_ 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 #![cfg_attr(docsrs, feature(doc_auto_cfg))]
  10
  11 #[macro_use] extern crate lightning;
  12 extern crate lightning_rapid_gossip_sync;
  13
  14 use lightning::chain;
  15 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
  16 use lightning::chain::chainmonitor::{ChainMonitor, Persist};
  17 use lightning::chain::keysinterface::{Sign, KeysInterface};
  18 use lightning::ln::channelmanager::ChannelManager;
  19 use lightning::ln::msgs::{ChannelMessageHandler, RoutingMessageHandler};
  20 use lightning::ln::peer_handler::{CustomMessageHandler, PeerManager, SocketDescriptor};
  21 use lightning::routing::gossip::{NetworkGraph, P2PGossipSync};
  22 use lightning::routing::scoring::WriteableScore;
  23 use lightning::util::events::{Event, EventHandler, EventsProvider};
  24 use lightning::util::logger::Logger;
  25 use lightning::util::persist::Persister;
  26 use lightning_rapid_gossip_sync::RapidGossipSync;
  27 use std::sync::Arc;
  28 use std::sync::atomic::{AtomicBool, Ordering};
  29 use std::thread;
  30 use std::thread::JoinHandle;
  31 use std::time::{Duration, Instant};
  32 use std::ops::Deref;
  33
  34 #[cfg(feature = "futures")]
  35 use futures::{select, future::FutureExt};
  36
  37 /// `BackgroundProcessor` takes care of tasks that (1) need to happen periodically to keep
  38 /// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
  39 /// responsibilities are:
  40 /// * Processing [`Event`]s with a user-provided [`EventHandler`].
  41 /// * Monitoring whether the [`ChannelManager`] needs to be re-persisted to disk, and if so,
  42 ///   writing it to disk/backups by invoking the callback given to it at startup.
  43 ///   [`ChannelManager`] persistence should be done in the background.
  44 /// * Calling [`ChannelManager::timer_tick_occurred`] and [`PeerManager::timer_tick_occurred`]
  45 ///   at the appropriate intervals.
  46 /// * Calling [`NetworkGraph::remove_stale_channels`] (if a [`GossipSync`] with a [`NetworkGraph`]
  47 ///   is provided to [`BackgroundProcessor::start`]).
  48 ///
  49 /// It will also call [`PeerManager::process_events`] periodically though this shouldn't be relied
  50 /// upon as doing so may result in high latency.
  51 ///
  52 /// # Note
  53 ///
  54 /// If [`ChannelManager`] persistence fails and the persisted manager becomes out-of-date, then
  55 /// there is a risk of channels force-closing on startup when the manager realizes it's outdated.
  56 /// However, as long as [`ChannelMonitor`] backups are sound, no funds besides those used for
  57 /// unilateral chain closure fees are at risk.
  58 ///
  59 /// [`ChannelMonitor`]: lightning::chain::channelmonitor::ChannelMonitor
  60 /// [`Event`]: lightning::util::events::Event
  61 #[must_use = "BackgroundProcessor will immediately stop on drop. It should be stored until shutdown."]
  62 pub struct BackgroundProcessor {
  63         stop_thread: Arc<AtomicBool>,
  64         thread_handle: Option<JoinHandle<Result<(), std::io::Error>>>,
  65 }
  66
  67 #[cfg(not(test))]
  68 const FRESHNESS_TIMER: u64 = 60;
  69 #[cfg(test)]
  70 const FRESHNESS_TIMER: u64 = 1;
  71
  72 #[cfg(all(not(test), not(debug_assertions)))]
  73 const PING_TIMER: u64 = 10;
  74 /// Signature operations take a lot longer without compiler optimisations.
  75 /// Increasing the ping timer allows for this but slower devices will be disconnected if the
  76 /// timeout is reached.
  77 #[cfg(all(not(test), debug_assertions))]
  78 const PING_TIMER: u64 = 30;
  79 #[cfg(test)]
  80 const PING_TIMER: u64 = 1;
  81
  82 /// Prune the network graph of stale entries hourly.
  83 const NETWORK_PRUNE_TIMER: u64 = 60 * 60;
  84
  85 #[cfg(not(test))]
  86 const SCORER_PERSIST_TIMER: u64 = 30;
  87 #[cfg(test)]
  88 const SCORER_PERSIST_TIMER: u64 = 1;
  89
  90 #[cfg(not(test))]
  91 const FIRST_NETWORK_PRUNE_TIMER: u64 = 60;
  92 #[cfg(test)]
  93 const FIRST_NETWORK_PRUNE_TIMER: u64 = 1;
  94
  95 /// Either [`P2PGossipSync`] or [`RapidGossipSync`].
  96 pub enum GossipSync<
  97         P: Deref<Target = P2PGossipSync<G, A, L>>,
  98         R: Deref<Target = RapidGossipSync<G, L>>,
  99         G: Deref<Target = NetworkGraph<L>>,
 100         A: Deref,
 101         L: Deref,
 102 >
 103 where A::Target: chain::Access, L::Target: Logger {
 104         /// Gossip sync via the lightning peer-to-peer network as defined by BOLT 7.
 105         P2P(P),
 106         /// Rapid gossip sync from a trusted server.
 107         Rapid(R),
 108         /// No gossip sync.
 109         None,
 110 }
 111
 112 impl<
 113         P: Deref<Target = P2PGossipSync<G, A, L>>,
 114         R: Deref<Target = RapidGossipSync<G, L>>,
 115         G: Deref<Target = NetworkGraph<L>>,
 116         A: Deref,
 117         L: Deref,
 118 > GossipSync<P, R, G, A, L>
 119 where A::Target: chain::Access, L::Target: Logger {
 120         fn network_graph(&self) -> Option<&G> {
 121                 match self {
 122                         GossipSync::P2P(gossip_sync) => Some(gossip_sync.network_graph()),
 123                         GossipSync::Rapid(gossip_sync) => Some(gossip_sync.network_graph()),
 124                         GossipSync::None => None,
 125                 }
 126         }
 127
 128         fn prunable_network_graph(&self) -> Option<&G> {
 129                 match self {
 130                         GossipSync::P2P(gossip_sync) => Some(gossip_sync.network_graph()),
 131                         GossipSync::Rapid(gossip_sync) => {
 132                                 if gossip_sync.is_initial_sync_complete() {
 133                                         Some(gossip_sync.network_graph())
 134                                 } else {
 135                                         None
 136                                 }
 137                         },
 138                         GossipSync::None => None,
 139                 }
 140         }
 141 }
 142
 143 /// (C-not exported) as the bindings concretize everything and have constructors for us
 144 impl<P: Deref<Target = P2PGossipSync<G, A, L>>, G: Deref<Target = NetworkGraph<L>>, A: Deref, L: Deref>
 145         GossipSync<P, &RapidGossipSync<G, L>, G, A, L>
 146 where
 147         A::Target: chain::Access,
 148         L::Target: Logger,
 149 {
 150         /// Initializes a new [`GossipSync::P2P`] variant.
 151         pub fn p2p(gossip_sync: P) -> Self {
 152                 GossipSync::P2P(gossip_sync)
 153         }
 154 }
 155
 156 /// (C-not exported) as the bindings concretize everything and have constructors for us
 157 impl<'a, R: Deref<Target = RapidGossipSync<G, L>>, G: Deref<Target = NetworkGraph<L>>, L: Deref>
 158         GossipSync<
 159                 &P2PGossipSync<G, &'a (dyn chain::Access + Send + Sync), L>,
 160                 R,
 161                 G,
 162                 &'a (dyn chain::Access + Send + Sync),
 163                 L,
 164         >
 165 where
 166         L::Target: Logger,
 167 {
 168         /// Initializes a new [`GossipSync::Rapid`] variant.
 169         pub fn rapid(gossip_sync: R) -> Self {
 170                 GossipSync::Rapid(gossip_sync)
 171         }
 172 }
 173
 174 /// (C-not exported) as the bindings concretize everything and have constructors for us
 175 impl<'a, L: Deref>
 176         GossipSync<
 177                 &P2PGossipSync<&'a NetworkGraph<L>, &'a (dyn chain::Access + Send + Sync), L>,
 178                 &RapidGossipSync<&'a NetworkGraph<L>, L>,
 179                 &'a NetworkGraph<L>,
 180                 &'a (dyn chain::Access + Send + Sync),
 181                 L,
 182         >
 183 where
 184         L::Target: Logger,
 185 {
 186         /// Initializes a new [`GossipSync::None`] variant.
 187         pub fn none() -> Self {
 188                 GossipSync::None
 189         }
 190 }
 191
 192 /// Decorates an [`EventHandler`] with common functionality provided by standard [`EventHandler`]s.
 193 struct DecoratingEventHandler<
 194         'a,
 195         E: EventHandler,
 196         PGS: Deref<Target = P2PGossipSync<G, A, L>>,
 197         RGS: Deref<Target = RapidGossipSync<G, L>>,
 198         G: Deref<Target = NetworkGraph<L>>,
 199         A: Deref,
 200         L: Deref,
 201 >
 202 where A::Target: chain::Access, L::Target: Logger {
 203         event_handler: E,
 204         gossip_sync: &'a GossipSync<PGS, RGS, G, A, L>,
 205 }
 206
 207 impl<
 208         'a,
 209         E: EventHandler,
 210         PGS: Deref<Target = P2PGossipSync<G, A, L>>,
 211         RGS: Deref<Target = RapidGossipSync<G, L>>,
 212         G: Deref<Target = NetworkGraph<L>>,
 213         A: Deref,
 214         L: Deref,
 215 > EventHandler for DecoratingEventHandler<'a, E, PGS, RGS, G, A, L>
 216 where A::Target: chain::Access, L::Target: Logger {
 217         fn handle_event(&self, event: &Event) {
 218                 if let Some(network_graph) = self.gossip_sync.network_graph() {
 219                         network_graph.handle_event(event);
 220                 }
 221                 self.event_handler.handle_event(event);
 222         }
 223 }
 224
 225 macro_rules! define_run_body {
 226         ($persister: ident, $event_handler: ident, $chain_monitor: ident, $channel_manager: ident,
 227          $gossip_sync: ident, $peer_manager: ident, $logger: ident, $scorer: ident,
 228          $loop_exit_check: expr, $await: expr)
 229         => { {
 230                 let event_handler = DecoratingEventHandler {
 231                         event_handler: $event_handler,
 232                         gossip_sync: &$gossip_sync,
 233                 };
 234
 235                 log_trace!($logger, "Calling ChannelManager's timer_tick_occurred on startup");
 236                 $channel_manager.timer_tick_occurred();
 237
 238                 let mut last_freshness_call = Instant::now();
 239                 let mut last_ping_call = Instant::now();
 240                 let mut last_prune_call = Instant::now();
 241                 let mut last_scorer_persist_call = Instant::now();
 242                 let mut have_pruned = false;
 243
 244                 loop {
 245                         $channel_manager.process_pending_events(&event_handler);
 246                         $chain_monitor.process_pending_events(&event_handler);
 247
 248                         // Note that the PeerManager::process_events may block on ChannelManager's locks,
 249                         // hence it comes last here. When the ChannelManager finishes whatever it's doing,
 250                         // we want to ensure we get into `persist_manager` as quickly as we can, especially
 251                         // without running the normal event processing above and handing events to users.
 252                         //
 253                         // Specifically, on an *extremely* slow machine, we may see ChannelManager start
 254                         // processing a message effectively at any point during this loop. In order to
 255                         // minimize the time between such processing completing and persisting the updated
 256                         // ChannelManager, we want to minimize methods blocking on a ChannelManager
 257                         // generally, and as a fallback place such blocking only immediately before
 258                         // persistence.
 259                         $peer_manager.process_events();
 260
 261                         // We wait up to 100ms, but track how long it takes to detect being put to sleep,
 262                         // see `await_start`'s use below.
 263                         let await_start = Instant::now();
 264                         let updates_available = $await;
 265                         let await_time = await_start.elapsed();
 266
 267                         if updates_available {
 268                                 log_trace!($logger, "Persisting ChannelManager...");
 269                                 $persister.persist_manager(&*$channel_manager)?;
 270                                 log_trace!($logger, "Done persisting ChannelManager.");
 271                         }
 272                         // Exit the loop if the background processor was requested to stop.
 273                         if $loop_exit_check {
 274                                 log_trace!($logger, "Terminating background processor.");
 275                                 break;
 276                         }
 277                         if last_freshness_call.elapsed().as_secs() > FRESHNESS_TIMER {
 278                                 log_trace!($logger, "Calling ChannelManager's timer_tick_occurred");
 279                                 $channel_manager.timer_tick_occurred();
 280                                 last_freshness_call = Instant::now();
 281                         }
 282                         if await_time > Duration::from_secs(1) {
 283                                 // On various platforms, we may be starved of CPU cycles for several reasons.
 284                                 // E.g. on iOS, if we've been in the background, we will be entirely paused.
 285                                 // Similarly, if we're on a desktop platform and the device has been asleep, we
 286                                 // may not get any cycles.
 287                                 // We detect this by checking if our max-100ms-sleep, above, ran longer than a
 288                                 // full second, at which point we assume sockets may have been killed (they
 289                                 // appear to be at least on some platforms, even if it has only been a second).
 290                                 // Note that we have to take care to not get here just because user event
 291                                 // processing was slow at the top of the loop. For example, the sample client
 292                                 // may call Bitcoin Core RPCs during event handling, which very often takes
 293                                 // more than a handful of seconds to complete, and shouldn't disconnect all our
 294                                 // peers.
 295                                 log_trace!($logger, "100ms sleep took more than a second, disconnecting peers.");
 296                                 $peer_manager.disconnect_all_peers();
 297                                 last_ping_call = Instant::now();
 298                         } else if last_ping_call.elapsed().as_secs() > PING_TIMER {
 299                                 log_trace!($logger, "Calling PeerManager's timer_tick_occurred");
 300                                 $peer_manager.timer_tick_occurred();
 301                                 last_ping_call = Instant::now();
 302                         }
 303
 304                         // Note that we want to run a graph prune once not long after startup before
 305                         // falling back to our usual hourly prunes. This avoids short-lived clients never
 306                         // pruning their network graph. We run once 60 seconds after startup before
 307                         // continuing our normal cadence.
 308                         if last_prune_call.elapsed().as_secs() > if have_pruned { NETWORK_PRUNE_TIMER } else { FIRST_NETWORK_PRUNE_TIMER } {
 309                                 // The network graph must not be pruned while rapid sync completion is pending
 310                                 log_trace!($logger, "Assessing prunability of network graph");
 311                                 if let Some(network_graph) = $gossip_sync.prunable_network_graph() {
 312                                         network_graph.remove_stale_channels();
 313
 314                                         if let Err(e) = $persister.persist_graph(network_graph) {
 315                                                 log_error!($logger, "Error: Failed to persist network graph, check your disk and permissions {}", e)
 316                                         }
 317
 318                                         last_prune_call = Instant::now();
 319                                         have_pruned = true;
 320                                 } else {
 321                                         log_trace!($logger, "Not pruning network graph, either due to pending rapid gossip sync or absence of a prunable graph.");
 322                                 }
 323                         }
 324
 325                         if last_scorer_persist_call.elapsed().as_secs() > SCORER_PERSIST_TIMER {
 326                                 if let Some(ref scorer) = $scorer {
 327                                         log_trace!($logger, "Persisting scorer");
 328                                         if let Err(e) = $persister.persist_scorer(&scorer) {
 329                                                 log_error!($logger, "Error: Failed to persist scorer, check your disk and permissions {}", e)
 330                                         }
 331                                 }
 332                                 last_scorer_persist_call = Instant::now();
 333                         }
 334                 }
 335
 336                 // After we exit, ensure we persist the ChannelManager one final time - this avoids
 337                 // some races where users quit while channel updates were in-flight, with
 338                 // ChannelMonitor update(s) persisted without a corresponding ChannelManager update.
 339                 $persister.persist_manager(&*$channel_manager)?;
 340
 341                 // Persist Scorer on exit
 342                 if let Some(ref scorer) = $scorer {
 343                         $persister.persist_scorer(&scorer)?;
 344                 }
 345
 346                 // Persist NetworkGraph on exit
 347                 if let Some(network_graph) = $gossip_sync.network_graph() {
 348                         $persister.persist_graph(network_graph)?;
 349                 }
 350
 351                 Ok(())
 352         } }
 353 }
 354
 355 /// Processes background events in a future.
 356 ///
 357 /// `sleeper` should return a future which completes in the given amount of time and returns a
 358 /// boolean indicating whether the background processing should continue. Once `sleeper` returns a
 359 /// future which outputs false, the loop will exit and this function's future will complete.
 360 ///
 361 /// See [`BackgroundProcessor::start`] for information on which actions this handles.
 362 #[cfg(feature = "futures")]
 363 pub async fn process_events_async<
 364         'a,
 365         Signer: 'static + Sign,
 366         CA: 'static + Deref + Send + Sync,
 367         CF: 'static + Deref + Send + Sync,
 368         CW: 'static + Deref + Send + Sync,
 369         T: 'static + Deref + Send + Sync,
 370         K: 'static + Deref + Send + Sync,
 371         F: 'static + Deref + Send + Sync,
 372         G: 'static + Deref<Target = NetworkGraph<L>> + Send + Sync,
 373         L: 'static + Deref + Send + Sync,
 374         P: 'static + Deref + Send + Sync,
 375         Descriptor: 'static + SocketDescriptor + Send + Sync,
 376         CMH: 'static + Deref + Send + Sync,
 377         RMH: 'static + Deref + Send + Sync,
 378         EH: 'static + EventHandler + Send,
 379         PS: 'static + Deref + Send,
 380         M: 'static + Deref<Target = ChainMonitor<Signer, CF, T, F, L, P>> + Send + Sync,
 381         CM: 'static + Deref<Target = ChannelManager<Signer, CW, T, K, F, L>> + Send + Sync,
 382         PGS: 'static + Deref<Target = P2PGossipSync<G, CA, L>> + Send + Sync,
 383         RGS: 'static + Deref<Target = RapidGossipSync<G, L>> + Send,
 384         UMH: 'static + Deref + Send + Sync,
 385         PM: 'static + Deref<Target = PeerManager<Descriptor, CMH, RMH, L, UMH>> + Send + Sync,
 386         S: 'static + Deref<Target = SC> + Send + Sync,
 387         SC: WriteableScore<'a>,
 388         SleepFuture: core::future::Future<Output = bool>,
 389         Sleeper: Fn(Duration) -> SleepFuture
 390 >(
 391         persister: PS, event_handler: EH, chain_monitor: M, channel_manager: CM,
 392         gossip_sync: GossipSync<PGS, RGS, G, CA, L>, peer_manager: PM, logger: L, scorer: Option<S>,
 393         sleeper: Sleeper,
 394 ) -> Result<(), std::io::Error>
 395 where
 396         CA::Target: 'static + chain::Access,
 397         CF::Target: 'static + chain::Filter,
 398         CW::Target: 'static + chain::Watch<Signer>,
 399         T::Target: 'static + BroadcasterInterface,
 400         K::Target: 'static + KeysInterface<Signer = Signer>,
 401         F::Target: 'static + FeeEstimator,
 402         L::Target: 'static + Logger,
 403         P::Target: 'static + Persist<Signer>,
 404         CMH::Target: 'static + ChannelMessageHandler,
 405         RMH::Target: 'static + RoutingMessageHandler,
 406         UMH::Target: 'static + CustomMessageHandler,
 407         PS::Target: 'static + Persister<'a, Signer, CW, T, K, F, L, SC>,
 408 {
 409         let mut should_continue = true;
 410         define_run_body!(persister, event_handler, chain_monitor, channel_manager,
 411                 gossip_sync, peer_manager, logger, scorer, should_continue, {
 412                         select! {
 413                                 _ = channel_manager.get_persistable_update_future().fuse() => true,
 414                                 cont = sleeper(Duration::from_millis(100)).fuse() => {
 415                                         should_continue = cont;
 416                                         false
 417                                 }
 418                         }
 419                 })
 420 }
 421
 422 impl BackgroundProcessor {
 423         /// Start a background thread that takes care of responsibilities enumerated in the [top-level
 424         /// documentation].
 425         ///
 426         /// The thread runs indefinitely unless the object is dropped, [`stop`] is called, or
 427         /// [`Persister::persist_manager`] returns an error. In case of an error, the error is retrieved by calling
 428         /// either [`join`] or [`stop`].
 429         ///
 430         /// # Data Persistence
 431         ///
 432         /// [`Persister::persist_manager`] is responsible for writing out the [`ChannelManager`] to disk, and/or
 433         /// uploading to one or more backup services. See [`ChannelManager::write`] for writing out a
 434         /// [`ChannelManager`]. See the `lightning-persister` crate for LDK's
 435         /// provided implementation.
 436         ///
 437         /// [`Persister::persist_graph`] is responsible for writing out the [`NetworkGraph`] to disk, if
 438         /// [`GossipSync`] is supplied. See [`NetworkGraph::write`] for writing out a [`NetworkGraph`].
 439         /// See the `lightning-persister` crate for LDK's provided implementation.
 440         ///
 441         /// Typically, users should either implement [`Persister::persist_manager`] to never return an
 442         /// error or call [`join`] and handle any error that may arise. For the latter case,
 443         /// `BackgroundProcessor` must be restarted by calling `start` again after handling the error.
 444         ///
 445         /// # Event Handling
 446         ///
 447         /// `event_handler` is responsible for handling events that users should be notified of (e.g.,
 448         /// payment failed). [`BackgroundProcessor`] may decorate the given [`EventHandler`] with common
 449         /// functionality implemented by other handlers.
 450         /// * [`P2PGossipSync`] if given will update the [`NetworkGraph`] based on payment failures.
 451         ///
 452         /// # Rapid Gossip Sync
 453         ///
 454         /// If rapid gossip sync is meant to run at startup, pass [`RapidGossipSync`] via `gossip_sync`
 455         /// to indicate that the [`BackgroundProcessor`] should not prune the [`NetworkGraph`] instance
 456         /// until the [`RapidGossipSync`] instance completes its first sync.
 457         ///
 458         /// [top-level documentation]: BackgroundProcessor
 459         /// [`join`]: Self::join
 460         /// [`stop`]: Self::stop
 461         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 462         /// [`ChannelManager::write`]: lightning::ln::channelmanager::ChannelManager#impl-Writeable
 463         /// [`Persister::persist_manager`]: lightning::util::persist::Persister::persist_manager
 464         /// [`Persister::persist_graph`]: lightning::util::persist::Persister::persist_graph
 465         /// [`NetworkGraph`]: lightning::routing::gossip::NetworkGraph
 466         /// [`NetworkGraph::write`]: lightning::routing::gossip::NetworkGraph#impl-Writeable
 467         pub fn start<
 468                 'a,
 469                 Signer: 'static + Sign,
 470                 CA: 'static + Deref + Send + Sync,
 471                 CF: 'static + Deref + Send + Sync,
 472                 CW: 'static + Deref + Send + Sync,
 473                 T: 'static + Deref + Send + Sync,
 474                 K: 'static + Deref + Send + Sync,
 475                 F: 'static + Deref + Send + Sync,
 476                 G: 'static + Deref<Target = NetworkGraph<L>> + Send + Sync,
 477                 L: 'static + Deref + Send + Sync,
 478                 P: 'static + Deref + Send + Sync,
 479                 Descriptor: 'static + SocketDescriptor + Send + Sync,
 480                 CMH: 'static + Deref + Send + Sync,
 481                 RMH: 'static + Deref + Send + Sync,
 482                 EH: 'static + EventHandler + Send,
 483                 PS: 'static + Deref + Send,
 484                 M: 'static + Deref<Target = ChainMonitor<Signer, CF, T, F, L, P>> + Send + Sync,
 485                 CM: 'static + Deref<Target = ChannelManager<Signer, CW, T, K, F, L>> + Send + Sync,
 486                 PGS: 'static + Deref<Target = P2PGossipSync<G, CA, L>> + Send + Sync,
 487                 RGS: 'static + Deref<Target = RapidGossipSync<G, L>> + Send,
 488                 UMH: 'static + Deref + Send + Sync,
 489                 PM: 'static + Deref<Target = PeerManager<Descriptor, CMH, RMH, L, UMH>> + Send + Sync,
 490                 S: 'static + Deref<Target = SC> + Send + Sync,
 491                 SC: WriteableScore<'a>,
 492         >(
 493                 persister: PS, event_handler: EH, chain_monitor: M, channel_manager: CM,
 494                 gossip_sync: GossipSync<PGS, RGS, G, CA, L>, peer_manager: PM, logger: L, scorer: Option<S>,
 495         ) -> Self
 496         where
 497                 CA::Target: 'static + chain::Access,
 498                 CF::Target: 'static + chain::Filter,
 499                 CW::Target: 'static + chain::Watch<Signer>,
 500                 T::Target: 'static + BroadcasterInterface,
 501                 K::Target: 'static + KeysInterface<Signer = Signer>,
 502                 F::Target: 'static + FeeEstimator,
 503                 L::Target: 'static + Logger,
 504                 P::Target: 'static + Persist<Signer>,
 505                 CMH::Target: 'static + ChannelMessageHandler,
 506                 RMH::Target: 'static + RoutingMessageHandler,
 507                 UMH::Target: 'static + CustomMessageHandler,
 508                 PS::Target: 'static + Persister<'a, Signer, CW, T, K, F, L, SC>,
 509         {
 510                 let stop_thread = Arc::new(AtomicBool::new(false));
 511                 let stop_thread_clone = stop_thread.clone();
 512                 let handle = thread::spawn(move || -> Result<(), std::io::Error> {
 513                         define_run_body!(persister, event_handler, chain_monitor, channel_manager,
 514                                 gossip_sync, peer_manager, logger, scorer, stop_thread.load(Ordering::Acquire),
 515                                 channel_manager.await_persistable_update_timeout(Duration::from_millis(100)))
 516                 });
 517                 Self { stop_thread: stop_thread_clone, thread_handle: Some(handle) }
 518         }
 519
 520         /// Join `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 521         /// [`ChannelManager`].
 522         ///
 523         /// # Panics
 524         ///
 525         /// This function panics if the background thread has panicked such as while persisting or
 526         /// handling events.
 527         ///
 528         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 529         pub fn join(mut self) -> Result<(), std::io::Error> {
 530                 assert!(self.thread_handle.is_some());
 531                 self.join_thread()
 532         }
 533
 534         /// Stop `BackgroundProcessor`'s thread, returning any error that occurred while persisting
 535         /// [`ChannelManager`].
 536         ///
 537         /// # Panics
 538         ///
 539         /// This function panics if the background thread has panicked such as while persisting or
 540         /// handling events.
 541         ///
 542         /// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 543         pub fn stop(mut self) -> Result<(), std::io::Error> {
 544                 assert!(self.thread_handle.is_some());
 545                 self.stop_and_join_thread()
 546         }
 547
 548         fn stop_and_join_thread(&mut self) -> Result<(), std::io::Error> {
 549                 self.stop_thread.store(true, Ordering::Release);
 550                 self.join_thread()
 551         }
 552
 553         fn join_thread(&mut self) -> Result<(), std::io::Error> {
 554                 match self.thread_handle.take() {
 555                         Some(handle) => handle.join().unwrap(),
 556                         None => Ok(()),
 557                 }
 558         }
 559 }
 560
 561 impl Drop for BackgroundProcessor {
 562         fn drop(&mut self) {
 563                 self.stop_and_join_thread().unwrap();
 564         }
 565 }
 566
 567 #[cfg(test)]
 568 mod tests {
 569         use bitcoin::blockdata::block::BlockHeader;
 570         use bitcoin::blockdata::constants::genesis_block;
 571         use bitcoin::blockdata::transaction::{Transaction, TxOut};
 572         use bitcoin::network::constants::Network;
 573         use lightning::chain::{BestBlock, Confirm, chainmonitor};
 574         use lightning::chain::channelmonitor::ANTI_REORG_DELAY;
 575         use lightning::chain::keysinterface::{InMemorySigner, Recipient, KeysInterface, KeysManager};
 576         use lightning::chain::transaction::OutPoint;
 577         use lightning::get_event_msg;
 578         use lightning::ln::channelmanager::{BREAKDOWN_TIMEOUT, ChainParameters, ChannelManager, SimpleArcChannelManager};
 579         use lightning::ln::features::{ChannelFeatures, InitFeatures};
 580         use lightning::ln::msgs::{ChannelMessageHandler, Init};
 581         use lightning::ln::peer_handler::{PeerManager, MessageHandler, SocketDescriptor, IgnoringMessageHandler};
 582         use lightning::routing::gossip::{NetworkGraph, P2PGossipSync};
 583         use lightning::util::config::UserConfig;
 584         use lightning::util::events::{Event, MessageSendEventsProvider, MessageSendEvent};
 585         use lightning::util::ser::Writeable;
 586         use lightning::util::test_utils;
 587         use lightning::util::persist::KVStorePersister;
 588         use lightning_invoice::payment::{InvoicePayer, Retry};
 589         use lightning_invoice::utils::DefaultRouter;
 590         use lightning_persister::FilesystemPersister;
 591         use std::fs;
 592         use std::path::PathBuf;
 593         use std::sync::{Arc, Mutex};
 594         use std::sync::mpsc::SyncSender;
 595         use std::time::Duration;
 596         use lightning::routing::scoring::{FixedPenaltyScorer};
 597         use lightning_rapid_gossip_sync::RapidGossipSync;
 598         use super::{BackgroundProcessor, GossipSync, FRESHNESS_TIMER};
 599
 600         const EVENT_DEADLINE: u64 = 5 * FRESHNESS_TIMER;
 601
 602         #[derive(Clone, Eq, Hash, PartialEq)]
 603         struct TestDescriptor{}
 604         impl SocketDescriptor for TestDescriptor {
 605                 fn send_data(&mut self, _data: &[u8], _resume_read: bool) -> usize {
 606                         0
 607                 }
 608
 609                 fn disconnect_socket(&mut self) {}
 610         }
 611
 612         type ChainMonitor = chainmonitor::ChainMonitor<InMemorySigner, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
 613
 614         type PGS = Arc<P2PGossipSync<Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>>;
 615         type RGS = Arc<RapidGossipSync<Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, Arc<test_utils::TestLogger>>>;
 616
 617         struct Node {
 618                 node: Arc<SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>>,
 619                 p2p_gossip_sync: PGS,
 620                 rapid_gossip_sync: RGS,
 621                 peer_manager: Arc<PeerManager<TestDescriptor, Arc<test_utils::TestChannelMessageHandler>, Arc<test_utils::TestRoutingMessageHandler>, Arc<test_utils::TestLogger>, IgnoringMessageHandler>>,
 622                 chain_monitor: Arc<ChainMonitor>,
 623                 persister: Arc<FilesystemPersister>,
 624                 tx_broadcaster: Arc<test_utils::TestBroadcaster>,
 625                 network_graph: Arc<NetworkGraph<Arc<test_utils::TestLogger>>>,
 626                 logger: Arc<test_utils::TestLogger>,
 627                 best_block: BestBlock,
 628                 scorer: Arc<Mutex<FixedPenaltyScorer>>,
 629         }
 630
 631         impl Node {
 632                 fn p2p_gossip_sync(&self) -> GossipSync<PGS, RGS, Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>> {
 633                         GossipSync::P2P(self.p2p_gossip_sync.clone())
 634                 }
 635
 636                 fn rapid_gossip_sync(&self) -> GossipSync<PGS, RGS, Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>> {
 637                         GossipSync::Rapid(self.rapid_gossip_sync.clone())
 638                 }
 639
 640                 fn no_gossip_sync(&self) -> GossipSync<PGS, RGS, Arc<NetworkGraph<Arc<test_utils::TestLogger>>>, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>> {
 641                         GossipSync::None
 642                 }
 643         }
 644
 645         impl Drop for Node {
 646                 fn drop(&mut self) {
 647                         let data_dir = self.persister.get_data_dir();
 648                         match fs::remove_dir_all(data_dir.clone()) {
 649                                 Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
 650                                 _ => {}
 651                         }
 652                 }
 653         }
 654
 655         struct Persister {
 656                 graph_error: Option<(std::io::ErrorKind, &'static str)>,
 657                 graph_persistence_notifier: Option<SyncSender<()>>,
 658                 manager_error: Option<(std::io::ErrorKind, &'static str)>,
 659                 scorer_error: Option<(std::io::ErrorKind, &'static str)>,
 660                 filesystem_persister: FilesystemPersister,
 661         }
 662
 663         impl Persister {
 664                 fn new(data_dir: String) -> Self {
 665                         let filesystem_persister = FilesystemPersister::new(data_dir.clone());
 666                         Self { graph_error: None, graph_persistence_notifier: None, manager_error: None, scorer_error: None, filesystem_persister }
 667                 }
 668
 669                 fn with_graph_error(self, error: std::io::ErrorKind, message: &'static str) -> Self {
 670                         Self { graph_error: Some((error, message)), ..self }
 671                 }
 672
 673                 fn with_graph_persistence_notifier(self, sender: SyncSender<()>) -> Self {
 674                         Self { graph_persistence_notifier: Some(sender), ..self }
 675                 }
 676
 677                 fn with_manager_error(self, error: std::io::ErrorKind, message: &'static str) -> Self {
 678                         Self { manager_error: Some((error, message)), ..self }
 679                 }
 680
 681                 fn with_scorer_error(self, error: std::io::ErrorKind, message: &'static str) -> Self {
 682                         Self { scorer_error: Some((error, message)), ..self }
 683                 }
 684         }
 685
 686         impl KVStorePersister for Persister {
 687                 fn persist<W: Writeable>(&self, key: &str, object: &W) -> std::io::Result<()> {
 688                         if key == "manager" {
 689                                 if let Some((error, message)) = self.manager_error {
 690                                         return Err(std::io::Error::new(error, message))
 691                                 }
 692                         }
 693
 694                         if key == "network_graph" {
 695                                 if let Some(sender) = &self.graph_persistence_notifier {
 696                                         sender.send(()).unwrap();
 697                                 };
 698
 699                                 if let Some((error, message)) = self.graph_error {
 700                                         return Err(std::io::Error::new(error, message))
 701                                 }
 702                         }
 703
 704                         if key == "scorer" {
 705                                 if let Some((error, message)) = self.scorer_error {
 706                                         return Err(std::io::Error::new(error, message))
 707                                 }
 708                         }
 709
 710                         self.filesystem_persister.persist(key, object)
 711                 }
 712         }
 713
 714         fn get_full_filepath(filepath: String, filename: String) -> String {
 715                 let mut path = PathBuf::from(filepath);
 716                 path.push(filename);
 717                 path.to_str().unwrap().to_string()
 718         }
 719
 720         fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
 721                 let mut nodes = Vec::new();
 722                 for i in 0..num_nodes {
 723                         let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new()), blocks: Arc::new(Mutex::new(Vec::new()))});
 724                         let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: Mutex::new(253) });
 725                         let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
 726                         let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
 727                         let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
 728                         let seed = [i as u8; 32];
 729                         let network = Network::Testnet;
 730                         let genesis_block = genesis_block(network);
 731                         let now = Duration::from_secs(genesis_block.header.time as u64);
 732                         let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
 733                         let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
 734                         let best_block = BestBlock::from_genesis(network);
 735                         let params = ChainParameters { network, best_block };
 736                         let manager = Arc::new(ChannelManager::new(fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster.clone(), logger.clone(), keys_manager.clone(), UserConfig::default(), params));
 737                         let network_graph = Arc::new(NetworkGraph::new(genesis_block.header.block_hash(), logger.clone()));
 738                         let p2p_gossip_sync = Arc::new(P2PGossipSync::new(network_graph.clone(), Some(chain_source.clone()), logger.clone()));
 739                         let rapid_gossip_sync = Arc::new(RapidGossipSync::new(network_graph.clone()));
 740                         let msg_handler = MessageHandler { chan_handler: Arc::new(test_utils::TestChannelMessageHandler::new()), route_handler: Arc::new(test_utils::TestRoutingMessageHandler::new() )};
 741                         let peer_manager = Arc::new(PeerManager::new(msg_handler, keys_manager.get_node_secret(Recipient::Node).unwrap(), &seed, logger.clone(), IgnoringMessageHandler{}));
 742                         let scorer = Arc::new(Mutex::new(test_utils::TestScorer::with_penalty(0)));
 743                         let node = Node { node: manager, p2p_gossip_sync, rapid_gossip_sync, peer_manager, chain_monitor, persister, tx_broadcaster, network_graph, logger, best_block, scorer };
 744                         nodes.push(node);
 745                 }
 746
 747                 for i in 0..num_nodes {
 748                         for j in (i+1)..num_nodes {
 749                                 nodes[i].node.peer_connected(&nodes[j].node.get_our_node_id(), &Init { features: InitFeatures::known(), remote_network_address: None });
 750                                 nodes[j].node.peer_connected(&nodes[i].node.get_our_node_id(), &Init { features: InitFeatures::known(), remote_network_address: None });
 751                         }
 752                 }
 753
 754                 nodes
 755         }
 756
 757         macro_rules! open_channel {
 758                 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
 759                         begin_open_channel!($node_a, $node_b, $channel_value);
 760                         let events = $node_a.node.get_and_clear_pending_events();
 761                         assert_eq!(events.len(), 1);
 762                         let (temporary_channel_id, tx) = handle_funding_generation_ready!(&events[0], $channel_value);
 763                         end_open_channel!($node_a, $node_b, temporary_channel_id, tx);
 764                         tx
 765                 }}
 766         }
 767
 768         macro_rules! begin_open_channel {
 769                 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
 770                         $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
 771                         $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
 772                         $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
 773                 }}
 774         }
 775
 776         macro_rules! handle_funding_generation_ready {
 777                 ($event: expr, $channel_value: expr) => {{
 778                         match $event {
 779                                 &Event::FundingGenerationReady { temporary_channel_id, channel_value_satoshis, ref output_script, user_channel_id, .. } => {
 780                                         assert_eq!(channel_value_satoshis, $channel_value);
 781                                         assert_eq!(user_channel_id, 42);
 782
 783                                         let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
 784                                                 value: channel_value_satoshis, script_pubkey: output_script.clone(),
 785                                         }]};
 786                                         (temporary_channel_id, tx)
 787                                 },
 788                                 _ => panic!("Unexpected event"),
 789                         }
 790                 }}
 791         }
 792
 793         macro_rules! end_open_channel {
 794                 ($node_a: expr, $node_b: expr, $temporary_channel_id: expr, $tx: expr) => {{
 795                         $node_a.node.funding_transaction_generated(&$temporary_channel_id, &$node_b.node.get_our_node_id(), $tx.clone()).unwrap();
 796                         $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
 797                         $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
 798                 }}
 799         }
 800
 801         fn confirm_transaction_depth(node: &mut Node, tx: &Transaction, depth: u32) {
 802                 for i in 1..=depth {
 803                         let prev_blockhash = node.best_block.block_hash();
 804                         let height = node.best_block.height() + 1;
 805                         let header = BlockHeader { version: 0x20000000, prev_blockhash, merkle_root: Default::default(), time: height, bits: 42, nonce: 42 };
 806                         let txdata = vec![(0, tx)];
 807                         node.best_block = BestBlock::new(header.block_hash(), height);
 808                         match i {
 809                                 1 => {
 810                                         node.node.transactions_confirmed(&header, &txdata, height);
 811                                         node.chain_monitor.transactions_confirmed(&header, &txdata, height);
 812                                 },
 813                                 x if x == depth => {
 814                                         node.node.best_block_updated(&header, height);
 815                                         node.chain_monitor.best_block_updated(&header, height);
 816                                 },
 817                                 _ => {},
 818                         }
 819                 }
 820         }
 821         fn confirm_transaction(node: &mut Node, tx: &Transaction) {
 822                 confirm_transaction_depth(node, tx, ANTI_REORG_DELAY);
 823         }
 824
 825         #[test]
 826         fn test_background_processor() {
 827                 // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
 828                 // updates. Also test that when new updates are available, the manager signals that it needs
 829                 // re-persistence and is successfully re-persisted.
 830                 let nodes = create_nodes(2, "test_background_processor".to_string());
 831
 832                 // Go through the channel creation process so that each node has something to persist. Since
 833                 // open_channel consumes events, it must complete before starting BackgroundProcessor to
 834                 // avoid a race with processing events.
 835                 let tx = open_channel!(nodes[0], nodes[1], 100000);
 836
 837                 // Initiate the background processors to watch each node.
 838                 let data_dir = nodes[0].persister.get_data_dir();
 839                 let persister = Arc::new(Persister::new(data_dir));
 840                 let event_handler = |_: &_| {};
 841                 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].p2p_gossip_sync(), nodes[0].peer_manager.clone(), nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
 842
 843                 macro_rules! check_persisted_data {
 844                         ($node: expr, $filepath: expr) => {
 845                                 let mut expected_bytes = Vec::new();
 846                                 loop {
 847                                         expected_bytes.clear();
 848                                         match $node.write(&mut expected_bytes) {
 849                                                 Ok(()) => {
 850                                                         match std::fs::read($filepath) {
 851                                                                 Ok(bytes) => {
 852                                                                         if bytes == expected_bytes {
 853                                                                                 break
 854                                                                         } else {
 855                                                                                 continue
 856                                                                         }
 857                                                                 },
 858                                                                 Err(_) => continue
 859                                                         }
 860                                                 },
 861                                                 Err(e) => panic!("Unexpected error: {}", e)
 862                                         }
 863                                 }
 864                         }
 865                 }
 866
 867                 // Check that the initial channel manager data is persisted as expected.
 868                 let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
 869                 check_persisted_data!(nodes[0].node, filepath.clone());
 870
 871                 loop {
 872                         if !nodes[0].node.get_persistence_condvar_value() { break }
 873                 }
 874
 875                 // Force-close the channel.
 876                 nodes[0].node.force_close_broadcasting_latest_txn(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id(), &nodes[1].node.get_our_node_id()).unwrap();
 877
 878                 // Check that the force-close updates are persisted.
 879                 check_persisted_data!(nodes[0].node, filepath.clone());
 880                 loop {
 881                         if !nodes[0].node.get_persistence_condvar_value() { break }
 882                 }
 883
 884                 // Check network graph is persisted
 885                 let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "network_graph".to_string());
 886                 check_persisted_data!(nodes[0].network_graph, filepath.clone());
 887
 888                 // Check scorer is persisted
 889                 let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "scorer".to_string());
 890                 check_persisted_data!(nodes[0].scorer, filepath.clone());
 891
 892                 assert!(bg_processor.stop().is_ok());
 893         }
 894
 895         #[test]
 896         fn test_timer_tick_called() {
 897                 // Test that ChannelManager's and PeerManager's `timer_tick_occurred` is called every
 898                 // `FRESHNESS_TIMER`.
 899                 let nodes = create_nodes(1, "test_timer_tick_called".to_string());
 900                 let data_dir = nodes[0].persister.get_data_dir();
 901                 let persister = Arc::new(Persister::new(data_dir));
 902                 let event_handler = |_: &_| {};
 903                 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].no_gossip_sync(), nodes[0].peer_manager.clone(), nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
 904                 loop {
 905                         let log_entries = nodes[0].logger.lines.lock().unwrap();
 906                         let desired_log = "Calling ChannelManager's timer_tick_occurred".to_string();
 907                         let second_desired_log = "Calling PeerManager's timer_tick_occurred".to_string();
 908                         if log_entries.get(&("lightning_background_processor".to_string(), desired_log)).is_some() &&
 909                                         log_entries.get(&("lightning_background_processor".to_string(), second_desired_log)).is_some() {
 910                                 break
 911                         }
 912                 }
 913
 914                 assert!(bg_processor.stop().is_ok());
 915         }
 916
 917         #[test]
 918         fn test_channel_manager_persist_error() {
 919                 // Test that if we encounter an error during manager persistence, the thread panics.
 920                 let nodes = create_nodes(2, "test_persist_error".to_string());
 921                 open_channel!(nodes[0], nodes[1], 100000);
 922
 923                 let data_dir = nodes[0].persister.get_data_dir();
 924                 let persister = Arc::new(Persister::new(data_dir).with_manager_error(std::io::ErrorKind::Other, "test"));
 925                 let event_handler = |_: &_| {};
 926                 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].no_gossip_sync(), nodes[0].peer_manager.clone(), nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
 927                 match bg_processor.join() {
 928                         Ok(_) => panic!("Expected error persisting manager"),
 929                         Err(e) => {
 930                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 931                                 assert_eq!(e.get_ref().unwrap().to_string(), "test");
 932                         },
 933                 }
 934         }
 935
 936         #[test]
 937         fn test_network_graph_persist_error() {
 938                 // Test that if we encounter an error during network graph persistence, an error gets returned.
 939                 let nodes = create_nodes(2, "test_persist_network_graph_error".to_string());
 940                 let data_dir = nodes[0].persister.get_data_dir();
 941                 let persister = Arc::new(Persister::new(data_dir).with_graph_error(std::io::ErrorKind::Other, "test"));
 942                 let event_handler = |_: &_| {};
 943                 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].p2p_gossip_sync(), nodes[0].peer_manager.clone(), nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
 944
 945                 match bg_processor.stop() {
 946                         Ok(_) => panic!("Expected error persisting network graph"),
 947                         Err(e) => {
 948                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 949                                 assert_eq!(e.get_ref().unwrap().to_string(), "test");
 950                         },
 951                 }
 952         }
 953
 954         #[test]
 955         fn test_scorer_persist_error() {
 956                 // Test that if we encounter an error during scorer persistence, an error gets returned.
 957                 let nodes = create_nodes(2, "test_persist_scorer_error".to_string());
 958                 let data_dir = nodes[0].persister.get_data_dir();
 959                 let persister = Arc::new(Persister::new(data_dir).with_scorer_error(std::io::ErrorKind::Other, "test"));
 960                 let event_handler = |_: &_| {};
 961                 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].no_gossip_sync(), nodes[0].peer_manager.clone(),  nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
 962
 963                 match bg_processor.stop() {
 964                         Ok(_) => panic!("Expected error persisting scorer"),
 965                         Err(e) => {
 966                                 assert_eq!(e.kind(), std::io::ErrorKind::Other);
 967                                 assert_eq!(e.get_ref().unwrap().to_string(), "test");
 968                         },
 969                 }
 970         }
 971
 972         #[test]
 973         fn test_background_event_handling() {
 974                 let mut nodes = create_nodes(2, "test_background_event_handling".to_string());
 975                 let channel_value = 100000;
 976                 let data_dir = nodes[0].persister.get_data_dir();
 977                 let persister = Arc::new(Persister::new(data_dir.clone()));
 978
 979                 // Set up a background event handler for FundingGenerationReady events.
 980                 let (sender, receiver) = std::sync::mpsc::sync_channel(1);
 981                 let event_handler = move |event: &Event| {
 982                         sender.send(handle_funding_generation_ready!(event, channel_value)).unwrap();
 983                 };
 984                 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].no_gossip_sync(), nodes[0].peer_manager.clone(), nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
 985
 986                 // Open a channel and check that the FundingGenerationReady event was handled.
 987                 begin_open_channel!(nodes[0], nodes[1], channel_value);
 988                 let (temporary_channel_id, funding_tx) = receiver
 989                         .recv_timeout(Duration::from_secs(EVENT_DEADLINE))
 990                         .expect("FundingGenerationReady not handled within deadline");
 991                 end_open_channel!(nodes[0], nodes[1], temporary_channel_id, funding_tx);
 992
 993                 // Confirm the funding transaction.
 994                 confirm_transaction(&mut nodes[0], &funding_tx);
 995                 let as_funding = get_event_msg!(nodes[0], MessageSendEvent::SendChannelReady, nodes[1].node.get_our_node_id());
 996                 confirm_transaction(&mut nodes[1], &funding_tx);
 997                 let bs_funding = get_event_msg!(nodes[1], MessageSendEvent::SendChannelReady, nodes[0].node.get_our_node_id());
 998                 nodes[0].node.handle_channel_ready(&nodes[1].node.get_our_node_id(), &bs_funding);
 999                 let _as_channel_update = get_event_msg!(nodes[0], MessageSendEvent::SendChannelUpdate, nodes[1].node.get_our_node_id());
1000                 nodes[1].node.handle_channel_ready(&nodes[0].node.get_our_node_id(), &as_funding);
1001                 let _bs_channel_update = get_event_msg!(nodes[1], MessageSendEvent::SendChannelUpdate, nodes[0].node.get_our_node_id());
1002
1003                 assert!(bg_processor.stop().is_ok());
1004
1005                 // Set up a background event handler for SpendableOutputs events.
1006                 let (sender, receiver) = std::sync::mpsc::sync_channel(1);
1007                 let event_handler = move |event: &Event| sender.send(event.clone()).unwrap();
1008                 let persister = Arc::new(Persister::new(data_dir));
1009                 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].no_gossip_sync(), nodes[0].peer_manager.clone(), nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
1010
1011                 // Force close the channel and check that the SpendableOutputs event was handled.
1012                 nodes[0].node.force_close_broadcasting_latest_txn(&nodes[0].node.list_channels()[0].channel_id, &nodes[1].node.get_our_node_id()).unwrap();
1013                 let commitment_tx = nodes[0].tx_broadcaster.txn_broadcasted.lock().unwrap().pop().unwrap();
1014                 confirm_transaction_depth(&mut nodes[0], &commitment_tx, BREAKDOWN_TIMEOUT as u32);
1015                 let event = receiver
1016                         .recv_timeout(Duration::from_secs(EVENT_DEADLINE))
1017                         .expect("SpendableOutputs not handled within deadline");
1018                 match event {
1019                         Event::SpendableOutputs { .. } => {},
1020                         Event::ChannelClosed { .. } => {},
1021                         _ => panic!("Unexpected event: {:?}", event),
1022                 }
1023
1024                 assert!(bg_processor.stop().is_ok());
1025         }
1026
1027         #[test]
1028         fn test_scorer_persistence() {
1029                 let nodes = create_nodes(2, "test_scorer_persistence".to_string());
1030                 let data_dir = nodes[0].persister.get_data_dir();
1031                 let persister = Arc::new(Persister::new(data_dir));
1032                 let event_handler = |_: &_| {};
1033                 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].no_gossip_sync(), nodes[0].peer_manager.clone(), nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
1034
1035                 loop {
1036                         let log_entries = nodes[0].logger.lines.lock().unwrap();
1037                         let expected_log = "Persisting scorer".to_string();
1038                         if log_entries.get(&("lightning_background_processor".to_string(), expected_log)).is_some() {
1039                                 break
1040                         }
1041                 }
1042
1043                 assert!(bg_processor.stop().is_ok());
1044         }
1045
1046         #[test]
1047         fn test_not_pruning_network_graph_until_graph_sync_completion() {
1048                 let nodes = create_nodes(2, "test_not_pruning_network_graph_until_graph_sync_completion".to_string());
1049                 let data_dir = nodes[0].persister.get_data_dir();
1050                 let (sender, receiver) = std::sync::mpsc::sync_channel(1);
1051                 let persister = Arc::new(Persister::new(data_dir.clone()).with_graph_persistence_notifier(sender));
1052                 let network_graph = nodes[0].network_graph.clone();
1053                 let features = ChannelFeatures::empty();
1054                 network_graph.add_channel_from_partial_announcement(42, 53, features, nodes[0].node.get_our_node_id(), nodes[1].node.get_our_node_id())
1055                         .expect("Failed to update channel from partial announcement");
1056                 let original_graph_description = network_graph.to_string();
1057                 assert!(original_graph_description.contains("42: features: 0000, node_one:"));
1058                 assert_eq!(network_graph.read_only().channels().len(), 1);
1059
1060                 let event_handler = |_: &_| {};
1061                 let background_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].rapid_gossip_sync(), nodes[0].peer_manager.clone(), nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
1062
1063                 loop {
1064                         let log_entries = nodes[0].logger.lines.lock().unwrap();
1065                         let expected_log_a = "Assessing prunability of network graph".to_string();
1066                         let expected_log_b = "Not pruning network graph, either due to pending rapid gossip sync or absence of a prunable graph.".to_string();
1067                         if log_entries.get(&("lightning_background_processor".to_string(), expected_log_a)).is_some() &&
1068                                 log_entries.get(&("lightning_background_processor".to_string(), expected_log_b)).is_some() {
1069                                 break
1070                         }
1071                 }
1072
1073                 let initialization_input = vec![
1074                         76, 68, 75, 1, 111, 226, 140, 10, 182, 241, 179, 114, 193, 166, 162, 70, 174, 99, 247,
1075                         79, 147, 30, 131, 101, 225, 90, 8, 156, 104, 214, 25, 0, 0, 0, 0, 0, 97, 227, 98, 218,
1076                         0, 0, 0, 4, 2, 22, 7, 207, 206, 25, 164, 197, 231, 230, 231, 56, 102, 61, 250, 251,
1077                         187, 172, 38, 46, 79, 247, 108, 44, 155, 48, 219, 238, 252, 53, 192, 6, 67, 2, 36, 125,
1078                         157, 176, 223, 175, 234, 116, 94, 248, 201, 225, 97, 235, 50, 47, 115, 172, 63, 136,
1079                         88, 216, 115, 11, 111, 217, 114, 84, 116, 124, 231, 107, 2, 158, 1, 242, 121, 152, 106,
1080                         204, 131, 186, 35, 93, 70, 216, 10, 237, 224, 183, 89, 95, 65, 3, 83, 185, 58, 138,
1081                         181, 64, 187, 103, 127, 68, 50, 2, 201, 19, 17, 138, 136, 149, 185, 226, 156, 137, 175,
1082                         110, 32, 237, 0, 217, 90, 31, 100, 228, 149, 46, 219, 175, 168, 77, 4, 143, 38, 128,
1083                         76, 97, 0, 0, 0, 2, 0, 0, 255, 8, 153, 192, 0, 2, 27, 0, 0, 0, 1, 0, 0, 255, 2, 68,
1084                         226, 0, 6, 11, 0, 1, 2, 3, 0, 0, 0, 2, 0, 40, 0, 0, 0, 0, 0, 0, 3, 232, 0, 0, 3, 232,
1085                         0, 0, 0, 1, 0, 0, 0, 0, 58, 85, 116, 216, 255, 8, 153, 192, 0, 2, 27, 0, 0, 25, 0, 0,
1086                         0, 1, 0, 0, 0, 125, 255, 2, 68, 226, 0, 6, 11, 0, 1, 5, 0, 0, 0, 0, 29, 129, 25, 192,
1087                 ];
1088                 nodes[0].rapid_gossip_sync.update_network_graph(&initialization_input[..]).unwrap();
1089
1090                 // this should have added two channels
1091                 assert_eq!(network_graph.read_only().channels().len(), 3);
1092
1093                 let _ = receiver
1094                         .recv_timeout(Duration::from_secs(super::FIRST_NETWORK_PRUNE_TIMER * 5))
1095                         .expect("Network graph not pruned within deadline");
1096
1097                 background_processor.stop().unwrap();
1098
1099                 // all channels should now be pruned
1100                 assert_eq!(network_graph.read_only().channels().len(), 0);
1101         }
1102
1103         #[test]
1104         fn test_invoice_payer() {
1105                 let keys_manager = test_utils::TestKeysInterface::new(&[0u8; 32], Network::Testnet);
1106                 let random_seed_bytes = keys_manager.get_secure_random_bytes();
1107                 let nodes = create_nodes(2, "test_invoice_payer".to_string());
1108
1109                 // Initiate the background processors to watch each node.
1110                 let data_dir = nodes[0].persister.get_data_dir();
1111                 let persister = Arc::new(Persister::new(data_dir));
1112                 let router = DefaultRouter::new(Arc::clone(&nodes[0].network_graph), Arc::clone(&nodes[0].logger), random_seed_bytes);
1113                 let invoice_payer = Arc::new(InvoicePayer::new(Arc::clone(&nodes[0].node), router, Arc::clone(&nodes[0].scorer), Arc::clone(&nodes[0].logger), |_: &_| {}, Retry::Attempts(2)));
1114                 let event_handler = Arc::clone(&invoice_payer);
1115                 let bg_processor = BackgroundProcessor::start(persister, event_handler, nodes[0].chain_monitor.clone(), nodes[0].node.clone(), nodes[0].no_gossip_sync(), nodes[0].peer_manager.clone(), nodes[0].logger.clone(), Some(nodes[0].scorer.clone()));
1116                 assert!(bg_processor.stop().is_ok());
1117         }
1118 }