lib.rs

			select_chain,
			block_import,
			env: proposer,
			sync_oracle: network.clone(),
			justification_sync_link: network.clone(),
			create_inherent_data_providers: move |parent, ()| {
				let client_clone = client_clone.clone();
				let overseer_handle = overseer_handle.clone();
				async move {
					let parachain = polkadot_node_core_parachains_inherent::ParachainsInherentDataProvider::create(
						&*client_clone,
						overseer_handle,
						parent,
					).await.map_err(|e| Box::new(e))?;

					let uncles = sc_consensus_uncles::create_uncles_inherent_data_provider(
						&*client_clone,
						parent,
					)?;

					let timestamp = sp_timestamp::InherentDataProvider::from_system_time();

					let slot =
						sp_consensus_babe::inherents::InherentDataProvider::from_timestamp_and_duration(
							*timestamp,
							slot_duration,
						);

					Ok((timestamp, slot, uncles, parachain))
				}
			},
			force_authoring,
			backoff_authoring_blocks,
			babe_link,
			can_author_with,
			block_proposal_slot_portion: babe::SlotProportion::new(2f32 / 3f32),
			max_block_proposal_slot_portion: None,
			telemetry: telemetry.as_ref().map(|x| x.handle()),
		};

		let babe = babe::start_babe(babe_config)?;
		task_manager.spawn_essential_handle().spawn_blocking("babe", babe);
	}

	// if the node isn't actively participating in consensus then it doesn't
	// need a keystore, regardless of which protocol we use below.
	let keystore_opt =
		if role.is_authority() { Some(keystore_container.sync_keystore()) } else { None };

	// We currently only run the BEEFY gadget on the Rococo and Wococo testnets.
	if !disable_beefy && (chain_spec.is_rococo() || chain_spec.is_wococo()) {
		let beefy_params = beefy_gadget::BeefyParams {
			client: client.clone(),
			backend: backend.clone(),
			key_store: keystore_opt.clone(),
			network: network.clone(),
			signed_commitment_sender: beefy_link,
			min_block_delta: if chain_spec.is_wococo() { 4 } else { 8 },
			prometheus_registry: prometheus_registry.clone(),
		};

		let gadget = beefy_gadget::start_beefy_gadget::<_, _, _, _>(beefy_params);

		// Wococo's purpose is to be a testbed for BEEFY, so if it fails we'll
		// bring the node down with it to make sure it is noticed.
		if chain_spec.is_wococo() {
			task_manager.spawn_essential_handle().spawn_blocking("beefy-gadget", gadget);
		} else {
			task_manager.spawn_handle().spawn_blocking("beefy-gadget", gadget);
		}
	}

	let config = grandpa::Config {
		// FIXME substrate#1578 make this available through chainspec
		gossip_duration: Duration::from_millis(1000),
		justification_period: 512,
		name: Some(name),
		observer_enabled: false,
		keystore: keystore_opt,
		local_role: role,
		telemetry: telemetry.as_ref().map(|x| x.handle()),
	};

	let enable_grandpa = !disable_grandpa;
	if enable_grandpa {
		// start the full GRANDPA voter
		// NOTE: unlike in substrate we are currently running the full
		// GRANDPA voter protocol for all full nodes (regardless of whether
		// they're validators or not). at this point the full voter should
		// provide better guarantees of block and vote data availability than
		// the observer.

		// add a custom voting rule to temporarily stop voting for new blocks
		// after the given pause block is finalized and restarting after the
		// given delay.
		let builder = grandpa::VotingRulesBuilder::default();

		let voting_rule = match grandpa_pause {
			Some((block, delay)) => {
				info!(
					block_number = %block,
					delay = %delay,
					"GRANDPA scheduled voting pause set for block #{} with a duration of {} blocks.",
					block,
					delay,
				);

				builder.add(grandpa_support::PauseAfterBlockFor(block, delay)).build()
			},
			None => builder.build(),
		};

		let grandpa_config = grandpa::GrandpaParams {
			config,
			link: link_half,
			network: network.clone(),
			voting_rule,
			prometheus_registry: prometheus_registry.clone(),
			shared_voter_state,
			telemetry: telemetry.as_ref().map(|x| x.handle()),
		};

		task_manager
			.spawn_essential_handle()
			.spawn_blocking("grandpa-voter", grandpa::run_grandpa_voter(grandpa_config)?);
	}

	network_starter.start_network();

	Ok(NewFull { task_manager, client, overseer_handle, network, rpc_handlers, backend })
}

/// Builds a new service for a light client.
#[cfg(feature = "light-node")]
fn new_light<Runtime, Dispatch>(
	mut config: Configuration,
) -> Result<(TaskManager, RpcHandlers), Error>
where
	Runtime: 'static + Send + Sync + ConstructRuntimeApi<Block, LightClient<Runtime, Dispatch>>,
	<Runtime as ConstructRuntimeApi<Block, LightClient<Runtime, Dispatch>>>::RuntimeApi:
		RuntimeApiCollection<StateBackend = sc_client_api::StateBackendFor<LightBackend, Block>>,
	Dispatch: NativeExecutionDispatch + 'static,
{
	set_prometheus_registry(&mut config)?;
	use sc_client_api::backend::RemoteBackend;

	let telemetry = config
		.telemetry_endpoints
		.clone()
		.filter(|x| !x.is_empty())
		.map(|endpoints| -> Result<_, telemetry::Error> {
			let worker = TelemetryWorker::new(16)?;
			let telemetry = worker.handle().new_telemetry(endpoints);
			Ok((worker, telemetry))
		})
		.transpose()?;

	let (client, backend, keystore_container, mut task_manager, on_demand) =
		service::new_light_parts::<Block, Runtime, Dispatch>(
			&config,
			telemetry.as_ref().map(|(_, telemetry)| telemetry.handle()),
		)?;

	let mut telemetry = telemetry.map(|(worker, telemetry)| {
		task_manager.spawn_handle().spawn("telemetry", worker.run());
		telemetry
	});

	config.network.extra_sets.push(grandpa::grandpa_peers_set_config());

	let select_chain = sc_consensus::LongestChain::new(backend.clone());

	let transaction_pool = Arc::new(sc_transaction_pool::BasicPool::new_light(
		config.transaction_pool.clone(),
		config.prometheus_registry(),
		task_manager.spawn_essential_handle(),
		client.clone(),
		on_demand.clone(),
	));

	let (grandpa_block_import, grandpa_link) = grandpa::block_import(
		client.clone(),
		&(client.clone() as Arc<_>),
		select_chain.clone(),
		telemetry.as_ref().map(|x| x.handle()),
	)?;
	let justification_import = grandpa_block_import.clone();

	let (babe_block_import, babe_link) = babe::block_import(
		babe::Config::get_or_compute(&*client)?,
		grandpa_block_import,
		client.clone(),
	)?;

	// FIXME: pruning task isn't started since light client doesn't do `AuthoritySetup`.
	let slot_duration = babe_link.config().slot_duration();
	let import_queue = babe::import_queue(
		babe_link,
		babe_block_import,
		Some(Box::new(justification_import)),
		client.clone(),
		select_chain.clone(),
		move |_, ()| async move {
			let timestamp = sp_timestamp::InherentDataProvider::from_system_time();

			let slot =
				sp_consensus_babe::inherents::InherentDataProvider::from_timestamp_and_duration(
					*timestamp,
					slot_duration,
				);

			Ok((timestamp, slot))
		},
		&task_manager.spawn_essential_handle(),
		config.prometheus_registry(),
		consensus_common::NeverCanAuthor,
		telemetry.as_ref().map(|x| x.handle()),
	)?;

	let warp_sync = Arc::new(grandpa::warp_proof::NetworkProvider::new(
		backend.clone(),
		grandpa_link.shared_authority_set().clone(),
	));

	let (network, system_rpc_tx, network_starter) =
		service::build_network(service::BuildNetworkParams {
			config: &config,
			client: client.clone(),
			transaction_pool: transaction_pool.clone(),
			spawn_handle: task_manager.spawn_handle(),
			import_queue,
			on_demand: Some(on_demand.clone()),
			block_announce_validator_builder: None,
			warp_sync: Some(warp_sync),
		})?;

	let enable_grandpa = !config.disable_grandpa;
	if enable_grandpa {
		let name = config.network.node_name.clone();

		let config = grandpa::Config {
			gossip_duration: Duration::from_millis(1000),
			justification_period: 512,
			name: Some(name),
			observer_enabled: false,
			keystore: None,
			local_role: config.role.clone(),
			telemetry: telemetry.as_ref().map(|x| x.handle()),
		};

		task_manager.spawn_handle().spawn_blocking(
			"grandpa-observer",
			grandpa::run_grandpa_observer(config, grandpa_link, network.clone())?,
		);
	}

	if config.offchain_worker.enabled {
		let _ = service::build_offchain_workers(
			&config,
			task_manager.spawn_handle(),
			client.clone(),
			network.clone(),
		);
	}

	let light_deps = polkadot_rpc::LightDeps {
		remote_blockchain: backend.remote_blockchain(),
		fetcher: on_demand.clone(),
		client: client.clone(),
		pool: transaction_pool.clone(),
	};

	let rpc_extensions = polkadot_rpc::create_light(light_deps);

	let rpc_handlers = service::spawn_tasks(service::SpawnTasksParams {
		on_demand: Some(on_demand),
		remote_blockchain: Some(backend.remote_blockchain()),
		rpc_extensions_builder: Box::new(service::NoopRpcExtensionBuilder(rpc_extensions)),
		task_manager: &mut task_manager,
		config,
		keystore: keystore_container.sync_keystore(),
		backend,
		transaction_pool,
		client,
		network,
		system_rpc_tx,
		telemetry: telemetry.as_mut(),
	})?;

	network_starter.start_network();

	Ok((task_manager, rpc_handlers))
}

macro_rules! chain_ops {
	($config:expr, $jaeger_agent:expr, $telemetry_worker_handle:expr; $scope:ident, $executor:ident, $variant:ident) => {{
		let telemetry_worker_handle = $telemetry_worker_handle;
		let jaeger_agent = $jaeger_agent;
		let mut config = $config;
		let basics = new_partial_basics::<$scope::RuntimeApi, $executor>(
			config,
			jaeger_agent,
			telemetry_worker_handle,
		)?;

		use ::sc_consensus::LongestChain;
		// use the longest chain selection, since there is no overseer available
		let chain_selection = LongestChain::new(basics.backend.clone());

		let service::PartialComponents { client, backend, import_queue, task_manager, .. } =
			new_partial::<$scope::RuntimeApi, $executor, LongestChain<_, Block>>(
				&mut config,
				basics,
				chain_selection,
			)?;
		Ok((Arc::new(Client::$variant(client)), backend, import_queue, task_manager))
	}};
}

/// Builds a new object suitable for chain operations.
#[cfg(feature = "full-node")]
pub fn new_chain_ops(
	mut config: &mut Configuration,
	jaeger_agent: Option<std::net::SocketAddr>,
) -> Result<
	(
		Arc<Client>,
		Arc<FullBackend>,
		sc_consensus::BasicQueue<Block, PrefixedMemoryDB<BlakeTwo256>>,
		TaskManager,
	),
	Error,
> {
	config.keystore = service::config::KeystoreConfig::InMemory;

	let telemetry_worker_handle = None;

	#[cfg(feature = "rococo-native")]
	if config.chain_spec.is_rococo() || config.chain_spec.is_wococo() {
		return chain_ops!(config, jaeger_agent, telemetry_worker_handle; rococo_runtime, RococoExecutorDispatch, Rococo)
	}

	#[cfg(feature = "kusama-native")]
	if config.chain_spec.is_kusama() {
		return chain_ops!(config, jaeger_agent, telemetry_worker_handle; kusama_runtime, KusamaExecutorDispatch, Kusama)
	}

	#[cfg(feature = "westend-native")]
	if config.chain_spec.is_westend() {
		return chain_ops!(config, jaeger_agent, telemetry_worker_handle; westend_runtime, WestendExecutorDispatch, Westend)
	}

	#[cfg(feature = "polkadot-native")]
	{
		return chain_ops!(config, jaeger_agent, telemetry_worker_handle; polkadot_runtime, PolkadotExecutorDispatch, Polkadot)
	}

	#[cfg(not(feature = "polkadot-native"))]
	Err(Error::NoRuntime)
}

/// Build a new light node.
#[cfg(feature = "light-node")]
pub fn build_light(config: Configuration) -> Result<(TaskManager, RpcHandlers), Error> {
	#[cfg(feature = "rococo-native")]
	if config.chain_spec.is_rococo() || config.chain_spec.is_wococo() {
		return new_light::<rococo_runtime::RuntimeApi, RococoExecutorDispatch>(config)
	}

	#[cfg(feature = "kusama-native")]
	if config.chain_spec.is_kusama() {
		return new_light::<kusama_runtime::RuntimeApi, KusamaExecutorDispatch>(config)
	}

	#[cfg(feature = "westend-native")]
	if config.chain_spec.is_westend() {
		return new_light::<westend_runtime::RuntimeApi, WestendExecutorDispatch>(config)
	}

	#[cfg(feature = "polkadot-native")]
	{
		return new_light::<polkadot_runtime::RuntimeApi, PolkadotExecutorDispatch>(config)
	}

	#[cfg(not(feature = "polkadot-native"))]
	Err(Error::NoRuntime)
}

#[cfg(feature = "full-node")]
pub fn build_full(
	config: Configuration,
	is_collator: IsCollator,
	grandpa_pause: Option<(u32, u32)>,
	disable_beefy: bool,
	jaeger_agent: Option<std::net::SocketAddr>,
	telemetry_worker_handle: Option<TelemetryWorkerHandle>,
	overseer_gen: impl OverseerGen,
) -> Result<NewFull<Client>, Error> {
	#[cfg(feature = "rococo-native")]
	if config.chain_spec.is_rococo() || config.chain_spec.is_wococo() {
		return new_full::<rococo_runtime::RuntimeApi, RococoExecutorDispatch, _>(
			config,
			is_collator,
			grandpa_pause,
			disable_beefy,
			jaeger_agent,
			telemetry_worker_handle,
			None,
			overseer_gen,
		)
		.map(|full| full.with_client(Client::Rococo))
	}

	#[cfg(feature = "kusama-native")]
	if config.chain_spec.is_kusama() {
		return new_full::<kusama_runtime::RuntimeApi, KusamaExecutorDispatch, _>(
			config,
			is_collator,
			grandpa_pause,
			disable_beefy,
			jaeger_agent,
			telemetry_worker_handle,
			None,
			overseer_gen,
		)
		.map(|full| full.with_client(Client::Kusama))
	}

	#[cfg(feature = "westend-native")]
	if config.chain_spec.is_westend() {
		return new_full::<westend_runtime::RuntimeApi, WestendExecutorDispatch, _>(
			config,
			is_collator,
			grandpa_pause,
			disable_beefy,
			jaeger_agent,
			telemetry_worker_handle,
			None,
			overseer_gen,
		)
		.map(|full| full.with_client(Client::Westend))
	}

	#[cfg(feature = "polkadot-native")]
	{
		return new_full::<polkadot_runtime::RuntimeApi, PolkadotExecutorDispatch, _>(
			config,
			is_collator,
			grandpa_pause,
			disable_beefy,
			jaeger_agent,
			telemetry_worker_handle,
			None,
			overseer_gen,
		)
		.map(|full| full.with_client(Client::Polkadot))
	}

	#[cfg(not(feature = "polkadot-native"))]
	Err(Error::NoRuntime)
}