CLI API refactoring and improvement (#4692)

It changes the way we extended the CLI functionalities of substrate to allow more flexibility. (If this was not clear, here is another version: it changes the `sc_cli` API to allow more flexibility).

This touches a few important things:
 - the startup of the async task with tokei:
    This was in node and node-template and I moved it to substrate. The idea is to have 1 time the code that handles unix signals (SIGTERM and SIGINT) properly. It is however possible to make this more generic to wait for a future instead and provide only a helper for the basic handling of SIGTERM and SIGINT.
 - increased the version of structopt and tokei
 - no more use of structopt internal's API
 - less use of generics

Related to #4643 and https://github.com/paritytech/cumulus/pull/42: the implementation of "into_configuration" and "get_config" are similar but with better flexibility so it is now possible in cumulus to have the command-line arguments only of the run command for polkadot if we want

Related to https://github.com/paritytech/cumulus/issues/24 and https://github.com/paritytech/cumulus/issues/34 : it will now be possible to make a configuration struct for polkadot with some overrides of the default parameters much more easily.

substrate/bin/node-template/src/chain_spec.rs

@@ -145,3 +145,10 @@ fn testnet_genesis(initial_authorities: Vec<(AuraId, GrandpaId)>,
 		}),
 	}
 }
+
+pub fn load_spec(id: &str) -> Result<Option<ChainSpec>, String> {
+	Ok(match Alternative::from(id) {
+		Some(spec) => Some(spec.load()?),
+		None => None,
+	})
+}

substrate/bin/node-template/src/cli.rs

@@ -1,121 +1,11 @@
-use crate::service;
-use futures::{future::{select, Map, Either}, FutureExt, channel::oneshot};
-use std::cell::RefCell;
-use tokio::runtime::Runtime;
-pub use sc_cli::{VersionInfo, IntoExit, error};
-use sc_cli::{display_role, informant, parse_and_prepare, ParseAndPrepare, NoCustom};
-use sc_service::{AbstractService, Roles as ServiceRoles, Configuration};
-use sp_consensus_aura::sr25519::{AuthorityPair as AuraPair};
-use crate::chain_spec;
-use log::info;
+use sc_cli::{RunCmd, Subcommand};
+use structopt::StructOpt;
 
-/// Parse command line arguments into service configuration.
-pub fn run<I, T, E>(args: I, exit: E, version: VersionInfo) -> error::Result<()> where
-	I: IntoIterator<Item = T>,
-	T: Into<std::ffi::OsString> + Clone,
-	E: IntoExit,
-{
-	type Config<T> = Configuration<(), T>;
-	match parse_and_prepare::<NoCustom, NoCustom, _>(&version, "substrate-node", args) {
-		ParseAndPrepare::Run(cmd) => cmd.run(load_spec, exit,
-		|exit, _cli_args, _custom_args, mut config: Config<_>| {
-			info!("{}", version.name);
-			info!("  version {}", config.full_version());
-			info!("  by {}, 2017, 2018", version.author);
-			info!("Chain specification: {}", config.chain_spec.name());
-			info!("Node name: {}", config.name);
-			info!("Roles: {}", display_role(&config));
-			let runtime = Runtime::new().map_err(|e| format!("{:?}", e))?;
-			config.tasks_executor = {
-				let runtime_handle = runtime.handle().clone();
-				Some(Box::new(move |fut| { runtime_handle.spawn(fut); }))
-			};
-			match config.roles {
-				ServiceRoles::LIGHT => run_until_exit(
-					runtime,
-					service::new_light(config)?,
-					exit
-				),
-				_ => run_until_exit(
-					runtime,
-					service::new_full(config)?,
-					exit
-				),
-			}
-		}),
-		ParseAndPrepare::BuildSpec(cmd) => cmd.run::<NoCustom, _, _, _>(load_spec),
-		ParseAndPrepare::ExportBlocks(cmd) => cmd.run_with_builder(|config: Config<_>|
-			Ok(new_full_start!(config).0), load_spec, exit),
-		ParseAndPrepare::ImportBlocks(cmd) => cmd.run_with_builder(|config: Config<_>|
-			Ok(new_full_start!(config).0), load_spec, exit),
-		ParseAndPrepare::CheckBlock(cmd) => cmd.run_with_builder(|config: Config<_>|
-			Ok(new_full_start!(config).0), load_spec, exit),
-		ParseAndPrepare::PurgeChain(cmd) => cmd.run(load_spec),
-		ParseAndPrepare::RevertChain(cmd) => cmd.run_with_builder(|config: Config<_>|
-			Ok(new_full_start!(config).0), load_spec),
-		ParseAndPrepare::CustomCommand(_) => Ok(())
-	}?;
+#[derive(Debug, StructOpt)]
+pub struct Cli {
+	#[structopt(subcommand)]
+	pub subcommand: Option<Subcommand>,
 
-	Ok(())
-}
-
-fn load_spec(id: &str) -> Result<Option<chain_spec::ChainSpec>, String> {
-	Ok(match chain_spec::Alternative::from(id) {
-		Some(spec) => Some(spec.load()?),
-		None => None,
-	})
-}
-
-fn run_until_exit<T, E>(
-	mut runtime: Runtime,
-	service: T,
-	e: E,
-) -> error::Result<()>
-where
-	T: AbstractService,
-	E: IntoExit,
-{
-	let (exit_send, exit) = oneshot::channel();
-
-	let informant = informant::build(&service);
-
-	let handle = runtime.spawn(select(exit, informant));
-
-	// we eagerly drop the service so that the internal exit future is fired,
-	// but we need to keep holding a reference to the global telemetry guard
-	let _telemetry = service.telemetry();
-
-	let exit = e.into_exit();
-	let service_res = runtime.block_on(select(service, exit));
-
-	let _ = exit_send.send(());
-
-	if let Err(e) = runtime.block_on(handle) {
-		log::error!("Error running node: {:?}", e);
-	}
-
-	match service_res {
-		Either::Left((res, _)) => res.map_err(error::Error::Service),
-		Either::Right((_, _)) => Ok(())
-	}
-}
-
-// handles ctrl-c
-pub struct Exit;
-impl IntoExit for Exit {
-	type Exit = Map<oneshot::Receiver<()>, fn(Result<(), oneshot::Canceled>) -> ()>;
-	fn into_exit(self) -> Self::Exit {
-		// can't use signal directly here because CtrlC takes only `Fn`.
-		let (exit_send, exit) = oneshot::channel();
-
-		let exit_send_cell = RefCell::new(Some(exit_send));
-		ctrlc::set_handler(move || {
-			let exit_send = exit_send_cell.try_borrow_mut().expect("signal handler not reentrant; qed").take();
-			if let Some(exit_send) = exit_send {
-				exit_send.send(()).expect("Error sending exit notification");
-			}
-		}).expect("Error setting Ctrl-C handler");
-
-		exit.map(drop)
-	}
+	#[structopt(flatten)]
+	pub run: RunCmd,
 }

substrate/bin/node-template/src/command.rs

@@ -0,0 +1,48 @@
+// Copyright 2017-2020 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Substrate is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+use sp_consensus_aura::sr25519::{AuthorityPair as AuraPair};
+use sc_cli::{VersionInfo, error};
+use crate::service;
+use crate::chain_spec;
+use crate::cli::Cli;
+
+/// Parse and run command line arguments
+pub fn run(version: VersionInfo) -> error::Result<()>
+{
+	let opt = sc_cli::from_args::<Cli>(&version);
+
+	let mut config = sc_service::Configuration::default();
+	config.impl_name = "node-template";
+
+	match opt.subcommand {
+		Some(subcommand) => sc_cli::run_subcommand(
+			config,
+			subcommand,
+			chain_spec::load_spec,
+			|config: _| Ok(new_full_start!(config).0),
+			&version,
+		),
+		None => sc_cli::run(
+			config,
+			opt.run,
+			service::new_light,
+			service::new_full,
+			chain_spec::load_spec,
+			&version,
+		)
+	}
+}

substrate/bin/node-template/src/main.rs

@@ -5,10 +5,11 @@ mod chain_spec;
 #[macro_use]
 mod service;
 mod cli;
+mod command;
 
-pub use sc_cli::{VersionInfo, IntoExit, error};
+pub use sc_cli::{VersionInfo, error};
 
-fn main() -> Result<(), cli::error::Error> {
+fn main() -> Result<(), error::Error> {
 	let version = VersionInfo {
 		name: "Substrate Node",
 		commit: env!("VERGEN_SHA_SHORT"),
@@ -17,7 +18,8 @@ fn main() -> Result<(), cli::error::Error> {
 		author: "Anonymous",
 		description: "Template Node",
 		support_url: "support.anonymous.an",
+		copyright_start_year: 2017,
 	};
 
-	cli::run(std::env::args(), cli::Exit, version)
+	command::run(version)
 }

substrate/bin/node-template/src/service.rs

@@ -77,7 +77,7 @@ macro_rules! new_full_start {
 }
 
 /// Builds a new service for a full client.
-pub fn new_full<C: Send + Default + 'static>(config: Configuration<C, GenesisConfig>)
+pub fn new_full(config: Configuration<GenesisConfig>)
 	-> Result<impl AbstractService, ServiceError>
 {
 	let is_authority = config.roles.is_authority();
@@ -192,7 +192,7 @@ pub fn new_full<C: Send + Default + 'static>(config: Configuration<C, GenesisCon
 }
 
 /// Builds a new service for a light client.
-pub fn new_light<C: Send + Default + 'static>(config: Configuration<C, GenesisConfig>)
+pub fn new_light(config: Configuration<GenesisConfig>)
 	-> Result<impl AbstractService, ServiceError>
 {
 	let inherent_data_providers = InherentDataProviders::new();