Local snapshot restore (#2058)

* restore from local snapshot

* update status with chunks done

* rework local restore trigger

ethcore/src/service.rs

@@ -186,7 +186,7 @@ impl IoHandler<ClientIoMessage> for ClientIoHandler {
 			ClientIoMessage::BlockVerified => { self.client.import_verified_blocks(); }
 			ClientIoMessage::NewTransactions(ref transactions) => { self.client.import_queued_transactions(transactions); }
 			ClientIoMessage::BeginRestoration(ref manifest) => {
-				if let Err(e) = self.snapshot.init_restore(manifest.clone()) {
+				if let Err(e) = self.snapshot.init_restore(manifest.clone(), true) {
 					warn!("Failed to initialize snapshot restoration: {}", e);
 				}
 			}

ethcore/src/snapshot/service.rs

@@ -35,7 +35,7 @@ use service::ClientIoMessage;
 
 use io::IoChannel;
 
-use util::{Bytes, H256, Mutex, RwLock, UtilError};
+use util::{Bytes, H256, Mutex, RwLock, RwLockReadGuard, UtilError};
 use util::journaldb::Algorithm;
 use util::kvdb::{Database, DatabaseConfig};
 use util::snappy;
@@ -70,7 +70,7 @@ struct Restoration {
 	block_chunks_left: HashSet<H256>,
 	state: StateRebuilder,
 	blocks: BlockRebuilder,
-	writer: LooseWriter,
+	writer: Option<LooseWriter>,
 	snappy_buffer: Bytes,
 	final_state_root: H256,
 	guard: Guard,
@@ -80,8 +80,8 @@ struct RestorationParams<'a> {
 	manifest: ManifestData, // manifest to base restoration on.
 	pruning: Algorithm, // pruning algorithm for the database.
 	db_path: PathBuf, // database path
-	db_config: &'a DatabaseConfig,
+	db_config: &'a DatabaseConfig, // configuration for the database.
-	writer: LooseWriter, // writer for recovered snapshot.
+	writer: Option<LooseWriter>, // writer for recovered snapshot.
 	genesis: &'a [u8], // genesis block of the chain.
 	guard: Guard, // guard for the restoration directory.
 }
@@ -120,7 +120,10 @@ impl Restoration {
 			let len = try!(snappy::decompress_into(chunk, &mut self.snappy_buffer));
 
 			try!(self.state.feed(&self.snappy_buffer[..len]));
-			try!(self.writer.write_state_chunk(hash, chunk));
+
+			if let Some(ref mut writer) = self.writer.as_mut() {
+				try!(writer.write_state_chunk(hash, chunk));
+			}
 		}
 
 		Ok(())
@@ -132,7 +135,9 @@ impl Restoration {
 			let len = try!(snappy::decompress_into(chunk, &mut self.snappy_buffer));
 
 			try!(self.blocks.feed(&self.snappy_buffer[..len], engine));
-			try!(self.writer.write_block_chunk(hash, chunk));
+			if let Some(ref mut writer) = self.writer.as_mut() {
+				try!(writer.write_block_chunk(hash, chunk));
+			}
 		}
 
 		Ok(())
@@ -157,7 +162,9 @@ impl Restoration {
 		// connect out-of-order chunks.
 		self.blocks.glue_chunks();
 
-		try!(self.writer.finish(self.manifest));
+		if let Some(writer) = self.writer {
+			try!(writer.finish(self.manifest));
+		}
 
 		self.guard.disarm();
 		Ok(())
@@ -300,6 +307,11 @@ impl Service {
 		Ok(())
 	}
 
+	/// Get a reference to the snapshot reader.
+	pub fn reader(&self) -> RwLockReadGuard<Option<LooseReader>> {
+		self.reader.read()
+	}
+
 	/// Tick the snapshot service. This will log any active snapshot
 	/// being taken.
 	pub fn tick(&self) {
@@ -351,11 +363,15 @@ impl Service {
 	}
 
 	/// Initialize the restoration synchronously.
-	pub fn init_restore(&self, manifest: ManifestData) -> Result<(), Error> {
+	/// The recover flag indicates whether to recover the restored snapshot.
+	pub fn init_restore(&self, manifest: ManifestData, recover: bool) -> Result<(), Error> {
 		let rest_dir = self.restoration_dir();
 
 		let mut res = self.restoration.lock();
 
+		self.state_chunks.store(0, Ordering::SeqCst);
+		self.block_chunks.store(0, Ordering::SeqCst);
+
 		// tear down existing restoration.
 		*res = None;
 
@@ -370,7 +386,10 @@ impl Service {
 		try!(fs::create_dir_all(&rest_dir));
 
 		// make new restoration.
-		let writer = try!(LooseWriter::new(self.temp_recovery_dir()));
+		let writer = match recover {
+			true => Some(try!(LooseWriter::new(self.temp_recovery_dir()))),
+			false => None
+		};
 
 		let params = RestorationParams {
 			manifest: manifest,
@@ -385,8 +404,8 @@ impl Service {
 		*res = Some(try!(Restoration::new(params)));
 
 		*self.status.lock() = RestorationStatus::Ongoing {
-			state_chunks_done: self.state_chunks.load(Ordering::Relaxed) as u32,
+			state_chunks_done: self.state_chunks.load(Ordering::SeqCst) as u32,
-			block_chunks_done: self.block_chunks.load(Ordering::Relaxed) as u32,
+			block_chunks_done: self.block_chunks.load(Ordering::SeqCst) as u32,
 		};
 		Ok(())
 	}
@@ -397,13 +416,13 @@ impl Service {
 	fn finalize_restoration(&self, rest: &mut Option<Restoration>) -> Result<(), Error> {
 		trace!(target: "snapshot", "finalizing restoration");
 
-		self.state_chunks.store(0, Ordering::SeqCst);
+		let recover = rest.as_ref().map_or(false, |rest| rest.writer.is_some());
-		self.block_chunks.store(0, Ordering::SeqCst);
 
 		// destroy the restoration before replacing databases and snapshot.
 		try!(rest.take().map(Restoration::finalize).unwrap_or(Ok(())));
 		try!(self.replace_client_db());
 
+		if recover {
 			let mut reader = self.reader.write();
 			*reader = None; // destroy the old reader if it existed.
 
@@ -422,10 +441,10 @@ impl Service {
 			trace!(target: "snapshot", "copying restored snapshot files over");
 			try!(fs::rename(self.temp_recovery_dir(), &snapshot_dir));
 
-		let _ = fs::remove_dir_all(self.restoration_dir());
-
 			*reader = Some(try!(LooseReader::new(snapshot_dir)));
+		}
 
+		let _ = fs::remove_dir_all(self.restoration_dir());
 		*self.status.lock() = RestorationStatus::Inactive;
 
 		Ok(())
@@ -506,7 +525,13 @@ impl SnapshotService for Service {
 	}
 
 	fn status(&self) -> RestorationStatus {
-		*self.status.lock()
+		let mut cur_status = self.status.lock();
+		if let RestorationStatus::Ongoing { ref mut state_chunks_done, ref mut block_chunks_done } = *cur_status {
+			*state_chunks_done = self.state_chunks.load(Ordering::SeqCst) as u32;
+			*block_chunks_done = self.block_chunks.load(Ordering::SeqCst) as u32;
+		}
+
+		cur_status.clone()
 	}
 
 	fn begin_restore(&self, manifest: ManifestData) {

parity/cli.rs

@@ -33,7 +33,7 @@ Usage:
   parity export [ <file> ] [options]
   parity signer new-token [options]
   parity snapshot <file> [options]
-  parity restore <file> [options]
+  parity restore [ <file> ] [options]
 
 Operating Options:
   --mode MODE              Set the operating mode. MODE can be one of:

parity/snapshot.rs

@@ -21,8 +21,9 @@ use std::path::{Path, PathBuf};
 use std::sync::Arc;
 
 use ethcore_logger::{setup_log, Config as LogConfig};
-use ethcore::snapshot::{Progress, RestorationStatus, SnapshotService};
+use ethcore::snapshot::{Progress, RestorationStatus, SnapshotService as SS};
 use ethcore::snapshot::io::{SnapshotReader, PackedReader, PackedWriter};
+use ethcore::snapshot::service::Service as SnapshotService;
 use ethcore::service::ClientService;
 use ethcore::client::{Mode, DatabaseCompactionProfile, Switch, VMType};
 use ethcore::miner::Miner;
@@ -62,6 +63,60 @@ pub struct SnapshotCommand {
 	pub block_at: BlockID,
 }
 
+// helper for reading chunks from arbitrary reader and feeding them into the
+// service.
+fn restore_using<R: SnapshotReader>(snapshot: Arc<SnapshotService>, reader: &R, recover: bool) -> Result<(), String> {
+	let manifest = reader.manifest();
+
+	info!("Restoring to block #{} (0x{:?})", manifest.block_number, manifest.block_hash);
+
+	try!(snapshot.init_restore(manifest.clone(), recover).map_err(|e| {
+		format!("Failed to begin restoration: {}", e)
+	}));
+
+	let (num_state, num_blocks) = (manifest.state_hashes.len(), manifest.block_hashes.len());
+
+	let informant_handle = snapshot.clone();
+	::std::thread::spawn(move || {
+ 		while let RestorationStatus::Ongoing { state_chunks_done, block_chunks_done } = informant_handle.status() {
+ 			info!("Processed {}/{} state chunks and {}/{} block chunks.",
+ 				state_chunks_done, num_state, block_chunks_done, num_blocks);
+ 			::std::thread::sleep(Duration::from_secs(5));
+ 		}
+ 	});
+
+ 	info!("Restoring state");
+ 	for &state_hash in &manifest.state_hashes {
+ 		if snapshot.status() == RestorationStatus::Failed {
+ 			return Err("Restoration failed".into());
+ 		}
+
+ 		let chunk = try!(reader.chunk(state_hash)
+			.map_err(|e| format!("Encountered error while reading chunk {:?}: {}", state_hash, e)));
+ 		snapshot.feed_state_chunk(state_hash, &chunk);
+ 	}
+
+	info!("Restoring blocks");
+	for &block_hash in &manifest.block_hashes {
+		if snapshot.status() == RestorationStatus::Failed {
+			return Err("Restoration failed".into());
+		}
+
+ 		let chunk = try!(reader.chunk(block_hash)
+			.map_err(|e| format!("Encountered error while reading chunk {:?}: {}", block_hash, e)));
+		snapshot.feed_block_chunk(block_hash, &chunk);
+	}
+
+	match snapshot.status() {
+		RestorationStatus::Ongoing { .. } => Err("Snapshot file is incomplete and missing chunks.".into()),
+		RestorationStatus::Failed => Err("Snapshot restoration failed.".into()),
+		RestorationStatus::Inactive => {
+			info!("Restoration complete.");
+			Ok(())
+		}
+	}
+}
+
 impl SnapshotCommand {
 	// shared portion of snapshot commands: start the client service
 	fn start_service(self) -> Result<(ClientService, Arc<PanicHandler>), String> {
@@ -106,70 +161,36 @@ impl SnapshotCommand {
 
 	/// restore from a snapshot
 	pub fn restore(self) -> Result<(), String> {
-		let file = try!(self.file_path.clone().ok_or("No file path provided.".to_owned()));
+		let file = self.file_path.clone();
 		let (service, _panic_handler) = try!(self.start_service());
 
 		warn!("Snapshot restoration is experimental and the format may be subject to change.");
 		warn!("On encountering an unexpected error, please ensure that you have a recent snapshot.");
 
 		let snapshot = service.snapshot_service();
+
+		if let Some(file) = file {
+			info!("Attempting to restore from snapshot at '{}'", file);
+
 			let reader = PackedReader::new(Path::new(&file))
 				.map_err(|e| format!("Couldn't open snapshot file: {}", e))
 				.and_then(|x| x.ok_or("Snapshot file has invalid format.".into()));
 
 			let reader = try!(reader);
-		let manifest = reader.manifest();
+			try!(restore_using(snapshot, &reader, true));
+		} else {
+			info!("Attempting to restore from local snapshot.");
 
-		// drop the client so we don't restore while it has open DB handles.
+			// attempting restoration with recovery will lead to deadlock
-		drop(service);
+			// as we currently hold a read lock on the service's reader.
-
+			match *snapshot.reader() {
-		try!(snapshot.init_restore(manifest.clone()).map_err(|e| {
+				Some(ref reader) => try!(restore_using(snapshot.clone(), reader, false)),
-			format!("Failed to begin restoration: {}", e)
+				None => return Err("No local snapshot found.".into()),
-		}));
-
-		let (num_state, num_blocks) = (manifest.state_hashes.len(), manifest.block_hashes.len());
-
-		let informant_handle = snapshot.clone();
-		::std::thread::spawn(move || {
- 			while let RestorationStatus::Ongoing { state_chunks_done, block_chunks_done } = informant_handle.status() {
- 				info!("Processed {}/{} state chunks and {}/{} block chunks.",
- 					state_chunks_done, num_state, block_chunks_done, num_blocks);
-
- 				::std::thread::sleep(Duration::from_secs(5));
 			}
- 		});
-
- 		info!("Restoring state");
- 		for &state_hash in &manifest.state_hashes {
- 			if snapshot.status() == RestorationStatus::Failed {
- 				return Err("Restoration failed".into());
 		}
 
- 			let chunk = try!(reader.chunk(state_hash)
-				.map_err(|e| format!("Encountered error while reading chunk {:?}: {}", state_hash, e)));
- 			snapshot.feed_state_chunk(state_hash, &chunk);
- 		}
-
-		info!("Restoring blocks");
-		for &block_hash in &manifest.block_hashes {
-			if snapshot.status() == RestorationStatus::Failed {
-				return Err("Restoration failed".into());
-			}
-
- 			let chunk = try!(reader.chunk(block_hash)
-				.map_err(|e| format!("Encountered error while reading chunk {:?}: {}", block_hash, e)));
-			snapshot.feed_block_chunk(block_hash, &chunk);
-		}
-
-		match snapshot.status() {
-			RestorationStatus::Ongoing { .. } => Err("Snapshot file is incomplete and missing chunks.".into()),
-			RestorationStatus::Failed => Err("Snapshot restoration failed.".into()),
-			RestorationStatus::Inactive => {
-				info!("Restoration complete.");
 		Ok(())
 	}
-		}
-	}
 
 	/// Take a snapshot from the head of the chain.
 	pub fn take_snapshot(self) -> Result<(), String> {

util/src/kvdb.rs

@@ -458,8 +458,6 @@ impl Database {
 		let mut backup_db = PathBuf::from(&self.path);
 		backup_db.pop();
 		backup_db.push("backup_db");
-		println!("Path at {:?}", self.path);
-		println!("Backup at {:?}", backup_db);
 
 		let existed = match fs::rename(&self.path, &backup_db) {
 			Ok(_) => true,