Allow integrated relay chain light client

client/cli/src/lib.rs

@@ -298,6 +298,11 @@ pub struct RunCmd {
 		alias = "relay-chain-rpc-url"
 	)]
 	pub relay_chain_rpc_urls: Vec<Url>,
+
+	/// EXPERIMENTAL: Embed a light client for the relay chain. Only supported for full-nodes.
+	/// Will use the specified relay chain chainspec.
+	#[arg(long, conflicts_with_all = ["relay_chain_rpc_urls", "collator"])]
+	pub relay_chain_light_client: bool,
 }
 
 impl RunCmd {
@@ -312,7 +317,10 @@ impl RunCmd {
 
 	/// Create [`CollatorOptions`] representing options only relevant to parachain collator nodes
 	pub fn collator_options(&self) -> CollatorOptions {
-		CollatorOptions { relay_chain_rpc_urls: self.relay_chain_rpc_urls.clone() }
+		CollatorOptions {
+			relay_chain_rpc_urls: self.relay_chain_rpc_urls.clone(),
+			relay_chain_light_client: self.relay_chain_light_client,
+		}
 	}
 }
 
@@ -321,6 +329,9 @@ impl RunCmd {
 pub struct CollatorOptions {
 	/// Location of relay chain full node
 	pub relay_chain_rpc_urls: Vec<Url>,
+
+	/// Use embedded light client for the relay chain
+	pub relay_chain_light_client: bool,
 }
 
 /// A non-redundant version of the `RunCmd` that sets the `validator` field when the

client/relay-chain-minimal-node/src/blockchain_rpc_client.rs

@@ -21,7 +21,7 @@ use cumulus_relay_chain_rpc_interface::RelayChainRpcClient;
 use futures::{Future, Stream, StreamExt};
 use polkadot_core_primitives::{Block, Hash, Header};
 use polkadot_overseer::RuntimeApiSubsystemClient;
-use polkadot_service::{AuxStore, HeaderBackend};
+use polkadot_service::HeaderBackend;
 use sc_authority_discovery::AuthorityDiscovery;
 
 use sp_api::{ApiError, RuntimeApiInfo};
@@ -52,28 +52,6 @@ impl BlockChainRpcClient {
 	}
 }
 
-// Implementation required by Availability-Distribution subsystem
-// but never called in our case.
-impl AuxStore for BlockChainRpcClient {
-	fn insert_aux<
-		'a,
-		'b: 'a,
-		'c: 'a,
-		I: IntoIterator<Item = &'a (&'c [u8], &'c [u8])>,
-		D: IntoIterator<Item = &'a &'b [u8]>,
-	>(
-		&self,
-		_insert: I,
-		_delete: D,
-	) -> sp_blockchain::Result<()> {
-		unimplemented!("Not supported on the RPC collator")
-	}
-
-	fn get_aux(&self, _key: &[u8]) -> sp_blockchain::Result<Option<Vec<u8>>> {
-		unimplemented!("Not supported on the RPC collator")
-	}
-}
-
 #[async_trait::async_trait]
 impl RuntimeApiSubsystemClient for BlockChainRpcClient {
 	async fn validators(

client/relay-chain-minimal-node/src/lib.rs

@@ -38,13 +38,14 @@ use futures::StreamExt;
 
 use sp_runtime::{app_crypto::Pair, traits::Block as BlockT};
 
+mod blockchain_rpc_client;
 mod collator_overseer;
-
 mod network;
 
-mod blockchain_rpc_client;
 pub use blockchain_rpc_client::BlockChainRpcClient;
 
+const LOG_TARGET: &str = "minimal-relaychain-node";
+
 fn build_authority_discovery_service<Block: BlockT>(
 	task_manager: &TaskManager,
 	client: Arc<BlockChainRpcClient>,
@@ -106,6 +107,40 @@ pub async fn build_minimal_relay_chain_node(
 	))
 }
 
+pub async fn build_minimal_relay_chain_node_light_client(
+	polkadot_config: Configuration,
+	task_manager: &mut TaskManager,
+) -> RelayChainResult<(Arc<(dyn RelayChainInterface + 'static)>, Option<CollatorPair>)> {
+	tracing::info!(
+		target: LOG_TARGET,
+		chain_name = polkadot_config.chain_spec.name(),
+		chain_id = polkadot_config.chain_spec.id(),
+		"Initializing embedded light client with chain spec."
+	);
+
+	let spec = polkadot_config
+		.chain_spec
+		.as_json(false)
+		.map_err(RelayChainError::GenericError)?;
+
+	let client = cumulus_relay_chain_rpc_interface::create_client_and_start_light_client_worker(
+		spec,
+		task_manager,
+	)
+	.await?;
+	let collator_pair = CollatorPair::generate().0;
+	let collator_node = new_minimal_relay_chain(
+		polkadot_config,
+		collator_pair.clone(),
+		Arc::new(BlockChainRpcClient::new(client.clone())),
+	)
+	.await?;
+	task_manager.add_child(collator_node.task_manager);
+	Ok((
+		Arc::new(RelayChainRpcInterface::new(client, collator_node.overseer_handle)),
+		Some(collator_pair),
+	))
+}
 /// Builds a minimal relay chain node. Chain data is fetched
 /// via [`BlockChainRpcClient`] and fed into the overseer and its subsystems.
 ///
@@ -117,8 +152,6 @@ pub async fn build_minimal_relay_chain_node(
 /// - NetworkBridgeRx
 /// - NetworkBridgeTx
 /// - RuntimeApi
-/// - ChainApi
-/// - AvailabilityDistribution
 #[sc_tracing::logging::prefix_logs_with("Relaychain")]
 async fn new_minimal_relay_chain(
 	mut config: Configuration,

client/relay-chain-rpc-interface/Cargo.toml

@@ -19,8 +19,10 @@ sp-state-machine = { git = "https://github.com/paritytech/substrate", branch = "
 sp-storage = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sc-client-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
 sc-rpc-api = { git = "https://github.com/paritytech/substrate", branch = "master" }
-tokio = { version = "1.25.0", features = ["sync"] }
+sc-service = { git = "https://github.com/paritytech/substrate", branch = "master" }
 
+tokio = { version = "1.25.0", features = ["sync"] }
+tokio-util = { version = "0.7.7", features = ["compat"] }
 futures = "0.3.26"
 futures-timer = "3.0.2"
 parity-scale-codec = "3.4.0"
@@ -31,3 +33,10 @@ url = "2.3.1"
 serde_json = "1.0.93"
 serde = "1.0.152"
 lru = "0.9.0"
+smoldot = { git = "https://github.com/smol-dot/smoldot", branch = "main" }
+smoldot-light = { git = "https://github.com/smol-dot/smoldot", branch = "main", default_features = false }
+parking_lot = "0.12.1"
+either = "1.8.1"
+event-listener = "2.5.3"
+thiserror = "1.0.38"
+soketto = "0.7.1"

client/relay-chain-rpc-interface/src/lib.rs

@@ -34,9 +34,15 @@ use std::pin::Pin;
 
 pub use url::Url;
 
+mod light_client_worker;
 mod reconnecting_ws_client;
 mod rpc_client;
-pub use rpc_client::{create_client_and_start_worker, RelayChainRpcClient};
+mod tokio_platform;
+
+pub use rpc_client::{
+	create_client_and_start_light_client_worker, create_client_and_start_worker,
+	RelayChainRpcClient,
+};
 
 const TIMEOUT_IN_SECONDS: u64 = 6;