_ Git - rust-lightning/blob - lightning-background-processor/src/lib.rs

   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.
   4
   5 #![deny(broken_intra_doc_links)]
   6 #![deny(missing_docs)]
   7 #![deny(unsafe_code)]
   8
   9 #[macro_use] extern crate lightning;
  10
  11 use lightning::chain;
  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;
  21 use std::sync::Arc;
  22 use std::sync::atomic::{AtomicBool, Ordering};
  23 use std::thread;
  24 use std::thread::JoinHandle;
  25 use std::time::{Duration, Instant};
  26 use std::ops::Deref;
  27
  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
  36 ///   background).
  37 ///
  38 /// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,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  40 /// outdated.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         thread_handle: Option<JoinHandle<Result<(), std::io::Error>>>,
  45 }
  46
  47 #[cfg(not(test))]
  48 const FRESHNESS_TIMER: u64 = 60;
  49 #[cfg(test)]
  50 const FRESHNESS_TIMER: u64 = 1;
  51
  52 const PING_TIMER: u64 = 5;
  53
  54 /// Trait which handles persisting a [`ChannelManager`] to disk.
  55 ///
  56 /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
  57 pub trait ChannelManagerPersister<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
  58 where
  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,
  64 {
  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.
  67         ///
  68         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
  69         fn persist_manager(&self, channel_manager: &ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error>;
  70 }
  71
  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>,
  80 {
  81         fn persist_manager(&self, channel_manager: &ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error> {
  82                 self(channel_manager)
  83         }
  84 }
  85
  86 impl BackgroundProcessor {
  87         /// Start a background thread that takes care of responsibilities enumerated in the [top-level
  88         /// documentation].
  89         ///
  90         /// The thread runs indefinitely unless the object is dropped, [`stop`] is called, or
  91         /// `persist_manager` returns an error. In case of an error, the error is retrieved by calling
  92         /// either [`join`] or [`stop`].
  93         ///
  94         /// Typically, users should either implement [`ChannelManagerPersister`] to never return an
  95         /// error or call [`join`] and handle any error that may arise. For the latter case, the
  96         /// `BackgroundProcessor` must be restarted by calling `start` again after handling the error.
  97         ///
  98         /// `persist_manager` is responsible for writing out the [`ChannelManager`] to disk, and/or
  99         /// uploading to one or more backup services. See [`ChannelManager::write`] for writing out a
 100         /// [`ChannelManager`]. See [`FilesystemPersister::persist_manager`] for Rust-Lightning's
 101         /// provided implementation.
 102         ///
 103         /// [top-level documentation]: Self
 104         /// [`join`]: Self::join
 105         /// [`stop`]: Self::stop
 106         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 107         /// [`ChannelManager::write`]: lightning::ln::channelmanager::ChannelManager#impl-Writeable
 108         /// [`FilesystemPersister::persist_manager`]: lightning_persister::FilesystemPersister::persist_manager
 109         pub fn start<
 110                 Signer: 'static + Sign,
 111                 CF: 'static + Deref + Send + Sync,
 112                 CW: 'static + Deref + Send + Sync,
 113                 T: 'static + Deref + Send + Sync,
 114                 K: 'static + Deref + Send + Sync,
 115                 F: 'static + Deref + Send + Sync,
 116                 L: 'static + Deref + Send + Sync,
 117                 P: 'static + Deref + Send + Sync,
 118                 Descriptor: 'static + SocketDescriptor + Send + Sync,
 119                 CMH: 'static + Deref + Send + Sync,
 120                 RMH: 'static + Deref + Send + Sync,
 121                 EH: 'static + EventHandler + Send + Sync,
 122                 CMP: 'static + Send + ChannelManagerPersister<Signer, CW, T, K, F, L>,
 123                 M: 'static + Deref<Target = ChainMonitor<Signer, CF, T, F, L, P>> + Send + Sync,
 124                 CM: 'static + Deref<Target = ChannelManager<Signer, CW, T, K, F, L>> + Send + Sync,
 125                 PM: 'static + Deref<Target = PeerManager<Descriptor, CMH, RMH, L>> + Send + Sync,
 126         >
 127         (persister: CMP, event_handler: EH, chain_monitor: M, channel_manager: CM, peer_manager: PM, logger: L) -> Self
 128         where
 129                 CF::Target: 'static + chain::Filter,
 130                 CW::Target: 'static + chain::Watch<Signer>,
 131                 T::Target: 'static + BroadcasterInterface,
 132                 K::Target: 'static + KeysInterface<Signer = Signer>,
 133                 F::Target: 'static + FeeEstimator,
 134                 L::Target: 'static + Logger,
 135                 P::Target: 'static + channelmonitor::Persist<Signer>,
 136                 CMH::Target: 'static + ChannelMessageHandler,
 137                 RMH::Target: 'static + RoutingMessageHandler,
 138         {
 139                 let stop_thread = Arc::new(AtomicBool::new(false));
 140                 let stop_thread_clone = stop_thread.clone();
 141                 let handle = thread::spawn(move || -> Result<(), std::io::Error> {
 142                         let mut last_freshness_call = Instant::now();
 143                         let mut last_ping_call = Instant::now();
 144                         loop {
 145                                 peer_manager.process_events();
 146                                 channel_manager.process_pending_events(&event_handler);
 147                                 chain_monitor.process_pending_events(&event_handler);
 148                                 let updates_available =
 149                                         channel_manager.await_persistable_update_timeout(Duration::from_millis(100));
 150                                 if updates_available {
 151                                         persister.persist_manager(&*channel_manager)?;
 152                                 }
 153                                 // Exit the loop if the background processor was requested to stop.
 154                                 if stop_thread.load(Ordering::Acquire) == true {
 155                                         log_trace!(logger, "Terminating background processor.");
 156                                         return Ok(());
 157                                 }
 158                                 if last_freshness_call.elapsed().as_secs() > FRESHNESS_TIMER {
 159                                         log_trace!(logger, "Calling ChannelManager's timer_tick_occurred");
 160                                         channel_manager.timer_tick_occurred();
 161                                         last_freshness_call = Instant::now();
 162                                 }
 163                                 if last_ping_call.elapsed().as_secs() > PING_TIMER {
 164                                         log_trace!(logger, "Calling PeerManager's timer_tick_occurred");
 165                                         peer_manager.timer_tick_occurred();
 166                                         last_ping_call = Instant::now();
 167                                 }
 168                         }
 169                 });
 170                 Self { stop_thread: stop_thread_clone, thread_handle: Some(handle) }
 171         }
 172
 173         /// Join `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 174         /// [`ChannelManager`].
 175         ///
 176         /// # Panics
 177         ///
 178         /// This function panics if the background thread has panicked such as while persisting or
 179         /// handling events.
 180         ///
 181         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 182         pub fn join(mut self) -> Result<(), std::io::Error> {
 183                 assert!(self.thread_handle.is_some());
 184                 self.join_thread()
 185         }
 186
 187         /// Stop `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 188         /// [`ChannelManager`].
 189         ///
 190         /// # Panics
 191         ///
 192         /// This function panics if the background thread has panicked such as while persisting or
 193         /// handling events.
 194         ///
 195         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 196         pub fn stop(mut self) -> Result<(), std::io::Error> {
 197                 assert!(self.thread_handle.is_some());
 198                 self.stop_and_join_thread()
 199         }
 200
 201         fn stop_and_join_thread(&mut self) -> Result<(), std::io::Error> {
 202                 self.stop_thread.store(true, Ordering::Release);
 203                 self.join_thread()
 204         }
 205
 206         fn join_thread(&mut self) -> Result<(), std::io::Error> {
 207                 match self.thread_handle.take() {
 208                         Some(handle) => handle.join().unwrap(),
 209                         None => Ok(()),
 210                 }
 211         }
 212 }
 213
 214 impl Drop for BackgroundProcessor {
 215         fn drop(&mut self) {
 216                 self.stop_and_join_thread().unwrap();
 217         }
 218 }
 219
 220 #[cfg(test)]
 221 mod tests {
 222         use bitcoin::blockdata::block::BlockHeader;
 223         use bitcoin::blockdata::constants::genesis_block;
 224         use bitcoin::blockdata::transaction::{Transaction, TxOut};
 225         use bitcoin::network::constants::Network;
 226         use lightning::chain::{BestBlock, Confirm, chainmonitor};
 227         use lightning::chain::channelmonitor::ANTI_REORG_DELAY;
 228         use lightning::chain::keysinterface::{InMemorySigner, KeysInterface, KeysManager};
 229         use lightning::chain::transaction::OutPoint;
 230         use lightning::get_event_msg;
 231         use lightning::ln::channelmanager::{BREAKDOWN_TIMEOUT, ChainParameters, ChannelManager, SimpleArcChannelManager};
 232         use lightning::ln::features::InitFeatures;
 233         use lightning::ln::msgs::ChannelMessageHandler;
 234         use lightning::ln::peer_handler::{PeerManager, MessageHandler, SocketDescriptor};
 235         use lightning::util::config::UserConfig;
 236         use lightning::util::events::{Event, MessageSendEventsProvider, MessageSendEvent};
 237         use lightning::util::ser::Writeable;
 238         use lightning::util::test_utils;
 239         use lightning_persister::FilesystemPersister;
 240         use std::fs;
 241         use std::path::PathBuf;
 242         use std::sync::{Arc, Mutex};
 243         use std::time::Duration;
 244         use super::{BackgroundProcessor, FRESHNESS_TIMER};
 245
 246         const EVENT_DEADLINE: u64 = 5 * FRESHNESS_TIMER;
 247
 248         #[derive(Clone, Eq, Hash, PartialEq)]
 249         struct TestDescriptor{}
 250         impl SocketDescriptor for TestDescriptor {
 251                 fn send_data(&mut self, _data: &[u8], _resume_read: bool) -> usize {
 252                         0
 253                 }
 254
 255                 fn disconnect_socket(&mut self) {}
 256         }
 257
 258         type ChainMonitor = chainmonitor::ChainMonitor<InMemorySigner, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
 259
 260         struct Node {
 261                 node: Arc<SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>>,
 262                 peer_manager: Arc<PeerManager<TestDescriptor, Arc<test_utils::TestChannelMessageHandler>, Arc<test_utils::TestRoutingMessageHandler>, Arc<test_utils::TestLogger>>>,
 263                 chain_monitor: Arc<ChainMonitor>,
 264                 persister: Arc<FilesystemPersister>,
 265                 tx_broadcaster: Arc<test_utils::TestBroadcaster>,
 266                 logger: Arc<test_utils::TestLogger>,
 267                 best_block: BestBlock,
 268         }
 269
 270         impl Drop for Node {
 271                 fn drop(&mut self) {
 272                         let data_dir = self.persister.get_data_dir();
 273                         match fs::remove_dir_all(data_dir.clone()) {
 274                                 Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
 275                                 _ => {}
 276                         }
 277                 }
 278         }
 279
 280         fn get_full_filepath(filepath: String, filename: String) -> String {
 281                 let mut path = PathBuf::from(filepath);
 282                 path.push(filename);
 283                 path.to_str().unwrap().to_string()
 284         }
 285
 286         fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
 287                 let mut nodes = Vec::new();
 288                 for i in 0..num_nodes {
 289                         let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new()), blocks: Arc::new(Mutex::new(Vec::new()))});
 290                         let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: Mutex::new(253) });
 291                         let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
 292                         let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
 293                         let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
 294                         let seed = [i as u8; 32];
 295                         let network = Network::Testnet;
 296                         let now = Duration::from_secs(genesis_block(network).header.time as u64);
 297                         let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
 298                         let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
 299                         let best_block = BestBlock::from_genesis(network);
 300                         let params = ChainParameters { network, best_block };
 301                         let manager = Arc::new(ChannelManager::new(fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster.clone(), logger.clone(), keys_manager.clone(), UserConfig::default(), params));
 302                         let msg_handler = MessageHandler { chan_handler: Arc::new(test_utils::TestChannelMessageHandler::new()), route_handler: Arc::new(test_utils::TestRoutingMessageHandler::new() )};
 303                         let peer_manager = Arc::new(PeerManager::new(msg_handler, keys_manager.get_node_secret(), &seed, logger.clone()));
 304                         let node = Node { node: manager, peer_manager, chain_monitor, persister, tx_broadcaster, logger, best_block };
 305                         nodes.push(node);
 306                 }
 307                 nodes
 308         }
 309
 310         macro_rules! open_channel {
 311                 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
 312                         begin_open_channel!($node_a, $node_b, $channel_value);
 313                         let events = $node_a.node.get_and_clear_pending_events();
 314                         assert_eq!(events.len(), 1);
 315                         let (temporary_channel_id, tx) = handle_funding_generation_ready!(events[0], $channel_value);
 316                         end_open_channel!($node_a, $node_b, temporary_channel_id, tx);
 317                         tx
 318                 }}
 319         }
 320
 321         macro_rules! begin_open_channel {
 322                 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
 323                         $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
 324                         $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
 325                         $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
 326                 }}
 327         }
 328
 329         macro_rules! handle_funding_generation_ready {
 330                 ($event: expr, $channel_value: expr) => {{
 331                         match $event {
 332                                 Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
 333                                         assert_eq!(*channel_value_satoshis, $channel_value);
 334                                         assert_eq!(user_channel_id, 42);
 335
 336                                         let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
 337                                                 value: *channel_value_satoshis, script_pubkey: output_script.clone(),
 338                                         }]};
 339                                         (*temporary_channel_id, tx)
 340                                 },
 341                                 _ => panic!("Unexpected event"),
 342                         }
 343                 }}
 344         }
 345
 346         macro_rules! end_open_channel {
 347                 ($node_a: expr, $node_b: expr, $temporary_channel_id: expr, $tx: expr) => {{
 348                         $node_a.node.funding_transaction_generated(&$temporary_channel_id, $tx.clone()).unwrap();
 349                         $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
 350                         $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
 351                 }}
 352         }
 353
 354         fn confirm_transaction_depth(node: &mut Node, tx: &Transaction, depth: u32) {
 355                 for i in 1..=depth {
 356                         let prev_blockhash = node.best_block.block_hash();
 357                         let height = node.best_block.height() + 1;
 358                         let header = BlockHeader { version: 0x20000000, prev_blockhash, merkle_root: Default::default(), time: height, bits: 42, nonce: 42 };
 359                         let txdata = vec![(0, tx)];
 360                         node.best_block = BestBlock::new(header.block_hash(), height);
 361                         match i {
 362                                 1 => {
 363                                         node.node.transactions_confirmed(&header, &txdata, height);
 364                                         node.chain_monitor.transactions_confirmed(&header, &txdata, height);
 365                                 },
 366                                 x if x == depth => {
 367                                         node.node.best_block_updated(&header, height);
 368                                         node.chain_monitor.best_block_updated(&header, height);
 369                                 },
 370                                 _ => {},
 371                         }
 372                 }
 373         }
 374         fn confirm_transaction(node: &mut Node, tx: &Transaction) {
 375                 confirm_transaction_depth(node, tx, ANTI_REORG_DELAY);
 376         }
 377
 378         #[test]
 379         fn test_background_processor() {
 380                 // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
 381                 // updates. Also test that when new updates are available, the manager signals that it needs
 382                 // re-persistence and is successfully re-persisted.
 383                 let nodes = create_nodes(2, "test_background_processor".to_string());
 384
 385                 // Go through the channel creation process so that each node has something to persist. Since
 386                 // open_channel consumes events, it must complete before starting BackgroundProcessor to
 387                 // avoid a race with processing events.
 388                 let tx = open_channel!(nodes[0], nodes[1], 100000);
 389
 390                 // Initiate the background processors to watch each node.
 391                 let data_dir = nodes[0].persister.get_data_dir();
 392                 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);
 393                 let event_handler = |_| {};
 394                 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());
 395
 396                 macro_rules! check_persisted_data {
 397                         ($node: expr, $filepath: expr, $expected_bytes: expr) => {
 398                                 match $node.write(&mut $expected_bytes) {
 399                                         Ok(()) => {
 400                                                 loop {
 401                                                         match std::fs::read($filepath) {
 402                                                                 Ok(bytes) => {
 403                                                                         if bytes == $expected_bytes {
 404                                                                                 break
 405                                                                         } else {
 406                                                                                 continue
 407                                                                         }
 408                                                                 },
 409                                                                 Err(_) => continue
 410                                                         }
 411                                                 }
 412                                         },
 413                                         Err(e) => panic!("Unexpected error: {}", e)
 414                                 }
 415                         }
 416                 }
 417
 418                 // Check that the initial channel manager data is persisted as expected.
 419                 let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
 420                 let mut expected_bytes = Vec::new();
 421                 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
 422                 loop {
 423                         if !nodes[0].node.get_persistence_condvar_value() { break }
 424                 }
 425
 426                 // Force-close the channel.
 427                 nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
 428
 429                 // Check that the force-close updates are persisted.
 430                 let mut expected_bytes = Vec::new();
 431                 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
 432                 loop {
 433                         if !nodes[0].node.get_persistence_condvar_value() { break }
 434                 }
 435
 436                 assert!(bg_processor.stop().is_ok());
 437         }
 438
 439         #[test]
 440         fn test_timer_tick_called() {
 441                 // Test that ChannelManager's and PeerManager's `timer_tick_occurred` is called every
 442                 // `FRESHNESS_TIMER`.
 443                 let nodes = create_nodes(1, "test_timer_tick_called".to_string());
 444                 let data_dir = nodes[0].persister.get_data_dir();
 445                 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);
 446                 let event_handler = |_| {};
 447                 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());
 448                 loop {
 449                         let log_entries = nodes[0].logger.lines.lock().unwrap();
 450                         let desired_log = "Calling ChannelManager's timer_tick_occurred".to_string();
 451                         let second_desired_log = "Calling PeerManager's timer_tick_occurred".to_string();
 452                         if log_entries.get(&("lightning_background_processor".to_string(), desired_log)).is_some() &&
 453                                         log_entries.get(&("lightning_background_processor".to_string(), second_desired_log)).is_some() {
 454                                 break
 455                         }
 456                 }
 457
 458                 assert!(bg_processor.stop().is_ok());
 459         }
 460
 461         #[test]
 462         fn test_persist_error() {
 463                 // Test that if we encounter an error during manager persistence, the thread panics.
 464                 let nodes = create_nodes(2, "test_persist_error".to_string());
 465                 open_channel!(nodes[0], nodes[1], 100000);
 466
 467                 let persister = |_: &_| Err(std::io::Error::new(std::io::ErrorKind::Other, "test"));
 468                 let event_handler = |_| {};
 469                 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());
 470                 match bg_processor.join() {
 471                         Ok(_) => panic!("Expected error persisting manager"),
 472                         Err(e) => {
 473                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 474                                 assert_eq!(e.get_ref().unwrap().to_string(), "test");
 475                         },
 476                 }
 477         }
 478
 479         #[test]
 480         fn test_background_event_handling() {
 481                 let mut nodes = create_nodes(2, "test_background_event_handling".to_string());
 482                 let channel_value = 100000;
 483                 let data_dir = nodes[0].persister.get_data_dir();
 484                 let persister = move |node: &_| FilesystemPersister::persist_manager(data_dir.clone(), node);
 485
 486                 // Set up a background event handler for FundingGenerationReady events.
 487                 let (sender, receiver) = std::sync::mpsc::sync_channel(1);
 488                 let event_handler = move |event| {
 489                         sender.send(handle_funding_generation_ready!(event, channel_value)).unwrap();
 490                 };
 491                 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());
 492
 493                 // Open a channel and check that the FundingGenerationReady event was handled.
 494                 begin_open_channel!(nodes[0], nodes[1], channel_value);
 495                 let (temporary_channel_id, funding_tx) = receiver
 496                         .recv_timeout(Duration::from_secs(EVENT_DEADLINE))
 497                         .expect("FundingGenerationReady not handled within deadline");
 498                 end_open_channel!(nodes[0], nodes[1], temporary_channel_id, funding_tx);
 499
 500                 // Confirm the funding transaction.
 501                 confirm_transaction(&mut nodes[0], &funding_tx);
 502                 let as_funding = get_event_msg!(nodes[0], MessageSendEvent::SendFundingLocked, nodes[1].node.get_our_node_id());
 503                 confirm_transaction(&mut nodes[1], &funding_tx);
 504                 let bs_funding = get_event_msg!(nodes[1], MessageSendEvent::SendFundingLocked, nodes[0].node.get_our_node_id());
 505                 nodes[0].node.handle_funding_locked(&nodes[1].node.get_our_node_id(), &bs_funding);
 506                 let _as_channel_update = get_event_msg!(nodes[0], MessageSendEvent::SendChannelUpdate, nodes[1].node.get_our_node_id());
 507                 nodes[1].node.handle_funding_locked(&nodes[0].node.get_our_node_id(), &as_funding);
 508                 let _bs_channel_update = get_event_msg!(nodes[1], MessageSendEvent::SendChannelUpdate, nodes[0].node.get_our_node_id());
 509
 510                 assert!(bg_processor.stop().is_ok());
 511
 512                 // Set up a background event handler for SpendableOutputs events.
 513                 let (sender, receiver) = std::sync::mpsc::sync_channel(1);
 514                 let event_handler = move |event| sender.send(event).unwrap();
 515                 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());
 516
 517                 // Force close the channel and check that the SpendableOutputs event was handled.
 518                 nodes[0].node.force_close_channel(&nodes[0].node.list_channels()[0].channel_id).unwrap();
 519                 let commitment_tx = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().pop().unwrap();
 520                 confirm_transaction_depth(&mut nodes[0], &commitment_tx, BREAKDOWN_TIMEOUT as u32);
 521                 let event = receiver
 522                         .recv_timeout(Duration::from_secs(EVENT_DEADLINE))
 523                         .expect("SpendableOutputs not handled within deadline");
 524                 match event {
 525                         Event::SpendableOutputs { .. } => {},
 526                         _ => panic!("Unexpected event: {:?}", event),
 527                 }
 528
 529                 assert!(bg_processor.stop().is_ok());
 530         }
 531 }