Integrate TierStore into NodeBuilder

Add native builder support for tiered storage by introducing
`TierStoreConfig`, backup and ephemeral store configuration methods,
and a `build_with_dynstore` path that wraps the provided store as the
primary tier and applies any configured secondary tiers.

This makes tiered storage a builder concern while keeping the Rust
`build_with_store` API ergonomic for native callers.

Note: The temporary `dead_code` allowance will be removed in a
follow-up commit once the new tier-store builder APIs are exercised.

Author: enigbe

src/builder.rs

@@ -58,6 +58,7 @@ use crate::event::EventQueue;
 use crate::fee_estimator::OnchainFeeEstimator;
 use crate::gossip::GossipSource;
 use crate::io::sqlite_store::SqliteStore;
+use crate::io::tier_store::TierStore;
 use crate::io::utils::{
 	read_all_objects, read_event_queue, read_external_pathfinding_scores_from_cache,
 	read_network_graph, read_node_metrics, read_output_sweeper, read_peer_info, read_scorer,
@@ -154,6 +155,21 @@ impl std::fmt::Debug for LogWriterConfig {
 	}
 }
 
+#[derive(Default)]
+struct TierStoreConfig {
+	ephemeral: Option<Arc<DynStore>>,
+	backup: Option<Arc<DynStore>>,
+}
+
+impl std::fmt::Debug for TierStoreConfig {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		f.debug_struct("TierStoreConfig")
+			.field("ephemeral", &self.ephemeral.as_ref().map(|_| "Arc<DynStore>"))
+			.field("backup", &self.backup.as_ref().map(|_| "Arc<DynStore>"))
+			.finish()
+	}
+}
+
 /// An error encountered during building a [`Node`].
 ///
 /// [`Node`]: crate::Node
@@ -289,6 +305,7 @@ pub struct NodeBuilder {
 	liquidity_source_config: Option<LiquiditySourceConfig>,
 	log_writer_config: Option<LogWriterConfig>,
 	async_payments_role: Option<AsyncPaymentsRole>,
+	tier_store_config: Option<TierStoreConfig>,
 	runtime_handle: Option<tokio::runtime::Handle>,
 	pathfinding_scores_sync_config: Option<PathfindingScoresSyncConfig>,
 	recovery_mode: bool,
@@ -307,6 +324,7 @@ impl NodeBuilder {
 		let gossip_source_config = None;
 		let liquidity_source_config = None;
 		let log_writer_config = None;
+		let tier_store_config = None;
 		let runtime_handle = None;
 		let pathfinding_scores_sync_config = None;
 		let recovery_mode = false;
@@ -316,6 +334,7 @@ impl NodeBuilder {
 			gossip_source_config,
 			liquidity_source_config,
 			log_writer_config,
+			tier_store_config,
 			runtime_handle,
 			async_payments_role: None,
 			pathfinding_scores_sync_config,
@@ -625,6 +644,34 @@ impl NodeBuilder {
 		self
 	}
 
+	/// Configures the backup store for local disaster recovery.
+	///
+	/// When building with tiered storage, this store receives a second durable
+	/// copy of data written to the primary store.
+	///
+	/// Writes and removals for primary-backed data only succeed once both the
+	/// primary and backup stores complete successfully.
+	///
+	/// If not set, durable data will be stored only in the primary store.
+	pub fn set_backup_store(&mut self, backup_store: Arc<DynStore>) -> &mut Self {
+		let tier_store_config = self.tier_store_config.get_or_insert(TierStoreConfig::default());
+		tier_store_config.backup = Some(backup_store);
+		self
+	}
+
+	/// Configures the ephemeral store for non-critical, frequently-accessed data.
+	///
+	/// When building with tiered storage, this store is used for ephemeral data like
+	/// the network graph and scorer data to reduce latency for reads. Data stored here
+	/// can be rebuilt if lost.
+	///
+	/// If not set, non-critical data will be stored in the primary store.
+	pub fn set_ephemeral_store(&mut self, ephemeral_store: Arc<DynStore>) -> &mut Self {
+		let tier_store_config = self.tier_store_config.get_or_insert(TierStoreConfig::default());
+		tier_store_config.ephemeral = Some(ephemeral_store);
+		self
+	}
+
 	/// Builds a [`Node`] instance with a [`SqliteStore`] backend and according to the options
 	/// previously configured.
 	pub fn build(&self, node_entropy: NodeEntropy) -> Result<Node, BuildError> {
@@ -780,8 +827,23 @@ impl NodeBuilder {
 	}
 
 	/// Builds a [`Node`] instance according to the options previously configured.
+	///
+	/// The provided `kv_store` will be used as the primary storage backend. Optionally,
+	/// an ephemeral store for frequently-accessed non-critical data (e.g., network graph, scorer)
+	/// and a backup store for local disaster recovery can be configured via
+	/// [`set_ephemeral_store`] and [`set_backup_store`].
+	///
+	/// [`set_ephemeral_store`]: Self::set_ephemeral_store
+	/// [`set_backup_store`]: Self::set_backup_store
 	pub fn build_with_store<S: SyncAndAsyncKVStore + Send + Sync + 'static>(
 		&self, node_entropy: NodeEntropy, kv_store: S,
+	) -> Result<Node, BuildError> {
+		let primary_store: Arc<DynStore> = Arc::new(DynStoreWrapper(kv_store));
+		self.build_with_dynstore(node_entropy, primary_store)
+	}
+
+	fn build_with_dynstore(
+		&self, node_entropy: NodeEntropy, primary_store: Arc<DynStore>,
 	) -> Result<Node, BuildError> {
 		let logger = setup_logger(&self.log_writer_config, &self.config)?;
 
@@ -800,6 +862,13 @@ impl NodeBuilder {
 			})?)
 		};
 
+		let ts_config = self.tier_store_config.as_ref();
+		let mut tier_store = TierStore::new(primary_store, Arc::clone(&logger));
+		if let Some(config) = ts_config {
+			config.ephemeral.as_ref().map(|s| tier_store.set_ephemeral_store(Arc::clone(s)));
+			config.backup.as_ref().map(|s| tier_store.set_backup_store(Arc::clone(s)));
+		}
+
 		let seed_bytes = node_entropy.to_seed_bytes();
 		let config = Arc::new(self.config.clone());
 
@@ -814,7 +883,7 @@ impl NodeBuilder {
 			seed_bytes,
 			runtime,
 			logger,
-			Arc::new(DynStoreWrapper(kv_store)),
+			Arc::new(DynStoreWrapper(tier_store)),
 		)
 	}
 }

src/io/tier_store.rs

@@ -4,7 +4,6 @@
 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
 // http://opensource.org/licenses/MIT>, at your option. You may not use this file except in
 // accordance with one or both of these licenses.
-#![allow(dead_code)] // TODO: Temporal warning silencer. Will be removed in later commit.
 
 use crate::io::utils::check_namespace_key_validity;
 use crate::logger::{LdkLogger, Logger};

src/types.rs

@@ -57,7 +57,7 @@ where
 {
 }
 
-pub(crate) trait DynStoreTrait: Send + Sync {
+pub trait DynStoreTrait: Send + Sync {
 	fn read_async(
 		&self, primary_namespace: &str, secondary_namespace: &str, key: &str,
 	) -> Pin<Box<dyn Future<Output = Result<Vec<u8>, bitcoin::io::Error>> + Send + 'static>>;