Move transaction broadcasting and fee estimation to dedicated modules

bindings/ldk_node.udl

@@ -108,6 +108,7 @@ enum NodeError {
 	"ChannelClosingFailed",
 	"ChannelConfigUpdateFailed",
 	"PersistenceFailed",
+	"FeerateEstimationUpdateFailed",
 	"WalletOperationFailed",
 	"OnchainTxSigningFailed",
 	"MessageSigningFailed",

src/builder.rs

@@ -1,10 +1,12 @@
 use crate::event::EventQueue;
+use crate::fee_estimator::OnchainFeeEstimator;
 use crate::gossip::GossipSource;
 use crate::io;
 use crate::io::sqlite_store::SqliteStore;
 use crate::logger::{log_error, FilesystemLogger, Logger};
 use crate::payment_store::PaymentStore;
 use crate::peer_store::PeerStore;
+use crate::tx_broadcaster::TransactionBroadcaster;
 use crate::types::{
 	ChainMonitor, ChannelManager, FakeMessageRouter, GossipSync, KeysManager, NetworkGraph,
 	OnionMessenger, PeerManager,
@@ -464,13 +466,19 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  BuildError::WalletSetupFailed
 	})?;
 
-	let (blockchain, tx_sync) = match chain_data_source_config {
+	let (blockchain, tx_sync, tx_broadcaster, fee_estimator) = match chain_data_source_config {
  Some(ChainDataSourceConfig::Esplora(server_url)) => {
  let tx_sync = Arc::new(EsploraSyncClient::new(server_url.clone(), Arc::clone(&logger)));
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
  None => {
  // Default to Esplora client.
@@ -479,20 +487,31 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
 	};
 
 	let runtime = Arc::new(RwLock::new(None));
-	let wallet =
- Arc::new(Wallet::new(blockchain, bdk_wallet, Arc::clone(&runtime), Arc::clone(&logger)));
+	let wallet = Arc::new(Wallet::new(
+ blockchain,
+ bdk_wallet,
+ Arc::clone(&tx_broadcaster),
+ Arc::clone(&fee_estimator),
+ Arc::clone(&logger),
+	));
 
 	// Initialize the ChainMonitor
 	let chain_monitor: Arc<ChainMonitor<K>> = Arc::new(chainmonitor::ChainMonitor::new(
  Some(Arc::clone(&tx_sync)),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&logger),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&kv_store),
 	));
 
@@ -592,9 +611,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  user_config,
@@ -616,9 +635,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  best_block: BestBlock::new(genesis_block_hash, 0),
  };
  channelmanager::ChannelManager::new(
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  Arc::clone(&keys_manager),
@@ -767,6 +786,8 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  config,
  wallet,
  tx_sync,
+ tx_broadcaster,
+ fee_estimator,
  event_queue,
  channel_manager,
  chain_monitor,

src/error.rs

@@ -25,6 +25,8 @@ pub enum Error {
 	ChannelConfigUpdateFailed,
 	/// Persistence failed.
 	PersistenceFailed,
+	/// A fee rate estimation update failed.
+	FeerateEstimationUpdateFailed,
 	/// A wallet operation failed.
 	WalletOperationFailed,
 	/// A signing operation for transaction failed.
@@ -79,6 +81,9 @@ impl fmt::Display for Error {
  Self::ChannelClosingFailed => write!(f, "Failed to close channel."),
  Self::ChannelConfigUpdateFailed => write!(f, "Failed to update channel config."),
  Self::PersistenceFailed => write!(f, "Failed to persist data."),
+ Self::FeerateEstimationUpdateFailed => {
+ write!(f, "Failed to update fee rate estimates.")
+ }
  Self::WalletOperationFailed => write!(f, "Failed to conduct wallet operation."),
  Self::OnchainTxSigningFailed => write!(f, "Failed to sign given transaction."),
  Self::MessageSigningFailed => write!(f, "Failed to sign given message."),

src/event.rs

@@ -1,6 +1,7 @@
-use crate::peer_store::{PeerInfo, PeerStore};
+use crate::types::{Broadcaster, FeeEstimator, Wallet};
 use crate::{
-	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, UserChannelId, Wallet,
+	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, PeerInfo, PeerStore,
+	UserChannelId,
 };
 
 use crate::payment_store::{
@@ -13,7 +14,9 @@ use crate::io::{
 };
 use crate::logger::{log_debug, log_error, log_info, Logger};
 
-use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
+use lightning::chain::chaininterface::{
+	BroadcasterInterface, ConfirmationTarget, FeeEstimator as LDKFeeEstimator,
+};
 use lightning::events::Event as LdkEvent;
 use lightning::events::PaymentPurpose;
 use lightning::impl_writeable_tlv_based_enum;
@@ -243,40 +246,45 @@ pub(crate) struct EventHandler<K: KVStore + Sync + Send, L: Deref>
 where
 	L::Target: Logger,
 {
-	wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>,
 	event_queue: Arc<EventQueue<K, L>>,
+	wallet: Arc<Wallet>,
 	channel_manager: Arc<ChannelManager<K>>,
+	tx_broadcaster: Arc<Broadcaster>,
+	fee_estimator: Arc<FeeEstimator>,
 	network_graph: Arc<NetworkGraph>,
 	keys_manager: Arc<KeysManager>,
 	payment_store: Arc<PaymentStore<K, L>>,
+	peer_store: Arc<PeerStore<K, L>>,
 	runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
 	logger: L,
 	config: Arc<Config>,
-	peer_store: Arc<PeerStore<K, L>>,
 }
 
 impl<K: KVStore + Sync + Send + 'static, L: Deref> EventHandler<K, L>
 where
 	L::Target: Logger,
 {
 	pub fn new(
- wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>, event_queue: Arc<EventQueue<K, L>>,
- channel_manager: Arc<ChannelManager<K>>, network_graph: Arc<NetworkGraph>,
+ event_queue: Arc<EventQueue<K, L>>, wallet: Arc<Wallet>,
+ channel_manager: Arc<ChannelManager<K>>, tx_broadcaster: Arc<Broadcaster>,
+ fee_estimator: Arc<FeeEstimator>, network_graph: Arc<NetworkGraph>,
  keys_manager: Arc<KeysManager>, payment_store: Arc<PaymentStore<K, L>>,
- runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>, logger: L, config: Arc<Config>,
-peer_store: Arc<PeerStore<K, L>>,
+peer_store: Arc<PeerStore<K, L>>, runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
+logger: L, config: Arc<Config>,
 	) -> Self {
  Self {
  event_queue,
  wallet,
  channel_manager,
+ tx_broadcaster,
+ fee_estimator,
  network_graph,
  keys_manager,
  payment_store,
+ peer_store,
  logger,
  runtime,
  config,
- peer_store,
  }
 	}
 
@@ -586,7 +594,7 @@ where
 
  let output_descriptors = &outputs.iter().collect::<Vec<_>>();
  let tx_feerate = self
- .wallet
+ .fee_estimator
  .get_est_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
 
  // We set nLockTime to the current height to discourage fee sniping.
@@ -603,7 +611,9 @@ where
  );
 
  match res {
- Ok(Some(spending_tx)) => self.wallet.broadcast_transactions(&[&spending_tx]),
+ Ok(Some(spending_tx)) => {
+ self.tx_broadcaster.broadcast_transactions(&[&spending_tx])
+ }
  Ok(None) => {
  log_debug!(self.logger, "Omitted spending static outputs: {:?}", outputs);
  }

src/fee_estimator.rs

@@ -0,0 +1,131 @@
+use crate::logger::{log_error, log_trace, Logger};
+use crate::Error;
+
+use lightning::chain::chaininterface::{
+	ConfirmationTarget, FeeEstimator, FEERATE_FLOOR_SATS_PER_KW,
+};
+
+use bdk::FeeRate;
+use esplora_client::AsyncClient as EsploraClient;
+
+use std::collections::HashMap;
+use std::ops::Deref;
+use std::sync::RwLock;
+
+pub(crate) struct OnchainFeeEstimator<L: Deref>
+where
+	L::Target: Logger,
+{
+	fee_rate_cache: RwLock<HashMap<ConfirmationTarget, FeeRate>>,
+	esplora_client: EsploraClient,
+	logger: L,
+}
+
+impl<L: Deref> OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	pub(crate) fn new(esplora_client: EsploraClient, logger: L) -> Self {
+ let fee_rate_cache = RwLock::new(HashMap::new());
+ Self { fee_rate_cache, esplora_client, logger }
+	}
+
+	pub(crate) async fn update_fee_estimates(&self) -> Result<(), Error> {
+ let confirmation_targets = vec![
+ ConfirmationTarget::OnChainSweep,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::AnchorChannelFee,
+ ConfirmationTarget::NonAnchorChannelFee,
+ ConfirmationTarget::ChannelCloseMinimum,
+ ];
+ for target in confirmation_targets {
+ let num_blocks = match target {
+ ConfirmationTarget::OnChainSweep => 6,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 1,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => 1008,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => 144,
+ ConfirmationTarget::AnchorChannelFee => 1008,
+ ConfirmationTarget::NonAnchorChannelFee => 12,
+ ConfirmationTarget::ChannelCloseMinimum => 144,
+ };
+
+ let estimates = self.esplora_client.get_fee_estimates().await.map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to retrieve fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let converted_estimates = esplora_client::convert_fee_rate(num_blocks, estimates)
+ .map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to convert fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let fee_rate = FeeRate::from_sat_per_vb(converted_estimates);
+
+ // LDK 0.0.118 introduced changes to the `ConfirmationTarget` semantics that
+ // require some post-estimation adjustments to the fee rates, which we do here.
+ let adjusted_fee_rate = match target {
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => {
+ let really_high_prio = fee_rate.as_sat_per_vb() * 10.0;
+ FeeRate::from_sat_per_vb(really_high_prio)
+ }
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => {
+ let slightly_less_than_background = fee_rate.fee_wu(1000) - 250;
+ FeeRate::from_sat_per_kwu(slightly_less_than_background as f32)
+ }
+ _ => fee_rate,
+ };
+
+ let mut locked_fee_rate_cache = self.fee_rate_cache.write().unwrap();
+ locked_fee_rate_cache.insert(target, adjusted_fee_rate);
+ log_trace!(
+ self.logger,
+ "Fee rate estimation updated for {:?}: {} sats/kwu",
+ target,
+ adjusted_fee_rate.fee_wu(1000)
+ );
+ }
+ Ok(())
+	}
+
+	pub(crate) fn estimate_fee_rate(&self, confirmation_target: ConfirmationTarget) -> FeeRate {
+ let locked_fee_rate_cache = self.fee_rate_cache.read().unwrap();
+
+ let fallback_sats_kwu = match confirmation_target {
+ ConfirmationTarget::OnChainSweep => 5000,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 25 * 250,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::AnchorChannelFee => 500,
+ ConfirmationTarget::NonAnchorChannelFee => 1000,
+ ConfirmationTarget::ChannelCloseMinimum => 500,
+ };
+
+ // We'll fall back on this, if we really don't have any other information.
+ let fallback_rate = FeeRate::from_sat_per_kwu(fallback_sats_kwu as f32);
+
+ *locked_fee_rate_cache.get(&confirmation_target).unwrap_or(&fallback_rate)
+	}
+}
+
+impl<L: Deref> FeeEstimator for OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
+ (self.estimate_fee_rate(confirmation_target).fee_wu(1000) as u32)
+ .max(FEERATE_FLOOR_SATS_PER_KW)
+	}
+}

bindings/ldk_node.udl

@@ -108,6 +108,7 @@ enum NodeError {
 	"ChannelClosingFailed",
 	"ChannelConfigUpdateFailed",
 	"PersistenceFailed",
+	"FeerateEstimationUpdateFailed",
 	"WalletOperationFailed",
 	"OnchainTxSigningFailed",
 	"MessageSigningFailed",

src/builder.rs

@@ -1,10 +1,12 @@
 use crate::event::EventQueue;
+use crate::fee_estimator::OnchainFeeEstimator;
 use crate::gossip::GossipSource;
 use crate::io;
 use crate::io::sqlite_store::SqliteStore;
 use crate::logger::{log_error, FilesystemLogger, Logger};
 use crate::payment_store::PaymentStore;
 use crate::peer_store::PeerStore;
+use crate::tx_broadcaster::TransactionBroadcaster;
 use crate::types::{
 	ChainMonitor, ChannelManager, FakeMessageRouter, GossipSync, KeysManager, NetworkGraph,
 	OnionMessenger, PeerManager,
@@ -464,13 +466,19 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  BuildError::WalletSetupFailed
 	})?;
 
-	let (blockchain, tx_sync) = match chain_data_source_config {
+	let (blockchain, tx_sync, tx_broadcaster, fee_estimator) = match chain_data_source_config {
  Some(ChainDataSourceConfig::Esplora(server_url)) => {
  let tx_sync = Arc::new(EsploraSyncClient::new(server_url.clone(), Arc::clone(&logger)));
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
  None => {
  // Default to Esplora client.
@@ -479,20 +487,31 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
 	};
 
 	let runtime = Arc::new(RwLock::new(None));
-	let wallet =
- Arc::new(Wallet::new(blockchain, bdk_wallet, Arc::clone(&runtime), Arc::clone(&logger)));
+	let wallet = Arc::new(Wallet::new(
+ blockchain,
+ bdk_wallet,
+ Arc::clone(&tx_broadcaster),
+ Arc::clone(&fee_estimator),
+ Arc::clone(&logger),
+	));
 
 	// Initialize the ChainMonitor
 	let chain_monitor: Arc<ChainMonitor<K>> = Arc::new(chainmonitor::ChainMonitor::new(
  Some(Arc::clone(&tx_sync)),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&logger),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&kv_store),
 	));
 
@@ -592,9 +611,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  user_config,
@@ -616,9 +635,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  best_block: BestBlock::new(genesis_block_hash, 0),
  };
  channelmanager::ChannelManager::new(
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  Arc::clone(&keys_manager),
@@ -767,6 +786,8 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  config,
  wallet,
  tx_sync,
+ tx_broadcaster,
+ fee_estimator,
  event_queue,
  channel_manager,
  chain_monitor,

src/error.rs

@@ -25,6 +25,8 @@ pub enum Error {
 	ChannelConfigUpdateFailed,
 	/// Persistence failed.
 	PersistenceFailed,
+	/// A fee rate estimation update failed.
+	FeerateEstimationUpdateFailed,
 	/// A wallet operation failed.
 	WalletOperationFailed,
 	/// A signing operation for transaction failed.
@@ -79,6 +81,9 @@ impl fmt::Display for Error {
  Self::ChannelClosingFailed => write!(f, "Failed to close channel."),
  Self::ChannelConfigUpdateFailed => write!(f, "Failed to update channel config."),
  Self::PersistenceFailed => write!(f, "Failed to persist data."),
+ Self::FeerateEstimationUpdateFailed => {
+ write!(f, "Failed to update fee rate estimates.")
+ }
  Self::WalletOperationFailed => write!(f, "Failed to conduct wallet operation."),
  Self::OnchainTxSigningFailed => write!(f, "Failed to sign given transaction."),
  Self::MessageSigningFailed => write!(f, "Failed to sign given message."),

src/event.rs

@@ -1,6 +1,7 @@
-use crate::peer_store::{PeerInfo, PeerStore};
+use crate::types::{Broadcaster, FeeEstimator, Wallet};
 use crate::{
-	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, UserChannelId, Wallet,
+	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, PeerInfo, PeerStore,
+	UserChannelId,
 };
 
 use crate::payment_store::{
@@ -13,7 +14,9 @@ use crate::io::{
 };
 use crate::logger::{log_debug, log_error, log_info, Logger};
 
-use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
+use lightning::chain::chaininterface::{
+	BroadcasterInterface, ConfirmationTarget, FeeEstimator as LDKFeeEstimator,
+};
 use lightning::events::Event as LdkEvent;
 use lightning::events::PaymentPurpose;
 use lightning::impl_writeable_tlv_based_enum;
@@ -243,40 +246,45 @@ pub(crate) struct EventHandler<K: KVStore + Sync + Send, L: Deref>
 where
 	L::Target: Logger,
 {
-	wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>,
 	event_queue: Arc<EventQueue<K, L>>,
+	wallet: Arc<Wallet>,
 	channel_manager: Arc<ChannelManager<K>>,
+	tx_broadcaster: Arc<Broadcaster>,
+	fee_estimator: Arc<FeeEstimator>,
 	network_graph: Arc<NetworkGraph>,
 	keys_manager: Arc<KeysManager>,
 	payment_store: Arc<PaymentStore<K, L>>,
+	peer_store: Arc<PeerStore<K, L>>,
 	runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
 	logger: L,
 	config: Arc<Config>,
-	peer_store: Arc<PeerStore<K, L>>,
 }
 
 impl<K: KVStore + Sync + Send + 'static, L: Deref> EventHandler<K, L>
 where
 	L::Target: Logger,
 {
 	pub fn new(
- wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>, event_queue: Arc<EventQueue<K, L>>,
- channel_manager: Arc<ChannelManager<K>>, network_graph: Arc<NetworkGraph>,
+ event_queue: Arc<EventQueue<K, L>>, wallet: Arc<Wallet>,
+ channel_manager: Arc<ChannelManager<K>>, tx_broadcaster: Arc<Broadcaster>,
+ fee_estimator: Arc<FeeEstimator>, network_graph: Arc<NetworkGraph>,
  keys_manager: Arc<KeysManager>, payment_store: Arc<PaymentStore<K, L>>,
- runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>, logger: L, config: Arc<Config>,
-peer_store: Arc<PeerStore<K, L>>,
+peer_store: Arc<PeerStore<K, L>>, runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
+logger: L, config: Arc<Config>,
 	) -> Self {
  Self {
  event_queue,
  wallet,
  channel_manager,
+ tx_broadcaster,
+ fee_estimator,
  network_graph,
  keys_manager,
  payment_store,
+ peer_store,
  logger,
  runtime,
  config,
- peer_store,
  }
 	}
 
@@ -586,7 +594,7 @@ where
 
  let output_descriptors = &outputs.iter().collect::<Vec<_>>();
  let tx_feerate = self
- .wallet
+ .fee_estimator
  .get_est_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
 
  // We set nLockTime to the current height to discourage fee sniping.
@@ -603,7 +611,9 @@ where
  );
 
  match res {
- Ok(Some(spending_tx)) => self.wallet.broadcast_transactions(&[&spending_tx]),
+ Ok(Some(spending_tx)) => {
+ self.tx_broadcaster.broadcast_transactions(&[&spending_tx])
+ }
  Ok(None) => {
  log_debug!(self.logger, "Omitted spending static outputs: {:?}", outputs);
  }

src/fee_estimator.rs

@@ -0,0 +1,131 @@
+use crate::logger::{log_error, log_trace, Logger};
+use crate::Error;
+
+use lightning::chain::chaininterface::{
+	ConfirmationTarget, FeeEstimator, FEERATE_FLOOR_SATS_PER_KW,
+};
+
+use bdk::FeeRate;
+use esplora_client::AsyncClient as EsploraClient;
+
+use std::collections::HashMap;
+use std::ops::Deref;
+use std::sync::RwLock;
+
+pub(crate) struct OnchainFeeEstimator<L: Deref>
+where
+	L::Target: Logger,
+{
+	fee_rate_cache: RwLock<HashMap<ConfirmationTarget, FeeRate>>,
+	esplora_client: EsploraClient,
+	logger: L,
+}
+
+impl<L: Deref> OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	pub(crate) fn new(esplora_client: EsploraClient, logger: L) -> Self {
+ let fee_rate_cache = RwLock::new(HashMap::new());
+ Self { fee_rate_cache, esplora_client, logger }
+	}
+
+	pub(crate) async fn update_fee_estimates(&self) -> Result<(), Error> {
+ let confirmation_targets = vec![
+ ConfirmationTarget::OnChainSweep,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::AnchorChannelFee,
+ ConfirmationTarget::NonAnchorChannelFee,
+ ConfirmationTarget::ChannelCloseMinimum,
+ ];
+ for target in confirmation_targets {
+ let num_blocks = match target {
+ ConfirmationTarget::OnChainSweep => 6,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 1,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => 1008,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => 144,
+ ConfirmationTarget::AnchorChannelFee => 1008,
+ ConfirmationTarget::NonAnchorChannelFee => 12,
+ ConfirmationTarget::ChannelCloseMinimum => 144,
+ };
+
+ let estimates = self.esplora_client.get_fee_estimates().await.map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to retrieve fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let converted_estimates = esplora_client::convert_fee_rate(num_blocks, estimates)
+ .map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to convert fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let fee_rate = FeeRate::from_sat_per_vb(converted_estimates);
+
+ // LDK 0.0.118 introduced changes to the `ConfirmationTarget` semantics that
+ // require some post-estimation adjustments to the fee rates, which we do here.
+ let adjusted_fee_rate = match target {
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => {
+ let really_high_prio = fee_rate.as_sat_per_vb() * 10.0;
+ FeeRate::from_sat_per_vb(really_high_prio)
+ }
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => {
+ let slightly_less_than_background = fee_rate.fee_wu(1000) - 250;
+ FeeRate::from_sat_per_kwu(slightly_less_than_background as f32)
+ }
+ _ => fee_rate,
+ };
+
+ let mut locked_fee_rate_cache = self.fee_rate_cache.write().unwrap();
+ locked_fee_rate_cache.insert(target, adjusted_fee_rate);
+ log_trace!(
+ self.logger,
+ "Fee rate estimation updated for {:?}: {} sats/kwu",
+ target,
+ adjusted_fee_rate.fee_wu(1000)
+ );
+ }
+ Ok(())
+	}
+
+	pub(crate) fn estimate_fee_rate(&self, confirmation_target: ConfirmationTarget) -> FeeRate {
+ let locked_fee_rate_cache = self.fee_rate_cache.read().unwrap();
+
+ let fallback_sats_kwu = match confirmation_target {
+ ConfirmationTarget::OnChainSweep => 5000,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 25 * 250,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::AnchorChannelFee => 500,
+ ConfirmationTarget::NonAnchorChannelFee => 1000,
+ ConfirmationTarget::ChannelCloseMinimum => 500,
+ };
+
+ // We'll fall back on this, if we really don't have any other information.
+ let fallback_rate = FeeRate::from_sat_per_kwu(fallback_sats_kwu as f32);
+
+ *locked_fee_rate_cache.get(&confirmation_target).unwrap_or(&fallback_rate)
+	}
+}
+
+impl<L: Deref> FeeEstimator for OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
+ (self.estimate_fee_rate(confirmation_target).fee_wu(1000) as u32)
+ .max(FEERATE_FLOOR_SATS_PER_KW)
+	}
+}

bindings/ldk_node.udl

@@ -108,6 +108,7 @@ enum NodeError {
 	"ChannelClosingFailed",
 	"ChannelConfigUpdateFailed",
 	"PersistenceFailed",
+	"FeerateEstimationUpdateFailed",
 	"WalletOperationFailed",
 	"OnchainTxSigningFailed",
 	"MessageSigningFailed",

src/builder.rs

@@ -1,10 +1,12 @@
 use crate::event::EventQueue;
+use crate::fee_estimator::OnchainFeeEstimator;
 use crate::gossip::GossipSource;
 use crate::io;
 use crate::io::sqlite_store::SqliteStore;
 use crate::logger::{log_error, FilesystemLogger, Logger};
 use crate::payment_store::PaymentStore;
 use crate::peer_store::PeerStore;
+use crate::tx_broadcaster::TransactionBroadcaster;
 use crate::types::{
 	ChainMonitor, ChannelManager, FakeMessageRouter, GossipSync, KeysManager, NetworkGraph,
 	OnionMessenger, PeerManager,
@@ -464,13 +466,19 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  BuildError::WalletSetupFailed
 	})?;
 
-	let (blockchain, tx_sync) = match chain_data_source_config {
+	let (blockchain, tx_sync, tx_broadcaster, fee_estimator) = match chain_data_source_config {
  Some(ChainDataSourceConfig::Esplora(server_url)) => {
  let tx_sync = Arc::new(EsploraSyncClient::new(server_url.clone(), Arc::clone(&logger)));
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
  None => {
  // Default to Esplora client.
@@ -479,20 +487,31 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
 	};
 
 	let runtime = Arc::new(RwLock::new(None));
-	let wallet =
- Arc::new(Wallet::new(blockchain, bdk_wallet, Arc::clone(&runtime), Arc::clone(&logger)));
+	let wallet = Arc::new(Wallet::new(
+ blockchain,
+ bdk_wallet,
+ Arc::clone(&tx_broadcaster),
+ Arc::clone(&fee_estimator),
+ Arc::clone(&logger),
+	));
 
 	// Initialize the ChainMonitor
 	let chain_monitor: Arc<ChainMonitor<K>> = Arc::new(chainmonitor::ChainMonitor::new(
  Some(Arc::clone(&tx_sync)),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&logger),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&kv_store),
 	));
 
@@ -592,9 +611,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  user_config,
@@ -616,9 +635,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  best_block: BestBlock::new(genesis_block_hash, 0),
  };
  channelmanager::ChannelManager::new(
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  Arc::clone(&keys_manager),
@@ -767,6 +786,8 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  config,
  wallet,
  tx_sync,
+ tx_broadcaster,
+ fee_estimator,
  event_queue,
  channel_manager,
  chain_monitor,

src/error.rs

@@ -25,6 +25,8 @@ pub enum Error {
 	ChannelConfigUpdateFailed,
 	/// Persistence failed.
 	PersistenceFailed,
+	/// A fee rate estimation update failed.
+	FeerateEstimationUpdateFailed,
 	/// A wallet operation failed.
 	WalletOperationFailed,
 	/// A signing operation for transaction failed.
@@ -79,6 +81,9 @@ impl fmt::Display for Error {
  Self::ChannelClosingFailed => write!(f, "Failed to close channel."),
  Self::ChannelConfigUpdateFailed => write!(f, "Failed to update channel config."),
  Self::PersistenceFailed => write!(f, "Failed to persist data."),
+ Self::FeerateEstimationUpdateFailed => {
+ write!(f, "Failed to update fee rate estimates.")
+ }
  Self::WalletOperationFailed => write!(f, "Failed to conduct wallet operation."),
  Self::OnchainTxSigningFailed => write!(f, "Failed to sign given transaction."),
  Self::MessageSigningFailed => write!(f, "Failed to sign given message."),

src/event.rs

@@ -1,6 +1,7 @@
-use crate::peer_store::{PeerInfo, PeerStore};
+use crate::types::{Broadcaster, FeeEstimator, Wallet};
 use crate::{
-	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, UserChannelId, Wallet,
+	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, PeerInfo, PeerStore,
+	UserChannelId,
 };
 
 use crate::payment_store::{
@@ -13,7 +14,9 @@ use crate::io::{
 };
 use crate::logger::{log_debug, log_error, log_info, Logger};
 
-use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
+use lightning::chain::chaininterface::{
+	BroadcasterInterface, ConfirmationTarget, FeeEstimator as LDKFeeEstimator,
+};
 use lightning::events::Event as LdkEvent;
 use lightning::events::PaymentPurpose;
 use lightning::impl_writeable_tlv_based_enum;
@@ -243,40 +246,45 @@ pub(crate) struct EventHandler<K: KVStore + Sync + Send, L: Deref>
 where
 	L::Target: Logger,
 {
-	wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>,
 	event_queue: Arc<EventQueue<K, L>>,
+	wallet: Arc<Wallet>,
 	channel_manager: Arc<ChannelManager<K>>,
+	tx_broadcaster: Arc<Broadcaster>,
+	fee_estimator: Arc<FeeEstimator>,
 	network_graph: Arc<NetworkGraph>,
 	keys_manager: Arc<KeysManager>,
 	payment_store: Arc<PaymentStore<K, L>>,
+	peer_store: Arc<PeerStore<K, L>>,
 	runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
 	logger: L,
 	config: Arc<Config>,
-	peer_store: Arc<PeerStore<K, L>>,
 }
 
 impl<K: KVStore + Sync + Send + 'static, L: Deref> EventHandler<K, L>
 where
 	L::Target: Logger,
 {
 	pub fn new(
- wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>, event_queue: Arc<EventQueue<K, L>>,
- channel_manager: Arc<ChannelManager<K>>, network_graph: Arc<NetworkGraph>,
+ event_queue: Arc<EventQueue<K, L>>, wallet: Arc<Wallet>,
+ channel_manager: Arc<ChannelManager<K>>, tx_broadcaster: Arc<Broadcaster>,
+ fee_estimator: Arc<FeeEstimator>, network_graph: Arc<NetworkGraph>,
  keys_manager: Arc<KeysManager>, payment_store: Arc<PaymentStore<K, L>>,
- runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>, logger: L, config: Arc<Config>,
-peer_store: Arc<PeerStore<K, L>>,
+peer_store: Arc<PeerStore<K, L>>, runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
+logger: L, config: Arc<Config>,
 	) -> Self {
  Self {
  event_queue,
  wallet,
  channel_manager,
+ tx_broadcaster,
+ fee_estimator,
  network_graph,
  keys_manager,
  payment_store,
+ peer_store,
  logger,
  runtime,
  config,
- peer_store,
  }
 	}
 
@@ -586,7 +594,7 @@ where
 
  let output_descriptors = &outputs.iter().collect::<Vec<_>>();
  let tx_feerate = self
- .wallet
+ .fee_estimator
  .get_est_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
 
  // We set nLockTime to the current height to discourage fee sniping.
@@ -603,7 +611,9 @@ where
  );
 
  match res {
- Ok(Some(spending_tx)) => self.wallet.broadcast_transactions(&[&spending_tx]),
+ Ok(Some(spending_tx)) => {
+ self.tx_broadcaster.broadcast_transactions(&[&spending_tx])
+ }
  Ok(None) => {
  log_debug!(self.logger, "Omitted spending static outputs: {:?}", outputs);
  }

src/fee_estimator.rs

@@ -0,0 +1,131 @@
+use crate::logger::{log_error, log_trace, Logger};
+use crate::Error;
+
+use lightning::chain::chaininterface::{
+	ConfirmationTarget, FeeEstimator, FEERATE_FLOOR_SATS_PER_KW,
+};
+
+use bdk::FeeRate;
+use esplora_client::AsyncClient as EsploraClient;
+
+use std::collections::HashMap;
+use std::ops::Deref;
+use std::sync::RwLock;
+
+pub(crate) struct OnchainFeeEstimator<L: Deref>
+where
+	L::Target: Logger,
+{
+	fee_rate_cache: RwLock<HashMap<ConfirmationTarget, FeeRate>>,
+	esplora_client: EsploraClient,
+	logger: L,
+}
+
+impl<L: Deref> OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	pub(crate) fn new(esplora_client: EsploraClient, logger: L) -> Self {
+ let fee_rate_cache = RwLock::new(HashMap::new());
+ Self { fee_rate_cache, esplora_client, logger }
+	}
+
+	pub(crate) async fn update_fee_estimates(&self) -> Result<(), Error> {
+ let confirmation_targets = vec![
+ ConfirmationTarget::OnChainSweep,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::AnchorChannelFee,
+ ConfirmationTarget::NonAnchorChannelFee,
+ ConfirmationTarget::ChannelCloseMinimum,
+ ];
+ for target in confirmation_targets {
+ let num_blocks = match target {
+ ConfirmationTarget::OnChainSweep => 6,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 1,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => 1008,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => 144,
+ ConfirmationTarget::AnchorChannelFee => 1008,
+ ConfirmationTarget::NonAnchorChannelFee => 12,
+ ConfirmationTarget::ChannelCloseMinimum => 144,
+ };
+
+ let estimates = self.esplora_client.get_fee_estimates().await.map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to retrieve fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let converted_estimates = esplora_client::convert_fee_rate(num_blocks, estimates)
+ .map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to convert fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let fee_rate = FeeRate::from_sat_per_vb(converted_estimates);
+
+ // LDK 0.0.118 introduced changes to the `ConfirmationTarget` semantics that
+ // require some post-estimation adjustments to the fee rates, which we do here.
+ let adjusted_fee_rate = match target {
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => {
+ let really_high_prio = fee_rate.as_sat_per_vb() * 10.0;
+ FeeRate::from_sat_per_vb(really_high_prio)
+ }
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => {
+ let slightly_less_than_background = fee_rate.fee_wu(1000) - 250;
+ FeeRate::from_sat_per_kwu(slightly_less_than_background as f32)
+ }
+ _ => fee_rate,
+ };
+
+ let mut locked_fee_rate_cache = self.fee_rate_cache.write().unwrap();
+ locked_fee_rate_cache.insert(target, adjusted_fee_rate);
+ log_trace!(
+ self.logger,
+ "Fee rate estimation updated for {:?}: {} sats/kwu",
+ target,
+ adjusted_fee_rate.fee_wu(1000)
+ );
+ }
+ Ok(())
+	}
+
+	pub(crate) fn estimate_fee_rate(&self, confirmation_target: ConfirmationTarget) -> FeeRate {
+ let locked_fee_rate_cache = self.fee_rate_cache.read().unwrap();
+
+ let fallback_sats_kwu = match confirmation_target {
+ ConfirmationTarget::OnChainSweep => 5000,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 25 * 250,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::AnchorChannelFee => 500,
+ ConfirmationTarget::NonAnchorChannelFee => 1000,
+ ConfirmationTarget::ChannelCloseMinimum => 500,
+ };
+
+ // We'll fall back on this, if we really don't have any other information.
+ let fallback_rate = FeeRate::from_sat_per_kwu(fallback_sats_kwu as f32);
+
+ *locked_fee_rate_cache.get(&confirmation_target).unwrap_or(&fallback_rate)
+	}
+}
+
+impl<L: Deref> FeeEstimator for OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
+ (self.estimate_fee_rate(confirmation_target).fee_wu(1000) as u32)
+ .max(FEERATE_FLOOR_SATS_PER_KW)
+	}
+}

bindings/ldk_node.udl

@@ -108,6 +108,7 @@ enum NodeError {
 	"ChannelClosingFailed",
 	"ChannelConfigUpdateFailed",
 	"PersistenceFailed",
+	"FeerateEstimationUpdateFailed",
 	"WalletOperationFailed",
 	"OnchainTxSigningFailed",
 	"MessageSigningFailed",

src/builder.rs

@@ -1,10 +1,12 @@
 use crate::event::EventQueue;
+use crate::fee_estimator::OnchainFeeEstimator;
 use crate::gossip::GossipSource;
 use crate::io;
 use crate::io::sqlite_store::SqliteStore;
 use crate::logger::{log_error, FilesystemLogger, Logger};
 use crate::payment_store::PaymentStore;
 use crate::peer_store::PeerStore;
+use crate::tx_broadcaster::TransactionBroadcaster;
 use crate::types::{
 	ChainMonitor, ChannelManager, FakeMessageRouter, GossipSync, KeysManager, NetworkGraph,
 	OnionMessenger, PeerManager,
@@ -464,13 +466,19 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  BuildError::WalletSetupFailed
 	})?;
 
-	let (blockchain, tx_sync) = match chain_data_source_config {
+	let (blockchain, tx_sync, tx_broadcaster, fee_estimator) = match chain_data_source_config {
  Some(ChainDataSourceConfig::Esplora(server_url)) => {
  let tx_sync = Arc::new(EsploraSyncClient::new(server_url.clone(), Arc::clone(&logger)));
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
  None => {
  // Default to Esplora client.
@@ -479,20 +487,31 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
 	};
 
 	let runtime = Arc::new(RwLock::new(None));
-	let wallet =
- Arc::new(Wallet::new(blockchain, bdk_wallet, Arc::clone(&runtime), Arc::clone(&logger)));
+	let wallet = Arc::new(Wallet::new(
+ blockchain,
+ bdk_wallet,
+ Arc::clone(&tx_broadcaster),
+ Arc::clone(&fee_estimator),
+ Arc::clone(&logger),
+	));
 
 	// Initialize the ChainMonitor
 	let chain_monitor: Arc<ChainMonitor<K>> = Arc::new(chainmonitor::ChainMonitor::new(
  Some(Arc::clone(&tx_sync)),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&logger),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&kv_store),
 	));
 
@@ -592,9 +611,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  user_config,
@@ -616,9 +635,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  best_block: BestBlock::new(genesis_block_hash, 0),
  };
  channelmanager::ChannelManager::new(
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  Arc::clone(&keys_manager),
@@ -767,6 +786,8 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  config,
  wallet,
  tx_sync,
+ tx_broadcaster,
+ fee_estimator,
  event_queue,
  channel_manager,
  chain_monitor,

src/error.rs

@@ -25,6 +25,8 @@ pub enum Error {
 	ChannelConfigUpdateFailed,
 	/// Persistence failed.
 	PersistenceFailed,
+	/// A fee rate estimation update failed.
+	FeerateEstimationUpdateFailed,
 	/// A wallet operation failed.
 	WalletOperationFailed,
 	/// A signing operation for transaction failed.
@@ -79,6 +81,9 @@ impl fmt::Display for Error {
  Self::ChannelClosingFailed => write!(f, "Failed to close channel."),
  Self::ChannelConfigUpdateFailed => write!(f, "Failed to update channel config."),
  Self::PersistenceFailed => write!(f, "Failed to persist data."),
+ Self::FeerateEstimationUpdateFailed => {
+ write!(f, "Failed to update fee rate estimates.")
+ }
  Self::WalletOperationFailed => write!(f, "Failed to conduct wallet operation."),
  Self::OnchainTxSigningFailed => write!(f, "Failed to sign given transaction."),
  Self::MessageSigningFailed => write!(f, "Failed to sign given message."),

src/event.rs

@@ -1,6 +1,7 @@
-use crate::peer_store::{PeerInfo, PeerStore};
+use crate::types::{Broadcaster, FeeEstimator, Wallet};
 use crate::{
-	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, UserChannelId, Wallet,
+	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, PeerInfo, PeerStore,
+	UserChannelId,
 };
 
 use crate::payment_store::{
@@ -13,7 +14,9 @@ use crate::io::{
 };
 use crate::logger::{log_debug, log_error, log_info, Logger};
 
-use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
+use lightning::chain::chaininterface::{
+	BroadcasterInterface, ConfirmationTarget, FeeEstimator as LDKFeeEstimator,
+};
 use lightning::events::Event as LdkEvent;
 use lightning::events::PaymentPurpose;
 use lightning::impl_writeable_tlv_based_enum;
@@ -243,40 +246,45 @@ pub(crate) struct EventHandler<K: KVStore + Sync + Send, L: Deref>
 where
 	L::Target: Logger,
 {
-	wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>,
 	event_queue: Arc<EventQueue<K, L>>,
+	wallet: Arc<Wallet>,
 	channel_manager: Arc<ChannelManager<K>>,
+	tx_broadcaster: Arc<Broadcaster>,
+	fee_estimator: Arc<FeeEstimator>,
 	network_graph: Arc<NetworkGraph>,
 	keys_manager: Arc<KeysManager>,
 	payment_store: Arc<PaymentStore<K, L>>,
+	peer_store: Arc<PeerStore<K, L>>,
 	runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
 	logger: L,
 	config: Arc<Config>,
-	peer_store: Arc<PeerStore<K, L>>,
 }
 
 impl<K: KVStore + Sync + Send + 'static, L: Deref> EventHandler<K, L>
 where
 	L::Target: Logger,
 {
 	pub fn new(
- wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>, event_queue: Arc<EventQueue<K, L>>,
- channel_manager: Arc<ChannelManager<K>>, network_graph: Arc<NetworkGraph>,
+ event_queue: Arc<EventQueue<K, L>>, wallet: Arc<Wallet>,
+ channel_manager: Arc<ChannelManager<K>>, tx_broadcaster: Arc<Broadcaster>,
+ fee_estimator: Arc<FeeEstimator>, network_graph: Arc<NetworkGraph>,
  keys_manager: Arc<KeysManager>, payment_store: Arc<PaymentStore<K, L>>,
- runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>, logger: L, config: Arc<Config>,
-peer_store: Arc<PeerStore<K, L>>,
+peer_store: Arc<PeerStore<K, L>>, runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
+logger: L, config: Arc<Config>,
 	) -> Self {
  Self {
  event_queue,
  wallet,
  channel_manager,
+ tx_broadcaster,
+ fee_estimator,
  network_graph,
  keys_manager,
  payment_store,
+ peer_store,
  logger,
  runtime,
  config,
- peer_store,
  }
 	}
 
@@ -586,7 +594,7 @@ where
 
  let output_descriptors = &outputs.iter().collect::<Vec<_>>();
  let tx_feerate = self
- .wallet
+ .fee_estimator
  .get_est_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
 
  // We set nLockTime to the current height to discourage fee sniping.
@@ -603,7 +611,9 @@ where
  );
 
  match res {
- Ok(Some(spending_tx)) => self.wallet.broadcast_transactions(&[&spending_tx]),
+ Ok(Some(spending_tx)) => {
+ self.tx_broadcaster.broadcast_transactions(&[&spending_tx])
+ }
  Ok(None) => {
  log_debug!(self.logger, "Omitted spending static outputs: {:?}", outputs);
  }

src/fee_estimator.rs

@@ -0,0 +1,131 @@
+use crate::logger::{log_error, log_trace, Logger};
+use crate::Error;
+
+use lightning::chain::chaininterface::{
+	ConfirmationTarget, FeeEstimator, FEERATE_FLOOR_SATS_PER_KW,
+};
+
+use bdk::FeeRate;
+use esplora_client::AsyncClient as EsploraClient;
+
+use std::collections::HashMap;
+use std::ops::Deref;
+use std::sync::RwLock;
+
+pub(crate) struct OnchainFeeEstimator<L: Deref>
+where
+	L::Target: Logger,
+{
+	fee_rate_cache: RwLock<HashMap<ConfirmationTarget, FeeRate>>,
+	esplora_client: EsploraClient,
+	logger: L,
+}
+
+impl<L: Deref> OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	pub(crate) fn new(esplora_client: EsploraClient, logger: L) -> Self {
+ let fee_rate_cache = RwLock::new(HashMap::new());
+ Self { fee_rate_cache, esplora_client, logger }
+	}
+
+	pub(crate) async fn update_fee_estimates(&self) -> Result<(), Error> {
+ let confirmation_targets = vec![
+ ConfirmationTarget::OnChainSweep,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::AnchorChannelFee,
+ ConfirmationTarget::NonAnchorChannelFee,
+ ConfirmationTarget::ChannelCloseMinimum,
+ ];
+ for target in confirmation_targets {
+ let num_blocks = match target {
+ ConfirmationTarget::OnChainSweep => 6,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 1,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => 1008,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => 144,
+ ConfirmationTarget::AnchorChannelFee => 1008,
+ ConfirmationTarget::NonAnchorChannelFee => 12,
+ ConfirmationTarget::ChannelCloseMinimum => 144,
+ };
+
+ let estimates = self.esplora_client.get_fee_estimates().await.map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to retrieve fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let converted_estimates = esplora_client::convert_fee_rate(num_blocks, estimates)
+ .map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to convert fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let fee_rate = FeeRate::from_sat_per_vb(converted_estimates);
+
+ // LDK 0.0.118 introduced changes to the `ConfirmationTarget` semantics that
+ // require some post-estimation adjustments to the fee rates, which we do here.
+ let adjusted_fee_rate = match target {
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => {
+ let really_high_prio = fee_rate.as_sat_per_vb() * 10.0;
+ FeeRate::from_sat_per_vb(really_high_prio)
+ }
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => {
+ let slightly_less_than_background = fee_rate.fee_wu(1000) - 250;
+ FeeRate::from_sat_per_kwu(slightly_less_than_background as f32)
+ }
+ _ => fee_rate,
+ };
+
+ let mut locked_fee_rate_cache = self.fee_rate_cache.write().unwrap();
+ locked_fee_rate_cache.insert(target, adjusted_fee_rate);
+ log_trace!(
+ self.logger,
+ "Fee rate estimation updated for {:?}: {} sats/kwu",
+ target,
+ adjusted_fee_rate.fee_wu(1000)
+ );
+ }
+ Ok(())
+	}
+
+	pub(crate) fn estimate_fee_rate(&self, confirmation_target: ConfirmationTarget) -> FeeRate {
+ let locked_fee_rate_cache = self.fee_rate_cache.read().unwrap();
+
+ let fallback_sats_kwu = match confirmation_target {
+ ConfirmationTarget::OnChainSweep => 5000,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 25 * 250,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::AnchorChannelFee => 500,
+ ConfirmationTarget::NonAnchorChannelFee => 1000,
+ ConfirmationTarget::ChannelCloseMinimum => 500,
+ };
+
+ // We'll fall back on this, if we really don't have any other information.
+ let fallback_rate = FeeRate::from_sat_per_kwu(fallback_sats_kwu as f32);
+
+ *locked_fee_rate_cache.get(&confirmation_target).unwrap_or(&fallback_rate)
+	}
+}
+
+impl<L: Deref> FeeEstimator for OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
+ (self.estimate_fee_rate(confirmation_target).fee_wu(1000) as u32)
+ .max(FEERATE_FLOOR_SATS_PER_KW)
+	}
+}

bindings/ldk_node.udl

@@ -108,6 +108,7 @@ enum NodeError {
 	"ChannelClosingFailed",
 	"ChannelConfigUpdateFailed",
 	"PersistenceFailed",
+	"FeerateEstimationUpdateFailed",
 	"WalletOperationFailed",
 	"OnchainTxSigningFailed",
 	"MessageSigningFailed",

src/builder.rs

@@ -1,10 +1,12 @@
 use crate::event::EventQueue;
+use crate::fee_estimator::OnchainFeeEstimator;
 use crate::gossip::GossipSource;
 use crate::io;
 use crate::io::sqlite_store::SqliteStore;
 use crate::logger::{log_error, FilesystemLogger, Logger};
 use crate::payment_store::PaymentStore;
 use crate::peer_store::PeerStore;
+use crate::tx_broadcaster::TransactionBroadcaster;
 use crate::types::{
 	ChainMonitor, ChannelManager, FakeMessageRouter, GossipSync, KeysManager, NetworkGraph,
 	OnionMessenger, PeerManager,
@@ -464,13 +466,19 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  BuildError::WalletSetupFailed
 	})?;
 
-	let (blockchain, tx_sync) = match chain_data_source_config {
+	let (blockchain, tx_sync, tx_broadcaster, fee_estimator) = match chain_data_source_config {
  Some(ChainDataSourceConfig::Esplora(server_url)) => {
  let tx_sync = Arc::new(EsploraSyncClient::new(server_url.clone(), Arc::clone(&logger)));
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
  None => {
  // Default to Esplora client.
@@ -479,20 +487,31 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
 	};
 
 	let runtime = Arc::new(RwLock::new(None));
-	let wallet =
- Arc::new(Wallet::new(blockchain, bdk_wallet, Arc::clone(&runtime), Arc::clone(&logger)));
+	let wallet = Arc::new(Wallet::new(
+ blockchain,
+ bdk_wallet,
+ Arc::clone(&tx_broadcaster),
+ Arc::clone(&fee_estimator),
+ Arc::clone(&logger),
+	));
 
 	// Initialize the ChainMonitor
 	let chain_monitor: Arc<ChainMonitor<K>> = Arc::new(chainmonitor::ChainMonitor::new(
  Some(Arc::clone(&tx_sync)),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&logger),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&kv_store),
 	));
 
@@ -592,9 +611,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  user_config,
@@ -616,9 +635,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  best_block: BestBlock::new(genesis_block_hash, 0),
  };
  channelmanager::ChannelManager::new(
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  Arc::clone(&keys_manager),
@@ -767,6 +786,8 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  config,
  wallet,
  tx_sync,
+ tx_broadcaster,
+ fee_estimator,
  event_queue,
  channel_manager,
  chain_monitor,

src/error.rs

@@ -25,6 +25,8 @@ pub enum Error {
 	ChannelConfigUpdateFailed,
 	/// Persistence failed.
 	PersistenceFailed,
+	/// A fee rate estimation update failed.
+	FeerateEstimationUpdateFailed,
 	/// A wallet operation failed.
 	WalletOperationFailed,
 	/// A signing operation for transaction failed.
@@ -79,6 +81,9 @@ impl fmt::Display for Error {
  Self::ChannelClosingFailed => write!(f, "Failed to close channel."),
  Self::ChannelConfigUpdateFailed => write!(f, "Failed to update channel config."),
  Self::PersistenceFailed => write!(f, "Failed to persist data."),
+ Self::FeerateEstimationUpdateFailed => {
+ write!(f, "Failed to update fee rate estimates.")
+ }
  Self::WalletOperationFailed => write!(f, "Failed to conduct wallet operation."),
  Self::OnchainTxSigningFailed => write!(f, "Failed to sign given transaction."),
  Self::MessageSigningFailed => write!(f, "Failed to sign given message."),

src/event.rs

@@ -1,6 +1,7 @@
-use crate::peer_store::{PeerInfo, PeerStore};
+use crate::types::{Broadcaster, FeeEstimator, Wallet};
 use crate::{
-	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, UserChannelId, Wallet,
+	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, PeerInfo, PeerStore,
+	UserChannelId,
 };
 
 use crate::payment_store::{
@@ -13,7 +14,9 @@ use crate::io::{
 };
 use crate::logger::{log_debug, log_error, log_info, Logger};
 
-use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
+use lightning::chain::chaininterface::{
+	BroadcasterInterface, ConfirmationTarget, FeeEstimator as LDKFeeEstimator,
+};
 use lightning::events::Event as LdkEvent;
 use lightning::events::PaymentPurpose;
 use lightning::impl_writeable_tlv_based_enum;
@@ -243,40 +246,45 @@ pub(crate) struct EventHandler<K: KVStore + Sync + Send, L: Deref>
 where
 	L::Target: Logger,
 {
-	wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>,
 	event_queue: Arc<EventQueue<K, L>>,
+	wallet: Arc<Wallet>,
 	channel_manager: Arc<ChannelManager<K>>,
+	tx_broadcaster: Arc<Broadcaster>,
+	fee_estimator: Arc<FeeEstimator>,
 	network_graph: Arc<NetworkGraph>,
 	keys_manager: Arc<KeysManager>,
 	payment_store: Arc<PaymentStore<K, L>>,
+	peer_store: Arc<PeerStore<K, L>>,
 	runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
 	logger: L,
 	config: Arc<Config>,
-	peer_store: Arc<PeerStore<K, L>>,
 }
 
 impl<K: KVStore + Sync + Send + 'static, L: Deref> EventHandler<K, L>
 where
 	L::Target: Logger,
 {
 	pub fn new(
- wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>, event_queue: Arc<EventQueue<K, L>>,
- channel_manager: Arc<ChannelManager<K>>, network_graph: Arc<NetworkGraph>,
+ event_queue: Arc<EventQueue<K, L>>, wallet: Arc<Wallet>,
+ channel_manager: Arc<ChannelManager<K>>, tx_broadcaster: Arc<Broadcaster>,
+ fee_estimator: Arc<FeeEstimator>, network_graph: Arc<NetworkGraph>,
  keys_manager: Arc<KeysManager>, payment_store: Arc<PaymentStore<K, L>>,
- runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>, logger: L, config: Arc<Config>,
-peer_store: Arc<PeerStore<K, L>>,
+peer_store: Arc<PeerStore<K, L>>, runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
+logger: L, config: Arc<Config>,
 	) -> Self {
  Self {
  event_queue,
  wallet,
  channel_manager,
+ tx_broadcaster,
+ fee_estimator,
  network_graph,
  keys_manager,
  payment_store,
+ peer_store,
  logger,
  runtime,
  config,
- peer_store,
  }
 	}
 
@@ -586,7 +594,7 @@ where
 
  let output_descriptors = &outputs.iter().collect::<Vec<_>>();
  let tx_feerate = self
- .wallet
+ .fee_estimator
  .get_est_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
 
  // We set nLockTime to the current height to discourage fee sniping.
@@ -603,7 +611,9 @@ where
  );
 
  match res {
- Ok(Some(spending_tx)) => self.wallet.broadcast_transactions(&[&spending_tx]),
+ Ok(Some(spending_tx)) => {
+ self.tx_broadcaster.broadcast_transactions(&[&spending_tx])
+ }
  Ok(None) => {
  log_debug!(self.logger, "Omitted spending static outputs: {:?}", outputs);
  }

src/fee_estimator.rs

@@ -0,0 +1,131 @@
+use crate::logger::{log_error, log_trace, Logger};
+use crate::Error;
+
+use lightning::chain::chaininterface::{
+	ConfirmationTarget, FeeEstimator, FEERATE_FLOOR_SATS_PER_KW,
+};
+
+use bdk::FeeRate;
+use esplora_client::AsyncClient as EsploraClient;
+
+use std::collections::HashMap;
+use std::ops::Deref;
+use std::sync::RwLock;
+
+pub(crate) struct OnchainFeeEstimator<L: Deref>
+where
+	L::Target: Logger,
+{
+	fee_rate_cache: RwLock<HashMap<ConfirmationTarget, FeeRate>>,
+	esplora_client: EsploraClient,
+	logger: L,
+}
+
+impl<L: Deref> OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	pub(crate) fn new(esplora_client: EsploraClient, logger: L) -> Self {
+ let fee_rate_cache = RwLock::new(HashMap::new());
+ Self { fee_rate_cache, esplora_client, logger }
+	}
+
+	pub(crate) async fn update_fee_estimates(&self) -> Result<(), Error> {
+ let confirmation_targets = vec![
+ ConfirmationTarget::OnChainSweep,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::AnchorChannelFee,
+ ConfirmationTarget::NonAnchorChannelFee,
+ ConfirmationTarget::ChannelCloseMinimum,
+ ];
+ for target in confirmation_targets {
+ let num_blocks = match target {
+ ConfirmationTarget::OnChainSweep => 6,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 1,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => 1008,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => 144,
+ ConfirmationTarget::AnchorChannelFee => 1008,
+ ConfirmationTarget::NonAnchorChannelFee => 12,
+ ConfirmationTarget::ChannelCloseMinimum => 144,
+ };
+
+ let estimates = self.esplora_client.get_fee_estimates().await.map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to retrieve fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let converted_estimates = esplora_client::convert_fee_rate(num_blocks, estimates)
+ .map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to convert fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let fee_rate = FeeRate::from_sat_per_vb(converted_estimates);
+
+ // LDK 0.0.118 introduced changes to the `ConfirmationTarget` semantics that
+ // require some post-estimation adjustments to the fee rates, which we do here.
+ let adjusted_fee_rate = match target {
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => {
+ let really_high_prio = fee_rate.as_sat_per_vb() * 10.0;
+ FeeRate::from_sat_per_vb(really_high_prio)
+ }
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => {
+ let slightly_less_than_background = fee_rate.fee_wu(1000) - 250;
+ FeeRate::from_sat_per_kwu(slightly_less_than_background as f32)
+ }
+ _ => fee_rate,
+ };
+
+ let mut locked_fee_rate_cache = self.fee_rate_cache.write().unwrap();
+ locked_fee_rate_cache.insert(target, adjusted_fee_rate);
+ log_trace!(
+ self.logger,
+ "Fee rate estimation updated for {:?}: {} sats/kwu",
+ target,
+ adjusted_fee_rate.fee_wu(1000)
+ );
+ }
+ Ok(())
+	}
+
+	pub(crate) fn estimate_fee_rate(&self, confirmation_target: ConfirmationTarget) -> FeeRate {
+ let locked_fee_rate_cache = self.fee_rate_cache.read().unwrap();
+
+ let fallback_sats_kwu = match confirmation_target {
+ ConfirmationTarget::OnChainSweep => 5000,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 25 * 250,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::AnchorChannelFee => 500,
+ ConfirmationTarget::NonAnchorChannelFee => 1000,
+ ConfirmationTarget::ChannelCloseMinimum => 500,
+ };
+
+ // We'll fall back on this, if we really don't have any other information.
+ let fallback_rate = FeeRate::from_sat_per_kwu(fallback_sats_kwu as f32);
+
+ *locked_fee_rate_cache.get(&confirmation_target).unwrap_or(&fallback_rate)
+	}
+}
+
+impl<L: Deref> FeeEstimator for OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
+ (self.estimate_fee_rate(confirmation_target).fee_wu(1000) as u32)
+ .max(FEERATE_FLOOR_SATS_PER_KW)
+	}
+}

bindings/ldk_node.udl

@@ -108,6 +108,7 @@ enum NodeError {
 	"ChannelClosingFailed",
 	"ChannelConfigUpdateFailed",
 	"PersistenceFailed",
+	"FeerateEstimationUpdateFailed",
 	"WalletOperationFailed",
 	"OnchainTxSigningFailed",
 	"MessageSigningFailed",

src/builder.rs

@@ -1,10 +1,12 @@
 use crate::event::EventQueue;
+use crate::fee_estimator::OnchainFeeEstimator;
 use crate::gossip::GossipSource;
 use crate::io;
 use crate::io::sqlite_store::SqliteStore;
 use crate::logger::{log_error, FilesystemLogger, Logger};
 use crate::payment_store::PaymentStore;
 use crate::peer_store::PeerStore;
+use crate::tx_broadcaster::TransactionBroadcaster;
 use crate::types::{
 	ChainMonitor, ChannelManager, FakeMessageRouter, GossipSync, KeysManager, NetworkGraph,
 	OnionMessenger, PeerManager,
@@ -464,13 +466,19 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  BuildError::WalletSetupFailed
 	})?;
 
-	let (blockchain, tx_sync) = match chain_data_source_config {
+	let (blockchain, tx_sync, tx_broadcaster, fee_estimator) = match chain_data_source_config {
  Some(ChainDataSourceConfig::Esplora(server_url)) => {
  let tx_sync = Arc::new(EsploraSyncClient::new(server_url.clone(), Arc::clone(&logger)));
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
  None => {
  // Default to Esplora client.
@@ -479,20 +487,31 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
 	};
 
 	let runtime = Arc::new(RwLock::new(None));
-	let wallet =
- Arc::new(Wallet::new(blockchain, bdk_wallet, Arc::clone(&runtime), Arc::clone(&logger)));
+	let wallet = Arc::new(Wallet::new(
+ blockchain,
+ bdk_wallet,
+ Arc::clone(&tx_broadcaster),
+ Arc::clone(&fee_estimator),
+ Arc::clone(&logger),
+	));
 
 	// Initialize the ChainMonitor
 	let chain_monitor: Arc<ChainMonitor<K>> = Arc::new(chainmonitor::ChainMonitor::new(
  Some(Arc::clone(&tx_sync)),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&logger),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&kv_store),
 	));
 
@@ -592,9 +611,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  user_config,
@@ -616,9 +635,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  best_block: BestBlock::new(genesis_block_hash, 0),
  };
  channelmanager::ChannelManager::new(
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  Arc::clone(&keys_manager),
@@ -767,6 +786,8 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  config,
  wallet,
  tx_sync,
+ tx_broadcaster,
+ fee_estimator,
  event_queue,
  channel_manager,
  chain_monitor,

src/error.rs

@@ -25,6 +25,8 @@ pub enum Error {
 	ChannelConfigUpdateFailed,
 	/// Persistence failed.
 	PersistenceFailed,
+	/// A fee rate estimation update failed.
+	FeerateEstimationUpdateFailed,
 	/// A wallet operation failed.
 	WalletOperationFailed,
 	/// A signing operation for transaction failed.
@@ -79,6 +81,9 @@ impl fmt::Display for Error {
  Self::ChannelClosingFailed => write!(f, "Failed to close channel."),
  Self::ChannelConfigUpdateFailed => write!(f, "Failed to update channel config."),
  Self::PersistenceFailed => write!(f, "Failed to persist data."),
+ Self::FeerateEstimationUpdateFailed => {
+ write!(f, "Failed to update fee rate estimates.")
+ }
  Self::WalletOperationFailed => write!(f, "Failed to conduct wallet operation."),
  Self::OnchainTxSigningFailed => write!(f, "Failed to sign given transaction."),
  Self::MessageSigningFailed => write!(f, "Failed to sign given message."),

src/event.rs

@@ -1,6 +1,7 @@
-use crate::peer_store::{PeerInfo, PeerStore};
+use crate::types::{Broadcaster, FeeEstimator, Wallet};
 use crate::{
-	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, UserChannelId, Wallet,
+	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, PeerInfo, PeerStore,
+	UserChannelId,
 };
 
 use crate::payment_store::{
@@ -13,7 +14,9 @@ use crate::io::{
 };
 use crate::logger::{log_debug, log_error, log_info, Logger};
 
-use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
+use lightning::chain::chaininterface::{
+	BroadcasterInterface, ConfirmationTarget, FeeEstimator as LDKFeeEstimator,
+};
 use lightning::events::Event as LdkEvent;
 use lightning::events::PaymentPurpose;
 use lightning::impl_writeable_tlv_based_enum;
@@ -243,40 +246,45 @@ pub(crate) struct EventHandler<K: KVStore + Sync + Send, L: Deref>
 where
 	L::Target: Logger,
 {
-	wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>,
 	event_queue: Arc<EventQueue<K, L>>,
+	wallet: Arc<Wallet>,
 	channel_manager: Arc<ChannelManager<K>>,
+	tx_broadcaster: Arc<Broadcaster>,
+	fee_estimator: Arc<FeeEstimator>,
 	network_graph: Arc<NetworkGraph>,
 	keys_manager: Arc<KeysManager>,
 	payment_store: Arc<PaymentStore<K, L>>,
+	peer_store: Arc<PeerStore<K, L>>,
 	runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
 	logger: L,
 	config: Arc<Config>,
-	peer_store: Arc<PeerStore<K, L>>,
 }
 
 impl<K: KVStore + Sync + Send + 'static, L: Deref> EventHandler<K, L>
 where
 	L::Target: Logger,
 {
 	pub fn new(
- wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>, event_queue: Arc<EventQueue<K, L>>,
- channel_manager: Arc<ChannelManager<K>>, network_graph: Arc<NetworkGraph>,
+ event_queue: Arc<EventQueue<K, L>>, wallet: Arc<Wallet>,
+ channel_manager: Arc<ChannelManager<K>>, tx_broadcaster: Arc<Broadcaster>,
+ fee_estimator: Arc<FeeEstimator>, network_graph: Arc<NetworkGraph>,
  keys_manager: Arc<KeysManager>, payment_store: Arc<PaymentStore<K, L>>,
- runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>, logger: L, config: Arc<Config>,
-peer_store: Arc<PeerStore<K, L>>,
+peer_store: Arc<PeerStore<K, L>>, runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
+logger: L, config: Arc<Config>,
 	) -> Self {
  Self {
  event_queue,
  wallet,
  channel_manager,
+ tx_broadcaster,
+ fee_estimator,
  network_graph,
  keys_manager,
  payment_store,
+ peer_store,
  logger,
  runtime,
  config,
- peer_store,
  }
 	}
 
@@ -586,7 +594,7 @@ where
 
  let output_descriptors = &outputs.iter().collect::<Vec<_>>();
  let tx_feerate = self
- .wallet
+ .fee_estimator
  .get_est_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
 
  // We set nLockTime to the current height to discourage fee sniping.
@@ -603,7 +611,9 @@ where
  );
 
  match res {
- Ok(Some(spending_tx)) => self.wallet.broadcast_transactions(&[&spending_tx]),
+ Ok(Some(spending_tx)) => {
+ self.tx_broadcaster.broadcast_transactions(&[&spending_tx])
+ }
  Ok(None) => {
  log_debug!(self.logger, "Omitted spending static outputs: {:?}", outputs);
  }

src/fee_estimator.rs

@@ -0,0 +1,131 @@
+use crate::logger::{log_error, log_trace, Logger};
+use crate::Error;
+
+use lightning::chain::chaininterface::{
+	ConfirmationTarget, FeeEstimator, FEERATE_FLOOR_SATS_PER_KW,
+};
+
+use bdk::FeeRate;
+use esplora_client::AsyncClient as EsploraClient;
+
+use std::collections::HashMap;
+use std::ops::Deref;
+use std::sync::RwLock;
+
+pub(crate) struct OnchainFeeEstimator<L: Deref>
+where
+	L::Target: Logger,
+{
+	fee_rate_cache: RwLock<HashMap<ConfirmationTarget, FeeRate>>,
+	esplora_client: EsploraClient,
+	logger: L,
+}
+
+impl<L: Deref> OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	pub(crate) fn new(esplora_client: EsploraClient, logger: L) -> Self {
+ let fee_rate_cache = RwLock::new(HashMap::new());
+ Self { fee_rate_cache, esplora_client, logger }
+	}
+
+	pub(crate) async fn update_fee_estimates(&self) -> Result<(), Error> {
+ let confirmation_targets = vec![
+ ConfirmationTarget::OnChainSweep,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::AnchorChannelFee,
+ ConfirmationTarget::NonAnchorChannelFee,
+ ConfirmationTarget::ChannelCloseMinimum,
+ ];
+ for target in confirmation_targets {
+ let num_blocks = match target {
+ ConfirmationTarget::OnChainSweep => 6,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 1,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => 1008,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => 144,
+ ConfirmationTarget::AnchorChannelFee => 1008,
+ ConfirmationTarget::NonAnchorChannelFee => 12,
+ ConfirmationTarget::ChannelCloseMinimum => 144,
+ };
+
+ let estimates = self.esplora_client.get_fee_estimates().await.map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to retrieve fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let converted_estimates = esplora_client::convert_fee_rate(num_blocks, estimates)
+ .map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to convert fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let fee_rate = FeeRate::from_sat_per_vb(converted_estimates);
+
+ // LDK 0.0.118 introduced changes to the `ConfirmationTarget` semantics that
+ // require some post-estimation adjustments to the fee rates, which we do here.
+ let adjusted_fee_rate = match target {
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => {
+ let really_high_prio = fee_rate.as_sat_per_vb() * 10.0;
+ FeeRate::from_sat_per_vb(really_high_prio)
+ }
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => {
+ let slightly_less_than_background = fee_rate.fee_wu(1000) - 250;
+ FeeRate::from_sat_per_kwu(slightly_less_than_background as f32)
+ }
+ _ => fee_rate,
+ };
+
+ let mut locked_fee_rate_cache = self.fee_rate_cache.write().unwrap();
+ locked_fee_rate_cache.insert(target, adjusted_fee_rate);
+ log_trace!(
+ self.logger,
+ "Fee rate estimation updated for {:?}: {} sats/kwu",
+ target,
+ adjusted_fee_rate.fee_wu(1000)
+ );
+ }
+ Ok(())
+	}
+
+	pub(crate) fn estimate_fee_rate(&self, confirmation_target: ConfirmationTarget) -> FeeRate {
+ let locked_fee_rate_cache = self.fee_rate_cache.read().unwrap();
+
+ let fallback_sats_kwu = match confirmation_target {
+ ConfirmationTarget::OnChainSweep => 5000,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 25 * 250,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::AnchorChannelFee => 500,
+ ConfirmationTarget::NonAnchorChannelFee => 1000,
+ ConfirmationTarget::ChannelCloseMinimum => 500,
+ };
+
+ // We'll fall back on this, if we really don't have any other information.
+ let fallback_rate = FeeRate::from_sat_per_kwu(fallback_sats_kwu as f32);
+
+ *locked_fee_rate_cache.get(&confirmation_target).unwrap_or(&fallback_rate)
+	}
+}
+
+impl<L: Deref> FeeEstimator for OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
+ (self.estimate_fee_rate(confirmation_target).fee_wu(1000) as u32)
+ .max(FEERATE_FLOOR_SATS_PER_KW)
+	}
+}

bindings/ldk_node.udl

@@ -108,6 +108,7 @@ enum NodeError {
 	"ChannelClosingFailed",
 	"ChannelConfigUpdateFailed",
 	"PersistenceFailed",
+	"FeerateEstimationUpdateFailed",
 	"WalletOperationFailed",
 	"OnchainTxSigningFailed",
 	"MessageSigningFailed",

src/builder.rs

@@ -1,10 +1,12 @@
 use crate::event::EventQueue;
+use crate::fee_estimator::OnchainFeeEstimator;
 use crate::gossip::GossipSource;
 use crate::io;
 use crate::io::sqlite_store::SqliteStore;
 use crate::logger::{log_error, FilesystemLogger, Logger};
 use crate::payment_store::PaymentStore;
 use crate::peer_store::PeerStore;
+use crate::tx_broadcaster::TransactionBroadcaster;
 use crate::types::{
 	ChainMonitor, ChannelManager, FakeMessageRouter, GossipSync, KeysManager, NetworkGraph,
 	OnionMessenger, PeerManager,
@@ -464,13 +466,19 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  BuildError::WalletSetupFailed
 	})?;
 
-	let (blockchain, tx_sync) = match chain_data_source_config {
+	let (blockchain, tx_sync, tx_broadcaster, fee_estimator) = match chain_data_source_config {
  Some(ChainDataSourceConfig::Esplora(server_url)) => {
  let tx_sync = Arc::new(EsploraSyncClient::new(server_url.clone(), Arc::clone(&logger)));
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
  None => {
  // Default to Esplora client.
@@ -479,20 +487,31 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
 	};
 
 	let runtime = Arc::new(RwLock::new(None));
-	let wallet =
- Arc::new(Wallet::new(blockchain, bdk_wallet, Arc::clone(&runtime), Arc::clone(&logger)));
+	let wallet = Arc::new(Wallet::new(
+ blockchain,
+ bdk_wallet,
+ Arc::clone(&tx_broadcaster),
+ Arc::clone(&fee_estimator),
+ Arc::clone(&logger),
+	));
 
 	// Initialize the ChainMonitor
 	let chain_monitor: Arc<ChainMonitor<K>> = Arc::new(chainmonitor::ChainMonitor::new(
  Some(Arc::clone(&tx_sync)),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&logger),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&kv_store),
 	));
 
@@ -592,9 +611,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  user_config,
@@ -616,9 +635,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  best_block: BestBlock::new(genesis_block_hash, 0),
  };
  channelmanager::ChannelManager::new(
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  Arc::clone(&keys_manager),
@@ -767,6 +786,8 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  config,
  wallet,
  tx_sync,
+ tx_broadcaster,
+ fee_estimator,
  event_queue,
  channel_manager,
  chain_monitor,

src/error.rs

@@ -25,6 +25,8 @@ pub enum Error {
 	ChannelConfigUpdateFailed,
 	/// Persistence failed.
 	PersistenceFailed,
+	/// A fee rate estimation update failed.
+	FeerateEstimationUpdateFailed,
 	/// A wallet operation failed.
 	WalletOperationFailed,
 	/// A signing operation for transaction failed.
@@ -79,6 +81,9 @@ impl fmt::Display for Error {
  Self::ChannelClosingFailed => write!(f, "Failed to close channel."),
  Self::ChannelConfigUpdateFailed => write!(f, "Failed to update channel config."),
  Self::PersistenceFailed => write!(f, "Failed to persist data."),
+ Self::FeerateEstimationUpdateFailed => {
+ write!(f, "Failed to update fee rate estimates.")
+ }
  Self::WalletOperationFailed => write!(f, "Failed to conduct wallet operation."),
  Self::OnchainTxSigningFailed => write!(f, "Failed to sign given transaction."),
  Self::MessageSigningFailed => write!(f, "Failed to sign given message."),

src/event.rs

@@ -1,6 +1,7 @@
-use crate::peer_store::{PeerInfo, PeerStore};
+use crate::types::{Broadcaster, FeeEstimator, Wallet};
 use crate::{
-	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, UserChannelId, Wallet,
+	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, PeerInfo, PeerStore,
+	UserChannelId,
 };
 
 use crate::payment_store::{
@@ -13,7 +14,9 @@ use crate::io::{
 };
 use crate::logger::{log_debug, log_error, log_info, Logger};
 
-use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
+use lightning::chain::chaininterface::{
+	BroadcasterInterface, ConfirmationTarget, FeeEstimator as LDKFeeEstimator,
+};
 use lightning::events::Event as LdkEvent;
 use lightning::events::PaymentPurpose;
 use lightning::impl_writeable_tlv_based_enum;
@@ -243,40 +246,45 @@ pub(crate) struct EventHandler<K: KVStore + Sync + Send, L: Deref>
 where
 	L::Target: Logger,
 {
-	wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>,
 	event_queue: Arc<EventQueue<K, L>>,
+	wallet: Arc<Wallet>,
 	channel_manager: Arc<ChannelManager<K>>,
+	tx_broadcaster: Arc<Broadcaster>,
+	fee_estimator: Arc<FeeEstimator>,
 	network_graph: Arc<NetworkGraph>,
 	keys_manager: Arc<KeysManager>,
 	payment_store: Arc<PaymentStore<K, L>>,
+	peer_store: Arc<PeerStore<K, L>>,
 	runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
 	logger: L,
 	config: Arc<Config>,
-	peer_store: Arc<PeerStore<K, L>>,
 }
 
 impl<K: KVStore + Sync + Send + 'static, L: Deref> EventHandler<K, L>
 where
 	L::Target: Logger,
 {
 	pub fn new(
- wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>, event_queue: Arc<EventQueue<K, L>>,
- channel_manager: Arc<ChannelManager<K>>, network_graph: Arc<NetworkGraph>,
+ event_queue: Arc<EventQueue<K, L>>, wallet: Arc<Wallet>,
+ channel_manager: Arc<ChannelManager<K>>, tx_broadcaster: Arc<Broadcaster>,
+ fee_estimator: Arc<FeeEstimator>, network_graph: Arc<NetworkGraph>,
  keys_manager: Arc<KeysManager>, payment_store: Arc<PaymentStore<K, L>>,
- runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>, logger: L, config: Arc<Config>,
-peer_store: Arc<PeerStore<K, L>>,
+peer_store: Arc<PeerStore<K, L>>, runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
+logger: L, config: Arc<Config>,
 	) -> Self {
  Self {
  event_queue,
  wallet,
  channel_manager,
+ tx_broadcaster,
+ fee_estimator,
  network_graph,
  keys_manager,
  payment_store,
+ peer_store,
  logger,
  runtime,
  config,
- peer_store,
  }
 	}
 
@@ -586,7 +594,7 @@ where
 
  let output_descriptors = &outputs.iter().collect::<Vec<_>>();
  let tx_feerate = self
- .wallet
+ .fee_estimator
  .get_est_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
 
  // We set nLockTime to the current height to discourage fee sniping.
@@ -603,7 +611,9 @@ where
  );
 
  match res {
- Ok(Some(spending_tx)) => self.wallet.broadcast_transactions(&[&spending_tx]),
+ Ok(Some(spending_tx)) => {
+ self.tx_broadcaster.broadcast_transactions(&[&spending_tx])
+ }
  Ok(None) => {
  log_debug!(self.logger, "Omitted spending static outputs: {:?}", outputs);
  }

src/fee_estimator.rs

@@ -0,0 +1,131 @@
+use crate::logger::{log_error, log_trace, Logger};
+use crate::Error;
+
+use lightning::chain::chaininterface::{
+	ConfirmationTarget, FeeEstimator, FEERATE_FLOOR_SATS_PER_KW,
+};
+
+use bdk::FeeRate;
+use esplora_client::AsyncClient as EsploraClient;
+
+use std::collections::HashMap;
+use std::ops::Deref;
+use std::sync::RwLock;
+
+pub(crate) struct OnchainFeeEstimator<L: Deref>
+where
+	L::Target: Logger,
+{
+	fee_rate_cache: RwLock<HashMap<ConfirmationTarget, FeeRate>>,
+	esplora_client: EsploraClient,
+	logger: L,
+}
+
+impl<L: Deref> OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	pub(crate) fn new(esplora_client: EsploraClient, logger: L) -> Self {
+ let fee_rate_cache = RwLock::new(HashMap::new());
+ Self { fee_rate_cache, esplora_client, logger }
+	}
+
+	pub(crate) async fn update_fee_estimates(&self) -> Result<(), Error> {
+ let confirmation_targets = vec![
+ ConfirmationTarget::OnChainSweep,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::AnchorChannelFee,
+ ConfirmationTarget::NonAnchorChannelFee,
+ ConfirmationTarget::ChannelCloseMinimum,
+ ];
+ for target in confirmation_targets {
+ let num_blocks = match target {
+ ConfirmationTarget::OnChainSweep => 6,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 1,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => 1008,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => 144,
+ ConfirmationTarget::AnchorChannelFee => 1008,
+ ConfirmationTarget::NonAnchorChannelFee => 12,
+ ConfirmationTarget::ChannelCloseMinimum => 144,
+ };
+
+ let estimates = self.esplora_client.get_fee_estimates().await.map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to retrieve fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let converted_estimates = esplora_client::convert_fee_rate(num_blocks, estimates)
+ .map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to convert fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let fee_rate = FeeRate::from_sat_per_vb(converted_estimates);
+
+ // LDK 0.0.118 introduced changes to the `ConfirmationTarget` semantics that
+ // require some post-estimation adjustments to the fee rates, which we do here.
+ let adjusted_fee_rate = match target {
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => {
+ let really_high_prio = fee_rate.as_sat_per_vb() * 10.0;
+ FeeRate::from_sat_per_vb(really_high_prio)
+ }
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => {
+ let slightly_less_than_background = fee_rate.fee_wu(1000) - 250;
+ FeeRate::from_sat_per_kwu(slightly_less_than_background as f32)
+ }
+ _ => fee_rate,
+ };
+
+ let mut locked_fee_rate_cache = self.fee_rate_cache.write().unwrap();
+ locked_fee_rate_cache.insert(target, adjusted_fee_rate);
+ log_trace!(
+ self.logger,
+ "Fee rate estimation updated for {:?}: {} sats/kwu",
+ target,
+ adjusted_fee_rate.fee_wu(1000)
+ );
+ }
+ Ok(())
+	}
+
+	pub(crate) fn estimate_fee_rate(&self, confirmation_target: ConfirmationTarget) -> FeeRate {
+ let locked_fee_rate_cache = self.fee_rate_cache.read().unwrap();
+
+ let fallback_sats_kwu = match confirmation_target {
+ ConfirmationTarget::OnChainSweep => 5000,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 25 * 250,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::AnchorChannelFee => 500,
+ ConfirmationTarget::NonAnchorChannelFee => 1000,
+ ConfirmationTarget::ChannelCloseMinimum => 500,
+ };
+
+ // We'll fall back on this, if we really don't have any other information.
+ let fallback_rate = FeeRate::from_sat_per_kwu(fallback_sats_kwu as f32);
+
+ *locked_fee_rate_cache.get(&confirmation_target).unwrap_or(&fallback_rate)
+	}
+}
+
+impl<L: Deref> FeeEstimator for OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
+ (self.estimate_fee_rate(confirmation_target).fee_wu(1000) as u32)
+ .max(FEERATE_FLOOR_SATS_PER_KW)
+	}
+}

bindings/ldk_node.udl

@@ -108,6 +108,7 @@ enum NodeError {
 	"ChannelClosingFailed",
 	"ChannelConfigUpdateFailed",
 	"PersistenceFailed",
+	"FeerateEstimationUpdateFailed",
 	"WalletOperationFailed",
 	"OnchainTxSigningFailed",
 	"MessageSigningFailed",

src/builder.rs

@@ -1,10 +1,12 @@
 use crate::event::EventQueue;
+use crate::fee_estimator::OnchainFeeEstimator;
 use crate::gossip::GossipSource;
 use crate::io;
 use crate::io::sqlite_store::SqliteStore;
 use crate::logger::{log_error, FilesystemLogger, Logger};
 use crate::payment_store::PaymentStore;
 use crate::peer_store::PeerStore;
+use crate::tx_broadcaster::TransactionBroadcaster;
 use crate::types::{
 	ChainMonitor, ChannelManager, FakeMessageRouter, GossipSync, KeysManager, NetworkGraph,
 	OnionMessenger, PeerManager,
@@ -464,13 +466,19 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  BuildError::WalletSetupFailed
 	})?;
 
-	let (blockchain, tx_sync) = match chain_data_source_config {
+	let (blockchain, tx_sync, tx_broadcaster, fee_estimator) = match chain_data_source_config {
  Some(ChainDataSourceConfig::Esplora(server_url)) => {
  let tx_sync = Arc::new(EsploraSyncClient::new(server_url.clone(), Arc::clone(&logger)));
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
  None => {
  // Default to Esplora client.
@@ -479,20 +487,31 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  let blockchain =
  EsploraBlockchain::from_client(tx_sync.client().clone(), BDK_CLIENT_STOP_GAP)
  .with_concurrency(BDK_CLIENT_CONCURRENCY);
- (blockchain, tx_sync)
+ let tx_broadcaster = Arc::new(TransactionBroadcaster::new(
+ tx_sync.client().clone(),
+ Arc::clone(&logger),
+ ));
+ let fee_estimator =
+ Arc::new(OnchainFeeEstimator::new(tx_sync.client().clone(), Arc::clone(&logger)));
+ (blockchain, tx_sync, tx_broadcaster, fee_estimator)
  }
 	};
 
 	let runtime = Arc::new(RwLock::new(None));
-	let wallet =
- Arc::new(Wallet::new(blockchain, bdk_wallet, Arc::clone(&runtime), Arc::clone(&logger)));
+	let wallet = Arc::new(Wallet::new(
+ blockchain,
+ bdk_wallet,
+ Arc::clone(&tx_broadcaster),
+ Arc::clone(&fee_estimator),
+ Arc::clone(&logger),
+	));
 
 	// Initialize the ChainMonitor
 	let chain_monitor: Arc<ChainMonitor<K>> = Arc::new(chainmonitor::ChainMonitor::new(
  Some(Arc::clone(&tx_sync)),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&logger),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&kv_store),
 	));
 
@@ -592,9 +611,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
  Arc::clone(&keys_manager),
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  user_config,
@@ -616,9 +635,9 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  best_block: BestBlock::new(genesis_block_hash, 0),
  };
  channelmanager::ChannelManager::new(
- Arc::clone(&wallet),
+ Arc::clone(&fee_estimator),
  Arc::clone(&chain_monitor),
- Arc::clone(&wallet),
+ Arc::clone(&tx_broadcaster),
  Arc::clone(&router),
  Arc::clone(&logger),
  Arc::clone(&keys_manager),
@@ -767,6 +786,8 @@ fn build_with_store_internal<K: KVStore + Sync + Send + 'static>(
  config,
  wallet,
  tx_sync,
+ tx_broadcaster,
+ fee_estimator,
  event_queue,
  channel_manager,
  chain_monitor,

src/error.rs

@@ -25,6 +25,8 @@ pub enum Error {
 	ChannelConfigUpdateFailed,
 	/// Persistence failed.
 	PersistenceFailed,
+	/// A fee rate estimation update failed.
+	FeerateEstimationUpdateFailed,
 	/// A wallet operation failed.
 	WalletOperationFailed,
 	/// A signing operation for transaction failed.
@@ -79,6 +81,9 @@ impl fmt::Display for Error {
  Self::ChannelClosingFailed => write!(f, "Failed to close channel."),
  Self::ChannelConfigUpdateFailed => write!(f, "Failed to update channel config."),
  Self::PersistenceFailed => write!(f, "Failed to persist data."),
+ Self::FeerateEstimationUpdateFailed => {
+ write!(f, "Failed to update fee rate estimates.")
+ }
  Self::WalletOperationFailed => write!(f, "Failed to conduct wallet operation."),
  Self::OnchainTxSigningFailed => write!(f, "Failed to sign given transaction."),
  Self::MessageSigningFailed => write!(f, "Failed to sign given message."),

src/event.rs

@@ -1,6 +1,7 @@
-use crate::peer_store::{PeerInfo, PeerStore};
+use crate::types::{Broadcaster, FeeEstimator, Wallet};
 use crate::{
-	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, UserChannelId, Wallet,
+	hex_utils, ChannelManager, Config, Error, KeysManager, NetworkGraph, PeerInfo, PeerStore,
+	UserChannelId,
 };
 
 use crate::payment_store::{
@@ -13,7 +14,9 @@ use crate::io::{
 };
 use crate::logger::{log_debug, log_error, log_info, Logger};
 
-use lightning::chain::chaininterface::{BroadcasterInterface, ConfirmationTarget, FeeEstimator};
+use lightning::chain::chaininterface::{
+	BroadcasterInterface, ConfirmationTarget, FeeEstimator as LDKFeeEstimator,
+};
 use lightning::events::Event as LdkEvent;
 use lightning::events::PaymentPurpose;
 use lightning::impl_writeable_tlv_based_enum;
@@ -243,40 +246,45 @@ pub(crate) struct EventHandler<K: KVStore + Sync + Send, L: Deref>
 where
 	L::Target: Logger,
 {
-	wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>,
 	event_queue: Arc<EventQueue<K, L>>,
+	wallet: Arc<Wallet>,
 	channel_manager: Arc<ChannelManager<K>>,
+	tx_broadcaster: Arc<Broadcaster>,
+	fee_estimator: Arc<FeeEstimator>,
 	network_graph: Arc<NetworkGraph>,
 	keys_manager: Arc<KeysManager>,
 	payment_store: Arc<PaymentStore<K, L>>,
+	peer_store: Arc<PeerStore<K, L>>,
 	runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
 	logger: L,
 	config: Arc<Config>,
-	peer_store: Arc<PeerStore<K, L>>,
 }
 
 impl<K: KVStore + Sync + Send + 'static, L: Deref> EventHandler<K, L>
 where
 	L::Target: Logger,
 {
 	pub fn new(
- wallet: Arc<Wallet<bdk::database::SqliteDatabase, L>>, event_queue: Arc<EventQueue<K, L>>,
- channel_manager: Arc<ChannelManager<K>>, network_graph: Arc<NetworkGraph>,
+ event_queue: Arc<EventQueue<K, L>>, wallet: Arc<Wallet>,
+ channel_manager: Arc<ChannelManager<K>>, tx_broadcaster: Arc<Broadcaster>,
+ fee_estimator: Arc<FeeEstimator>, network_graph: Arc<NetworkGraph>,
  keys_manager: Arc<KeysManager>, payment_store: Arc<PaymentStore<K, L>>,
- runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>, logger: L, config: Arc<Config>,
-peer_store: Arc<PeerStore<K, L>>,
+peer_store: Arc<PeerStore<K, L>>, runtime: Arc<RwLock<Option<tokio::runtime::Runtime>>>,
+logger: L, config: Arc<Config>,
 	) -> Self {
  Self {
  event_queue,
  wallet,
  channel_manager,
+ tx_broadcaster,
+ fee_estimator,
  network_graph,
  keys_manager,
  payment_store,
+ peer_store,
  logger,
  runtime,
  config,
- peer_store,
  }
 	}
 
@@ -586,7 +594,7 @@ where
 
  let output_descriptors = &outputs.iter().collect::<Vec<_>>();
  let tx_feerate = self
- .wallet
+ .fee_estimator
  .get_est_sat_per_1000_weight(ConfirmationTarget::NonAnchorChannelFee);
 
  // We set nLockTime to the current height to discourage fee sniping.
@@ -603,7 +611,9 @@ where
  );
 
  match res {
- Ok(Some(spending_tx)) => self.wallet.broadcast_transactions(&[&spending_tx]),
+ Ok(Some(spending_tx)) => {
+ self.tx_broadcaster.broadcast_transactions(&[&spending_tx])
+ }
  Ok(None) => {
  log_debug!(self.logger, "Omitted spending static outputs: {:?}", outputs);
  }

src/fee_estimator.rs

@@ -0,0 +1,131 @@
+use crate::logger::{log_error, log_trace, Logger};
+use crate::Error;
+
+use lightning::chain::chaininterface::{
+	ConfirmationTarget, FeeEstimator, FEERATE_FLOOR_SATS_PER_KW,
+};
+
+use bdk::FeeRate;
+use esplora_client::AsyncClient as EsploraClient;
+
+use std::collections::HashMap;
+use std::ops::Deref;
+use std::sync::RwLock;
+
+pub(crate) struct OnchainFeeEstimator<L: Deref>
+where
+	L::Target: Logger,
+{
+	fee_rate_cache: RwLock<HashMap<ConfirmationTarget, FeeRate>>,
+	esplora_client: EsploraClient,
+	logger: L,
+}
+
+impl<L: Deref> OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	pub(crate) fn new(esplora_client: EsploraClient, logger: L) -> Self {
+ let fee_rate_cache = RwLock::new(HashMap::new());
+ Self { fee_rate_cache, esplora_client, logger }
+	}
+
+	pub(crate) async fn update_fee_estimates(&self) -> Result<(), Error> {
+ let confirmation_targets = vec![
+ ConfirmationTarget::OnChainSweep,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee,
+ ConfirmationTarget::AnchorChannelFee,
+ ConfirmationTarget::NonAnchorChannelFee,
+ ConfirmationTarget::ChannelCloseMinimum,
+ ];
+ for target in confirmation_targets {
+ let num_blocks = match target {
+ ConfirmationTarget::OnChainSweep => 6,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 1,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => 1008,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => 144,
+ ConfirmationTarget::AnchorChannelFee => 1008,
+ ConfirmationTarget::NonAnchorChannelFee => 12,
+ ConfirmationTarget::ChannelCloseMinimum => 144,
+ };
+
+ let estimates = self.esplora_client.get_fee_estimates().await.map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to retrieve fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let converted_estimates = esplora_client::convert_fee_rate(num_blocks, estimates)
+ .map_err(|e| {
+ log_error!(
+ self.logger,
+ "Failed to convert fee rate estimates for {:?}: {}",
+ target,
+ e
+ );
+ Error::FeerateEstimationUpdateFailed
+ })?;
+
+ let fee_rate = FeeRate::from_sat_per_vb(converted_estimates);
+
+ // LDK 0.0.118 introduced changes to the `ConfirmationTarget` semantics that
+ // require some post-estimation adjustments to the fee rates, which we do here.
+ let adjusted_fee_rate = match target {
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => {
+ let really_high_prio = fee_rate.as_sat_per_vb() * 10.0;
+ FeeRate::from_sat_per_vb(really_high_prio)
+ }
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => {
+ let slightly_less_than_background = fee_rate.fee_wu(1000) - 250;
+ FeeRate::from_sat_per_kwu(slightly_less_than_background as f32)
+ }
+ _ => fee_rate,
+ };
+
+ let mut locked_fee_rate_cache = self.fee_rate_cache.write().unwrap();
+ locked_fee_rate_cache.insert(target, adjusted_fee_rate);
+ log_trace!(
+ self.logger,
+ "Fee rate estimation updated for {:?}: {} sats/kwu",
+ target,
+ adjusted_fee_rate.fee_wu(1000)
+ );
+ }
+ Ok(())
+	}
+
+	pub(crate) fn estimate_fee_rate(&self, confirmation_target: ConfirmationTarget) -> FeeRate {
+ let locked_fee_rate_cache = self.fee_rate_cache.read().unwrap();
+
+ let fallback_sats_kwu = match confirmation_target {
+ ConfirmationTarget::OnChainSweep => 5000,
+ ConfirmationTarget::MaxAllowedNonAnchorChannelRemoteFee => 25 * 250,
+ ConfirmationTarget::MinAllowedAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::MinAllowedNonAnchorChannelRemoteFee => FEERATE_FLOOR_SATS_PER_KW,
+ ConfirmationTarget::AnchorChannelFee => 500,
+ ConfirmationTarget::NonAnchorChannelFee => 1000,
+ ConfirmationTarget::ChannelCloseMinimum => 500,
+ };
+
+ // We'll fall back on this, if we really don't have any other information.
+ let fallback_rate = FeeRate::from_sat_per_kwu(fallback_sats_kwu as f32);
+
+ *locked_fee_rate_cache.get(&confirmation_target).unwrap_or(&fallback_rate)
+	}
+}
+
+impl<L: Deref> FeeEstimator for OnchainFeeEstimator<L>
+where
+	L::Target: Logger,
+{
+	fn get_est_sat_per_1000_weight(&self, confirmation_target: ConfirmationTarget) -> u32 {
+ (self.estimate_fee_rate(confirmation_target).fee_wu(1000) as u32)
+ .max(FEERATE_FLOOR_SATS_PER_KW)
+	}
+}