ChannelManager persistence

Cargo.toml

@@ -5,6 +5,7 @@ members = [
  "lightning-block-sync",
  "lightning-net-tokio",
  "lightning-persister",
+ "background-processor",
 ]
 
 # Our tests do actual crypo and lots of work, the tradeoff for -O1 is well worth it.

background-processor/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "background-processor"
+version = "0.1.0"
+authors = ["Valentine Wallace <vwallace@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bitcoin = "0.24"
+lightning = { version = "0.0.12", path = "../lightning", features = ["allow_wallclock_use"] }
+lightning-persister = { version = "0.0.1", path = "../lightning-persister" }
+
+[dev-dependencies]
+lightning = { version = "0.0.12", path = "../lightning", features = ["_test_utils"] }

background-processor/src/lib.rs

@@ -0,0 +1,294 @@
+#[macro_use] extern crate lightning;
+
+use lightning::chain;
+use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+use lightning::chain::keysinterface::{ChannelKeys, KeysInterface};
+use lightning::ln::channelmanager::ChannelManager;
+use lightning::util::logger::Logger;
+use lightning::util::ser::Writeable;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::thread;
+use std::thread::JoinHandle;
+use std::time::{Duration, Instant};
+
+/// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
+/// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
+/// responsibilities are:
+/// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
+/// writing it to disk/backups by invoking the callback given to it at startup.
+/// ChannelManager persistence should be done in the background.
+/// * Calling `ChannelManager::timer_chan_freshness_every_min()` every minute (can be done in the
+/// background).
+///
+/// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
+/// then there is a risk of channels force-closing on startup when the manager realizes it's
+/// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
+/// for unilateral chain closure fees are at risk.
+pub struct BackgroundProcessor {
+	stop_thread: Arc<AtomicBool>,
+	/// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
+	/// exits due to an error while persisting.
+	pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
+}
+
+#[cfg(not(test))]
+const CHAN_FRESHNESS_TIMER: u64 = 60;
+#[cfg(test)]
+const CHAN_FRESHNESS_TIMER: u64 = 1;
+
+impl BackgroundProcessor {
+	/// Start a background thread that takes care of responsibilities enumerated in the top-level
+	/// documentation.
+	///
+	/// If `persist_manager` returns an error, then this thread will return said error (and `start()`
+	/// will need to be called again to restart the `BackgroundProcessor`). Users should wait on
+	/// [`thread_handle`]'s `join()` method to be able to tell if and when an error is returned, or
+	/// implement `persist_manager` such that an error is never returned to the `BackgroundProcessor`
+	///
+	/// `persist_manager` is responsible for writing out the `ChannelManager` to disk, and/or uploading
+	/// to one or more backup services. See [`ChannelManager::write`] for writing out a `ChannelManager`.
+	/// See [`FilesystemPersister::persist_manager`] for Rust-Lightning's provided implementation.
+	///
+	/// [`thread_handle`]: struct.BackgroundProcessor.html#structfield.thread_handle
+	/// [`ChannelManager::write`]: ../lightning/ln/channelmanager/struct.ChannelManager.html#method.write
+	/// [`FilesystemPersister::persist_manager`]: ../lightning_persister/struct.FilesystemPersister.html#impl
+	pub fn start<PM, ChanSigner, M, T, K, F, L>(persist_manager: PM, manager: Arc<ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>, logger: Arc<L>) -> Self
+	where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ PM: 'static + Send + Fn(&ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>,
+	{
+ let stop_thread = Arc::new(AtomicBool::new(false));
+ let stop_thread_clone = stop_thread.clone();
+ let handle = thread::spawn(move || -> Result<(), std::io::Error> {
+ let mut current_time = Instant::now();
+ loop {
+ let updates_available = manager.wait_timeout(Duration::from_millis(100));
+ if updates_available {
+ persist_manager(&*manager)?;
+ }
+ // Exit the loop if the background processor was requested to stop.
+ if stop_thread.load(Ordering::Acquire) == true {
+ log_trace!(logger, "Terminating background processor.");
+ return Ok(())
+ }
+ if current_time.elapsed().as_secs() > CHAN_FRESHNESS_TIMER {
+ log_trace!(logger, "Calling manager's timer_chan_freshness_every_min");
+ manager.timer_chan_freshness_every_min();
+ current_time = Instant::now();
+ }
+ }
+ });
+ Self {
+ stop_thread: stop_thread_clone,
+ thread_handle: handle,
+ }
+	}
+
+	/// Stop `BackgroundProcessor`'s thread.
+	pub fn stop(self) -> Result<(), std::io::Error> {
+ self.stop_thread.store(true, Ordering::Release);
+ self.thread_handle.join().unwrap()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use bitcoin::blockdata::constants::genesis_block;
+	use bitcoin::blockdata::transaction::{Transaction, TxOut};
+	use bitcoin::network::constants::Network;
+	use lightning::chain;
+	use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+	use lightning::chain::chainmonitor;
+	use lightning::chain::keysinterface::{ChannelKeys, InMemoryChannelKeys, KeysInterface, KeysManager};
+	use lightning::chain::transaction::OutPoint;
+	use lightning::get_event_msg;
+	use lightning::ln::channelmanager::{ChannelManager, SimpleArcChannelManager};
+	use lightning::ln::features::InitFeatures;
+	use lightning::ln::msgs::ChannelMessageHandler;
+	use lightning::util::config::UserConfig;
+	use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
+	use lightning::util::logger::Logger;
+	use lightning::util::ser::Writeable;
+	use lightning::util::test_utils;
+	use lightning_persister::FilesystemPersister;
+	use std::fs;
+	use std::path::PathBuf;
+	use std::sync::{Arc, Mutex};
+	use std::time::Duration;
+	use super::BackgroundProcessor;
+
+	type ChainMonitor = chainmonitor::ChainMonitor<InMemoryChannelKeys, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
+
+	struct Node {
+ node: SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>,
+ persister: Arc<FilesystemPersister>,
+ logger: Arc<test_utils::TestLogger>,
+	}
+
+	impl Drop for Node {
+ fn drop(&mut self) {
+ let data_dir = self.persister.get_data_dir();
+ match fs::remove_dir_all(data_dir.clone()) {
+ Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
+ _ => {}
+ }
+ }
+	}
+
+	fn get_full_filepath(filepath: String, filename: String) -> String {
+ let mut path = PathBuf::from(filepath);
+ path.push(filename);
+ path.to_str().unwrap().to_string()
+	}
+
+	fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
+ let mut nodes = Vec::new();
+ for i in 0..num_nodes {
+ let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
+ let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
+ let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+ let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
+ let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
+ let seed = [i as u8; 32];
+ let network = Network::Testnet;
+ let now = Duration::from_secs(genesis_block(network).header.time as u64);
+ let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
+ let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
+ let manager = Arc::new(ChannelManager::new(Network::Testnet, fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), i));
+ let node = Node { node: manager, persister, logger };
+ nodes.push(node);
+ }
+ nodes
+	}
+
+	macro_rules! open_channel {
+ ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
+ $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
+ $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
+ let events = $node_a.node.get_and_clear_pending_events();
+ assert_eq!(events.len(), 1);
+ let (temporary_channel_id, tx, funding_output) = match events[0] {
+ Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
+ assert_eq!(*channel_value_satoshis, $channel_value);
+ assert_eq!(user_channel_id, 42);
+
+ let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
+ value: *channel_value_satoshis, script_pubkey: output_script.clone(),
+ }]};
+ let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
+ (*temporary_channel_id, tx, funding_outpoint)
+ },
+ _ => panic!("Unexpected event"),
+ };
+
+ $node_a.node.funding_transaction_generated(&temporary_channel_id, funding_output);
+ $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
+ tx
+ }}
+	}
+
+	#[test]
+	fn test_background_processor() {
+ // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
+ // updates. Also test that when new updates are available, the manager signals that it needs
+ // re-persistence and is successfully re-persisted.
+ let nodes = create_nodes(2, "test_background_processor".to_string());
+
+ // Initiate the background processors to watch each node.
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+
+ // Go through the channel creation process until each node should have something persisted.
+ let tx = open_channel!(nodes[0], nodes[1], 100000);
+
+ macro_rules! check_persisted_data {
+ ($node: expr, $filepath: expr, $expected_bytes: expr) => {
+ match $node.write(&mut $expected_bytes) {
+ Ok(()) => {
+ loop {
+ match std::fs::read($filepath) {
+ Ok(bytes) => {
+ if bytes == $expected_bytes {
+ break
+ } else {
+ continue
+ }
+ },
+ Err(_) => continue
+ }
+ }
+ },
+ Err(e) => panic!("Unexpected error: {}", e)
+ }
+ }
+ }
+
+ // Check that the initial channel manager data is persisted as expected.
+ let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ // Force-close the channel.
+ nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
+
+ // Check that the force-close updates are persisted.
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_chan_freshness_called() {
+ // Test that ChannelManager's `timer_chan_freshness_every_min` is called every
+ // `CHAN_FRESHNESS_TIMER`.
+ let nodes = create_nodes(1, "test_chan_freshness_called".to_string());
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+ loop {
+ let log_entries = nodes[0].logger.lines.lock().unwrap();
+ let desired_log = "Calling manager's timer_chan_freshness_every_min".to_string();
+ if log_entries.get(&("background_processor".to_string(), desired_log)).is_some() {
+ break
+ }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_persist_error() {
+ // Test that if we encounter an error during manager persistence, the thread panics.
+ fn persist_manager<ChanSigner, M, T, K, F, L>(_data: &ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>
+ where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ {
+ Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
+ }
+
+ let nodes = create_nodes(2, "test_persist_error".to_string());
+ let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].logger.clone());
+ open_channel!(nodes[0], nodes[1], 100000);
+
+ let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");
+	}
+}

lightning-persister/Cargo.toml

@@ -12,6 +12,9 @@ bitcoin = "0.24"
 lightning = { version = "0.0.12", path = "../lightning" }
 libc = "0.2"
 
+[target.'cfg(windows)'.dependencies]
+winapi = { version = "0.3", features = ["winbase"] }
+
 [dev-dependencies.bitcoin]
 version = "0.24"
 features = ["bitcoinconsensus"]

Cargo.toml

@@ -5,6 +5,7 @@ members = [
  "lightning-block-sync",
  "lightning-net-tokio",
  "lightning-persister",
+ "background-processor",
 ]
 
 # Our tests do actual crypo and lots of work, the tradeoff for -O1 is well worth it.

background-processor/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "background-processor"
+version = "0.1.0"
+authors = ["Valentine Wallace <vwallace@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bitcoin = "0.24"
+lightning = { version = "0.0.12", path = "../lightning", features = ["allow_wallclock_use"] }
+lightning-persister = { version = "0.0.1", path = "../lightning-persister" }
+
+[dev-dependencies]
+lightning = { version = "0.0.12", path = "../lightning", features = ["_test_utils"] }

background-processor/src/lib.rs

@@ -0,0 +1,294 @@
+#[macro_use] extern crate lightning;
+
+use lightning::chain;
+use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+use lightning::chain::keysinterface::{ChannelKeys, KeysInterface};
+use lightning::ln::channelmanager::ChannelManager;
+use lightning::util::logger::Logger;
+use lightning::util::ser::Writeable;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::thread;
+use std::thread::JoinHandle;
+use std::time::{Duration, Instant};
+
+/// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
+/// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
+/// responsibilities are:
+/// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
+/// writing it to disk/backups by invoking the callback given to it at startup.
+/// ChannelManager persistence should be done in the background.
+/// * Calling `ChannelManager::timer_chan_freshness_every_min()` every minute (can be done in the
+/// background).
+///
+/// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
+/// then there is a risk of channels force-closing on startup when the manager realizes it's
+/// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
+/// for unilateral chain closure fees are at risk.
+pub struct BackgroundProcessor {
+	stop_thread: Arc<AtomicBool>,
+	/// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
+	/// exits due to an error while persisting.
+	pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
+}
+
+#[cfg(not(test))]
+const CHAN_FRESHNESS_TIMER: u64 = 60;
+#[cfg(test)]
+const CHAN_FRESHNESS_TIMER: u64 = 1;
+
+impl BackgroundProcessor {
+	/// Start a background thread that takes care of responsibilities enumerated in the top-level
+	/// documentation.
+	///
+	/// If `persist_manager` returns an error, then this thread will return said error (and `start()`
+	/// will need to be called again to restart the `BackgroundProcessor`). Users should wait on
+	/// [`thread_handle`]'s `join()` method to be able to tell if and when an error is returned, or
+	/// implement `persist_manager` such that an error is never returned to the `BackgroundProcessor`
+	///
+	/// `persist_manager` is responsible for writing out the `ChannelManager` to disk, and/or uploading
+	/// to one or more backup services. See [`ChannelManager::write`] for writing out a `ChannelManager`.
+	/// See [`FilesystemPersister::persist_manager`] for Rust-Lightning's provided implementation.
+	///
+	/// [`thread_handle`]: struct.BackgroundProcessor.html#structfield.thread_handle
+	/// [`ChannelManager::write`]: ../lightning/ln/channelmanager/struct.ChannelManager.html#method.write
+	/// [`FilesystemPersister::persist_manager`]: ../lightning_persister/struct.FilesystemPersister.html#impl
+	pub fn start<PM, ChanSigner, M, T, K, F, L>(persist_manager: PM, manager: Arc<ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>, logger: Arc<L>) -> Self
+	where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ PM: 'static + Send + Fn(&ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>,
+	{
+ let stop_thread = Arc::new(AtomicBool::new(false));
+ let stop_thread_clone = stop_thread.clone();
+ let handle = thread::spawn(move || -> Result<(), std::io::Error> {
+ let mut current_time = Instant::now();
+ loop {
+ let updates_available = manager.wait_timeout(Duration::from_millis(100));
+ if updates_available {
+ persist_manager(&*manager)?;
+ }
+ // Exit the loop if the background processor was requested to stop.
+ if stop_thread.load(Ordering::Acquire) == true {
+ log_trace!(logger, "Terminating background processor.");
+ return Ok(())
+ }
+ if current_time.elapsed().as_secs() > CHAN_FRESHNESS_TIMER {
+ log_trace!(logger, "Calling manager's timer_chan_freshness_every_min");
+ manager.timer_chan_freshness_every_min();
+ current_time = Instant::now();
+ }
+ }
+ });
+ Self {
+ stop_thread: stop_thread_clone,
+ thread_handle: handle,
+ }
+	}
+
+	/// Stop `BackgroundProcessor`'s thread.
+	pub fn stop(self) -> Result<(), std::io::Error> {
+ self.stop_thread.store(true, Ordering::Release);
+ self.thread_handle.join().unwrap()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use bitcoin::blockdata::constants::genesis_block;
+	use bitcoin::blockdata::transaction::{Transaction, TxOut};
+	use bitcoin::network::constants::Network;
+	use lightning::chain;
+	use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+	use lightning::chain::chainmonitor;
+	use lightning::chain::keysinterface::{ChannelKeys, InMemoryChannelKeys, KeysInterface, KeysManager};
+	use lightning::chain::transaction::OutPoint;
+	use lightning::get_event_msg;
+	use lightning::ln::channelmanager::{ChannelManager, SimpleArcChannelManager};
+	use lightning::ln::features::InitFeatures;
+	use lightning::ln::msgs::ChannelMessageHandler;
+	use lightning::util::config::UserConfig;
+	use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
+	use lightning::util::logger::Logger;
+	use lightning::util::ser::Writeable;
+	use lightning::util::test_utils;
+	use lightning_persister::FilesystemPersister;
+	use std::fs;
+	use std::path::PathBuf;
+	use std::sync::{Arc, Mutex};
+	use std::time::Duration;
+	use super::BackgroundProcessor;
+
+	type ChainMonitor = chainmonitor::ChainMonitor<InMemoryChannelKeys, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
+
+	struct Node {
+ node: SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>,
+ persister: Arc<FilesystemPersister>,
+ logger: Arc<test_utils::TestLogger>,
+	}
+
+	impl Drop for Node {
+ fn drop(&mut self) {
+ let data_dir = self.persister.get_data_dir();
+ match fs::remove_dir_all(data_dir.clone()) {
+ Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
+ _ => {}
+ }
+ }
+	}
+
+	fn get_full_filepath(filepath: String, filename: String) -> String {
+ let mut path = PathBuf::from(filepath);
+ path.push(filename);
+ path.to_str().unwrap().to_string()
+	}
+
+	fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
+ let mut nodes = Vec::new();
+ for i in 0..num_nodes {
+ let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
+ let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
+ let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+ let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
+ let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
+ let seed = [i as u8; 32];
+ let network = Network::Testnet;
+ let now = Duration::from_secs(genesis_block(network).header.time as u64);
+ let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
+ let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
+ let manager = Arc::new(ChannelManager::new(Network::Testnet, fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), i));
+ let node = Node { node: manager, persister, logger };
+ nodes.push(node);
+ }
+ nodes
+	}
+
+	macro_rules! open_channel {
+ ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
+ $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
+ $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
+ let events = $node_a.node.get_and_clear_pending_events();
+ assert_eq!(events.len(), 1);
+ let (temporary_channel_id, tx, funding_output) = match events[0] {
+ Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
+ assert_eq!(*channel_value_satoshis, $channel_value);
+ assert_eq!(user_channel_id, 42);
+
+ let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
+ value: *channel_value_satoshis, script_pubkey: output_script.clone(),
+ }]};
+ let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
+ (*temporary_channel_id, tx, funding_outpoint)
+ },
+ _ => panic!("Unexpected event"),
+ };
+
+ $node_a.node.funding_transaction_generated(&temporary_channel_id, funding_output);
+ $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
+ tx
+ }}
+	}
+
+	#[test]
+	fn test_background_processor() {
+ // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
+ // updates. Also test that when new updates are available, the manager signals that it needs
+ // re-persistence and is successfully re-persisted.
+ let nodes = create_nodes(2, "test_background_processor".to_string());
+
+ // Initiate the background processors to watch each node.
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+
+ // Go through the channel creation process until each node should have something persisted.
+ let tx = open_channel!(nodes[0], nodes[1], 100000);
+
+ macro_rules! check_persisted_data {
+ ($node: expr, $filepath: expr, $expected_bytes: expr) => {
+ match $node.write(&mut $expected_bytes) {
+ Ok(()) => {
+ loop {
+ match std::fs::read($filepath) {
+ Ok(bytes) => {
+ if bytes == $expected_bytes {
+ break
+ } else {
+ continue
+ }
+ },
+ Err(_) => continue
+ }
+ }
+ },
+ Err(e) => panic!("Unexpected error: {}", e)
+ }
+ }
+ }
+
+ // Check that the initial channel manager data is persisted as expected.
+ let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ // Force-close the channel.
+ nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
+
+ // Check that the force-close updates are persisted.
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_chan_freshness_called() {
+ // Test that ChannelManager's `timer_chan_freshness_every_min` is called every
+ // `CHAN_FRESHNESS_TIMER`.
+ let nodes = create_nodes(1, "test_chan_freshness_called".to_string());
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+ loop {
+ let log_entries = nodes[0].logger.lines.lock().unwrap();
+ let desired_log = "Calling manager's timer_chan_freshness_every_min".to_string();
+ if log_entries.get(&("background_processor".to_string(), desired_log)).is_some() {
+ break
+ }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_persist_error() {
+ // Test that if we encounter an error during manager persistence, the thread panics.
+ fn persist_manager<ChanSigner, M, T, K, F, L>(_data: &ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>
+ where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ {
+ Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
+ }
+
+ let nodes = create_nodes(2, "test_persist_error".to_string());
+ let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].logger.clone());
+ open_channel!(nodes[0], nodes[1], 100000);
+
+ let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");
+	}
+}

lightning-persister/Cargo.toml

@@ -12,6 +12,9 @@ bitcoin = "0.24"
 lightning = { version = "0.0.12", path = "../lightning" }
 libc = "0.2"
 
+[target.'cfg(windows)'.dependencies]
+winapi = { version = "0.3", features = ["winbase"] }
+
 [dev-dependencies.bitcoin]
 version = "0.24"
 features = ["bitcoinconsensus"]

Cargo.toml

@@ -5,6 +5,7 @@ members = [
  "lightning-block-sync",
  "lightning-net-tokio",
  "lightning-persister",
+ "background-processor",
 ]
 
 # Our tests do actual crypo and lots of work, the tradeoff for -O1 is well worth it.

background-processor/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "background-processor"
+version = "0.1.0"
+authors = ["Valentine Wallace <vwallace@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bitcoin = "0.24"
+lightning = { version = "0.0.12", path = "../lightning", features = ["allow_wallclock_use"] }
+lightning-persister = { version = "0.0.1", path = "../lightning-persister" }
+
+[dev-dependencies]
+lightning = { version = "0.0.12", path = "../lightning", features = ["_test_utils"] }

background-processor/src/lib.rs

@@ -0,0 +1,294 @@
+#[macro_use] extern crate lightning;
+
+use lightning::chain;
+use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+use lightning::chain::keysinterface::{ChannelKeys, KeysInterface};
+use lightning::ln::channelmanager::ChannelManager;
+use lightning::util::logger::Logger;
+use lightning::util::ser::Writeable;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::thread;
+use std::thread::JoinHandle;
+use std::time::{Duration, Instant};
+
+/// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
+/// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
+/// responsibilities are:
+/// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
+/// writing it to disk/backups by invoking the callback given to it at startup.
+/// ChannelManager persistence should be done in the background.
+/// * Calling `ChannelManager::timer_chan_freshness_every_min()` every minute (can be done in the
+/// background).
+///
+/// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
+/// then there is a risk of channels force-closing on startup when the manager realizes it's
+/// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
+/// for unilateral chain closure fees are at risk.
+pub struct BackgroundProcessor {
+	stop_thread: Arc<AtomicBool>,
+	/// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
+	/// exits due to an error while persisting.
+	pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
+}
+
+#[cfg(not(test))]
+const CHAN_FRESHNESS_TIMER: u64 = 60;
+#[cfg(test)]
+const CHAN_FRESHNESS_TIMER: u64 = 1;
+
+impl BackgroundProcessor {
+	/// Start a background thread that takes care of responsibilities enumerated in the top-level
+	/// documentation.
+	///
+	/// If `persist_manager` returns an error, then this thread will return said error (and `start()`
+	/// will need to be called again to restart the `BackgroundProcessor`). Users should wait on
+	/// [`thread_handle`]'s `join()` method to be able to tell if and when an error is returned, or
+	/// implement `persist_manager` such that an error is never returned to the `BackgroundProcessor`
+	///
+	/// `persist_manager` is responsible for writing out the `ChannelManager` to disk, and/or uploading
+	/// to one or more backup services. See [`ChannelManager::write`] for writing out a `ChannelManager`.
+	/// See [`FilesystemPersister::persist_manager`] for Rust-Lightning's provided implementation.
+	///
+	/// [`thread_handle`]: struct.BackgroundProcessor.html#structfield.thread_handle
+	/// [`ChannelManager::write`]: ../lightning/ln/channelmanager/struct.ChannelManager.html#method.write
+	/// [`FilesystemPersister::persist_manager`]: ../lightning_persister/struct.FilesystemPersister.html#impl
+	pub fn start<PM, ChanSigner, M, T, K, F, L>(persist_manager: PM, manager: Arc<ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>, logger: Arc<L>) -> Self
+	where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ PM: 'static + Send + Fn(&ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>,
+	{
+ let stop_thread = Arc::new(AtomicBool::new(false));
+ let stop_thread_clone = stop_thread.clone();
+ let handle = thread::spawn(move || -> Result<(), std::io::Error> {
+ let mut current_time = Instant::now();
+ loop {
+ let updates_available = manager.wait_timeout(Duration::from_millis(100));
+ if updates_available {
+ persist_manager(&*manager)?;
+ }
+ // Exit the loop if the background processor was requested to stop.
+ if stop_thread.load(Ordering::Acquire) == true {
+ log_trace!(logger, "Terminating background processor.");
+ return Ok(())
+ }
+ if current_time.elapsed().as_secs() > CHAN_FRESHNESS_TIMER {
+ log_trace!(logger, "Calling manager's timer_chan_freshness_every_min");
+ manager.timer_chan_freshness_every_min();
+ current_time = Instant::now();
+ }
+ }
+ });
+ Self {
+ stop_thread: stop_thread_clone,
+ thread_handle: handle,
+ }
+	}
+
+	/// Stop `BackgroundProcessor`'s thread.
+	pub fn stop(self) -> Result<(), std::io::Error> {
+ self.stop_thread.store(true, Ordering::Release);
+ self.thread_handle.join().unwrap()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use bitcoin::blockdata::constants::genesis_block;
+	use bitcoin::blockdata::transaction::{Transaction, TxOut};
+	use bitcoin::network::constants::Network;
+	use lightning::chain;
+	use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+	use lightning::chain::chainmonitor;
+	use lightning::chain::keysinterface::{ChannelKeys, InMemoryChannelKeys, KeysInterface, KeysManager};
+	use lightning::chain::transaction::OutPoint;
+	use lightning::get_event_msg;
+	use lightning::ln::channelmanager::{ChannelManager, SimpleArcChannelManager};
+	use lightning::ln::features::InitFeatures;
+	use lightning::ln::msgs::ChannelMessageHandler;
+	use lightning::util::config::UserConfig;
+	use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
+	use lightning::util::logger::Logger;
+	use lightning::util::ser::Writeable;
+	use lightning::util::test_utils;
+	use lightning_persister::FilesystemPersister;
+	use std::fs;
+	use std::path::PathBuf;
+	use std::sync::{Arc, Mutex};
+	use std::time::Duration;
+	use super::BackgroundProcessor;
+
+	type ChainMonitor = chainmonitor::ChainMonitor<InMemoryChannelKeys, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
+
+	struct Node {
+ node: SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>,
+ persister: Arc<FilesystemPersister>,
+ logger: Arc<test_utils::TestLogger>,
+	}
+
+	impl Drop for Node {
+ fn drop(&mut self) {
+ let data_dir = self.persister.get_data_dir();
+ match fs::remove_dir_all(data_dir.clone()) {
+ Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
+ _ => {}
+ }
+ }
+	}
+
+	fn get_full_filepath(filepath: String, filename: String) -> String {
+ let mut path = PathBuf::from(filepath);
+ path.push(filename);
+ path.to_str().unwrap().to_string()
+	}
+
+	fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
+ let mut nodes = Vec::new();
+ for i in 0..num_nodes {
+ let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
+ let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
+ let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+ let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
+ let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
+ let seed = [i as u8; 32];
+ let network = Network::Testnet;
+ let now = Duration::from_secs(genesis_block(network).header.time as u64);
+ let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
+ let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
+ let manager = Arc::new(ChannelManager::new(Network::Testnet, fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), i));
+ let node = Node { node: manager, persister, logger };
+ nodes.push(node);
+ }
+ nodes
+	}
+
+	macro_rules! open_channel {
+ ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
+ $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
+ $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
+ let events = $node_a.node.get_and_clear_pending_events();
+ assert_eq!(events.len(), 1);
+ let (temporary_channel_id, tx, funding_output) = match events[0] {
+ Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
+ assert_eq!(*channel_value_satoshis, $channel_value);
+ assert_eq!(user_channel_id, 42);
+
+ let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
+ value: *channel_value_satoshis, script_pubkey: output_script.clone(),
+ }]};
+ let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
+ (*temporary_channel_id, tx, funding_outpoint)
+ },
+ _ => panic!("Unexpected event"),
+ };
+
+ $node_a.node.funding_transaction_generated(&temporary_channel_id, funding_output);
+ $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
+ tx
+ }}
+	}
+
+	#[test]
+	fn test_background_processor() {
+ // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
+ // updates. Also test that when new updates are available, the manager signals that it needs
+ // re-persistence and is successfully re-persisted.
+ let nodes = create_nodes(2, "test_background_processor".to_string());
+
+ // Initiate the background processors to watch each node.
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+
+ // Go through the channel creation process until each node should have something persisted.
+ let tx = open_channel!(nodes[0], nodes[1], 100000);
+
+ macro_rules! check_persisted_data {
+ ($node: expr, $filepath: expr, $expected_bytes: expr) => {
+ match $node.write(&mut $expected_bytes) {
+ Ok(()) => {
+ loop {
+ match std::fs::read($filepath) {
+ Ok(bytes) => {
+ if bytes == $expected_bytes {
+ break
+ } else {
+ continue
+ }
+ },
+ Err(_) => continue
+ }
+ }
+ },
+ Err(e) => panic!("Unexpected error: {}", e)
+ }
+ }
+ }
+
+ // Check that the initial channel manager data is persisted as expected.
+ let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ // Force-close the channel.
+ nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
+
+ // Check that the force-close updates are persisted.
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_chan_freshness_called() {
+ // Test that ChannelManager's `timer_chan_freshness_every_min` is called every
+ // `CHAN_FRESHNESS_TIMER`.
+ let nodes = create_nodes(1, "test_chan_freshness_called".to_string());
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+ loop {
+ let log_entries = nodes[0].logger.lines.lock().unwrap();
+ let desired_log = "Calling manager's timer_chan_freshness_every_min".to_string();
+ if log_entries.get(&("background_processor".to_string(), desired_log)).is_some() {
+ break
+ }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_persist_error() {
+ // Test that if we encounter an error during manager persistence, the thread panics.
+ fn persist_manager<ChanSigner, M, T, K, F, L>(_data: &ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>
+ where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ {
+ Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
+ }
+
+ let nodes = create_nodes(2, "test_persist_error".to_string());
+ let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].logger.clone());
+ open_channel!(nodes[0], nodes[1], 100000);
+
+ let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");
+	}
+}

lightning-persister/Cargo.toml

@@ -12,6 +12,9 @@ bitcoin = "0.24"
 lightning = { version = "0.0.12", path = "../lightning" }
 libc = "0.2"
 
+[target.'cfg(windows)'.dependencies]
+winapi = { version = "0.3", features = ["winbase"] }
+
 [dev-dependencies.bitcoin]
 version = "0.24"
 features = ["bitcoinconsensus"]

Cargo.toml

@@ -5,6 +5,7 @@ members = [
  "lightning-block-sync",
  "lightning-net-tokio",
  "lightning-persister",
+ "background-processor",
 ]
 
 # Our tests do actual crypo and lots of work, the tradeoff for -O1 is well worth it.

background-processor/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "background-processor"
+version = "0.1.0"
+authors = ["Valentine Wallace <vwallace@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bitcoin = "0.24"
+lightning = { version = "0.0.12", path = "../lightning", features = ["allow_wallclock_use"] }
+lightning-persister = { version = "0.0.1", path = "../lightning-persister" }
+
+[dev-dependencies]
+lightning = { version = "0.0.12", path = "../lightning", features = ["_test_utils"] }

background-processor/src/lib.rs

@@ -0,0 +1,294 @@
+#[macro_use] extern crate lightning;
+
+use lightning::chain;
+use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+use lightning::chain::keysinterface::{ChannelKeys, KeysInterface};
+use lightning::ln::channelmanager::ChannelManager;
+use lightning::util::logger::Logger;
+use lightning::util::ser::Writeable;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::thread;
+use std::thread::JoinHandle;
+use std::time::{Duration, Instant};
+
+/// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
+/// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
+/// responsibilities are:
+/// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
+/// writing it to disk/backups by invoking the callback given to it at startup.
+/// ChannelManager persistence should be done in the background.
+/// * Calling `ChannelManager::timer_chan_freshness_every_min()` every minute (can be done in the
+/// background).
+///
+/// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
+/// then there is a risk of channels force-closing on startup when the manager realizes it's
+/// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
+/// for unilateral chain closure fees are at risk.
+pub struct BackgroundProcessor {
+	stop_thread: Arc<AtomicBool>,
+	/// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
+	/// exits due to an error while persisting.
+	pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
+}
+
+#[cfg(not(test))]
+const CHAN_FRESHNESS_TIMER: u64 = 60;
+#[cfg(test)]
+const CHAN_FRESHNESS_TIMER: u64 = 1;
+
+impl BackgroundProcessor {
+	/// Start a background thread that takes care of responsibilities enumerated in the top-level
+	/// documentation.
+	///
+	/// If `persist_manager` returns an error, then this thread will return said error (and `start()`
+	/// will need to be called again to restart the `BackgroundProcessor`). Users should wait on
+	/// [`thread_handle`]'s `join()` method to be able to tell if and when an error is returned, or
+	/// implement `persist_manager` such that an error is never returned to the `BackgroundProcessor`
+	///
+	/// `persist_manager` is responsible for writing out the `ChannelManager` to disk, and/or uploading
+	/// to one or more backup services. See [`ChannelManager::write`] for writing out a `ChannelManager`.
+	/// See [`FilesystemPersister::persist_manager`] for Rust-Lightning's provided implementation.
+	///
+	/// [`thread_handle`]: struct.BackgroundProcessor.html#structfield.thread_handle
+	/// [`ChannelManager::write`]: ../lightning/ln/channelmanager/struct.ChannelManager.html#method.write
+	/// [`FilesystemPersister::persist_manager`]: ../lightning_persister/struct.FilesystemPersister.html#impl
+	pub fn start<PM, ChanSigner, M, T, K, F, L>(persist_manager: PM, manager: Arc<ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>, logger: Arc<L>) -> Self
+	where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ PM: 'static + Send + Fn(&ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>,
+	{
+ let stop_thread = Arc::new(AtomicBool::new(false));
+ let stop_thread_clone = stop_thread.clone();
+ let handle = thread::spawn(move || -> Result<(), std::io::Error> {
+ let mut current_time = Instant::now();
+ loop {
+ let updates_available = manager.wait_timeout(Duration::from_millis(100));
+ if updates_available {
+ persist_manager(&*manager)?;
+ }
+ // Exit the loop if the background processor was requested to stop.
+ if stop_thread.load(Ordering::Acquire) == true {
+ log_trace!(logger, "Terminating background processor.");
+ return Ok(())
+ }
+ if current_time.elapsed().as_secs() > CHAN_FRESHNESS_TIMER {
+ log_trace!(logger, "Calling manager's timer_chan_freshness_every_min");
+ manager.timer_chan_freshness_every_min();
+ current_time = Instant::now();
+ }
+ }
+ });
+ Self {
+ stop_thread: stop_thread_clone,
+ thread_handle: handle,
+ }
+	}
+
+	/// Stop `BackgroundProcessor`'s thread.
+	pub fn stop(self) -> Result<(), std::io::Error> {
+ self.stop_thread.store(true, Ordering::Release);
+ self.thread_handle.join().unwrap()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use bitcoin::blockdata::constants::genesis_block;
+	use bitcoin::blockdata::transaction::{Transaction, TxOut};
+	use bitcoin::network::constants::Network;
+	use lightning::chain;
+	use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+	use lightning::chain::chainmonitor;
+	use lightning::chain::keysinterface::{ChannelKeys, InMemoryChannelKeys, KeysInterface, KeysManager};
+	use lightning::chain::transaction::OutPoint;
+	use lightning::get_event_msg;
+	use lightning::ln::channelmanager::{ChannelManager, SimpleArcChannelManager};
+	use lightning::ln::features::InitFeatures;
+	use lightning::ln::msgs::ChannelMessageHandler;
+	use lightning::util::config::UserConfig;
+	use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
+	use lightning::util::logger::Logger;
+	use lightning::util::ser::Writeable;
+	use lightning::util::test_utils;
+	use lightning_persister::FilesystemPersister;
+	use std::fs;
+	use std::path::PathBuf;
+	use std::sync::{Arc, Mutex};
+	use std::time::Duration;
+	use super::BackgroundProcessor;
+
+	type ChainMonitor = chainmonitor::ChainMonitor<InMemoryChannelKeys, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
+
+	struct Node {
+ node: SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>,
+ persister: Arc<FilesystemPersister>,
+ logger: Arc<test_utils::TestLogger>,
+	}
+
+	impl Drop for Node {
+ fn drop(&mut self) {
+ let data_dir = self.persister.get_data_dir();
+ match fs::remove_dir_all(data_dir.clone()) {
+ Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
+ _ => {}
+ }
+ }
+	}
+
+	fn get_full_filepath(filepath: String, filename: String) -> String {
+ let mut path = PathBuf::from(filepath);
+ path.push(filename);
+ path.to_str().unwrap().to_string()
+	}
+
+	fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
+ let mut nodes = Vec::new();
+ for i in 0..num_nodes {
+ let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
+ let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
+ let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+ let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
+ let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
+ let seed = [i as u8; 32];
+ let network = Network::Testnet;
+ let now = Duration::from_secs(genesis_block(network).header.time as u64);
+ let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
+ let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
+ let manager = Arc::new(ChannelManager::new(Network::Testnet, fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), i));
+ let node = Node { node: manager, persister, logger };
+ nodes.push(node);
+ }
+ nodes
+	}
+
+	macro_rules! open_channel {
+ ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
+ $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
+ $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
+ let events = $node_a.node.get_and_clear_pending_events();
+ assert_eq!(events.len(), 1);
+ let (temporary_channel_id, tx, funding_output) = match events[0] {
+ Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
+ assert_eq!(*channel_value_satoshis, $channel_value);
+ assert_eq!(user_channel_id, 42);
+
+ let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
+ value: *channel_value_satoshis, script_pubkey: output_script.clone(),
+ }]};
+ let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
+ (*temporary_channel_id, tx, funding_outpoint)
+ },
+ _ => panic!("Unexpected event"),
+ };
+
+ $node_a.node.funding_transaction_generated(&temporary_channel_id, funding_output);
+ $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
+ tx
+ }}
+	}
+
+	#[test]
+	fn test_background_processor() {
+ // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
+ // updates. Also test that when new updates are available, the manager signals that it needs
+ // re-persistence and is successfully re-persisted.
+ let nodes = create_nodes(2, "test_background_processor".to_string());
+
+ // Initiate the background processors to watch each node.
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+
+ // Go through the channel creation process until each node should have something persisted.
+ let tx = open_channel!(nodes[0], nodes[1], 100000);
+
+ macro_rules! check_persisted_data {
+ ($node: expr, $filepath: expr, $expected_bytes: expr) => {
+ match $node.write(&mut $expected_bytes) {
+ Ok(()) => {
+ loop {
+ match std::fs::read($filepath) {
+ Ok(bytes) => {
+ if bytes == $expected_bytes {
+ break
+ } else {
+ continue
+ }
+ },
+ Err(_) => continue
+ }
+ }
+ },
+ Err(e) => panic!("Unexpected error: {}", e)
+ }
+ }
+ }
+
+ // Check that the initial channel manager data is persisted as expected.
+ let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ // Force-close the channel.
+ nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
+
+ // Check that the force-close updates are persisted.
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_chan_freshness_called() {
+ // Test that ChannelManager's `timer_chan_freshness_every_min` is called every
+ // `CHAN_FRESHNESS_TIMER`.
+ let nodes = create_nodes(1, "test_chan_freshness_called".to_string());
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+ loop {
+ let log_entries = nodes[0].logger.lines.lock().unwrap();
+ let desired_log = "Calling manager's timer_chan_freshness_every_min".to_string();
+ if log_entries.get(&("background_processor".to_string(), desired_log)).is_some() {
+ break
+ }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_persist_error() {
+ // Test that if we encounter an error during manager persistence, the thread panics.
+ fn persist_manager<ChanSigner, M, T, K, F, L>(_data: &ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>
+ where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ {
+ Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
+ }
+
+ let nodes = create_nodes(2, "test_persist_error".to_string());
+ let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].logger.clone());
+ open_channel!(nodes[0], nodes[1], 100000);
+
+ let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");
+	}
+}

lightning-persister/Cargo.toml

@@ -12,6 +12,9 @@ bitcoin = "0.24"
 lightning = { version = "0.0.12", path = "../lightning" }
 libc = "0.2"
 
+[target.'cfg(windows)'.dependencies]
+winapi = { version = "0.3", features = ["winbase"] }
+
 [dev-dependencies.bitcoin]
 version = "0.24"
 features = ["bitcoinconsensus"]

Cargo.toml

@@ -5,6 +5,7 @@ members = [
  "lightning-block-sync",
  "lightning-net-tokio",
  "lightning-persister",
+ "background-processor",
 ]
 
 # Our tests do actual crypo and lots of work, the tradeoff for -O1 is well worth it.

background-processor/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "background-processor"
+version = "0.1.0"
+authors = ["Valentine Wallace <vwallace@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bitcoin = "0.24"
+lightning = { version = "0.0.12", path = "../lightning", features = ["allow_wallclock_use"] }
+lightning-persister = { version = "0.0.1", path = "../lightning-persister" }
+
+[dev-dependencies]
+lightning = { version = "0.0.12", path = "../lightning", features = ["_test_utils"] }

background-processor/src/lib.rs

@@ -0,0 +1,294 @@
+#[macro_use] extern crate lightning;
+
+use lightning::chain;
+use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+use lightning::chain::keysinterface::{ChannelKeys, KeysInterface};
+use lightning::ln::channelmanager::ChannelManager;
+use lightning::util::logger::Logger;
+use lightning::util::ser::Writeable;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::thread;
+use std::thread::JoinHandle;
+use std::time::{Duration, Instant};
+
+/// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
+/// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
+/// responsibilities are:
+/// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
+/// writing it to disk/backups by invoking the callback given to it at startup.
+/// ChannelManager persistence should be done in the background.
+/// * Calling `ChannelManager::timer_chan_freshness_every_min()` every minute (can be done in the
+/// background).
+///
+/// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
+/// then there is a risk of channels force-closing on startup when the manager realizes it's
+/// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
+/// for unilateral chain closure fees are at risk.
+pub struct BackgroundProcessor {
+	stop_thread: Arc<AtomicBool>,
+	/// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
+	/// exits due to an error while persisting.
+	pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
+}
+
+#[cfg(not(test))]
+const CHAN_FRESHNESS_TIMER: u64 = 60;
+#[cfg(test)]
+const CHAN_FRESHNESS_TIMER: u64 = 1;
+
+impl BackgroundProcessor {
+	/// Start a background thread that takes care of responsibilities enumerated in the top-level
+	/// documentation.
+	///
+	/// If `persist_manager` returns an error, then this thread will return said error (and `start()`
+	/// will need to be called again to restart the `BackgroundProcessor`). Users should wait on
+	/// [`thread_handle`]'s `join()` method to be able to tell if and when an error is returned, or
+	/// implement `persist_manager` such that an error is never returned to the `BackgroundProcessor`
+	///
+	/// `persist_manager` is responsible for writing out the `ChannelManager` to disk, and/or uploading
+	/// to one or more backup services. See [`ChannelManager::write`] for writing out a `ChannelManager`.
+	/// See [`FilesystemPersister::persist_manager`] for Rust-Lightning's provided implementation.
+	///
+	/// [`thread_handle`]: struct.BackgroundProcessor.html#structfield.thread_handle
+	/// [`ChannelManager::write`]: ../lightning/ln/channelmanager/struct.ChannelManager.html#method.write
+	/// [`FilesystemPersister::persist_manager`]: ../lightning_persister/struct.FilesystemPersister.html#impl
+	pub fn start<PM, ChanSigner, M, T, K, F, L>(persist_manager: PM, manager: Arc<ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>, logger: Arc<L>) -> Self
+	where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ PM: 'static + Send + Fn(&ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>,
+	{
+ let stop_thread = Arc::new(AtomicBool::new(false));
+ let stop_thread_clone = stop_thread.clone();
+ let handle = thread::spawn(move || -> Result<(), std::io::Error> {
+ let mut current_time = Instant::now();
+ loop {
+ let updates_available = manager.wait_timeout(Duration::from_millis(100));
+ if updates_available {
+ persist_manager(&*manager)?;
+ }
+ // Exit the loop if the background processor was requested to stop.
+ if stop_thread.load(Ordering::Acquire) == true {
+ log_trace!(logger, "Terminating background processor.");
+ return Ok(())
+ }
+ if current_time.elapsed().as_secs() > CHAN_FRESHNESS_TIMER {
+ log_trace!(logger, "Calling manager's timer_chan_freshness_every_min");
+ manager.timer_chan_freshness_every_min();
+ current_time = Instant::now();
+ }
+ }
+ });
+ Self {
+ stop_thread: stop_thread_clone,
+ thread_handle: handle,
+ }
+	}
+
+	/// Stop `BackgroundProcessor`'s thread.
+	pub fn stop(self) -> Result<(), std::io::Error> {
+ self.stop_thread.store(true, Ordering::Release);
+ self.thread_handle.join().unwrap()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use bitcoin::blockdata::constants::genesis_block;
+	use bitcoin::blockdata::transaction::{Transaction, TxOut};
+	use bitcoin::network::constants::Network;
+	use lightning::chain;
+	use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+	use lightning::chain::chainmonitor;
+	use lightning::chain::keysinterface::{ChannelKeys, InMemoryChannelKeys, KeysInterface, KeysManager};
+	use lightning::chain::transaction::OutPoint;
+	use lightning::get_event_msg;
+	use lightning::ln::channelmanager::{ChannelManager, SimpleArcChannelManager};
+	use lightning::ln::features::InitFeatures;
+	use lightning::ln::msgs::ChannelMessageHandler;
+	use lightning::util::config::UserConfig;
+	use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
+	use lightning::util::logger::Logger;
+	use lightning::util::ser::Writeable;
+	use lightning::util::test_utils;
+	use lightning_persister::FilesystemPersister;
+	use std::fs;
+	use std::path::PathBuf;
+	use std::sync::{Arc, Mutex};
+	use std::time::Duration;
+	use super::BackgroundProcessor;
+
+	type ChainMonitor = chainmonitor::ChainMonitor<InMemoryChannelKeys, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
+
+	struct Node {
+ node: SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>,
+ persister: Arc<FilesystemPersister>,
+ logger: Arc<test_utils::TestLogger>,
+	}
+
+	impl Drop for Node {
+ fn drop(&mut self) {
+ let data_dir = self.persister.get_data_dir();
+ match fs::remove_dir_all(data_dir.clone()) {
+ Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
+ _ => {}
+ }
+ }
+	}
+
+	fn get_full_filepath(filepath: String, filename: String) -> String {
+ let mut path = PathBuf::from(filepath);
+ path.push(filename);
+ path.to_str().unwrap().to_string()
+	}
+
+	fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
+ let mut nodes = Vec::new();
+ for i in 0..num_nodes {
+ let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
+ let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
+ let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+ let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
+ let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
+ let seed = [i as u8; 32];
+ let network = Network::Testnet;
+ let now = Duration::from_secs(genesis_block(network).header.time as u64);
+ let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
+ let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
+ let manager = Arc::new(ChannelManager::new(Network::Testnet, fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), i));
+ let node = Node { node: manager, persister, logger };
+ nodes.push(node);
+ }
+ nodes
+	}
+
+	macro_rules! open_channel {
+ ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
+ $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
+ $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
+ let events = $node_a.node.get_and_clear_pending_events();
+ assert_eq!(events.len(), 1);
+ let (temporary_channel_id, tx, funding_output) = match events[0] {
+ Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
+ assert_eq!(*channel_value_satoshis, $channel_value);
+ assert_eq!(user_channel_id, 42);
+
+ let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
+ value: *channel_value_satoshis, script_pubkey: output_script.clone(),
+ }]};
+ let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
+ (*temporary_channel_id, tx, funding_outpoint)
+ },
+ _ => panic!("Unexpected event"),
+ };
+
+ $node_a.node.funding_transaction_generated(&temporary_channel_id, funding_output);
+ $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
+ tx
+ }}
+	}
+
+	#[test]
+	fn test_background_processor() {
+ // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
+ // updates. Also test that when new updates are available, the manager signals that it needs
+ // re-persistence and is successfully re-persisted.
+ let nodes = create_nodes(2, "test_background_processor".to_string());
+
+ // Initiate the background processors to watch each node.
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+
+ // Go through the channel creation process until each node should have something persisted.
+ let tx = open_channel!(nodes[0], nodes[1], 100000);
+
+ macro_rules! check_persisted_data {
+ ($node: expr, $filepath: expr, $expected_bytes: expr) => {
+ match $node.write(&mut $expected_bytes) {
+ Ok(()) => {
+ loop {
+ match std::fs::read($filepath) {
+ Ok(bytes) => {
+ if bytes == $expected_bytes {
+ break
+ } else {
+ continue
+ }
+ },
+ Err(_) => continue
+ }
+ }
+ },
+ Err(e) => panic!("Unexpected error: {}", e)
+ }
+ }
+ }
+
+ // Check that the initial channel manager data is persisted as expected.
+ let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ // Force-close the channel.
+ nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
+
+ // Check that the force-close updates are persisted.
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_chan_freshness_called() {
+ // Test that ChannelManager's `timer_chan_freshness_every_min` is called every
+ // `CHAN_FRESHNESS_TIMER`.
+ let nodes = create_nodes(1, "test_chan_freshness_called".to_string());
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+ loop {
+ let log_entries = nodes[0].logger.lines.lock().unwrap();
+ let desired_log = "Calling manager's timer_chan_freshness_every_min".to_string();
+ if log_entries.get(&("background_processor".to_string(), desired_log)).is_some() {
+ break
+ }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_persist_error() {
+ // Test that if we encounter an error during manager persistence, the thread panics.
+ fn persist_manager<ChanSigner, M, T, K, F, L>(_data: &ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>
+ where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ {
+ Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
+ }
+
+ let nodes = create_nodes(2, "test_persist_error".to_string());
+ let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].logger.clone());
+ open_channel!(nodes[0], nodes[1], 100000);
+
+ let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");
+	}
+}

lightning-persister/Cargo.toml

@@ -12,6 +12,9 @@ bitcoin = "0.24"
 lightning = { version = "0.0.12", path = "../lightning" }
 libc = "0.2"
 
+[target.'cfg(windows)'.dependencies]
+winapi = { version = "0.3", features = ["winbase"] }
+
 [dev-dependencies.bitcoin]
 version = "0.24"
 features = ["bitcoinconsensus"]

Cargo.toml

@@ -5,6 +5,7 @@ members = [
  "lightning-block-sync",
  "lightning-net-tokio",
  "lightning-persister",
+ "background-processor",
 ]
 
 # Our tests do actual crypo and lots of work, the tradeoff for -O1 is well worth it.

background-processor/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "background-processor"
+version = "0.1.0"
+authors = ["Valentine Wallace <vwallace@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bitcoin = "0.24"
+lightning = { version = "0.0.12", path = "../lightning", features = ["allow_wallclock_use"] }
+lightning-persister = { version = "0.0.1", path = "../lightning-persister" }
+
+[dev-dependencies]
+lightning = { version = "0.0.12", path = "../lightning", features = ["_test_utils"] }

background-processor/src/lib.rs

@@ -0,0 +1,294 @@
+#[macro_use] extern crate lightning;
+
+use lightning::chain;
+use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+use lightning::chain::keysinterface::{ChannelKeys, KeysInterface};
+use lightning::ln::channelmanager::ChannelManager;
+use lightning::util::logger::Logger;
+use lightning::util::ser::Writeable;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::thread;
+use std::thread::JoinHandle;
+use std::time::{Duration, Instant};
+
+/// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
+/// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
+/// responsibilities are:
+/// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
+/// writing it to disk/backups by invoking the callback given to it at startup.
+/// ChannelManager persistence should be done in the background.
+/// * Calling `ChannelManager::timer_chan_freshness_every_min()` every minute (can be done in the
+/// background).
+///
+/// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
+/// then there is a risk of channels force-closing on startup when the manager realizes it's
+/// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
+/// for unilateral chain closure fees are at risk.
+pub struct BackgroundProcessor {
+	stop_thread: Arc<AtomicBool>,
+	/// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
+	/// exits due to an error while persisting.
+	pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
+}
+
+#[cfg(not(test))]
+const CHAN_FRESHNESS_TIMER: u64 = 60;
+#[cfg(test)]
+const CHAN_FRESHNESS_TIMER: u64 = 1;
+
+impl BackgroundProcessor {
+	/// Start a background thread that takes care of responsibilities enumerated in the top-level
+	/// documentation.
+	///
+	/// If `persist_manager` returns an error, then this thread will return said error (and `start()`
+	/// will need to be called again to restart the `BackgroundProcessor`). Users should wait on
+	/// [`thread_handle`]'s `join()` method to be able to tell if and when an error is returned, or
+	/// implement `persist_manager` such that an error is never returned to the `BackgroundProcessor`
+	///
+	/// `persist_manager` is responsible for writing out the `ChannelManager` to disk, and/or uploading
+	/// to one or more backup services. See [`ChannelManager::write`] for writing out a `ChannelManager`.
+	/// See [`FilesystemPersister::persist_manager`] for Rust-Lightning's provided implementation.
+	///
+	/// [`thread_handle`]: struct.BackgroundProcessor.html#structfield.thread_handle
+	/// [`ChannelManager::write`]: ../lightning/ln/channelmanager/struct.ChannelManager.html#method.write
+	/// [`FilesystemPersister::persist_manager`]: ../lightning_persister/struct.FilesystemPersister.html#impl
+	pub fn start<PM, ChanSigner, M, T, K, F, L>(persist_manager: PM, manager: Arc<ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>, logger: Arc<L>) -> Self
+	where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ PM: 'static + Send + Fn(&ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>,
+	{
+ let stop_thread = Arc::new(AtomicBool::new(false));
+ let stop_thread_clone = stop_thread.clone();
+ let handle = thread::spawn(move || -> Result<(), std::io::Error> {
+ let mut current_time = Instant::now();
+ loop {
+ let updates_available = manager.wait_timeout(Duration::from_millis(100));
+ if updates_available {
+ persist_manager(&*manager)?;
+ }
+ // Exit the loop if the background processor was requested to stop.
+ if stop_thread.load(Ordering::Acquire) == true {
+ log_trace!(logger, "Terminating background processor.");
+ return Ok(())
+ }
+ if current_time.elapsed().as_secs() > CHAN_FRESHNESS_TIMER {
+ log_trace!(logger, "Calling manager's timer_chan_freshness_every_min");
+ manager.timer_chan_freshness_every_min();
+ current_time = Instant::now();
+ }
+ }
+ });
+ Self {
+ stop_thread: stop_thread_clone,
+ thread_handle: handle,
+ }
+	}
+
+	/// Stop `BackgroundProcessor`'s thread.
+	pub fn stop(self) -> Result<(), std::io::Error> {
+ self.stop_thread.store(true, Ordering::Release);
+ self.thread_handle.join().unwrap()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use bitcoin::blockdata::constants::genesis_block;
+	use bitcoin::blockdata::transaction::{Transaction, TxOut};
+	use bitcoin::network::constants::Network;
+	use lightning::chain;
+	use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+	use lightning::chain::chainmonitor;
+	use lightning::chain::keysinterface::{ChannelKeys, InMemoryChannelKeys, KeysInterface, KeysManager};
+	use lightning::chain::transaction::OutPoint;
+	use lightning::get_event_msg;
+	use lightning::ln::channelmanager::{ChannelManager, SimpleArcChannelManager};
+	use lightning::ln::features::InitFeatures;
+	use lightning::ln::msgs::ChannelMessageHandler;
+	use lightning::util::config::UserConfig;
+	use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
+	use lightning::util::logger::Logger;
+	use lightning::util::ser::Writeable;
+	use lightning::util::test_utils;
+	use lightning_persister::FilesystemPersister;
+	use std::fs;
+	use std::path::PathBuf;
+	use std::sync::{Arc, Mutex};
+	use std::time::Duration;
+	use super::BackgroundProcessor;
+
+	type ChainMonitor = chainmonitor::ChainMonitor<InMemoryChannelKeys, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
+
+	struct Node {
+ node: SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>,
+ persister: Arc<FilesystemPersister>,
+ logger: Arc<test_utils::TestLogger>,
+	}
+
+	impl Drop for Node {
+ fn drop(&mut self) {
+ let data_dir = self.persister.get_data_dir();
+ match fs::remove_dir_all(data_dir.clone()) {
+ Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
+ _ => {}
+ }
+ }
+	}
+
+	fn get_full_filepath(filepath: String, filename: String) -> String {
+ let mut path = PathBuf::from(filepath);
+ path.push(filename);
+ path.to_str().unwrap().to_string()
+	}
+
+	fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
+ let mut nodes = Vec::new();
+ for i in 0..num_nodes {
+ let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
+ let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
+ let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+ let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
+ let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
+ let seed = [i as u8; 32];
+ let network = Network::Testnet;
+ let now = Duration::from_secs(genesis_block(network).header.time as u64);
+ let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
+ let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
+ let manager = Arc::new(ChannelManager::new(Network::Testnet, fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), i));
+ let node = Node { node: manager, persister, logger };
+ nodes.push(node);
+ }
+ nodes
+	}
+
+	macro_rules! open_channel {
+ ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
+ $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
+ $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
+ let events = $node_a.node.get_and_clear_pending_events();
+ assert_eq!(events.len(), 1);
+ let (temporary_channel_id, tx, funding_output) = match events[0] {
+ Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
+ assert_eq!(*channel_value_satoshis, $channel_value);
+ assert_eq!(user_channel_id, 42);
+
+ let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
+ value: *channel_value_satoshis, script_pubkey: output_script.clone(),
+ }]};
+ let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
+ (*temporary_channel_id, tx, funding_outpoint)
+ },
+ _ => panic!("Unexpected event"),
+ };
+
+ $node_a.node.funding_transaction_generated(&temporary_channel_id, funding_output);
+ $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
+ tx
+ }}
+	}
+
+	#[test]
+	fn test_background_processor() {
+ // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
+ // updates. Also test that when new updates are available, the manager signals that it needs
+ // re-persistence and is successfully re-persisted.
+ let nodes = create_nodes(2, "test_background_processor".to_string());
+
+ // Initiate the background processors to watch each node.
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+
+ // Go through the channel creation process until each node should have something persisted.
+ let tx = open_channel!(nodes[0], nodes[1], 100000);
+
+ macro_rules! check_persisted_data {
+ ($node: expr, $filepath: expr, $expected_bytes: expr) => {
+ match $node.write(&mut $expected_bytes) {
+ Ok(()) => {
+ loop {
+ match std::fs::read($filepath) {
+ Ok(bytes) => {
+ if bytes == $expected_bytes {
+ break
+ } else {
+ continue
+ }
+ },
+ Err(_) => continue
+ }
+ }
+ },
+ Err(e) => panic!("Unexpected error: {}", e)
+ }
+ }
+ }
+
+ // Check that the initial channel manager data is persisted as expected.
+ let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ // Force-close the channel.
+ nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
+
+ // Check that the force-close updates are persisted.
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_chan_freshness_called() {
+ // Test that ChannelManager's `timer_chan_freshness_every_min` is called every
+ // `CHAN_FRESHNESS_TIMER`.
+ let nodes = create_nodes(1, "test_chan_freshness_called".to_string());
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+ loop {
+ let log_entries = nodes[0].logger.lines.lock().unwrap();
+ let desired_log = "Calling manager's timer_chan_freshness_every_min".to_string();
+ if log_entries.get(&("background_processor".to_string(), desired_log)).is_some() {
+ break
+ }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_persist_error() {
+ // Test that if we encounter an error during manager persistence, the thread panics.
+ fn persist_manager<ChanSigner, M, T, K, F, L>(_data: &ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>
+ where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ {
+ Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
+ }
+
+ let nodes = create_nodes(2, "test_persist_error".to_string());
+ let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].logger.clone());
+ open_channel!(nodes[0], nodes[1], 100000);
+
+ let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");
+	}
+}

lightning-persister/Cargo.toml

@@ -12,6 +12,9 @@ bitcoin = "0.24"
 lightning = { version = "0.0.12", path = "../lightning" }
 libc = "0.2"
 
+[target.'cfg(windows)'.dependencies]
+winapi = { version = "0.3", features = ["winbase"] }
+
 [dev-dependencies.bitcoin]
 version = "0.24"
 features = ["bitcoinconsensus"]

Cargo.toml

@@ -5,6 +5,7 @@ members = [
  "lightning-block-sync",
  "lightning-net-tokio",
  "lightning-persister",
+ "background-processor",
 ]
 
 # Our tests do actual crypo and lots of work, the tradeoff for -O1 is well worth it.

background-processor/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "background-processor"
+version = "0.1.0"
+authors = ["Valentine Wallace <vwallace@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bitcoin = "0.24"
+lightning = { version = "0.0.12", path = "../lightning", features = ["allow_wallclock_use"] }
+lightning-persister = { version = "0.0.1", path = "../lightning-persister" }
+
+[dev-dependencies]
+lightning = { version = "0.0.12", path = "../lightning", features = ["_test_utils"] }

background-processor/src/lib.rs

@@ -0,0 +1,294 @@
+#[macro_use] extern crate lightning;
+
+use lightning::chain;
+use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+use lightning::chain::keysinterface::{ChannelKeys, KeysInterface};
+use lightning::ln::channelmanager::ChannelManager;
+use lightning::util::logger::Logger;
+use lightning::util::ser::Writeable;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::thread;
+use std::thread::JoinHandle;
+use std::time::{Duration, Instant};
+
+/// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
+/// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
+/// responsibilities are:
+/// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
+/// writing it to disk/backups by invoking the callback given to it at startup.
+/// ChannelManager persistence should be done in the background.
+/// * Calling `ChannelManager::timer_chan_freshness_every_min()` every minute (can be done in the
+/// background).
+///
+/// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
+/// then there is a risk of channels force-closing on startup when the manager realizes it's
+/// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
+/// for unilateral chain closure fees are at risk.
+pub struct BackgroundProcessor {
+	stop_thread: Arc<AtomicBool>,
+	/// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
+	/// exits due to an error while persisting.
+	pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
+}
+
+#[cfg(not(test))]
+const CHAN_FRESHNESS_TIMER: u64 = 60;
+#[cfg(test)]
+const CHAN_FRESHNESS_TIMER: u64 = 1;
+
+impl BackgroundProcessor {
+	/// Start a background thread that takes care of responsibilities enumerated in the top-level
+	/// documentation.
+	///
+	/// If `persist_manager` returns an error, then this thread will return said error (and `start()`
+	/// will need to be called again to restart the `BackgroundProcessor`). Users should wait on
+	/// [`thread_handle`]'s `join()` method to be able to tell if and when an error is returned, or
+	/// implement `persist_manager` such that an error is never returned to the `BackgroundProcessor`
+	///
+	/// `persist_manager` is responsible for writing out the `ChannelManager` to disk, and/or uploading
+	/// to one or more backup services. See [`ChannelManager::write`] for writing out a `ChannelManager`.
+	/// See [`FilesystemPersister::persist_manager`] for Rust-Lightning's provided implementation.
+	///
+	/// [`thread_handle`]: struct.BackgroundProcessor.html#structfield.thread_handle
+	/// [`ChannelManager::write`]: ../lightning/ln/channelmanager/struct.ChannelManager.html#method.write
+	/// [`FilesystemPersister::persist_manager`]: ../lightning_persister/struct.FilesystemPersister.html#impl
+	pub fn start<PM, ChanSigner, M, T, K, F, L>(persist_manager: PM, manager: Arc<ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>, logger: Arc<L>) -> Self
+	where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ PM: 'static + Send + Fn(&ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>,
+	{
+ let stop_thread = Arc::new(AtomicBool::new(false));
+ let stop_thread_clone = stop_thread.clone();
+ let handle = thread::spawn(move || -> Result<(), std::io::Error> {
+ let mut current_time = Instant::now();
+ loop {
+ let updates_available = manager.wait_timeout(Duration::from_millis(100));
+ if updates_available {
+ persist_manager(&*manager)?;
+ }
+ // Exit the loop if the background processor was requested to stop.
+ if stop_thread.load(Ordering::Acquire) == true {
+ log_trace!(logger, "Terminating background processor.");
+ return Ok(())
+ }
+ if current_time.elapsed().as_secs() > CHAN_FRESHNESS_TIMER {
+ log_trace!(logger, "Calling manager's timer_chan_freshness_every_min");
+ manager.timer_chan_freshness_every_min();
+ current_time = Instant::now();
+ }
+ }
+ });
+ Self {
+ stop_thread: stop_thread_clone,
+ thread_handle: handle,
+ }
+	}
+
+	/// Stop `BackgroundProcessor`'s thread.
+	pub fn stop(self) -> Result<(), std::io::Error> {
+ self.stop_thread.store(true, Ordering::Release);
+ self.thread_handle.join().unwrap()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use bitcoin::blockdata::constants::genesis_block;
+	use bitcoin::blockdata::transaction::{Transaction, TxOut};
+	use bitcoin::network::constants::Network;
+	use lightning::chain;
+	use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+	use lightning::chain::chainmonitor;
+	use lightning::chain::keysinterface::{ChannelKeys, InMemoryChannelKeys, KeysInterface, KeysManager};
+	use lightning::chain::transaction::OutPoint;
+	use lightning::get_event_msg;
+	use lightning::ln::channelmanager::{ChannelManager, SimpleArcChannelManager};
+	use lightning::ln::features::InitFeatures;
+	use lightning::ln::msgs::ChannelMessageHandler;
+	use lightning::util::config::UserConfig;
+	use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
+	use lightning::util::logger::Logger;
+	use lightning::util::ser::Writeable;
+	use lightning::util::test_utils;
+	use lightning_persister::FilesystemPersister;
+	use std::fs;
+	use std::path::PathBuf;
+	use std::sync::{Arc, Mutex};
+	use std::time::Duration;
+	use super::BackgroundProcessor;
+
+	type ChainMonitor = chainmonitor::ChainMonitor<InMemoryChannelKeys, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
+
+	struct Node {
+ node: SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>,
+ persister: Arc<FilesystemPersister>,
+ logger: Arc<test_utils::TestLogger>,
+	}
+
+	impl Drop for Node {
+ fn drop(&mut self) {
+ let data_dir = self.persister.get_data_dir();
+ match fs::remove_dir_all(data_dir.clone()) {
+ Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
+ _ => {}
+ }
+ }
+	}
+
+	fn get_full_filepath(filepath: String, filename: String) -> String {
+ let mut path = PathBuf::from(filepath);
+ path.push(filename);
+ path.to_str().unwrap().to_string()
+	}
+
+	fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
+ let mut nodes = Vec::new();
+ for i in 0..num_nodes {
+ let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
+ let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
+ let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+ let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
+ let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
+ let seed = [i as u8; 32];
+ let network = Network::Testnet;
+ let now = Duration::from_secs(genesis_block(network).header.time as u64);
+ let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
+ let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
+ let manager = Arc::new(ChannelManager::new(Network::Testnet, fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), i));
+ let node = Node { node: manager, persister, logger };
+ nodes.push(node);
+ }
+ nodes
+	}
+
+	macro_rules! open_channel {
+ ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
+ $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
+ $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
+ let events = $node_a.node.get_and_clear_pending_events();
+ assert_eq!(events.len(), 1);
+ let (temporary_channel_id, tx, funding_output) = match events[0] {
+ Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
+ assert_eq!(*channel_value_satoshis, $channel_value);
+ assert_eq!(user_channel_id, 42);
+
+ let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
+ value: *channel_value_satoshis, script_pubkey: output_script.clone(),
+ }]};
+ let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
+ (*temporary_channel_id, tx, funding_outpoint)
+ },
+ _ => panic!("Unexpected event"),
+ };
+
+ $node_a.node.funding_transaction_generated(&temporary_channel_id, funding_output);
+ $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
+ tx
+ }}
+	}
+
+	#[test]
+	fn test_background_processor() {
+ // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
+ // updates. Also test that when new updates are available, the manager signals that it needs
+ // re-persistence and is successfully re-persisted.
+ let nodes = create_nodes(2, "test_background_processor".to_string());
+
+ // Initiate the background processors to watch each node.
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+
+ // Go through the channel creation process until each node should have something persisted.
+ let tx = open_channel!(nodes[0], nodes[1], 100000);
+
+ macro_rules! check_persisted_data {
+ ($node: expr, $filepath: expr, $expected_bytes: expr) => {
+ match $node.write(&mut $expected_bytes) {
+ Ok(()) => {
+ loop {
+ match std::fs::read($filepath) {
+ Ok(bytes) => {
+ if bytes == $expected_bytes {
+ break
+ } else {
+ continue
+ }
+ },
+ Err(_) => continue
+ }
+ }
+ },
+ Err(e) => panic!("Unexpected error: {}", e)
+ }
+ }
+ }
+
+ // Check that the initial channel manager data is persisted as expected.
+ let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ // Force-close the channel.
+ nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
+
+ // Check that the force-close updates are persisted.
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_chan_freshness_called() {
+ // Test that ChannelManager's `timer_chan_freshness_every_min` is called every
+ // `CHAN_FRESHNESS_TIMER`.
+ let nodes = create_nodes(1, "test_chan_freshness_called".to_string());
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+ loop {
+ let log_entries = nodes[0].logger.lines.lock().unwrap();
+ let desired_log = "Calling manager's timer_chan_freshness_every_min".to_string();
+ if log_entries.get(&("background_processor".to_string(), desired_log)).is_some() {
+ break
+ }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_persist_error() {
+ // Test that if we encounter an error during manager persistence, the thread panics.
+ fn persist_manager<ChanSigner, M, T, K, F, L>(_data: &ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>
+ where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ {
+ Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
+ }
+
+ let nodes = create_nodes(2, "test_persist_error".to_string());
+ let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].logger.clone());
+ open_channel!(nodes[0], nodes[1], 100000);
+
+ let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");
+	}
+}

lightning-persister/Cargo.toml

@@ -12,6 +12,9 @@ bitcoin = "0.24"
 lightning = { version = "0.0.12", path = "../lightning" }
 libc = "0.2"
 
+[target.'cfg(windows)'.dependencies]
+winapi = { version = "0.3", features = ["winbase"] }
+
 [dev-dependencies.bitcoin]
 version = "0.24"
 features = ["bitcoinconsensus"]

Cargo.toml

@@ -5,6 +5,7 @@ members = [
  "lightning-block-sync",
  "lightning-net-tokio",
  "lightning-persister",
+ "background-processor",
 ]
 
 # Our tests do actual crypo and lots of work, the tradeoff for -O1 is well worth it.

background-processor/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "background-processor"
+version = "0.1.0"
+authors = ["Valentine Wallace <vwallace@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bitcoin = "0.24"
+lightning = { version = "0.0.12", path = "../lightning", features = ["allow_wallclock_use"] }
+lightning-persister = { version = "0.0.1", path = "../lightning-persister" }
+
+[dev-dependencies]
+lightning = { version = "0.0.12", path = "../lightning", features = ["_test_utils"] }

background-processor/src/lib.rs

@@ -0,0 +1,294 @@
+#[macro_use] extern crate lightning;
+
+use lightning::chain;
+use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+use lightning::chain::keysinterface::{ChannelKeys, KeysInterface};
+use lightning::ln::channelmanager::ChannelManager;
+use lightning::util::logger::Logger;
+use lightning::util::ser::Writeable;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::thread;
+use std::thread::JoinHandle;
+use std::time::{Duration, Instant};
+
+/// BackgroundProcessor takes care of tasks that (1) need to happen periodically to keep
+/// Rust-Lightning running properly, and (2) either can or should be run in the background. Its
+/// responsibilities are:
+/// * Monitoring whether the ChannelManager needs to be re-persisted to disk, and if so,
+/// writing it to disk/backups by invoking the callback given to it at startup.
+/// ChannelManager persistence should be done in the background.
+/// * Calling `ChannelManager::timer_chan_freshness_every_min()` every minute (can be done in the
+/// background).
+///
+/// Note that if ChannelManager persistence fails and the persisted manager becomes out-of-date,
+/// then there is a risk of channels force-closing on startup when the manager realizes it's
+/// outdated. However, as long as `ChannelMonitor` backups are sound, no funds besides those used
+/// for unilateral chain closure fees are at risk.
+pub struct BackgroundProcessor {
+	stop_thread: Arc<AtomicBool>,
+	/// May be used to retrieve and handle the error if `BackgroundProcessor`'s thread
+	/// exits due to an error while persisting.
+	pub thread_handle: JoinHandle<Result<(), std::io::Error>>,
+}
+
+#[cfg(not(test))]
+const CHAN_FRESHNESS_TIMER: u64 = 60;
+#[cfg(test)]
+const CHAN_FRESHNESS_TIMER: u64 = 1;
+
+impl BackgroundProcessor {
+	/// Start a background thread that takes care of responsibilities enumerated in the top-level
+	/// documentation.
+	///
+	/// If `persist_manager` returns an error, then this thread will return said error (and `start()`
+	/// will need to be called again to restart the `BackgroundProcessor`). Users should wait on
+	/// [`thread_handle`]'s `join()` method to be able to tell if and when an error is returned, or
+	/// implement `persist_manager` such that an error is never returned to the `BackgroundProcessor`
+	///
+	/// `persist_manager` is responsible for writing out the `ChannelManager` to disk, and/or uploading
+	/// to one or more backup services. See [`ChannelManager::write`] for writing out a `ChannelManager`.
+	/// See [`FilesystemPersister::persist_manager`] for Rust-Lightning's provided implementation.
+	///
+	/// [`thread_handle`]: struct.BackgroundProcessor.html#structfield.thread_handle
+	/// [`ChannelManager::write`]: ../lightning/ln/channelmanager/struct.ChannelManager.html#method.write
+	/// [`FilesystemPersister::persist_manager`]: ../lightning_persister/struct.FilesystemPersister.html#impl
+	pub fn start<PM, ChanSigner, M, T, K, F, L>(persist_manager: PM, manager: Arc<ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>>, logger: Arc<L>) -> Self
+	where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ PM: 'static + Send + Fn(&ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>,
+	{
+ let stop_thread = Arc::new(AtomicBool::new(false));
+ let stop_thread_clone = stop_thread.clone();
+ let handle = thread::spawn(move || -> Result<(), std::io::Error> {
+ let mut current_time = Instant::now();
+ loop {
+ let updates_available = manager.wait_timeout(Duration::from_millis(100));
+ if updates_available {
+ persist_manager(&*manager)?;
+ }
+ // Exit the loop if the background processor was requested to stop.
+ if stop_thread.load(Ordering::Acquire) == true {
+ log_trace!(logger, "Terminating background processor.");
+ return Ok(())
+ }
+ if current_time.elapsed().as_secs() > CHAN_FRESHNESS_TIMER {
+ log_trace!(logger, "Calling manager's timer_chan_freshness_every_min");
+ manager.timer_chan_freshness_every_min();
+ current_time = Instant::now();
+ }
+ }
+ });
+ Self {
+ stop_thread: stop_thread_clone,
+ thread_handle: handle,
+ }
+	}
+
+	/// Stop `BackgroundProcessor`'s thread.
+	pub fn stop(self) -> Result<(), std::io::Error> {
+ self.stop_thread.store(true, Ordering::Release);
+ self.thread_handle.join().unwrap()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use bitcoin::blockdata::constants::genesis_block;
+	use bitcoin::blockdata::transaction::{Transaction, TxOut};
+	use bitcoin::network::constants::Network;
+	use lightning::chain;
+	use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
+	use lightning::chain::chainmonitor;
+	use lightning::chain::keysinterface::{ChannelKeys, InMemoryChannelKeys, KeysInterface, KeysManager};
+	use lightning::chain::transaction::OutPoint;
+	use lightning::get_event_msg;
+	use lightning::ln::channelmanager::{ChannelManager, SimpleArcChannelManager};
+	use lightning::ln::features::InitFeatures;
+	use lightning::ln::msgs::ChannelMessageHandler;
+	use lightning::util::config::UserConfig;
+	use lightning::util::events::{Event, EventsProvider, MessageSendEventsProvider, MessageSendEvent};
+	use lightning::util::logger::Logger;
+	use lightning::util::ser::Writeable;
+	use lightning::util::test_utils;
+	use lightning_persister::FilesystemPersister;
+	use std::fs;
+	use std::path::PathBuf;
+	use std::sync::{Arc, Mutex};
+	use std::time::Duration;
+	use super::BackgroundProcessor;
+
+	type ChainMonitor = chainmonitor::ChainMonitor<InMemoryChannelKeys, Arc<test_utils::TestChainSource>, Arc<test_utils::TestBroadcaster>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>, Arc<FilesystemPersister>>;
+
+	struct Node {
+ node: SimpleArcChannelManager<ChainMonitor, test_utils::TestBroadcaster, test_utils::TestFeeEstimator, test_utils::TestLogger>,
+ persister: Arc<FilesystemPersister>,
+ logger: Arc<test_utils::TestLogger>,
+	}
+
+	impl Drop for Node {
+ fn drop(&mut self) {
+ let data_dir = self.persister.get_data_dir();
+ match fs::remove_dir_all(data_dir.clone()) {
+ Err(e) => println!("Failed to remove test persister directory {}: {}", data_dir, e),
+ _ => {}
+ }
+ }
+	}
+
+	fn get_full_filepath(filepath: String, filename: String) -> String {
+ let mut path = PathBuf::from(filepath);
+ path.push(filename);
+ path.to_str().unwrap().to_string()
+	}
+
+	fn create_nodes(num_nodes: usize, persist_dir: String) -> Vec<Node> {
+ let mut nodes = Vec::new();
+ for i in 0..num_nodes {
+ let tx_broadcaster = Arc::new(test_utils::TestBroadcaster{txn_broadcasted: Mutex::new(Vec::new())});
+ let fee_estimator = Arc::new(test_utils::TestFeeEstimator { sat_per_kw: 253 });
+ let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+ let logger = Arc::new(test_utils::TestLogger::with_id(format!("node {}", i)));
+ let persister = Arc::new(FilesystemPersister::new(format!("{}_persister_{}", persist_dir, i)));
+ let seed = [i as u8; 32];
+ let network = Network::Testnet;
+ let now = Duration::from_secs(genesis_block(network).header.time as u64);
+ let keys_manager = Arc::new(KeysManager::new(&seed, now.as_secs(), now.subsec_nanos()));
+ let chain_monitor = Arc::new(chainmonitor::ChainMonitor::new(Some(chain_source.clone()), tx_broadcaster.clone(), logger.clone(), fee_estimator.clone(), persister.clone()));
+ let manager = Arc::new(ChannelManager::new(Network::Testnet, fee_estimator.clone(), chain_monitor.clone(), tx_broadcaster, logger.clone(), keys_manager.clone(), UserConfig::default(), i));
+ let node = Node { node: manager, persister, logger };
+ nodes.push(node);
+ }
+ nodes
+	}
+
+	macro_rules! open_channel {
+ ($node_a: expr, $node_b: expr, $channel_value: expr) => {{
+ $node_a.node.create_channel($node_b.node.get_our_node_id(), $channel_value, 100, 42, None).unwrap();
+ $node_b.node.handle_open_channel(&$node_a.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_a, MessageSendEvent::SendOpenChannel, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_accept_channel(&$node_b.node.get_our_node_id(), InitFeatures::known(), &get_event_msg!($node_b, MessageSendEvent::SendAcceptChannel, $node_a.node.get_our_node_id()));
+ let events = $node_a.node.get_and_clear_pending_events();
+ assert_eq!(events.len(), 1);
+ let (temporary_channel_id, tx, funding_output) = match events[0] {
+ Event::FundingGenerationReady { ref temporary_channel_id, ref channel_value_satoshis, ref output_script, user_channel_id } => {
+ assert_eq!(*channel_value_satoshis, $channel_value);
+ assert_eq!(user_channel_id, 42);
+
+ let tx = Transaction { version: 1 as i32, lock_time: 0, input: Vec::new(), output: vec![TxOut {
+ value: *channel_value_satoshis, script_pubkey: output_script.clone(),
+ }]};
+ let funding_outpoint = OutPoint { txid: tx.txid(), index: 0 };
+ (*temporary_channel_id, tx, funding_outpoint)
+ },
+ _ => panic!("Unexpected event"),
+ };
+
+ $node_a.node.funding_transaction_generated(&temporary_channel_id, funding_output);
+ $node_b.node.handle_funding_created(&$node_a.node.get_our_node_id(), &get_event_msg!($node_a, MessageSendEvent::SendFundingCreated, $node_b.node.get_our_node_id()));
+ $node_a.node.handle_funding_signed(&$node_b.node.get_our_node_id(), &get_event_msg!($node_b, MessageSendEvent::SendFundingSigned, $node_a.node.get_our_node_id()));
+ tx
+ }}
+	}
+
+	#[test]
+	fn test_background_processor() {
+ // Test that when a new channel is created, the ChannelManager needs to be re-persisted with
+ // updates. Also test that when new updates are available, the manager signals that it needs
+ // re-persistence and is successfully re-persisted.
+ let nodes = create_nodes(2, "test_background_processor".to_string());
+
+ // Initiate the background processors to watch each node.
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+
+ // Go through the channel creation process until each node should have something persisted.
+ let tx = open_channel!(nodes[0], nodes[1], 100000);
+
+ macro_rules! check_persisted_data {
+ ($node: expr, $filepath: expr, $expected_bytes: expr) => {
+ match $node.write(&mut $expected_bytes) {
+ Ok(()) => {
+ loop {
+ match std::fs::read($filepath) {
+ Ok(bytes) => {
+ if bytes == $expected_bytes {
+ break
+ } else {
+ continue
+ }
+ },
+ Err(_) => continue
+ }
+ }
+ },
+ Err(e) => panic!("Unexpected error: {}", e)
+ }
+ }
+ }
+
+ // Check that the initial channel manager data is persisted as expected.
+ let filepath = get_full_filepath("test_background_processor_persister_0".to_string(), "manager".to_string());
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ // Force-close the channel.
+ nodes[0].node.force_close_channel(&OutPoint { txid: tx.txid(), index: 0 }.to_channel_id()).unwrap();
+
+ // Check that the force-close updates are persisted.
+ let mut expected_bytes = Vec::new();
+ check_persisted_data!(nodes[0].node, filepath.clone(), expected_bytes);
+ loop {
+ if !nodes[0].node.get_persistence_condvar_value() { break }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_chan_freshness_called() {
+ // Test that ChannelManager's `timer_chan_freshness_every_min` is called every
+ // `CHAN_FRESHNESS_TIMER`.
+ let nodes = create_nodes(1, "test_chan_freshness_called".to_string());
+ let data_dir = nodes[0].persister.get_data_dir();
+ let callback = move |node: &ChannelManager<InMemoryChannelKeys, Arc<ChainMonitor>, Arc<test_utils::TestBroadcaster>, Arc<KeysManager>, Arc<test_utils::TestFeeEstimator>, Arc<test_utils::TestLogger>>| FilesystemPersister::persist_manager(data_dir.clone(), node);
+ let bg_processor = BackgroundProcessor::start(callback, nodes[0].node.clone(), nodes[0].logger.clone());
+ loop {
+ let log_entries = nodes[0].logger.lines.lock().unwrap();
+ let desired_log = "Calling manager's timer_chan_freshness_every_min".to_string();
+ if log_entries.get(&("background_processor".to_string(), desired_log)).is_some() {
+ break
+ }
+ }
+
+ assert!(bg_processor.stop().is_ok());
+	}
+
+	#[test]
+	fn test_persist_error() {
+ // Test that if we encounter an error during manager persistence, the thread panics.
+ fn persist_manager<ChanSigner, M, T, K, F, L>(_data: &ChannelManager<ChanSigner, Arc<M>, Arc<T>, Arc<K>, Arc<F>, Arc<L>>) -> Result<(), std::io::Error>
+ where ChanSigner: 'static + ChannelKeys + Writeable,
+ M: 'static + chain::Watch<Keys=ChanSigner>,
+ T: 'static + BroadcasterInterface,
+ K: 'static + KeysInterface<ChanKeySigner=ChanSigner>,
+ F: 'static + FeeEstimator,
+ L: 'static + Logger,
+ {
+ Err(std::io::Error::new(std::io::ErrorKind::Other, "test"))
+ }
+
+ let nodes = create_nodes(2, "test_persist_error".to_string());
+ let bg_processor = BackgroundProcessor::start(persist_manager, nodes[0].node.clone(), nodes[0].logger.clone());
+ open_channel!(nodes[0], nodes[1], 100000);
+
+ let _ = bg_processor.thread_handle.join().unwrap().expect_err("Errored persisting manager: test");
+	}
+}

lightning-persister/Cargo.toml

@@ -12,6 +12,9 @@ bitcoin = "0.24"
 lightning = { version = "0.0.12", path = "../lightning" }
 libc = "0.2"
 
+[target.'cfg(windows)'.dependencies]
+winapi = { version = "0.3", features = ["winbase"] }
+
 [dev-dependencies.bitcoin]
 version = "0.24"
 features = ["bitcoinconsensus"]