Add LSPS2 client config to ldk-server

Expose LSPS2 client settings in `ldk-server-config.toml` so nodes can
be configured to source just-in-time liquidity from an LSP. This also
keeps the workspace green by fixing the existing `clippy` warning in
`ldk-server-cli`.

Generated with the assistance of AI.

Co-Authored-By: HAL 9000

Author: tnull

ldk-server/ldk-server-config.toml

@@ -43,6 +43,15 @@ server_url = "https://mempool.space/api"      # Esplora endpoint
 connection_string = ""                        # RabbitMQ connection string
 exchange_name = ""
 
+# LSPS2 Client Support
+[liquidity.lsps2_client]
+# The public key of the LSPS2 LSP we source just-in-time liquidity from.
+node_pubkey = "<lsp node pubkey>"
+# Address to connect to the LSPS2 LSP (IPv4:port, IPv6:port, OnionV3:port, or hostname:port).
+address = "<lsp ip address>:9735"
+# Optional token for authenticating to the LSP.
+# token = ""
+
 # Experimental LSPS2 Service Support
 # CAUTION: LSPS2 support is highly experimental and for testing purposes only.
 [liquidity.lsps2_service]

ldk-server/src/main.rs

@@ -172,6 +172,14 @@ fn main() {
 		builder.set_gossip_source_rgs(rgs_server_url);
 	}
 
+	if let Some(lsps2_client_config) = config_file.lsps2_client_config {
+		builder.set_liquidity_source_lsps2(
+			lsps2_client_config.node_id,
+			lsps2_client_config.address,
+			lsps2_client_config.token,
+		);
+	}
+
 	// LSPS2 support is highly experimental and for testing purposes only.
 	#[cfg(feature = "experimental-lsps2-support")]
 	builder.set_liquidity_provider_lsps2(

ldk-server/src/util/config.rs

@@ -13,6 +13,7 @@ use std::str::FromStr;
 use std::{fs, io};
 
 use clap::Parser;
+use ldk_node::bitcoin::secp256k1::PublicKey;
 use ldk_node::bitcoin::Network;
 use ldk_node::lightning::ln::msgs::SocketAddress;
 use ldk_node::lightning::routing::gossip::NodeAlias;
@@ -47,14 +48,25 @@ pub struct Config {
 	pub storage_dir_path: Option<String>,
 	pub chain_source: ChainSource,
 	pub rgs_server_url: Option<String>,
+	#[cfg_attr(not(feature = "events-rabbitmq"), allow(dead_code))]
 	pub rabbitmq_connection_string: String,
+	#[cfg_attr(not(feature = "events-rabbitmq"), allow(dead_code))]
 	pub rabbitmq_exchange_name: String,
+	pub lsps2_client_config: Option<LSPSClientConfig>,
+	#[cfg_attr(not(feature = "experimental-lsps2-support"), allow(dead_code))]
 	pub lsps2_service_config: Option<LSPS2ServiceConfig>,
 	pub log_level: LevelFilter,
 	pub log_file_path: Option<String>,
 	pub pathfinding_scores_source_url: Option<String>,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct LSPSClientConfig {
+	pub node_id: PublicKey,
+	pub address: SocketAddress,
+	pub token: Option<String>,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct TlsConfig {
 	pub cert_path: Option<String>,
@@ -325,6 +337,13 @@ impl ConfigBuilder {
 		#[cfg(not(feature = "events-rabbitmq"))]
 		let (rabbitmq_connection_string, rabbitmq_exchange_name) = (String::new(), String::new());
 
+		let lsps2_client_config = self
+			.lsps2
+			.as_ref()
+			.and_then(|liquidity| liquidity.lsps2_client.as_ref())
+			.map(LSPSClientConfig::try_from)
+			.transpose()?;
+
 		#[cfg(feature = "experimental-lsps2-support")]
 		let lsps2_service_config = {
 			let liquidity = self.lsps2.ok_or_else(|| io::Error::new(
@@ -355,6 +374,7 @@ impl ConfigBuilder {
 			rgs_server_url: self.rgs_server_url,
 			rabbitmq_connection_string,
 			rabbitmq_exchange_name,
+			lsps2_client_config,
 			lsps2_service_config,
 			log_level,
 			log_file_path: self.log_file_path,
@@ -436,9 +456,17 @@ struct TomlTlsConfig {
 
 #[derive(Deserialize, Serialize)]
 struct LiquidityConfig {
+	lsps2_client: Option<LSPSClientTomlConfig>,
 	lsps2_service: Option<LSPS2ServiceTomlConfig>,
 }
 
+#[derive(Deserialize, Serialize, Debug)]
+struct LSPSClientTomlConfig {
+	node_pubkey: String,
+	address: String,
+	token: Option<String>,
+}
+
 #[derive(Deserialize, Serialize, Debug)]
 struct LSPS2ServiceTomlConfig {
 	advertise_service: bool,
@@ -483,6 +511,27 @@ impl From<LSPS2ServiceTomlConfig> for LSPS2ServiceConfig {
 	}
 }
 
+impl TryFrom<&LSPSClientTomlConfig> for LSPSClientConfig {
+	type Error = io::Error;
+
+	fn try_from(value: &LSPSClientTomlConfig) -> Result<Self, Self::Error> {
+		let node_id = PublicKey::from_str(&value.node_pubkey).map_err(|e| {
+			io::Error::new(
+				io::ErrorKind::InvalidInput,
+				format!("Invalid liquidity client node pubkey configured: {e}"),
+			)
+		})?;
+		let address = SocketAddress::from_str(&value.address).map_err(|e| {
+			io::Error::new(
+				io::ErrorKind::InvalidInput,
+				format!("Invalid liquidity client address configured: {e}"),
+			)
+		})?;
+
+		Ok(Self { node_id, address, token: value.token.clone() })
+	}
+}
+
 #[derive(Parser, Debug)]
 #[command(
 	version,
@@ -630,6 +679,7 @@ fn parse_host_port(addr: &str) -> io::Result<(String, u16)> {
 mod tests {
 	use std::str::FromStr;
 
+	use ldk_node::bitcoin::secp256k1::PublicKey;
 	use ldk_node::bitcoin::Network;
 	use ldk_node::lightning::ln::msgs::SocketAddress;
 
@@ -665,6 +715,11 @@ mod tests {
 				connection_string = "rabbitmq_connection_string"
 				exchange_name = "rabbitmq_exchange_name"
 
+				[liquidity.lsps2_client]
+				node_pubkey = "0217890e3aad8d35bc054f43acc00084b25229ecff0ab68debd82883ad65ee8266"
+				address = "127.0.0.1:39735"
+				token = "lsps2-token"
+
 				[liquidity.lsps2_service]
 				advertise_service = false
 				channel_opening_fee_ppm = 1000            # 0.1% fee
@@ -759,6 +814,14 @@ mod tests {
 			rgs_server_url: Some("https://rapidsync.lightningdevkit.org/snapshot/v2/".to_string()),
 			rabbitmq_connection_string: expected_rabbit_conn,
 			rabbitmq_exchange_name: expected_rabbit_exchange,
+			lsps2_client_config: Some(LSPSClientConfig {
+				node_id: PublicKey::from_str(
+					"0217890e3aad8d35bc054f43acc00084b25229ecff0ab68debd82883ad65ee8266",
+				)
+				.unwrap(),
+				address: SocketAddress::from_str("127.0.0.1:39735").unwrap(),
+				token: Some("lsps2-token".to_string()),
+			}),
 			lsps2_service_config: Some(LSPS2ServiceConfig {
 				require_token: None,
 				advertise_service: false,
@@ -786,6 +849,7 @@ mod tests {
 		assert_eq!(config.rgs_server_url, expected.rgs_server_url);
 		assert_eq!(config.rabbitmq_connection_string, expected.rabbitmq_connection_string);
 		assert_eq!(config.rabbitmq_exchange_name, expected.rabbitmq_exchange_name);
+		assert_eq!(config.lsps2_client_config, expected.lsps2_client_config);
 		#[cfg(feature = "experimental-lsps2-support")]
 		assert_eq!(config.lsps2_service_config.is_some(), expected.lsps2_service_config.is_some());
 		assert_eq!(config.log_level, expected.log_level);
@@ -822,6 +886,10 @@ mod tests {
 			connection_string = "rabbitmq_connection_string"
 			exchange_name = "rabbitmq_exchange_name"
 
+			[liquidity.lsps2_client]
+			node_pubkey = "0217890e3aad8d35bc054f43acc00084b25229ecff0ab68debd82883ad65ee8266"
+			address = "127.0.0.1:39735"
+
 			[liquidity.lsps2_service]
 			advertise_service = false
 			channel_opening_fee_ppm = 1000            # 0.1% fee
@@ -875,6 +943,10 @@ mod tests {
 			connection_string = "rabbitmq_connection_string"
 			exchange_name = "rabbitmq_exchange_name"
 
+			[liquidity.lsps2_client]
+			node_pubkey = "0217890e3aad8d35bc054f43acc00084b25229ecff0ab68debd82883ad65ee8266"
+			address = "127.0.0.1:39735"
+
 			[liquidity.lsps2_service]
 			advertise_service = false
 			channel_opening_fee_ppm = 1000            # 0.1% fee
@@ -935,6 +1007,10 @@ mod tests {
 			connection_string = "rabbitmq_connection_string"
 			exchange_name = "rabbitmq_exchange_name"
 
+			[liquidity.lsps2_client]
+			node_pubkey = "0217890e3aad8d35bc054f43acc00084b25229ecff0ab68debd82883ad65ee8266"
+			address = "127.0.0.1:39735"
+
 			[liquidity.lsps2_service]
 			advertise_service = false
 			channel_opening_fee_ppm = 1000            # 0.1% fee
@@ -1080,6 +1156,7 @@ mod tests {
 			rgs_server_url: None,
 			rabbitmq_connection_string: String::new(),
 			rabbitmq_exchange_name: String::new(),
+			lsps2_client_config: None,
 			lsps2_service_config: None,
 			log_level: LevelFilter::Trace,
 			log_file_path: Some("/var/log/ldk-server.log".to_string()),
@@ -1173,6 +1250,14 @@ mod tests {
 			rgs_server_url: Some("https://rapidsync.lightningdevkit.org/snapshot/v2/".to_string()),
 			rabbitmq_connection_string: expected_rabbit_conn,
 			rabbitmq_exchange_name: expected_rabbit_exchange,
+			lsps2_client_config: Some(LSPSClientConfig {
+				node_id: PublicKey::from_str(
+					"0217890e3aad8d35bc054f43acc00084b25229ecff0ab68debd82883ad65ee8266",
+				)
+				.unwrap(),
+				address: SocketAddress::from_str("127.0.0.1:39735").unwrap(),
+				token: Some("lsps2-token".to_string()),
+			}),
 			lsps2_service_config: Some(LSPS2ServiceConfig {
 				require_token: None,
 				advertise_service: false,
@@ -1199,6 +1284,7 @@ mod tests {
 		assert_eq!(config.rgs_server_url, expected.rgs_server_url);
 		assert_eq!(config.rabbitmq_connection_string, expected.rabbitmq_connection_string);
 		assert_eq!(config.rabbitmq_exchange_name, expected.rabbitmq_exchange_name);
+		assert_eq!(config.lsps2_client_config, expected.lsps2_client_config);
 		#[cfg(feature = "experimental-lsps2-support")]
 		assert_eq!(config.lsps2_service_config.is_some(), expected.lsps2_service_config.is_some());
 		assert_eq!(config.pathfinding_scores_source_url, expected.pathfinding_scores_source_url);