Simplify a few chain components creation APIs related to the service (#6611)

* Simplify a few chain components creation APIs related to the service

* Fix basic-authorship doc tests

* Remove DefaultQueue

* Update client/service/src/builder.rs

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

* Move ExecutionExtensions comment around

* Remove unused BlakeTwo256

Co-authored-by: André Silva <123550+andresilva@users.noreply.github.com>

substrate/client/service/src/builder.rs

@@ -66,8 +66,6 @@ use sc_client_api::{
 use sp_blockchain::{HeaderMetadata, HeaderBackend};
 use crate::{ServiceComponents, TelemetryOnConnectSinks, RpcHandlers, NetworkStatusSinks};
 
-pub type BackgroundTask = Pin<Box<dyn Future<Output=()> + Send>>;
-
 /// Aggregator for the components required to build a service.
 ///
 /// # Usage
@@ -518,6 +516,11 @@ impl<TBl, TRtApi, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TExPool, TRpc, Backend>
 		self.remote_backend.clone()
 	}
 
+	/// Returns a spawn handle created by the task manager.
+	pub fn spawn_handle(&self) -> SpawnTaskHandle {
+		self.task_manager.spawn_handle()
+	}
+
 	/// Consume the builder and return the parts needed for chain operations.
 	pub fn to_chain_ops_parts(self) -> (Arc<TCl>, Arc<Backend>, TImpQu, TaskManager) {
 		(self.client, self.backend, self.import_queue, self.task_manager)
@@ -728,15 +731,11 @@ impl<TBl, TRtApi, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TExPool, TRpc, Backend>
 		self,
 		transaction_pool_builder: impl FnOnce(
 			&Self,
-		) -> Result<(UExPool, Option<BackgroundTask>), Error>,
+		) -> Result<Arc<UExPool>, Error>,
 	) -> Result<ServiceBuilder<TBl, TRtApi, TCl, TFchr, TSc, TImpQu, TFprb, TFpp,
 		UExPool, TRpc, Backend>, Error>
 	where TSc: Clone, TFchr: Clone {
-		let (transaction_pool, background_task) = transaction_pool_builder(&self)?;
-
-		if let Some(background_task) = background_task{
-			self.task_manager.spawn_handle().spawn("txpool-background", background_task);
-		}
+		let transaction_pool = transaction_pool_builder(&self)?;
 
 		Ok(ServiceBuilder {
 			config: self.config,
@@ -749,7 +748,7 @@ impl<TBl, TRtApi, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TExPool, TRpc, Backend>
 			import_queue: self.import_queue,
 			finality_proof_request_builder: self.finality_proof_request_builder,
 			finality_proof_provider: self.finality_proof_provider,
-			transaction_pool: Arc::new(transaction_pool),
+			transaction_pool: transaction_pool,
 			rpc_extensions_builder: self.rpc_extensions_builder,
 			remote_backend: self.remote_backend,
 			block_announce_validator_builder: self.block_announce_validator_builder,
@@ -978,12 +977,7 @@ ServiceBuilder<
 		// Prometheus metrics.
 		let metrics_service = if let Some(PrometheusConfig { port, registry }) = config.prometheus_config.clone() {
 			// Set static metrics.
-			let metrics = MetricsService::with_prometheus(
-				&registry,
-				&config.network.node_name,
-				&config.impl_version,
-				&config.role,
-			)?;
+			let metrics = MetricsService::with_prometheus(&registry, &config)?;
 			spawn_handle.spawn(
 				"prometheus-endpoint",
 				prometheus_endpoint::init_prometheus(port, registry).map(drop)
@@ -1122,10 +1116,6 @@ ServiceBuilder<
 
 	/// Builds the full service.
 	pub fn build_full(self) -> Result<ServiceComponents<TBl, TBackend, TSc, TExPool, TCl>, Error> {
-		// make transaction pool available for off-chain runtime calls.
-		self.client.execution_extensions()
-			.register_transaction_pool(Arc::downgrade(&self.transaction_pool) as _);
-
 		self.build_common()
 	}
 }

substrate/client/service/src/config.rs

@@ -181,6 +181,11 @@ impl Configuration {
 	pub fn display_role(&self) -> String {
 		self.role.to_string()
 	}
+
+	/// Returns the prometheus metrics registry, if available.
+	pub fn prometheus_registry<'a>(&'a self) -> Option<&'a Registry> {
+		self.prometheus_config.as_ref().map(|config| &config.registry)
+	}
 }
 
 /// Available RPC methods.

substrate/client/service/src/lib.rs

@@ -577,11 +577,14 @@ mod tests {
 		// given
 		let (client, longest_chain) = TestClientBuilder::new().build_with_longest_chain();
 		let client = Arc::new(client);
-		let pool = Arc::new(BasicPool::new(
+		let spawner = sp_core::testing::SpawnBlockingExecutor::new();
+		let pool = BasicPool::new_full(
 			Default::default(),
 			Arc::new(FullChainApi::new(client.clone(), None)),
 			None,
-		).0);
+			spawner,
+			client.clone(),
+		);
 		let source = sp_runtime::transaction_validity::TransactionSource::External;
 		let best = longest_chain.best_chain().unwrap();
 		let transaction = Transfer {

substrate/client/service/src/metrics.rs

@@ -18,7 +18,7 @@
 
 use std::{convert::TryFrom, time::SystemTime};
 
-use crate::NetworkStatus;
+use crate::{NetworkStatus, config::Configuration};
 use prometheus_endpoint::{register, Gauge, U64, F64, Registry, PrometheusError, Opts, GaugeVec};
 use sc_telemetry::{telemetry, SUBSTRATE_INFO};
 use sp_runtime::traits::{NumberFor, Block, SaturatedConversion, UniqueSaturatedInto};
@@ -261,17 +261,17 @@ impl MetricsService {
 
 
 impl MetricsService {
-	pub fn with_prometheus(registry: &Registry, name: &str, version: &str, role: &Role)
+	pub fn with_prometheus(registry: &Registry, config: &Configuration)
 		-> Result<Self, PrometheusError>
 	{
-		let role_bits = match role {
+		let role_bits = match config.role {
 			Role::Full => 1u64,
 			Role::Light => 2u64,
 			Role::Sentry { .. } => 3u64,
 			Role::Authority { .. } => 4u64,
 		};
 
-		PrometheusMetrics::setup(registry, name, version, role_bits).map(|p| {
+		PrometheusMetrics::setup(registry, &config.network.node_name, &config.impl_version, role_bits).map(|p| {
 			Self::inner_new(Some(p))
 		})
 	}