Only use internal runtime in VssStore

We previously attempted to drop the internal runtime from `VssStore`,
resulting into blocking behavior. While we recently made changes that
improved our situation (having VSS CI pass again pretty reliably), we
just ran into yet another case where the VSS CI hung (cf.
https://github.com/lightningdevkit/vss-server/actions/runs/19023212819/job/54322173817?pr=59).

Here we attempt to restore even more of the original pre-
ab3d78d / lightningdevkit#623 behavior to get rid of
the reappearing blocking behavior, i.e., only use the internal runtime
in `VssStore`.

Author: tnull

src/builder.rs

@@ -732,11 +732,10 @@ impl NodeBuilder {
 		let vss_seed_bytes: [u8; 32] = vss_xprv.private_key.secret_bytes();
 
 		let vss_store =
-			VssStore::new(vss_url, store_id, vss_seed_bytes, header_provider, Arc::clone(&runtime))
-				.map_err(|e| {
-					log_error!(logger, "Failed to setup store: {}", e);
-					BuildError::KVStoreSetupFailed
-				})?;
+			VssStore::new(vss_url, store_id, vss_seed_bytes, header_provider).map_err(|e| {
+				log_error!(logger, "Failed to setup store: {}", e);
+				BuildError::KVStoreSetupFailed
+			})?;
 
 		build_with_store_internal(
 			config,

src/io/vss_store.rs

@@ -31,7 +31,6 @@ use vss_client_ng::util::key_obfuscator::KeyObfuscator;
 use vss_client_ng::util::storable_builder::{EntropySource, StorableBuilder};
 
 use crate::io::utils::check_namespace_key_validity;
-use crate::runtime::Runtime;
 
 // We set this to a small number of threads that would still allow to make some progress if one
 // would hit a blocking case
@@ -44,7 +43,6 @@ pub struct VssStore {
 	// Version counter to ensure that writes are applied in the correct order. It is assumed that read and list
 	// operations aren't sensitive to the order of execution.
 	next_version: AtomicU64,
-	runtime: Arc<Runtime>,
 	// A VSS-internal runtime we use to avoid any deadlocks we could hit when waiting on a spawned
 	// blocking task to finish while the blocked thread had acquired the reactor. In particular,
 	// this works around a previously-hit case where a concurrent call to
@@ -57,7 +55,7 @@ pub struct VssStore {
 impl VssStore {
 	pub(crate) fn new(
 		base_url: String, store_id: String, vss_seed: [u8; 32],
-		header_provider: Arc<dyn VssHeaderProvider>, runtime: Arc<Runtime>,
+		header_provider: Arc<dyn VssHeaderProvider>,
 	) -> io::Result<Self> {
 		let inner = Arc::new(VssStoreInner::new(base_url, store_id, vss_seed, header_provider)?);
 		let next_version = AtomicU64::new(1);
@@ -75,7 +73,7 @@ impl VssStore {
 				.unwrap(),
 		);
 
-		Ok(Self { inner, next_version, runtime, internal_runtime })
+		Ok(Self { inner, next_version, internal_runtime })
 	}
 
 	// Same logic as for the obfuscated keys below, but just for locking, using the plaintext keys
@@ -122,13 +120,14 @@ impl KVStoreSync for VssStore {
 			async move { inner.read_internal(primary_namespace, secondary_namespace, key).await };
 		// TODO: We could drop the timeout here once we ensured vss-client's Retry logic always
 		// times out.
-		let spawned_fut = internal_runtime.spawn(async move {
-			tokio::time::timeout(VSS_IO_TIMEOUT, fut).await.map_err(|_| {
-				let msg = "VssStore::read timed out";
-				Error::new(ErrorKind::Other, msg)
-			})
-		});
-		self.runtime.block_on(spawned_fut).expect("We should always finish")?
+		tokio::task::block_in_place(move || {
+			internal_runtime.block_on(async move {
+				tokio::time::timeout(VSS_IO_TIMEOUT, fut).await.map_err(|_| {
+					let msg = "VssStore::read timed out";
+					Error::new(ErrorKind::Other, msg)
+				})
+			})?
+		})
 	}
 
 	fn write(
@@ -160,13 +159,14 @@ impl KVStoreSync for VssStore {
 		};
 		// TODO: We could drop the timeout here once we ensured vss-client's Retry logic always
 		// times out.
-		let spawned_fut = internal_runtime.spawn(async move {
-			tokio::time::timeout(VSS_IO_TIMEOUT, fut).await.map_err(|_| {
-				let msg = "VssStore::write timed out";
-				Error::new(ErrorKind::Other, msg)
-			})
-		});
-		self.runtime.block_on(spawned_fut).expect("We should always finish")?
+		tokio::task::block_in_place(move || {
+			internal_runtime.block_on(async move {
+				tokio::time::timeout(VSS_IO_TIMEOUT, fut).await.map_err(|_| {
+					let msg = "VssStore::write timed out";
+					Error::new(ErrorKind::Other, msg)
+				})
+			})?
+		})
 	}
 
 	fn remove(
@@ -197,13 +197,14 @@ impl KVStoreSync for VssStore {
 		};
 		// TODO: We could drop the timeout here once we ensured vss-client's Retry logic always
 		// times out.
-		let spawned_fut = internal_runtime.spawn(async move {
-			tokio::time::timeout(VSS_IO_TIMEOUT, fut).await.map_err(|_| {
-				let msg = "VssStore::remove timed out";
-				Error::new(ErrorKind::Other, msg)
-			})
-		});
-		self.runtime.block_on(spawned_fut).expect("We should always finish")?
+		tokio::task::block_in_place(move || {
+			internal_runtime.block_on(async move {
+				tokio::time::timeout(VSS_IO_TIMEOUT, fut).await.map_err(|_| {
+					let msg = "VssStore::remove timed out";
+					Error::new(ErrorKind::Other, msg)
+				})
+			})?
+		})
 	}
 
 	fn list(&self, primary_namespace: &str, secondary_namespace: &str) -> io::Result<Vec<String>> {
@@ -218,13 +219,14 @@ impl KVStoreSync for VssStore {
 		let fut = async move { inner.list_internal(primary_namespace, secondary_namespace).await };
 		// TODO: We could drop the timeout here once we ensured vss-client's Retry logic always
 		// times out.
-		let spawned_fut = internal_runtime.spawn(async move {
-			tokio::time::timeout(VSS_IO_TIMEOUT, fut).await.map_err(|_| {
-				let msg = "VssStore::list timed out";
-				Error::new(ErrorKind::Other, msg)
-			})
-		});
-		self.runtime.block_on(spawned_fut).expect("We should always finish")?
+		tokio::task::block_in_place(move || {
+			internal_runtime.block_on(async move {
+				tokio::time::timeout(VSS_IO_TIMEOUT, fut).await.map_err(|_| {
+					let msg = "VssStore::list timed out";
+					Error::new(ErrorKind::Other, msg)
+				})
+			})?
+		})
 	}
 }
 
@@ -597,7 +599,6 @@ mod tests {
 
 	use super::*;
 	use crate::io::test_utils::do_read_write_remove_list_persist;
-	use crate::logger::Logger;
 
 	#[test]
 	fn vss_read_write_remove_list_persist() {
@@ -607,10 +608,8 @@ mod tests {
 		let mut vss_seed = [0u8; 32];
 		rng.fill_bytes(&mut vss_seed);
 		let header_provider = Arc::new(FixedHeaders::new(HashMap::new()));
-		let logger = Arc::new(Logger::new_log_facade());
-		let runtime = Arc::new(Runtime::new(logger).unwrap());
 		let vss_store =
-			VssStore::new(vss_base_url, rand_store_id, vss_seed, header_provider, runtime).unwrap();
+			VssStore::new(vss_base_url, rand_store_id, vss_seed, header_provider).unwrap();
 
 		do_read_write_remove_list_persist(&vss_store);
 	}
@@ -623,10 +622,8 @@ mod tests {
 		let mut vss_seed = [0u8; 32];
 		rng.fill_bytes(&mut vss_seed);
 		let header_provider = Arc::new(FixedHeaders::new(HashMap::new()));
-		let logger = Arc::new(Logger::new_log_facade());
-		let runtime = Arc::new(Runtime::new(logger).unwrap());
 		let vss_store =
-			VssStore::new(vss_base_url, rand_store_id, vss_seed, header_provider, runtime).unwrap();
+			VssStore::new(vss_base_url, rand_store_id, vss_seed, header_provider).unwrap();
 
 		do_read_write_remove_list_persist(&vss_store);
 		drop(vss_store)