_ 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  38 /// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,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  40 /// outdated.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 #[must_use = "BackgroundProcessor will immediately stop on drop. It should be stored until shutdown."]
  43 pub struct BackgroundProcessor {
  44         stop_thread: Arc<AtomicBool>,
  45         thread_handle: Option<JoinHandle<Result<(), std::io::Error>>>,
  46 }
  47
  48 #[cfg(not(test))]
  49 const FRESHNESS_TIMER: u64 = 60;
  50 #[cfg(test)]
  51 const FRESHNESS_TIMER: u64 = 1;
  52
  53 #[cfg(not(debug_assertions))]
  54 const PING_TIMER: u64 = 5;
  55 /// Signature operations take a lot longer without compiler optimisations.
  56 /// Increasing the ping timer allows for this but slower devices will be disconnected if the
  57 /// timeout is reached.
  58 #[cfg(debug_assertions)]
  59 const PING_TIMER: u64 = 30;
  60
  61 /// Trait which handles persisting a [`ChannelManager`] to disk.
  62 ///
  63 /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
  64 pub trait ChannelManagerPersister<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
  65 where
  66         M::Target: 'static + chain::Watch<Signer>,
  67         T::Target: 'static + BroadcasterInterface,
  68         K::Target: 'static + KeysInterface<Signer = Signer>,
  69         F::Target: 'static + FeeEstimator,
  70         L::Target: 'static + Logger,
  71 {
  72         /// Persist the given [`ChannelManager`] to disk, returning an error if persistence failed
  73         /// (which will cause the [`BackgroundProcessor`] which called this method to exit.
  74         ///
  75         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
  76         fn persist_manager(&self, channel_manager: &ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error>;
  77 }
  78
  79 impl<Fun, Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
  80 ChannelManagerPersister<Signer, M, T, K, F, L> for Fun where
  81         M::Target: 'static + chain::Watch<Signer>,
  82         T::Target: 'static + BroadcasterInterface,
  83         K::Target: 'static + KeysInterface<Signer = Signer>,
  84         F::Target: 'static + FeeEstimator,
  85         L::Target: 'static + Logger,
  86         Fun: Fn(&ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error>,
  87 {
  88         fn persist_manager(&self, channel_manager: &ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error> {
  89                 self(channel_manager)
  90         }
  91 }
  92
  93 impl BackgroundProcessor {
  94         /// Start a background thread that takes care of responsibilities enumerated in the [top-level
  95         /// documentation].
  96         ///
  97         /// The thread runs indefinitely unless the object is dropped, [`stop`] is called, or
  98         /// `persist_manager` returns an error. In case of an error, the error is retrieved by calling
  99         /// either [`join`] or [`stop`].
 100         ///
 101         /// Typically, users should either implement [`ChannelManagerPersister`] to never return an
 102         /// error or call [`join`] and handle any error that may arise. For the latter case, the
 103         /// `BackgroundProcessor` must be restarted by calling `start` again after handling the error.
 104         ///
 105         /// `persist_manager` is responsible for writing out the [`ChannelManager`] to disk, and/or
 106         /// uploading to one or more backup services. See [`ChannelManager::write`] for writing out a
 107         /// [`ChannelManager`]. See [`FilesystemPersister::persist_manager`] for Rust-Lightning's
 108         /// provided implementation.
 109         ///
 110         /// [top-level documentation]: Self
 111         /// [`join`]: Self::join
 112         /// [`stop`]: Self::stop
 113         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 114         /// [`ChannelManager::write`]: lightning::ln::channelmanager::ChannelManager#impl-Writeable
 115         /// [`FilesystemPersister::persist_manager`]: lightning_persister::FilesystemPersister::persist_manager
 116         pub fn start<
 117                 Signer: 'static + Sign,
 118                 CF: 'static + Deref + Send + Sync,
 119                 CW: 'static + Deref + Send + Sync,
 120                 T: 'static + Deref + Send + Sync,
 121                 K: 'static + Deref + Send + Sync,
 122                 F: 'static + Deref + Send + Sync,
 123                 L: 'static + Deref + Send + Sync,
 124                 P: 'static + Deref + Send + Sync,
 125                 Descriptor: 'static + SocketDescriptor + Send + Sync,
 126                 CMH: 'static + Deref + Send + Sync,
 127                 RMH: 'static + Deref + Send + Sync,
 128                 EH: 'static + EventHandler + Send + Sync,
 129                 CMP: 'static + Send + ChannelManagerPersister<Signer, CW, T, K, F, L>,
 130                 M: 'static + Deref<Target = ChainMonitor<Signer, CF, T, F, L, P>> + Send + Sync,
 131                 CM: 'static + Deref<Target = ChannelManager<Signer, CW, T, K, F, L>> + Send + Sync,
 132                 PM: 'static + Deref<Target = PeerManager<Descriptor, CMH, RMH, L>> + Send + Sync,
 133         >
 134         (persister: CMP, event_handler: EH, chain_monitor: M, channel_manager: CM, peer_manager: PM, logger: L) -> Self
 135         where
 136                 CF::Target: 'static + chain::Filter,
 137                 CW::Target: 'static + chain::Watch<Signer>,
 138                 T::Target: 'static + BroadcasterInterface,
 139                 K::Target: 'static + KeysInterface<Signer = Signer>,
 140                 F::Target: 'static + FeeEstimator,
 141                 L::Target: 'static + Logger,
 142                 P::Target: 'static + channelmonitor::Persist<Signer>,
 143                 CMH::Target: 'static + ChannelMessageHandler,
 144                 RMH::Target: 'static + RoutingMessageHandler,
 145         {
 146                 let stop_thread = Arc::new(AtomicBool::new(false));
 147                 let stop_thread_clone = stop_thread.clone();
 148                 let handle = thread::spawn(move || -> Result<(), std::io::Error> {
 149                         log_trace!(logger, "Calling ChannelManager's timer_tick_occurred on startup");
 150                         channel_manager.timer_tick_occurred();
 151
 152                         let mut last_freshness_call = Instant::now();
 153                         let mut last_ping_call = Instant::now();
 154                         loop {
 155                                 peer_manager.process_events();
 156                                 channel_manager.process_pending_events(&event_handler);
 157                                 chain_monitor.process_pending_events(&event_handler);
 158                                 let updates_available =
 159                                         channel_manager.await_persistable_update_timeout(Duration::from_millis(100));
 160                                 if updates_available {
 161                                         persister.persist_manager(&*channel_manager)?;
 162                                 }
 163                                 // Exit the loop if the background processor was requested to stop.
 164                                 if stop_thread.load(Ordering::Acquire) == true {
 165                                         log_trace!(logger, "Terminating background processor.");
 166                                         return Ok(());
 167                                 }
 168                                 if last_freshness_call.elapsed().as_secs() > FRESHNESS_TIMER {
 169                                         log_trace!(logger, "Calling ChannelManager's timer_tick_occurred");
 170                                         channel_manager.timer_tick_occurred();
 171                                         last_freshness_call = Instant::now();
 172                                 }
 173                                 if last_ping_call.elapsed().as_secs() > PING_TIMER * 2 {
 174                                         // On various platforms, we may be starved of CPU cycles for several reasons.
 175                                         // E.g. on iOS, if we've been in the background, we will be entirely paused.
 176                                         // Similarly, if we're on a desktop platform and the device has been asleep, we
 177                                         // may not get any cycles.
 178                                         // In any case, if we've been entirely paused for more than double our ping
 179                                         // timer, we should have disconnected all sockets by now (and they're probably
 180                                         // dead anyway), so disconnect them by calling `timer_tick_occurred()` twice.
 181                                         log_trace!(logger, "Awoke after more than double our ping timer, disconnecting peers.");
 182                                         peer_manager.timer_tick_occurred();
 183                                         peer_manager.timer_tick_occurred();
 184                                         last_ping_call = Instant::now();
 185                                 } else if last_ping_call.elapsed().as_secs() > PING_TIMER {
 186                                         log_trace!(logger, "Calling PeerManager's timer_tick_occurred");
 187                                         peer_manager.timer_tick_occurred();
 188                                         last_ping_call = Instant::now();
 189                                 }
 190                         }
 191                 });
 192                 Self { stop_thread: stop_thread_clone, thread_handle: Some(handle) }
 193         }
 194
 195         /// Join `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 196         /// [`ChannelManager`].
 197         ///
 198         /// # Panics
 199         ///
 200         /// This function panics if the background thread has panicked such as while persisting or
 201         /// handling events.
 202         ///
 203         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 204         pub fn join(mut self) -> Result<(), std::io::Error> {
 205                 assert!(self.thread_handle.is_some());
 206                 self.join_thread()
 207         }
 208
 209         /// Stop `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 210         /// [`ChannelManager`].
 211         ///
 212         /// # Panics
 213         ///
 214         /// This function panics if the background thread has panicked such as while persisting or
 215         /// handling events.
 216         ///
 217         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 218         pub fn stop(mut self) -> Result<(), std::io::Error> {
 219                 assert!(self.thread_handle.is_some());
 220                 self.stop_and_join_thread()
 221         }
 222
 223         fn stop_and_join_thread(&mut self) -> Result<(), std::io::Error> {
 224                 self.stop_thread.store(true, Ordering::Release);
 225                 self.join_thread()
 226         }
 227
 228         fn join_thread(&mut self) -> Result<(), std::io::Error> {
 229                 match self.thread_handle.take() {
 230                         Some(handle) => handle.join().unwrap(),
 231                         None => Ok(()),
 232                 }
 233         }
 234 }
 235
 236 impl Drop for BackgroundProcessor {
 237         fn drop(&mut self) {
 238                 self.stop_and_join_thread().unwrap();
 239         }
 240 }
 241
 242 #[cfg(test)]
 243 mod tests {
 244         use bitcoin::blockdata::block::BlockHeader;
 245         use bitcoin::blockdata::constants::genesis_block;
 246         use bitcoin::blockdata::transaction::{Transaction, TxOut};
 247         use bitcoin::network::constants::Network;
 248         use lightning::chain::{BestBlock, Confirm, chainmonitor};
 249         use lightning::chain::channelmonitor::ANTI_REORG_DELAY;
 250         use lightning::chain::keysinterface::{InMemorySigner, KeysInterface, KeysManager};
 251         use lightning::chain::transaction::OutPoint;
 252         use lightning::get_event_msg;
 253         use lightning::ln::channelmanager::{BREAKDOWN_TIMEOUT, ChainParameters, ChannelManager, SimpleArcChannelManager};
 254         use lightning::ln::features::InitFeatures;
 255         use lightning::ln::msgs::{ChannelMessageHandler, Init};
 256         use lightning::ln::peer_handler::{PeerManager, MessageHandler, SocketDescriptor};
 257         use lightning::util::config::UserConfig;
 258         use lightning::util::events::{Event, MessageSendEventsProvider, MessageSendEvent};
 259         use lightning::util::ser::Writeable;
 260         use lightning::util::test_utils;
 261         use lightning_persister::FilesystemPersister;
 262         use std::fs;
 263         use std::path::PathBuf;
 264         use std::sync::{Arc, Mutex};
 265         use std::time::Duration;
 266         use super::{BackgroundProcessor, FRESHNESS_TIMER};
 267
 268         const EVENT_DEADLINE: u64 = 5 * FRESHNESS_TIMER;
 269
 270         #[derive(Clone, Eq, Hash, PartialEq)]
 271         struct TestDescriptor{}
 272         impl SocketDescriptor for TestDescriptor {
 273                 fn send_data(&mut self, _data: &[u8], _resume_read: bool) -> usize {
 274                         0
 275                 }
 276
 277                 fn disconnect_socket(&mut self) {}
 278         }
 279
 280         type ChainMonitor = chainmonitor::ChainMonitor<InMemorySigner, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
 281
 282         struct Node {
 283                 node: Arc<SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>>,
 284                 peer_manager: Arc<PeerManager<TestDescriptor, Arc<test_utils::TestChannelMessageHandler>, Arc<test_utils::TestRoutingMessageHandler>, Arc<test_utils::TestLogger>>>,
 285                 chain_monitor: Arc<ChainMonitor>,
 286                 persister: Arc<FilesystemPersister>,
 287                 tx_broadcaster: Arc<test_utils::TestBroadcaster>,
 288                 logger: Arc<test_utils::TestLogger>,
 289                 best_block: BestBlock,
 290         }
 291
 292         impl Drop for Node {
 293                 fn drop(&mut self) {
 294                         let data_dir = self.persister.get_data_dir();
 295                         match fs::remove_dir_all(data_dir.clone()) {
 296                                 Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
 297                                 _ => {}
 298                         }
 299                 }
 300         }
 301
 302         fn get_full_filepath(filepath: String, filename: String) -> String {
 303                 let mut path = PathBuf::from(filepath);
 304                 path.push(filename);
 305                 path.to_str().unwrap().to_string()
 306         }
 307
 308         fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
 309                 let mut nodes = Vec::new();
 310                 for i in 0..num_nodes {
 311                         let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new()), blocks: Arc::new(Mutex::new(Vec::new()))});
 312                         let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: Mutex::new(253) });
 313                         let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
 314                         let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
 315                         let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
 316                         let seed = [i as u8; 32];
 317                         let network = Network::Testnet;
 318                         let now = Duration::from_secs(genesis_block(network).header.time as u64);
 319                         let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
 320                         let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
 321                         let best_block = BestBlock::from_genesis(network);
 322                         let params = ChainParameters { network, best_block };
 323                         let manager = Arc::new(ChannelManager::new(fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster.clone(), logger.clone(), keys_manager.clone(), UserConfig::default(), params));
 324                         let msg_handler = MessageHandler { chan_handler: Arc::new(test_utils::TestChannelMessageHandler::new()), route_handler: Arc::new(test_utils::TestRoutingMessageHandler::new() )};
 325                         let peer_manager = Arc::new(PeerManager::new(msg_handler, keys_manager.get_node_secret(), &seed, logger.clone()));
 326                         let node = Node { node: manager, peer_manager, chain_monitor, persister, tx_broadcaster, logger, best_block };
 327                         nodes.push(node);
 328                 }
 329
 330                 for i in 0..num_nodes {
 331                         for j in (i+1)..num_nodes {
 332                                 nodes[i].node.peer_connected(&nodes[j].node.get_our_node_id(), &Init { features: InitFeatures::known() });
 333                                 nodes[j].node.peer_connected(&nodes[i].node.get_our_node_id(), &Init { features: InitFeatures::known() });
 334                         }
 335                 }
 336
 337                 nodes
 338         }
 339
 340         macro_rules! open_channel {
 341                 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
 342                         begin_open_channel!($node_a, $node_b, $channel_value);
 343                         let events = $node_a.node.get_and_clear_pending_events();
 344                         assert_eq!(events.len(), 1);
 345                         let (temporary_channel_id, tx) = handle_funding_generation_ready!(events[0], $channel_value);
 346                         end_open_channel!($node_a, $node_b, temporary_channel_id, tx);
 347                         tx
 348                 }}
 349         }
 350
 351         macro_rules! begin_open_channel {
 352                 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
 353                         $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
 354                         $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
 355                         $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
 356                 }}
 357         }
 358
 359         macro_rules! handle_funding_generation_ready {
 360                 ($event: expr, $channel_value: expr) => {{
 361                         match $event {
 362                                 Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
 363                                         assert_eq!(*channel_value_satoshis, $channel_value);
 364                                         assert_eq!(user_channel_id, 42);
 365
 366                                         let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
 367                                                 value: *channel_value_satoshis, script_pubkey: output_script.clone(),
 368                                         }]};
 369                                         (*temporary_channel_id, tx)
 370                                 },
 371                                 _ => panic!("Unexpected event"),
 372                         }
 373                 }}
 374         }
 375
 376         macro_rules! end_open_channel {
 377                 ($node_a: expr, $node_b: expr, $temporary_channel_id: expr, $tx: expr) => {{
 378                         $node_a.node.funding_transaction_generated(&$temporary_channel_id, $tx.clone()).unwrap();
 379                         $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
 380                         $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
 381                 }}
 382         }
 383
 384         fn confirm_transaction_depth(node: &mut Node, tx: &Transaction, depth: u32) {
 385                 for i in 1..=depth {
 386                         let prev_blockhash = node.best_block.block_hash();
 387                         let height = node.best_block.height() + 1;
 388                         let header = BlockHeader { version: 0x20000000, prev_blockhash, merkle_root: Default::default(), time: height, bits: 42, nonce: 42 };
 389                         let txdata = vec![(0, tx)];
 390                         node.best_block = BestBlock::new(header.block_hash(), height);
 391                         match i {
 392                                 1 => {
 393                                         node.node.transactions_confirmed(&header, &txdata, height);
 394                                         node.chain_monitor.transactions_confirmed(&header, &txdata, height);
 395                                 },
 396                                 x if x == depth => {
 397                                         node.node.best_block_updated(&header, height);
 398                                         node.chain_monitor.best_block_updated(&header, height);
 399                                 },
 400                                 _ => {},
 401                         }
 402                 }
 403         }
 404         fn confirm_transaction(node: &mut Node, tx: &Transaction) {
 405                 confirm_transaction_depth(node, tx, ANTI_REORG_DELAY);
 406         }
 407
 408         #[test]
 409         fn test_background_processor() {
 410                 // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
 411                 // updates. Also test that when new updates are available, the manager signals that it needs
 412                 // re-persistence and is successfully re-persisted.
 413                 let nodes = create_nodes(2, "test_background_processor".to_string());
 414
 415                 // Go through the channel creation process so that each node has something to persist. Since
 416                 // open_channel consumes events, it must complete before starting BackgroundProcessor to
 417                 // avoid a race with processing events.
 418                 let tx = open_channel!(nodes[0], nodes[1], 100000);
 419
 420                 // Initiate the background processors to watch each node.
 421                 let data_dir = nodes[0].persister.get_data_dir();
 422                 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);
 423                 let event_handler = |_| {};
 424                 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());
 425
 426                 macro_rules! check_persisted_data {
 427                         ($node: expr, $filepath: expr, $expected_bytes: expr) => {
 428                                 match $node.write(&mut $expected_bytes) {
 429                                         Ok(()) => {
 430                                                 loop {
 431                                                         match std::fs::read($filepath) {
 432                                                                 Ok(bytes) => {
 433                                                                         if bytes == $expected_bytes {
 434                                                                                 break
 435                                                                         } else {
 436                                                                                 continue
 437                                                                         }
 438                                                                 },
 439                                                                 Err(_) => continue
 440                                                         }
 441                                                 }
 442                                         },
 443                                         Err(e) => panic!("Unexpected error: {}", e)
 444                                 }
 445                         }
 446                 }
 447
 448                 // Check that the initial channel manager data is persisted as expected.
 449                 let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
 450                 let mut expected_bytes = Vec::new();
 451                 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
 452                 loop {
 453                         if !nodes[0].node.get_persistence_condvar_value() { break }
 454                 }
 455
 456                 // Force-close the channel.
 457                 nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
 458
 459                 // Check that the force-close updates are persisted.
 460                 let mut expected_bytes = Vec::new();
 461                 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
 462                 loop {
 463                         if !nodes[0].node.get_persistence_condvar_value() { break }
 464                 }
 465
 466                 assert!(bg_processor.stop().is_ok());
 467         }
 468
 469         #[test]
 470         fn test_timer_tick_called() {
 471                 // Test that ChannelManager's and PeerManager's `timer_tick_occurred` is called every
 472                 // `FRESHNESS_TIMER`.
 473                 let nodes = create_nodes(1, "test_timer_tick_called".to_string());
 474                 let data_dir = nodes[0].persister.get_data_dir();
 475                 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);
 476                 let event_handler = |_| {};
 477                 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());
 478                 loop {
 479                         let log_entries = nodes[0].logger.lines.lock().unwrap();
 480                         let desired_log = "Calling ChannelManager's timer_tick_occurred".to_string();
 481                         let second_desired_log = "Calling PeerManager's timer_tick_occurred".to_string();
 482                         if log_entries.get(&("lightning_background_processor".to_string(), desired_log)).is_some() &&
 483                                         log_entries.get(&("lightning_background_processor".to_string(), second_desired_log)).is_some() {
 484                                 break
 485                         }
 486                 }
 487
 488                 assert!(bg_processor.stop().is_ok());
 489         }
 490
 491         #[test]
 492         fn test_persist_error() {
 493                 // Test that if we encounter an error during manager persistence, the thread panics.
 494                 let nodes = create_nodes(2, "test_persist_error".to_string());
 495                 open_channel!(nodes[0], nodes[1], 100000);
 496
 497                 let persister = |_: &_| Err(std::io::Error::new(std::io::ErrorKind::Other, "test"));
 498                 let event_handler = |_| {};
 499                 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());
 500                 match bg_processor.join() {
 501                         Ok(_) => panic!("Expected error persisting manager"),
 502                         Err(e) => {
 503                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 504                                 assert_eq!(e.get_ref().unwrap().to_string(), "test");
 505                         },
 506                 }
 507         }
 508
 509         #[test]
 510         fn test_background_event_handling() {
 511                 let mut nodes = create_nodes(2, "test_background_event_handling".to_string());
 512                 let channel_value = 100000;
 513                 let data_dir = nodes[0].persister.get_data_dir();
 514                 let persister = move |node: &_| FilesystemPersister::persist_manager(data_dir.clone(), node);
 515
 516                 // Set up a background event handler for FundingGenerationReady events.
 517                 let (sender, receiver) = std::sync::mpsc::sync_channel(1);
 518                 let event_handler = move |event| {
 519                         sender.send(handle_funding_generation_ready!(event, channel_value)).unwrap();
 520                 };
 521                 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());
 522
 523                 // Open a channel and check that the FundingGenerationReady event was handled.
 524                 begin_open_channel!(nodes[0], nodes[1], channel_value);
 525                 let (temporary_channel_id, funding_tx) = receiver
 526                         .recv_timeout(Duration::from_secs(EVENT_DEADLINE))
 527                         .expect("FundingGenerationReady not handled within deadline");
 528                 end_open_channel!(nodes[0], nodes[1], temporary_channel_id, funding_tx);
 529
 530                 // Confirm the funding transaction.
 531                 confirm_transaction(&mut nodes[0], &funding_tx);
 532                 let as_funding = get_event_msg!(nodes[0], MessageSendEvent::SendFundingLocked, nodes[1].node.get_our_node_id());
 533                 confirm_transaction(&mut nodes[1], &funding_tx);
 534                 let bs_funding = get_event_msg!(nodes[1], MessageSendEvent::SendFundingLocked, nodes[0].node.get_our_node_id());
 535                 nodes[0].node.handle_funding_locked(&nodes[1].node.get_our_node_id(), &bs_funding);
 536                 let _as_channel_update = get_event_msg!(nodes[0], MessageSendEvent::SendChannelUpdate, nodes[1].node.get_our_node_id());
 537                 nodes[1].node.handle_funding_locked(&nodes[0].node.get_our_node_id(), &as_funding);
 538                 let _bs_channel_update = get_event_msg!(nodes[1], MessageSendEvent::SendChannelUpdate, nodes[0].node.get_our_node_id());
 539
 540                 assert!(bg_processor.stop().is_ok());
 541
 542                 // Set up a background event handler for SpendableOutputs events.
 543                 let (sender, receiver) = std::sync::mpsc::sync_channel(1);
 544                 let event_handler = move |event| sender.send(event).unwrap();
 545                 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());
 546
 547                 // Force close the channel and check that the SpendableOutputs event was handled.
 548                 nodes[0].node.force_close_channel(&nodes[0].node.list_channels()[0].channel_id).unwrap();
 549                 let commitment_tx = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().pop().unwrap();
 550                 confirm_transaction_depth(&mut nodes[0], &commitment_tx, BREAKDOWN_TIMEOUT as u32);
 551                 let event = receiver
 552                         .recv_timeout(Duration::from_secs(EVENT_DEADLINE))
 553                         .expect("SpendableOutputs not handled within deadline");
 554                 match event {
 555                         Event::SpendableOutputs { .. } => {},
 556                         _ => panic!("Unexpected event: {:?}", event),
 557                 }
 558
 559                 assert!(bg_processor.stop().is_ok());
 560         }
 561 }