From 5c4d2912e04af1d115c64cca32317e548e3c45a7 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Mon, 27 Sep 2021 20:03:12 +0000
Subject: [PATCH] Use an explicit handle when spawning RPC calls

This resolves a panic like the following, which is caused when a
non-Tokio thread tries to broadcast a transaction, for example
when a transaction is broadcasted indirectly by the background
processor.

```
thread '<unnamed>' panicked at 'there is no reactor running, must be called from the context of a Tokio 1.x runtime', src/bitcoind_client.rs:253:9
```
---
 src/bitcoind_client.rs | 14 +++++++++-----
 src/main.rs            |  1 +
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/src/bitcoind_client.rs b/src/bitcoind_client.rs
index 73ee635..0b37ac3 100644
--- a/src/bitcoind_client.rs
+++ b/src/bitcoind_client.rs
@@ -24,6 +24,7 @@ pub struct BitcoindClient {
 	rpc_user: String,
 	rpc_password: String,
 	fees: Arc<HashMap<Target, AtomicU32>>,
+	handle: tokio::runtime::Handle,
 }
 
 #[derive(Clone, Eq, Hash, PartialEq)]
@@ -66,6 +67,7 @@ const MIN_FEERATE: u32 = 253;
 impl BitcoindClient {
 	pub async fn new(
 		host: String, port: u16, rpc_user: String, rpc_password: String,
+		handle: tokio::runtime::Handle,
 	) -> std::io::Result<Self> {
 		let http_endpoint = HttpEndpoint::for_host(host.clone()).with_port(port);
 		let rpc_credentials =
@@ -89,19 +91,21 @@ impl BitcoindClient {
 			rpc_user,
 			rpc_password,
 			fees: Arc::new(fees),
+			handle: handle.clone(),
 		};
 		BitcoindClient::poll_for_fee_estimates(
 			client.fees.clone(),
 			client.bitcoind_rpc_client.clone(),
-		)
-		.await;
+			handle,
+		);
 		Ok(client)
 	}
 
-	async fn poll_for_fee_estimates(
+	fn poll_for_fee_estimates(
 		fees: Arc<HashMap<Target, AtomicU32>>, rpc_client: Arc<Mutex<RpcClient>>,
+		handle: tokio::runtime::Handle,
 	) {
-		tokio::spawn(async move {
+		handle.spawn(async move {
 			loop {
 				let background_estimate = {
 					let mut rpc = rpc_client.lock().await;
@@ -250,7 +254,7 @@ impl BroadcasterInterface for BitcoindClient {
 	fn broadcast_transaction(&self, tx: &Transaction) {
 		let bitcoind_rpc_client = self.bitcoind_rpc_client.clone();
 		let tx_serialized = serde_json::json!(encode::serialize_hex(tx));
-		tokio::spawn(async move {
+		self.handle.spawn(async move {
 			let mut rpc = bitcoind_rpc_client.lock().await;
 			// This may error due to RL calling `broadcast_transaction` with the same transaction
 			// multiple times, but the error is safe to ignore.
diff --git a/src/main.rs b/src/main.rs
index 955fc4d..6f35975 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -299,6 +299,7 @@ async fn start_ldk() {
 		args.bitcoind_rpc_port,
 		args.bitcoind_rpc_username.clone(),
 		args.bitcoind_rpc_password.clone(),
+		tokio::runtime::Handle::current(),
 	)
 	.await
 	{
-- 
2.30.2