Add timeout for on-chain syncing

.. to make progress and unblock the `Mutex` even if BDK's wallet `sync` would never return.

Author: tnull

bindings/ldk_node.udl

@@ -158,6 +158,7 @@ enum NodeError {
 	"PersistenceFailed",
 	"FeerateEstimationUpdateFailed",
 	"WalletOperationFailed",
+	"WalletOperationTimeout",
 	"OnchainTxSigningFailed",
 	"MessageSigningFailed",
 	"TxSyncFailed",

src/config.rs

@@ -45,6 +45,9 @@ pub(crate) const NODE_ANN_BCAST_INTERVAL: Duration = Duration::from_secs(60 * 60
 // The lower limit which we apply to any configured wallet sync intervals.
 pub(crate) const WALLET_SYNC_INTERVAL_MINIMUM_SECS: u64 = 10;
 
+// The timeout after which we abort a wallet syncing operation.
+pub(crate) const BDK_WALLET_SYNC_TIMEOUT_SECS: u64 = 90;
+
 // The length in bytes of our wallets' keys seed.
 pub(crate) const WALLET_KEYS_SEED_LEN: usize = 64;
 

src/error.rs

@@ -35,6 +35,8 @@ pub enum Error {
 	FeerateEstimationUpdateFailed,
 	/// A wallet operation failed.
 	WalletOperationFailed,
+	/// A wallet operation timed out.
+	WalletOperationTimeout,
 	/// A signing operation for transaction failed.
 	OnchainTxSigningFailed,
 	/// A signing operation for message failed.
@@ -112,6 +114,7 @@ impl fmt::Display for Error {
 				write!(f, "Failed to update fee rate estimates.")
 			},
 			Self::WalletOperationFailed => write!(f, "Failed to conduct wallet operation."),
+			Self::WalletOperationTimeout => write!(f, "A wallet operation timed out."),
 			Self::OnchainTxSigningFailed => write!(f, "Failed to sign given transaction."),
 			Self::MessageSigningFailed => write!(f, "Failed to sign given message."),
 			Self::TxSyncFailed => write!(f, "Failed to sync transactions."),

src/wallet.rs

@@ -1,5 +1,6 @@
 use crate::logger::{log_error, log_info, log_trace, Logger};
 
+use crate::config::BDK_WALLET_SYNC_TIMEOUT_SECS;
 use crate::Error;
 
 use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
@@ -36,6 +37,7 @@ use bitcoin::{ScriptBuf, Transaction, TxOut, Txid};
 use std::mem;
 use std::ops::{Deref, DerefMut};
 use std::sync::{Arc, Mutex, RwLock};
+use std::time::Duration;
 
 enum WalletSyncStatus {
 	Completed,
@@ -100,34 +102,46 @@ where
 		let res = {
 			let sync_options = SyncOptions { progress: None };
 			let wallet_lock = self.inner.lock().unwrap();
-			match wallet_lock.sync(&self.blockchain, sync_options).await {
-				Ok(()) => {
-					// TODO: Drop this workaround after BDK 1.0 upgrade.
-					// Update balance cache after syncing.
-					if let Ok(balance) = wallet_lock.get_balance() {
-						*self.balance_cache.write().unwrap() = balance;
-					}
-					Ok(())
-				},
-				Err(e) => match e {
-					bdk::Error::Esplora(ref be) => match **be {
-						bdk::blockchain::esplora::EsploraError::Reqwest(_) => {
-							log_error!(
-								self.logger,
-								"Sync failed due to HTTP connection error: {}",
-								e
-							);
-							Err(From::from(e))
+
+			let timeout_fut = tokio::time::timeout(
+				Duration::from_secs(BDK_WALLET_SYNC_TIMEOUT_SECS),
+				wallet_lock.sync(&self.blockchain, sync_options),
+			);
+
+			match timeout_fut.await {
+				Ok(res) => match res {
+					Ok(()) => {
+						// TODO: Drop this workaround after BDK 1.0 upgrade.
+						// Update balance cache after syncing.
+						if let Ok(balance) = wallet_lock.get_balance() {
+							*self.balance_cache.write().unwrap() = balance;
+						}
+						Ok(())
+					},
+					Err(e) => match e {
+						bdk::Error::Esplora(ref be) => match **be {
+							bdk::blockchain::esplora::EsploraError::Reqwest(_) => {
+								log_error!(
+									self.logger,
+									"Sync failed due to HTTP connection error: {}",
+									e
+								);
+								Err(From::from(e))
+							},
+							_ => {
+								log_error!(self.logger, "Sync failed due to Esplora error: {}", e);
+								Err(From::from(e))
+							},
 						},
 						_ => {
-							log_error!(self.logger, "Sync failed due to Esplora error: {}", e);
+							log_error!(self.logger, "Wallet sync error: {}", e);
 							Err(From::from(e))
 						},
 					},
-					_ => {
-						log_error!(self.logger, "Wallet sync error: {}", e);
-						Err(From::from(e))
-					},
+				},
+				Err(e) => {
+					log_error!(self.logger, "On-chain wallet sync timed out: {}", e);
+					Err(Error::WalletOperationTimeout)
 				},
 			}
 		};