_transaction_generated(&temporary_channel_id, funding_output);
204 $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
205 $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
211 fn test_background_processor() {
212 // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
213 // updates. Also test that when new updates are available, the manager signals that it needs
214 // re-persistence and is successfully re-persisted.
215 let nodes = create_nodes(2, "test_background_processor".to_string());
217 // Initiate the background processors to watch each node.
218 let data_dir = nodes[0].persister.get_data_dir();
219 let callback = move |node: &ChannelManager<InMemorySigner, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
220 let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
222 // Go through the channel creation process until each node should have something persisted.
223 let tx = open_channel!(nodes[0], nodes[1], 100000);
225 macro_rules! check_persisted_data {
226 ($node: expr, $filepath: expr, $expected_bytes: expr) => {
227 match $node.write(&mut $expected_bytes) {
230 match std::fs::read($filepath) {
232 if bytes == $expected_bytes {
242 Err(e) => panic!("Unexpected error: {}", e)
247 // Check that the initial channel manager data is persisted as expected.
248 let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
249 let mut expected_bytes = Vec::new();
250 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
252 if !nodes[0].node.get_persistence_condvar_value() { break }
255 // Force-close the channel.
256 nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
258 // Check that the force-close updates are persisted.
259 let mut expected_bytes = Vec::new();
260 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
262 if !nodes[0].node.get_persistence_condvar_value() { break }
265 assert!(bg_processor.stop().is_ok());
269 fn test_chan_freshness_called() {
270 // Test that ChannelManager's `timer_chan_freshness_every_min` is called every
271 // `CHAN_FRESHNESS_TIMER`.
272 let nodes = create_nodes(1, "test_chan_freshness_called".to_string());
273 let data_dir = nodes[0].persister.get_data_dir();
274 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);
275 let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
277 let log_entries = nodes[0].logger.lines.lock().unwrap();
278 let desired_log = "Calling manager's timer_chan_freshness_every_min".to_string();
279 if log_entries.get(&("lightning_background_processor".to_string(), desired_log)).is_some() {
284 assert!(bg_processor.stop().is_ok());
288 fn test_persist_error() {
289 // Test that if we encounter an error during manager persistence, the thread panics.
290 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>
291 where Signer: 'static + Sign,
292 M: 'static + chain::Watch<Signer>,
293 T: 'static + BroadcasterInterface,
294 K: 'static + KeysInterface<Signer=Signer>,
295 F: 'static + FeeEstimator,
298 Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
301 let nodes = create_nodes(2, "test_persist_error".to_string());
302 let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].logger.clone());
303 open_channel!(nodes[0], nodes[1], 100000);
305 let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");