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

   1 #![deny(broken_intra_doc_links)]
   2 #![deny(unsafe_code)]
   3
   4 #[macro_use] extern crate lightning;
   5
   6 use lightning::chain;
   7 use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
   8 use lightning::chain::keysinterface::{Sign, KeysInterface};
   9 use lightning::ln::channelmanager::ChannelManager;
  10 use lightning::util::logger::Logger;
  11 use std::sync::Arc;
  12 use std::sync::atomic::{AtomicBool, Ordering};
  13 use std::thread;
  14 use std::thread::JoinHandle;
  15 use std::time::{Duration, Instant};
  16
  17 /// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
  18 /// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
  19 /// responsibilities are:
  20 /// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
  21 ///   writing it to disk/backups by invoking the callback given to it at startup.
  22 ///   ChannelManager persistence should be done in the background.
  23 /// * Calling `ChannelManager::timer_chan_freshness_every_min()` every minute (can be done in the
  24 ///   background).
  25 ///
  26 /// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
  27 /// then there is a risk of channels force-closing on startup when the manager realizes it's
  28 /// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
  29 /// for unilateral chain closure fees are at risk.
  30 pub struct BackgroundProcessor {
  31         stop_thread: Arc<AtomicBool>,
  32         /// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
  33         /// exits due to an error while persisting.
  34         pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
  35 }
  36
  37 #[cfg(not(test))]
  38 const CHAN_FRESHNESS_TIMER: u64 = 60;
  39 #[cfg(test)]
  40 const CHAN_FRESHNESS_TIMER: u64 = 1;
  41
  42 impl BackgroundProcessor {
  43         /// Start a background thread that takes care of responsibilities enumerated in the top-level
  44         /// documentation.
  45         ///
  46         /// If `persist_manager` returns an error, then this thread will return said error (and `start()`
  47         /// will need to be called again to restart the `BackgroundProcessor`). Users should wait on
  48         /// [`thread_handle`]'s `join()` method to be able to tell if and when an error is returned, or
  49         /// implement `persist_manager` such that an error is never returned to the `BackgroundProcessor`
  50         ///
  51         /// `persist_manager` is responsible for writing out the `ChannelManager` to disk, and/or uploading
  52         /// to one or more backup services. See [`ChannelManager::write`] for writing out a `ChannelManager`.
  53         /// See [`FilesystemPersister::persist_manager`] for Rust-Lightning's provided implementation.
  54         ///
  55         /// [`thread_handle`]: struct.BackgroundProcessor.html#structfield.thread_handle
  56         /// [`ChannelManager::write`]: ../lightning/ln/channelmanager/struct.ChannelManager.html#method.write
  57         /// [`FilesystemPersister::persist_manager`]: ../lightning_persister/struct.FilesystemPersister.html#impl
  58         pub fn start<PM, Signer, M, T, K, F, L>(persist_manager: PM, manager: Arc<ChannelManager<Signer, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>, logger: Arc<L>) -> Self
  59         where Signer: 'static + Sign,
  60               M: 'static + chain::Watch<Signer>,
  61               T: 'static + BroadcasterInterface,
  62               K: 'static + KeysInterface<Signer=Signer>,
  63               F: 'static + FeeEstimator,
  64               L: 'static + Logger,
  65               PM: 'static + Send + Fn(&ChannelManager<Signer, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>,
  66         {
  67                 let stop_thread = Arc::new(AtomicBool::new(false));
  68                 let stop_thread_clone = stop_thread.clone();
  69                 let handle = thread::spawn(move || -> Result<(), std::io::Error> {
  70                         let mut current_time = Instant::now();
  71                         loop {
  72                                 let updates_available = manager.await_persistable_update_timeout(Duration::from_millis(100));
  73                                 if updates_available {
  74                                         persist_manager(&*manager)?;
  75                                 }
  76                                 // Exit the loop if the background processor was requested to stop.
  77                                 if stop_thread.load(Ordering::Acquire) == true {
  78                                         log_trace!(logger, "Terminating background processor.");
  79                                         return Ok(())
  80                                 }
  81                                 if current_time.elapsed().as_secs() > CHAN_FRESHNESS_TIMER {
  82                                         log_trace!(logger, "Calling manager's timer_chan_freshness_every_min");
  83                                         manager.timer_chan_freshness_every_min();
  84                                         current_time = Instant::now();
  85                                 }
  86                         }
  87                 });
  88                 Self {
  89                         stop_thread: stop_thread_clone,
  90                         thread_handle: handle,
  91                 }
  92         }
  93
  94         /// Stop `BackgroundProcessor`'s thread.
  95         pub fn stop(self) -> Result<(), std::io::Error> {
  96                 self.stop_thread.store(true, Ordering::Release);
  97                 self.thread_handle.join().unwrap()
  98         }
  99 }
 100
 101 #[cfg(test)]
 102 mod tests {
 103         use bitcoin::blockdata::constants::genesis_block;
 104         use bitcoin::blockdata::transaction::{Transaction, TxOut};
 105         use bitcoin::network::constants::Network;
 106         use lightning::chain;
 107         use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
 108         use lightning::chain::chainmonitor;
 109         use lightning::chain::keysinterface::{Sign, InMemorySigner, KeysInterface, KeysManager};
 110         use lightning::chain::transaction::OutPoint;
 111         use lightning::get_event_msg;
 112         use lightning::ln::channelmanager::{ChainParameters, ChannelManager, SimpleArcChannelManager};
 113         use lightning::ln::features::InitFeatures;
 114         use lightning::ln::msgs::ChannelMessageHandler;
 115         use lightning::util::config::UserConfig;
 116         use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
 117         use lightning::util::logger::Logger;
 118         use lightning::util::ser::Writeable;
 119         use lightning::util::test_utils;
 120         use lightning_persister::FilesystemPersister;
 121         use std::fs;
 122         use std::path::PathBuf;
 123         use std::sync::{Arc, Mutex};
 124         use std::time::Duration;
 125         use super::BackgroundProcessor;
 126
 127         type ChainMonitor = chainmonitor::ChainMonitor<InMemorySigner, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
 128
 129         struct Node {
 130                 node: Arc<SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>>,
 131                 persister: Arc<FilesystemPersister>,
 132                 logger: Arc<test_utils::TestLogger>,
 133         }
 134
 135         impl Drop for Node {
 136                 fn drop(&mut self) {
 137                         let data_dir = self.persister.get_data_dir();
 138                         match fs::remove_dir_all(data_dir.clone()) {
 139                                 Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
 140                                 _ => {}
 141                         }
 142                 }
 143         }
 144
 145         fn get_full_filepath(filepath: String, filename: String) -> String {
 146                 let mut path = PathBuf::from(filepath);
 147                 path.push(filename);
 148                 path.to_str().unwrap().to_string()
 149         }
 150
 151         fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
 152                 let mut nodes = Vec::new();
 153                 for i in 0..num_nodes {
 154                         let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
 155                         let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
 156                         let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
 157                         let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
 158                         let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
 159                         let seed = [i as u8; 32];
 160                         let network = Network::Testnet;
 161                         let genesis_block = genesis_block(network);
 162                         let now = Duration::from_secs(genesis_block.header.time as u64);
 163                         let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
 164                         let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
 165                         let params = ChainParameters {
 166                                 network,
 167                                 latest_hash: genesis_block.block_hash(),
 168                                 latest_height: 0,
 169                         };
 170                         let manager = Arc::new(ChannelManager::new(fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), params));
 171                         let node = Node { node: manager, persister, logger };
 172                         nodes.push(node);
 173                 }
 174                 nodes
 175         }
 176
 177         macro_rules! open_channel {
 178                 ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
 179                         $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
 180                         $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
 181                         $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
 182                         let events = $node_a.node.get_and_clear_pending_events();
 183                         assert_eq!(events.len(), 1);
 184                         let (temporary_channel_id, tx, funding_output) = match events[0] {
 185                                 Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
 186                                         assert_eq!(*channel_value_satoshis, $channel_value);
 187                                         assert_eq!(user_channel_id, 42);
 188
 189                                         let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
 190                                                 value: *channel_value_satoshis, script_pubkey: output_script.clone(),
 191                                         }]};
 192                                         let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
 193                                         (*temporary_channel_id, tx, funding_outpoint)
 194                                 },
 195                                 _ => panic!("Unexpected event"),
 196                         };
 197
 198                         $node_a.node.funding_transaction_generated(&temporary_channel_id, funding_output);
 199                         $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
 200                         $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
 201                         tx
 202                 }}
 203         }
 204
 205         #[test]
 206         fn test_background_processor() {
 207                 // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
 208                 // updates. Also test that when new updates are available, the manager signals that it needs
 209                 // re-persistence and is successfully re-persisted.
 210                 let nodes = create_nodes(2, "test_background_processor".to_string());
 211
 212                 // Initiate the background processors to watch each node.
 213                 let data_dir = nodes[0].persister.get_data_dir();
 214                 let callback = move |node: &ChannelManager<InMemorySigner, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
 215                 let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
 216
 217                 // Go through the channel creation process until each node should have something persisted.
 218                 let tx = open_channel!(nodes[0], nodes[1], 100000);
 219
 220                 macro_rules! check_persisted_data {
 221                         ($node: expr, $filepath: expr, $expected_bytes: expr) => {
 222                                 match $node.write(&mut $expected_bytes) {
 223                                         Ok(()) => {
 224                                                 loop {
 225                                                         match std::fs::read($filepath) {
 226                                                                 Ok(bytes) => {
 227                                                                         if bytes == $expected_bytes {
 228                                                                                 break
 229                                                                         } else {
 230                                                                                 continue
 231                                                                         }
 232                                                                 },
 233                                                                 Err(_) => continue
 234                                                         }
 235                                                 }
 236                                         },
 237                                         Err(e) => panic!("Unexpected error: {}", e)
 238                                 }
 239                         }
 240                 }
 241
 242                 // Check that the initial channel manager data is persisted as expected.
 243                 let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
 244                 let mut expected_bytes = Vec::new();
 245                 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
 246                 loop {
 247                         if !nodes[0].node.get_persistence_condvar_value() { break }
 248                 }
 249
 250                 // Force-close the channel.
 251                 nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
 252
 253                 // Check that the force-close updates are persisted.
 254                 let mut expected_bytes = Vec::new();
 255                 check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
 256                 loop {
 257                         if !nodes[0].node.get_persistence_condvar_value() { break }
 258                 }
 259
 260                 assert!(bg_processor.stop().is_ok());
 261         }
 262
 263         #[test]
 264         fn test_chan_freshness_called() {
 265                 // Test that ChannelManager's `timer_chan_freshness_every_min` is called every
 266                 // `CHAN_FRESHNESS_TIMER`.
 267                 let nodes = create_nodes(1, "test_chan_freshness_called".to_string());
 268                 let data_dir = nodes[0].persister.get_data_dir();
 269                 let callback = move |node: &ChannelManager<InMemorySigner, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
 270                 let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
 271                 loop {
 272                         let log_entries = nodes[0].logger.lines.lock().unwrap();
 273                         let desired_log = "Calling manager's timer_chan_freshness_every_min".to_string();
 274                         if log_entries.get(&("lightning_background_processor".to_string(), desired_log)).is_some() {
 275                                 break
 276                         }
 277                 }
 278
 279                 assert!(bg_processor.stop().is_ok());
 280         }
 281
 282         #[test]
 283         fn test_persist_error() {
 284                 // Test that if we encounter an error during manager persistence, the thread panics.
 285                 fn persist_manager<Signer, M, T, K, F, L>(_data: &ChannelManager<Signer, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>
 286                 where Signer: 'static + Sign,
 287                       M: 'static + chain::Watch<Signer>,
 288                       T: 'static + BroadcasterInterface,
 289                       K: 'static + KeysInterface<Signer=Signer>,
 290                       F: 'static + FeeEstimator,
 291                       L: 'static + Logger,
 292                 {
 293                         Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
 294                 }
 295
 296                 let nodes = create_nodes(2, "test_persist_error".to_string());
 297                 let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].logger.clone());
 298                 open_channel!(nodes[0], nodes[1], 100000);
 299
 300                 let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");
 301         }
 302 }