Start minimal relay node if relay_chain_rpc_url is set

node/cli/src/command.rs

@@ -21,7 +21,7 @@ use cli_opt::{EthApi, RpcConfig};
 use cumulus_client_cli::generate_genesis_block;
 use cumulus_primitives_core::ParaId;
 use frame_benchmarking_cli::BenchmarkCmd;
-use log::info;
+use log::{info, warn};
 use parity_scale_codec::Encode;
 #[cfg(feature = "westend-native")]
 use polkadot_service::WestendChainSpec;
@@ -812,6 +812,22 @@ pub fn run() -> Result<()> {
 				info!("Parachain id: {:?}", id);
 				info!("Parachain Account: {}", parachain_account);
 				info!("Parachain genesis state: {}", genesis_state);
+				info!(
+					"Is collating: {}",
+					if config.role.is_authority() {
+						"yes"
+					} else {
+						"no"
+					}
+				);
+
+				if rpc_config.relay_chain_rpc_url.is_some() && cli.relaychain_args.len() > 0 {
+					warn!(
+						"Detected relay chain node arguments together with \
+					--relay-chain-rpc-url. This command starts a minimal Polkadot node that only \
+					uses a network-related subset of all relay chain CLI options."
+					);
+				}
 
 				match &config.chain_spec {
 					#[cfg(feature = "moonriver-native")]

node/service/Cargo.toml

@@ -113,6 +113,7 @@ cumulus-primitives-core = { git = "https://github.com/purestake/cumulus", branch
 cumulus-primitives-parachain-inherent = { git = "https://github.com/purestake/cumulus", branch = "moonbeam-polkadot-v0.9.32" }
 cumulus-relay-chain-inprocess-interface = { git = "https://github.com/purestake/cumulus", branch = "moonbeam-polkadot-v0.9.32" }
 cumulus-relay-chain-interface = { git = "https://github.com/purestake/cumulus", branch = "moonbeam-polkadot-v0.9.32" }
+cumulus-relay-chain-minimal-node = { git = "https://github.com/purestake/cumulus", branch = "moonbeam-polkadot-v0.9.32" }
 cumulus-relay-chain-rpc-interface = { git = "https://github.com/purestake/cumulus", branch = "moonbeam-polkadot-v0.9.32" }
 cumulus-test-relay-sproof-builder = { git = "https://github.com/purestake/cumulus", branch = "moonbeam-polkadot-v0.9.32" }
 nimbus-consensus = { git = "https://github.com/purestake/nimbus", branch = "moonbeam-polkadot-v0.9.32" }

node/service/src/lib.rs

@@ -22,7 +22,23 @@
 //! Full Service: A complete parachain node including the pool, rpc, network, embedded relay chain
 //! Dev Service: A leaner service without the relay chain backing.
 
+pub mod rpc;
+
 use cli_opt::{EthApi as EthApiCmd, RpcConfig};
+use cumulus_client_cli::CollatorOptions;
+use cumulus_client_consensus_common::ParachainConsensus;
+use cumulus_client_network::BlockAnnounceValidator;
+use cumulus_client_service::{
+	prepare_node_config, start_collator, start_full_node, StartCollatorParams, StartFullNodeParams,
+};
+use cumulus_primitives_core::relay_chain::v2::CollatorPair;
+use cumulus_primitives_core::ParaId;
+use cumulus_primitives_parachain_inherent::{
+	MockValidationDataInherentDataProvider, MockXcmConfig,
+};
+use cumulus_relay_chain_inprocess_interface::build_inprocess_relay_chain;
+use cumulus_relay_chain_interface::{RelayChainError, RelayChainInterface, RelayChainResult};
+use cumulus_relay_chain_minimal_node::build_minimal_relay_chain_node;
 use fc_consensus::FrontierBlockImport;
 use fc_db::DatabaseSource;
 use fc_rpc_core::types::{FeeHistoryCache, FilterPool};
@@ -34,19 +50,6 @@ pub use moonbase_runtime;
 pub use moonbeam_runtime;
 #[cfg(feature = "moonriver-native")]
 pub use moonriver_runtime;
-use std::{collections::BTreeMap, sync::Mutex, time::Duration};
-pub mod rpc;
-use cumulus_client_consensus_common::ParachainConsensus;
-use cumulus_client_network::BlockAnnounceValidator;
-use cumulus_client_service::{
-	prepare_node_config, start_collator, start_full_node, StartCollatorParams, StartFullNodeParams,
-};
-use cumulus_primitives_core::ParaId;
-use cumulus_primitives_parachain_inherent::{
-	MockValidationDataInherentDataProvider, MockXcmConfig,
-};
-use cumulus_relay_chain_inprocess_interface::build_inprocess_relay_chain;
-use cumulus_relay_chain_interface::{RelayChainError, RelayChainInterface};
 use nimbus_consensus::NimbusManualSealConsensusDataProvider;
 use nimbus_consensus::{BuildNimbusConsensusParams, NimbusConsensus};
 use nimbus_primitives::NimbusId;
@@ -63,6 +66,7 @@ use sp_api::ConstructRuntimeApi;
 use sp_blockchain::HeaderBackend;
 use sp_keystore::SyncCryptoStorePtr;
 use std::sync::Arc;
+use std::{collections::BTreeMap, sync::Mutex, time::Duration};
 use substrate_prometheus_endpoint::Registry;
 
 pub use client::*;
@@ -494,6 +498,31 @@ where
 	})
 }
 
+async fn build_relay_chain_interface(
+	polkadot_config: Configuration,
+	parachain_config: &Configuration,
+	telemetry_worker_handle: Option<TelemetryWorkerHandle>,
+	task_manager: &mut TaskManager,
+	collator_options: CollatorOptions,
+	hwbench: Option<sc_sysinfo::HwBench>,
+) -> RelayChainResult<(
+	Arc<(dyn RelayChainInterface + 'static)>,
+	Option<CollatorPair>,
+)> {
+	match collator_options.relay_chain_rpc_url {
+		Some(relay_chain_url) => {
+			build_minimal_relay_chain_node(polkadot_config, task_manager, relay_chain_url).await
+		}
+		None => build_inprocess_relay_chain(
+			polkadot_config,
+			parachain_config,
+			telemetry_worker_handle,
+			task_manager,
+			hwbench,
+		),
+	}
+}
+
 /// Start a node with the given parachain `Configuration` and relay chain `Configuration`.
 ///
 /// This is the actual implementation that is abstract over the executor and the runtime api.
@@ -531,6 +560,10 @@ where
 {
 	let mut parachain_config = prepare_node_config(parachain_config);
 
+	let collator_options = CollatorOptions {
+		relay_chain_rpc_url: rpc_config.relay_chain_rpc_url.clone(),
+	};
+
 	let params = new_partial(&mut parachain_config, false)?;
 	let (
 		_block_import,
@@ -545,13 +578,15 @@ where
 	let backend = params.backend.clone();
 	let mut task_manager = params.task_manager;
 
-	let (relay_chain_interface, collator_key) = build_inprocess_relay_chain(
+	let (relay_chain_interface, collator_key) = build_relay_chain_interface(
 		polkadot_config,
 		&parachain_config,
 		telemetry_worker_handle,
 		&mut task_manager,
-		None,
+		collator_options.clone(),
+		hwbench.clone(),
 	)
+	.await
 	.map_err(|e| match e {
 		RelayChainError::ServiceError(polkadot_service::Error::Sub(x)) => x,
 		s => s.to_string().into(),