Expose splice negotiation events over gRPC

docs/api-guide.md

@@ -212,6 +212,8 @@ See [Pagination](#pagination) below for how to page through results.
 | `PaymentClaimable`  | A hodl invoice payment arrived and is waiting to be claimed or failed |
 | `PaymentForwarded`  | A payment was routed through this node                                |
 | `ChannelStateChanged` | A channel changed state (pending, ready, open failed, closed)      |
+| `SpliceNegotiated` | A channel splice was negotiated and the funding transaction is pending confirmation |
+| `SpliceNegotiationFailed` | A channel splice negotiation round failed                       |
 
 Events are broadcast to all connected subscribers. The server uses a bounded broadcast channel
 (capacity 1024). A slow subscriber that falls behind will miss events.

e2e-tests/tests/e2e.rs

@@ -1200,11 +1200,24 @@ async fn splice_in_via_cli(splice_amount: &str) {
 	let server_b = LdkServerHandle::start(&bitcoind).await;
 	let user_channel_id = setup_funded_channel(&bitcoind, &server_a, &server_b, 100_000).await;
 
+	let mut events_a = server_a.client().subscribe_events().await.unwrap();
+
 	let output = run_cli(
 		&server_a,
 		&["splice-in", &user_channel_id, server_b.node_id(), splice_amount],
 	);
 	assert!(output.is_object());
+
+	let event_a =
+		wait_for_event(&mut events_a, |e| matches!(e, Event::SpliceNegotiated(_))).await;
+	match &event_a.event {
+		Some(Event::SpliceNegotiated(splice_negotiated)) => {
+			assert_eq!(splice_negotiated.user_channel_id, user_channel_id);
+			assert_eq!(splice_negotiated.counterparty_node_id, server_b.node_id());
+			assert!(!splice_negotiated.new_funding_txo.is_empty());
+		},
+		other => panic!("expected SpliceNegotiated event, got {other:?}"),
+	}
 }
 
 #[tokio::test]

ldk-server-grpc/src/events.rs

@@ -14,7 +14,7 @@
 #[allow(clippy::derive_partial_eq_without_eq)]
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct EventEnvelope {
-	#[prost(oneof = "event_envelope::Event", tags = "2, 3, 4, 6, 7, 8")]
+	#[prost(oneof = "event_envelope::Event", tags = "2, 3, 4, 6, 7, 8, 9, 10")]
 	pub event: ::core::option::Option<event_envelope::Event>,
 }
 /// Nested message and enum types in `EventEnvelope`.
@@ -36,6 +36,10 @@ pub mod event_envelope {
 		PaymentClaimable(super::PaymentClaimable),
 		#[prost(message, tag = "8")]
 		ChannelStateChanged(super::ChannelStateChanged),
+		#[prost(message, tag = "9")]
+		SpliceNegotiated(super::SpliceNegotiated),
+		#[prost(message, tag = "10")]
+		SpliceNegotiationFailed(super::SpliceNegotiationFailed),
 	}
 }
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
@@ -140,6 +144,38 @@ pub struct ChannelStateChanged {
 	#[prost(enumeration = "ChannelClosureInitiator", tag = "7")]
 	pub closure_initiator: i32,
 }
+/// SpliceNegotiated indicates a channel splice has been negotiated and the funding
+/// transaction is pending confirmation on-chain.
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "serde", serde(rename_all = "snake_case"))]
+#[cfg_attr(feature = "serde", serde(default))]
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct SpliceNegotiated {
+	#[prost(string, tag = "1")]
+	pub channel_id: ::prost::alloc::string::String,
+	#[prost(string, tag = "2")]
+	pub user_channel_id: ::prost::alloc::string::String,
+	#[prost(string, tag = "3")]
+	pub counterparty_node_id: ::prost::alloc::string::String,
+	/// The outpoint of the channel's splice funding transaction.
+	#[prost(string, tag = "4")]
+	pub new_funding_txo: ::prost::alloc::string::String,
+}
+/// SpliceNegotiationFailed indicates a channel splice negotiation round has failed.
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "serde", serde(rename_all = "snake_case"))]
+#[cfg_attr(feature = "serde", serde(default))]
+#[allow(clippy::derive_partial_eq_without_eq)]
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct SpliceNegotiationFailed {
+	#[prost(string, tag = "1")]
+	pub channel_id: ::prost::alloc::string::String,
+	#[prost(string, tag = "2")]
+	pub user_channel_id: ::prost::alloc::string::String,
+	#[prost(string, tag = "3")]
+	pub counterparty_node_id: ::prost::alloc::string::String,
+}
 /// PaymentReceived indicates a payment has been received.
 #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 #[cfg_attr(feature = "serde", serde(rename_all = "snake_case"))]

ldk-server-grpc/src/proto/events.proto

@@ -11,6 +11,8 @@ message EventEnvelope {
     PaymentForwarded payment_forwarded = 6;
     PaymentClaimable payment_claimable = 7;
     ChannelStateChanged channel_state_changed = 8;
+    SpliceNegotiated splice_negotiated = 9;
+    SpliceNegotiationFailed splice_negotiation_failed = 10;
   }
 }
 
@@ -120,6 +122,23 @@ message ChannelStateChanged {
   ChannelClosureInitiator closure_initiator = 7;
 }
 
+// SpliceNegotiated indicates a channel splice has been negotiated and the funding
+// transaction is pending confirmation on-chain.
+message SpliceNegotiated {
+  string channel_id = 1;
+  string user_channel_id = 2;
+  string counterparty_node_id = 3;
+  // The outpoint of the channel's splice funding transaction.
+  string new_funding_txo = 4;
+}
+
+// SpliceNegotiationFailed indicates a channel splice negotiation round has failed.
+message SpliceNegotiationFailed {
+  string channel_id = 1;
+  string user_channel_id = 2;
+  string counterparty_node_id = 3;
+}
+
 // PaymentReceived indicates a payment has been received.
 message PaymentReceived {
   // The payment details for the payment in event.

ldk-server/src/main.rs

@@ -634,11 +634,57 @@ fn main() {
 								}
 							}
 						},
-						_ => {
+						Event::SpliceNegotiated {
+							channel_id,
+							user_channel_id,
+							counterparty_node_id,
+							new_funding_txo,
+						} => {
+							info!(
+								"SPLICE_NEGOTIATED: {} from counterparty {}",
+								channel_id, counterparty_node_id
+							);
+
+							send_channel_state_event(
+								event_envelope::Event::SpliceNegotiated(events::SpliceNegotiated {
+									channel_id: channel_id.0.to_lower_hex_string(),
+									user_channel_id: user_channel_id.0.to_string(),
+									counterparty_node_id: counterparty_node_id.to_string(),
+									new_funding_txo: new_funding_txo.to_string(),
+								}),
+								&event_sender,
+							);
+
 							if let Err(e) = event_node.event_handled() {
 								error!("Failed to mark event as handled: {e}");
 							}
 						},
+						Event::SpliceNegotiationFailed {
+							channel_id,
+							user_channel_id,
+							counterparty_node_id,
+						} => {
+							info!(
+								"SPLICE_NEGOTIATION_FAILED: {} from counterparty {}",
+								channel_id, counterparty_node_id
+							);
+
+							send_channel_state_event(
+								event_envelope::Event::SpliceNegotiationFailed(
+									events::SpliceNegotiationFailed {
+										channel_id: channel_id.0.to_lower_hex_string(),
+										user_channel_id: user_channel_id.0.to_string(),
+										counterparty_node_id: counterparty_node_id.to_string(),
+									},
+								),
+								&event_sender,
+							);
+
+							if let Err(e) = event_node.event_handled() {
+								error!("Failed to mark event as handled: {e}");
+							}
+						},
+
 					}
 				},
 				res = grpc_listener.accept() => {