implement Persist and Persister with generic KVStorePersister trait

Author: johncantrell97

lightning-background-processor/src/lib.rs

@@ -20,6 +20,7 @@ use lightning::ln::peer_handler::{CustomMessageHandler, PeerManager, SocketDescr
 use lightning::routing::network_graph::{NetworkGraph, NetGraphMsgHandler};
 use lightning::util::events::{Event, EventHandler, EventsProvider};
 use lightning::util::logger::Logger;
+use lightning::util::persist::Persister;
 use std::sync::Arc;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::thread;
@@ -80,22 +81,7 @@ const FIRST_NETWORK_PRUNE_TIMER: u64 = 60;
 #[cfg(test)]
 const FIRST_NETWORK_PRUNE_TIMER: u64 = 1;
 
-/// Trait that handles persisting a [`ChannelManager`] and [`NetworkGraph`] to disk.
-pub trait Persister<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>
-where
-	M::Target: 'static + chain::Watch<Signer>,
-	T::Target: 'static + BroadcasterInterface,
-	K::Target: 'static + KeysInterface<Signer = Signer>,
-	F::Target: 'static + FeeEstimator,
-	L::Target: 'static + Logger,
-{
-	/// Persist the given [`ChannelManager`] to disk, returning an error if persistence failed
-	/// (which will cause the [`BackgroundProcessor`] which called this method to exit).
-	fn persist_manager(&self, channel_manager: &ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error>;
-
-	/// Persist the given [`NetworkGraph`] to disk, returning an error if persistence failed.
-	fn persist_graph(&self, network_graph: &NetworkGraph) -> Result<(), std::io::Error>;
-}
+
 
 /// Decorates an [`EventHandler`] with common functionality provided by standard [`EventHandler`]s.
 struct DecoratingEventHandler<
@@ -133,6 +119,7 @@ impl BackgroundProcessor {
 	/// The thread runs indefinitely unless the object is dropped, [`stop`] is called, or
 	/// [`Persister::persist_manager`] returns an error. In case of an error, the error is retrieved by calling
 	/// either [`join`] or [`stop`].
+	/// 
 	///
 	/// # Data Persistence
 	///
@@ -142,7 +129,7 @@ impl BackgroundProcessor {
 	/// provided implementation.
 	///
 	/// [`Persister::persist_graph`] is responsible for writing out the [`NetworkGraph`] to disk. See
-	/// [`NetworkGraph::write`] for writing out a [`NetworkGraph`]. See [`FilesystemPersister::persist_network_graph`]
+	/// [`NetworkGraph::write`] for writing out a [`NetworkGraph`]. See [`FilesystemPersister::persist_graph`]
 	/// for Rust-Lightning's provided implementation.
 	///
 	/// Typically, users should either implement [`Persister::persist_manager`] to never return an
@@ -161,8 +148,8 @@ impl BackgroundProcessor {
 	/// [`stop`]: Self::stop
 	/// [`ChannelManager`]: lightning::ln::channelmanager::ChannelManager
 	/// [`ChannelManager::write`]: lightning::ln::channelmanager::ChannelManager#impl-Writeable
-	/// [`FilesystemPersister::persist_manager`]: lightning_persister::FilesystemPersister::persist_manager
-	/// [`FilesystemPersister::persist_network_graph`]: lightning_persister::FilesystemPersister::persist_network_graph
+	/// [`FilesystemPersister::persist_manager`]: lightning_persister::FilesystemPersister#impl-Persister
+	/// [`FilesystemPersister::persist_graph`]: lightning_persister::FilesystemPersister#impl-Persister
 	/// [`NetworkGraph`]: lightning::routing::network_graph::NetworkGraph
 	/// [`NetworkGraph::write`]: lightning::routing::network_graph::NetworkGraph#impl-Writeable
 	pub fn start<
@@ -365,10 +352,11 @@ mod tests {
 	use lightning::util::logger::Logger;
 	use lightning::util::ser::Writeable;
 	use lightning::util::test_utils;
+	use lightning::util::persist::KVStorePersister;
 	use lightning_invoice::payment::{InvoicePayer, RetryAttempts};
 	use lightning_invoice::utils::DefaultRouter;
-	use lightning_persister::FilesystemPersister;
-	use std::fs;
+	use lightning_persister::{FilesystemPersister};
+	use std::fs::{self, File};
 	use std::ops::Deref;
 	use std::path::PathBuf;
 	use std::sync::{Arc, Mutex};
@@ -414,7 +402,7 @@ mod tests {
 	struct Persister {
 		data_dir: String,
 		graph_error: Option<(std::io::ErrorKind, &'static str)>,
-		manager_error: Option<(std::io::ErrorKind, &'static str)>
+		manager_error: Option<(std::io::ErrorKind, &'static str)>,
 	}
 
 	impl Persister {
@@ -431,25 +419,23 @@ mod tests {
 		}
 	}
 
-	impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L:Deref> super::Persister<Signer, M, T, K, F, L> for Persister where
-		M::Target: 'static + chain::Watch<Signer>,
-		T::Target: 'static + BroadcasterInterface,
-		K::Target: 'static + KeysInterface<Signer = Signer>,
-		F::Target: 'static + FeeEstimator,
-		L::Target: 'static + Logger,
-	{
-		fn persist_manager(&self, channel_manager: &ChannelManager<Signer, M, T, K, F, L>) -> Result<(), std::io::Error> {
-			match self.manager_error {
-				None => FilesystemPersister::persist_manager(self.data_dir.clone(), channel_manager),
-				Some((error, message)) => Err(std::io::Error::new(error, message)),
+	impl KVStorePersister for Persister {
+		fn persist<W: Writeable>(&self, key: String, object: &W) -> std::io::Result<()> {
+			if key == self.get_channel_manager_key() {
+				return match self.manager_error {
+					None => Ok(()),
+					Some((error, message)) => Err(std::io::Error::new(error, message))
+				}
 			}
-		}
 
-		fn persist_graph(&self, network_graph: &NetworkGraph) -> Result<(), std::io::Error> {
-			match self.graph_error {
-				None => FilesystemPersister::persist_network_graph(self.data_dir.clone(), network_graph),
-				Some((error, message)) => Err(std::io::Error::new(error, message)),
+			if key == self.get_network_graph_key() {
+				return match self.graph_error {
+					None => Ok(()),
+					Some((error, message)) => Err(std::io::Error::new(error, message))
+				}
 			}
+
+			Ok(())
 		}
 	}
 

lightning-persister/src/lib.rs

@@ -15,22 +15,15 @@ extern crate bitcoin;
 extern crate libc;
 
 use bitcoin::hash_types::{BlockHash, Txid};
-use bitcoin::hashes::hex::{FromHex, ToHex};
-use lightning::routing::network_graph::NetworkGraph;
-use crate::util::DiskWriteable;
-use lightning::chain;
-use lightning::chain::chaininterface::{BroadcasterInterface, FeeEstimator};
-use lightning::chain::channelmonitor::{ChannelMonitor, ChannelMonitorUpdate};
-use lightning::chain::chainmonitor;
+use bitcoin::hashes::hex::FromHex;
+use lightning::chain::channelmonitor::ChannelMonitor;
 use lightning::chain::keysinterface::{Sign, KeysInterface};
-use lightning::chain::transaction::OutPoint;
-use lightning::ln::channelmanager::ChannelManager;
-use lightning::util::logger::Logger;
 use lightning::util::ser::{ReadableArgs, Writeable};
+use lightning::util::persist::KVStorePersister;
 use std::fs;
-use std::io::{Cursor, Error};
+use std::io::Cursor;
 use std::ops::Deref;
-use std::path::{Path, PathBuf};
+use std::path::{Path, PathBuf, MAIN_SEPARATOR};
 
 /// FilesystemPersister persists channel data on disk, where each channel's
 /// data is stored in a file named after its funding outpoint.
@@ -48,31 +41,6 @@ pub struct FilesystemPersister {
 	path_to_channel_data: String,
 }
 
-impl<Signer: Sign> DiskWriteable for ChannelMonitor<Signer> {
-	fn write_to_file(&self, writer: &mut fs::File) -> Result<(), Error> {
-		self.write(writer)
-	}
-}
-
-impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> DiskWriteable for ChannelManager<Signer, M, T, K, F, L>
-where
-	M::Target: chain::Watch<Signer>,
-	T::Target: BroadcasterInterface,
-	K::Target: KeysInterface<Signer=Signer>,
-	F::Target: FeeEstimator,
-	L::Target: Logger,
-{
-	fn write_to_file(&self, writer: &mut fs::File) -> Result<(), std::io::Error> {
-		self.write(writer)
-	}
-}
-
-impl DiskWriteable for NetworkGraph {
-	fn write_to_file(&self, writer: &mut fs::File) -> Result<(), std::io::Error> {
-		self.write(writer)
-	}
-}
-
 impl FilesystemPersister {
 	/// Initialize a new FilesystemPersister and set the path to the individual channels'
 	/// files.
@@ -87,34 +55,8 @@ impl FilesystemPersister {
 		self.path_to_channel_data.clone()
 	}
 
-	pub(crate) fn path_to_monitor_data(&self) -> PathBuf {
-		let mut path = PathBuf::from(self.path_to_channel_data.clone());
-		path.push("monitors");
-		path
-	}
-
-	/// Writes the provided `ChannelManager` to the path provided at `FilesystemPersister`
-	/// initialization, within a file called "manager".
-	pub fn persist_manager<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref>(
-		data_dir: String,
-		manager: &ChannelManager<Signer, M, T, K, F, L>
-	) -> Result<(), std::io::Error>
-	where
-		M::Target: chain::Watch<Signer>,
-		T::Target: BroadcasterInterface,
-		K::Target: KeysInterface<Signer=Signer>,
-		F::Target: FeeEstimator,
-		L::Target: Logger,
-	{
-		let path = PathBuf::from(data_dir);
-		util::write_to_file(path, "manager".to_string(), manager)
-	}
-
-	/// Write the provided `NetworkGraph` to the path provided at `FilesystemPersister`
-	/// initialization, within a file called "network_graph"
-	pub fn persist_network_graph(data_dir: String, network_graph: &NetworkGraph) -> Result<(), std::io::Error> {
-		let path = PathBuf::from(data_dir);
-		util::write_to_file(path, "network_graph".to_string(), network_graph)
+	pub(crate) fn path_to_monitor_data(&self) -> String {
+			format!("{}{}monitors", self.path_to_channel_data, MAIN_SEPARATOR)
 	}
 
 	/// Read `ChannelMonitor`s from disk.
@@ -124,7 +66,7 @@ impl FilesystemPersister {
 		where K::Target: KeysInterface<Signer=Signer> + Sized,
 	{
 		let path = self.path_to_monitor_data();
-		if !Path::new(&path).exists() {
+		if !Path::new(&PathBuf::from(&path)).exists() {
 			return Ok(Vec::new());
 		}
 		let mut res = Vec::new();
@@ -180,22 +122,9 @@ impl FilesystemPersister {
 	}
 }
 
-impl<ChannelSigner: Sign> chainmonitor::Persist<ChannelSigner> for FilesystemPersister {
-	// TODO: We really need a way for the persister to inform the user that its time to crash/shut
-	// down once these start returning failure.
-	// A PermanentFailure implies we need to shut down since we're force-closing channels without
-	// even broadcasting!
-
-	fn persist_new_channel(&self, funding_txo: OutPoint, monitor: &ChannelMonitor<ChannelSigner>, _update_id: chainmonitor::MonitorUpdateId) -> Result<(), chain::ChannelMonitorUpdateErr> {
-		let filename = format!("{}_{}", funding_txo.txid.to_hex(), funding_txo.index);
-		util::write_to_file(self.path_to_monitor_data(), filename, monitor)
-			.map_err(|_| chain::ChannelMonitorUpdateErr::PermanentFailure)
-	}
-
-	fn update_persisted_channel(&self, funding_txo: OutPoint, _update: &Option<ChannelMonitorUpdate>, monitor: &ChannelMonitor<ChannelSigner>, _update_id: chainmonitor::MonitorUpdateId) -> Result<(), chain::ChannelMonitorUpdateErr> {
-		let filename = format!("{}_{}", funding_txo.txid.to_hex(), funding_txo.index);
-		util::write_to_file(self.path_to_monitor_data(), filename, monitor)
-			.map_err(|_| chain::ChannelMonitorUpdateErr::PermanentFailure)
+impl KVStorePersister for FilesystemPersister {
+	fn persist<W: Writeable>(&self, key: String, object: &W) -> std::io::Result<()> {
+		util::write_to_file(format!("{}{}{}", self.path_to_channel_data, MAIN_SEPARATOR, key), object)
 	}
 }
 

lightning-persister/src/util.rs

@@ -7,21 +7,14 @@ use std::path::{Path, PathBuf};
 #[cfg(not(target_os = "windows"))]
 use std::os::unix::io::AsRawFd;
 
+use lightning::util::ser::Writeable;
+
 #[cfg(target_os = "windows")]
 use {
 	std::ffi::OsStr,
 	std::os::windows::ffi::OsStrExt
 };
 
-pub(crate) trait DiskWriteable {
-	fn write_to_file(&self, writer: &mut fs::File) -> Result<(), std::io::Error>;
-}
-
-pub(crate) fn get_full_filepath(mut filepath: PathBuf, filename: String) -> String {
-	filepath.push(filename);
-	filepath.to_str().unwrap().to_string()
-}
-
 #[cfg(target_os = "windows")]
 macro_rules! call {
 	($e: expr) => (
@@ -39,21 +32,25 @@ fn path_to_windows_str<T: AsRef<OsStr>>(path: T) -> Vec<winapi::shared::ntdef::W
 }
 
 #[allow(bare_trait_objects)]
-pub(crate) fn write_to_file<D: DiskWriteable>(path: PathBuf, filename: String, data: &D) -> std::io::Result<()> {
-	fs::create_dir_all(path.clone())?;
+pub(crate) fn write_to_file<W: Writeable>(filename_with_path: String, data: &W) -> std::io::Result<()> {
+	let mut tmp_filename = filename_with_path.clone();
+	tmp_filename.push_str(".tmp");
+
+	let full_path = PathBuf::from(&filename_with_path);
+	let path = full_path.parent().unwrap();
+	fs::create_dir_all(path)?;
 	// Do a crazy dance with lots of fsync()s to be overly cautious here...
 	// We never want to end up in a state where we've lost the old data, or end up using the
 	// old data on power loss after we've returned.
 	// The way to atomically write a file on Unix platforms is:
 	// open(tmpname), write(tmpfile), fsync(tmpfile), close(tmpfile), rename(), fsync(dir)
-	let filename_with_path = get_full_filepath(path, filename);
-	let tmp_filename = format!("{}.tmp", filename_with_path.clone());
+	
 
 	{
 		// Note that going by rust-lang/rust@d602a6b, on MacOS it is only safe to use
 		// rust stdlib 1.36 or higher.
 		let mut f = fs::File::create(&tmp_filename)?;
-		data.write_to_file(&mut f)?;
+		data.write(&mut f)?;
 		f.sync_all()?;
 	}
 	// Fsync the parent directory on Unix.
@@ -87,15 +84,17 @@ pub(crate) fn write_to_file<D: DiskWriteable>(path: PathBuf, filename: String, d
 
 #[cfg(test)]
 mod tests {
-	use super::{DiskWriteable, get_full_filepath, write_to_file};
+	use lightning::util::ser::{Writer, Writeable};
+
+use super::{write_to_file};
 	use std::fs;
 	use std::io;
 	use std::io::Write;
-	use std::path::PathBuf;
+	use std::path::{PathBuf, MAIN_SEPARATOR};
 
 	struct TestWriteable{}
-	impl DiskWriteable for TestWriteable {
-		fn write_to_file(&self, writer: &mut fs::File) -> Result<(), io::Error> {
+	impl Writeable for TestWriteable {
+		fn write<W: Writer>(&self, writer: &mut W) -> Result<(), std::io::Error> {
 			writer.write_all(&[42; 1])
 		}
 	}
@@ -113,7 +112,8 @@ mod tests {
 		let mut perms = fs::metadata(path.to_string()).unwrap().permissions();
 		perms.set_readonly(true);
 		fs::set_permissions(path.to_string(), perms).unwrap();
-		match write_to_file(PathBuf::from(path.to_string()), filename, &test_writeable) {
+
+		match write_to_file(format!("{}{}{}", path, MAIN_SEPARATOR, filename), &test_writeable) {
 			Err(e) => assert_eq!(e.kind(), io::ErrorKind::PermissionDenied),
 			_ => panic!("Unexpected error message")
 		}
@@ -131,10 +131,11 @@ mod tests {
 	fn test_rename_failure() {
 		let test_writeable = TestWriteable{};
 		let filename = "test_rename_failure_filename";
-		let path = PathBuf::from("test_rename_failure_dir");
+		let path = "test_rename_failure_dir";
+		let full_file_path = format!("{}{}{}", path, MAIN_SEPARATOR, filename);
 		// Create the channel data file and make it a directory.
-		fs::create_dir_all(get_full_filepath(path.clone(), filename.to_string())).unwrap();
-		match write_to_file(path.clone(), filename.to_string(), &test_writeable) {
+		fs::create_dir_all(full_file_path.clone()).unwrap();
+		match write_to_file(full_file_path, &test_writeable) {
 			Err(e) => assert_eq!(e.raw_os_error(), Some(libc::EISDIR)),
 			_ => panic!("Unexpected Ok(())")
 		}
@@ -144,16 +145,17 @@ mod tests {
 	#[test]
 	fn test_diskwriteable_failure() {
 		struct FailingWriteable {}
-		impl DiskWriteable for FailingWriteable {
-			fn write_to_file(&self, _writer: &mut fs::File) -> Result<(), std::io::Error> {
+		impl Writeable for FailingWriteable {
+			fn write<W: Writer>(&self, _writer: &mut W) -> Result<(), std::io::Error> {
 				Err(std::io::Error::new(std::io::ErrorKind::Other, "expected failure"))
 			}
 		}
 
 		let filename = "test_diskwriteable_failure";
-		let path = PathBuf::from("test_diskwriteable_failure_dir");
+		let path = "test_diskwriteable_failure_dir";
 		let test_writeable = FailingWriteable{};
-		match write_to_file(path.clone(), filename.to_string(), &test_writeable) {
+		let full_path = format!("{}{}{}", path, MAIN_SEPARATOR, filename);
+		match write_to_file(full_path.clone(), &test_writeable) {
 			Err(e) => {
 				assert_eq!(e.kind(), std::io::ErrorKind::Other);
 				assert_eq!(e.get_ref().unwrap().to_string(), "expected failure");
@@ -170,12 +172,11 @@ mod tests {
 	fn test_tmp_file_creation_failure() {
 		let test_writeable = TestWriteable{};
 		let filename = "test_tmp_file_creation_failure_filename".to_string();
-		let path = PathBuf::from("test_tmp_file_creation_failure_dir");
-
-		// Create the tmp file and make it a directory.
-		let tmp_path = get_full_filepath(path.clone(), format!("{}.tmp", filename.clone()));
+		let path = "test_tmp_file_creation_failure_dir";
+		let tmp_path = format!("{}{}{}.tmp", path, MAIN_SEPARATOR, filename.clone());
+		let full_filepath = format!("{}{}{}", path, MAIN_SEPARATOR, filename);
 		fs::create_dir_all(tmp_path).unwrap();
-		match write_to_file(path, filename, &test_writeable) {
+		match write_to_file(full_filepath, &test_writeable) {
 			Err(e) => {
 				#[cfg(not(target_os = "windows"))]
 				assert_eq!(e.raw_os_error(), Some(libc::EISDIR));