impl Debug for sc_service::Configuration

client/chain-spec/src/lib.rs

@@ -158,3 +158,9 @@ pub trait ChainSpec: BuildStorage + Send {
 	/// This will be used as storage at genesis.
 	fn set_storage(&mut self, storage: Storage);
 }
+
+impl std::fmt::Debug for dyn ChainSpec {
+	fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+		write!(f, "ChainSpec(name = {:?}, id = {:?})", self.name(), self.id())
+	}
+}

client/cli/src/config.rs

@@ -28,15 +28,12 @@ use names::{Generator, Name};
 use sc_client_api::execution_extensions::ExecutionStrategies;
 use sc_service::config::{
 	BasePath, Configuration, DatabaseConfig, ExtTransport, KeystoreConfig, NetworkConfiguration,
-	NodeKeyConfig, OffchainWorkerConfig, PrometheusConfig, PruningMode, Role, RpcMethods, TaskType,
-	TelemetryEndpoints, TransactionPoolOptions, WasmExecutionMethod,
+	NodeKeyConfig, OffchainWorkerConfig, PrometheusConfig, PruningMode, Role, RpcMethods,
+	TaskExecutor, TelemetryEndpoints, TransactionPoolOptions, WasmExecutionMethod,
 };
 use sc_service::{ChainSpec, TracingReceiver};
-use std::future::Future;
 use std::net::SocketAddr;
 use std::path::PathBuf;
-use std::pin::Pin;
-use std::sync::Arc;
 
 /// The maximum number of characters for a node name.
 pub(crate) const NODE_NAME_MAX_LENGTH: usize = 32;
@@ -409,7 +406,7 @@ pub trait CliConfiguration: Sized {
 	fn create_configuration<C: SubstrateCli>(
 		&self,
 		cli: &C,
-		task_executor: Arc<dyn Fn(Pin<Box<dyn Future<Output = ()> + Send>>, TaskType) + Send + Sync>,
+		task_executor: TaskExecutor,
 	) -> Result<Configuration> {
 		let is_dev = self.is_dev()?;
 		let chain_id = self.chain_id(is_dev)?;

client/cli/src/lib.rs

@@ -37,11 +37,8 @@ use log::info;
 pub use params::*;
 use regex::Regex;
 pub use runner::*;
-use sc_service::{ChainSpec, Configuration, TaskType};
-use std::future::Future;
+use sc_service::{ChainSpec, Configuration, TaskExecutor};
 use std::io::Write;
-use std::pin::Pin;
-use std::sync::Arc;
 pub use structopt;
 use structopt::{
 	clap::{self, AppSettings},
@@ -199,7 +196,7 @@ pub trait SubstrateCli: Sized {
 	fn create_configuration<T: CliConfiguration>(
 		&self,
 		command: &T,
-		task_executor: Arc<dyn Fn(Pin<Box<dyn Future<Output = ()> + Send>>, TaskType) + Send + Sync>,
+		task_executor: TaskExecutor,
 	) -> error::Result<Configuration> {
 		command.create_configuration(self, task_executor)
 	}

client/cli/src/runner.rs

@@ -29,7 +29,7 @@ use sc_service::{AbstractService, Configuration, Role, ServiceBuilderCommand, Ta
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT};
 use sp_utils::metrics::{TOKIO_THREADS_ALIVE, TOKIO_THREADS_TOTAL};
 use sp_version::RuntimeVersion;
-use std::{fmt::Debug, marker::PhantomData, str::FromStr, sync::Arc};
+use std::{fmt::Debug, marker::PhantomData, str::FromStr};
 
 #[cfg(target_family = "unix")]
 async fn main<F, E>(func: F) -> std::result::Result<(), Box<dyn std::error::Error>>
@@ -119,23 +119,21 @@ impl<C: SubstrateCli> Runner<C> {
 		let tokio_runtime = build_runtime()?;
 		let runtime_handle = tokio_runtime.handle().clone();
 
-		let task_executor = Arc::new(
-			move |fut, task_type| {
-				match task_type {
-					TaskType::Async => { runtime_handle.spawn(fut); }
-					TaskType::Blocking => {
-						runtime_handle.spawn( async move {
-							// `spawn_blocking` is looking for the current runtime, and as such has to be called
-							// from within `spawn`.
-							tokio::task::spawn_blocking(move || futures::executor::block_on(fut))
-						});
-					}
+		let task_executor = move |fut, task_type| {
+			match task_type {
+				TaskType::Async => { runtime_handle.spawn(fut); }
+				TaskType::Blocking => {
+					runtime_handle.spawn(async move {
+						// `spawn_blocking` is looking for the current runtime, and as such has to
+						// be called from within `spawn`.
+						tokio::task::spawn_blocking(move || futures::executor::block_on(fut))
+					});
 				}
 			}
-		);
+		};
 
 		Ok(Runner {
-			config: command.create_configuration(cli, task_executor)?,
+			config: command.create_configuration(cli, task_executor.into())?,
 			tokio_runtime,
 			phantom: PhantomData,
 		})

client/db/src/lib.rs

@@ -271,7 +271,7 @@ pub struct DatabaseSettings {
 }
 
 /// Where to find the database..
-#[derive(Clone)]
+#[derive(Debug, Clone)]
 pub enum DatabaseSettingsSrc {
 	/// Load a RocksDB database from a given path. Recommended for most uses.
 	RocksDb {

client/service/src/config.rs

@@ -34,6 +34,7 @@ use prometheus_endpoint::Registry;
 use tempfile::TempDir;
 
 /// Service configuration.
+#[derive(Debug)]
 pub struct Configuration {
 	/// Implementation name
 	pub impl_name: &'static str,
@@ -42,7 +43,7 @@ pub struct Configuration {
 	/// Node role.
 	pub role: Role,
 	/// How to spawn background tasks. Mandatory, otherwise creating a `Service` will error.
-	pub task_executor: Arc<dyn Fn(Pin<Box<dyn Future<Output = ()> + Send>>, TaskType) + Send + Sync>,
+	pub task_executor: TaskExecutor,
 	/// Extrinsic pool configuration.
 	pub transaction_pool: TransactionPoolOptions,
 	/// Network configuration.
@@ -120,7 +121,7 @@ pub enum TaskType {
 }
 
 /// Configuration of the client keystore.
-#[derive(Clone)]
+#[derive(Debug, Clone)]
 pub enum KeystoreConfig {
 	/// Keystore at a path on-disk. Recommended for native nodes.
 	Path {
@@ -143,7 +144,7 @@ impl KeystoreConfig {
 	}
 }
 /// Configuration of the database of the client.
-#[derive(Clone, Default)]
+#[derive(Debug, Clone, Default)]
 pub struct OffchainWorkerConfig {
 	/// If this is allowed.
 	pub enabled: bool,
@@ -152,7 +153,7 @@ pub struct OffchainWorkerConfig {
 }
 
 /// Configuration of the Prometheus endpoint.
-#[derive(Clone)]
+#[derive(Debug, Clone)]
 pub struct PrometheusConfig {
 	/// Port to use.
 	pub port: SocketAddr,
@@ -199,6 +200,7 @@ impl Default for RpcMethods {
 }
 
 /// The base path that is used for everything that needs to be write on disk to run a node.
+#[derive(Debug)]
 pub enum BasePath {
 	/// A temporary directory is used as base path and will be deleted when dropped.
 	#[cfg(not(target_os = "unknown"))]
@@ -253,3 +255,69 @@ impl std::convert::From<PathBuf> for BasePath {
 		BasePath::new(path)
 	}
 }
+
+type TaskExecutorInner = Arc<dyn Fn(Pin<Box<dyn Future<Output = ()> + Send>>, TaskType) + Send + Sync>;
+
+/// Callable object that execute tasks.
+///
+/// This struct can be created easily using `Into`.
+///
+/// # Examples
+///
+/// ## Using tokio
+///
+/// ```
+/// # use sc_service::TaskExecutor;
+/// # mod tokio { pub mod runtime {
+/// # #[derive(Clone)]
+/// # pub struct Runtime;
+/// # impl Runtime {
+/// # pub fn new() -> Result<Self, ()> { Ok(Runtime) }
+/// # pub fn handle(&self) -> &Self { &self }
+/// # pub fn spawn(&self, _: std::pin::Pin<Box<dyn futures::future::Future<Output = ()> + Send>>) {}
+/// # }
+/// # } }
+/// use tokio::runtime::Runtime;
+///
+/// let runtime = Runtime::new().unwrap();
+/// let handle = runtime.handle().clone();
+/// let task_executor: TaskExecutor = (move |future, _task_type| {
+///		handle.spawn(future);
+///	}).into();
+/// ```
+///
+/// ## Using async-std
+///
+/// ```
+/// # use sc_service::TaskExecutor;
+/// # mod async_std { pub mod task {
+/// # pub fn spawn(_: std::pin::Pin<Box<dyn futures::future::Future<Output = ()> + Send>>) {}
+/// # } }
+/// let task_executor: TaskExecutor = (|future, _task_type| {
+///		async_std::task::spawn(future);
+///	}).into();
+/// ```
+#[derive(Clone)]
+pub struct TaskExecutor(TaskExecutorInner);
+
+impl std::fmt::Debug for TaskExecutor {
+	fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+		write!(f, "TaskExecutor")
+	}
+}
+
+impl<F> std::convert::From<F> for TaskExecutor
+where
+	F: Fn(Pin<Box<dyn Future<Output = ()> + Send>>, TaskType) + Send + Sync + 'static,
+{
+	fn from(x: F) -> Self {
+		Self(Arc::new(x))
+	}
+}
+
+impl TaskExecutor {
+	/// Spawns a new asynchronous task.
+	pub fn spawn(&self, future: Pin<Box<dyn Future<Output = ()> + Send>>, task_type: TaskType) {
+		self.0(future, task_type)
+	}
+}

client/service/src/lib.rs

@@ -65,7 +65,9 @@ pub use self::builder::{
 	ServiceBuilder, ServiceBuilderCommand, TFullClient, TLightClient, TFullBackend, TLightBackend,
 	TFullCallExecutor, TLightCallExecutor, RpcExtensionBuilder,
 };
-pub use config::{BasePath, Configuration, DatabaseConfig, PruningMode, Role, RpcMethods, TaskType};
+pub use config::{
+	BasePath, Configuration, DatabaseConfig, PruningMode, Role, RpcMethods, TaskExecutor, TaskType,
+};
 pub use sc_chain_spec::{
 	ChainSpec, GenericChainSpec, Properties, RuntimeGenesis, Extension as ChainSpecExtension,
 	NoExtension, ChainType,

client/service/src/task_manager.rs

@@ -13,7 +13,7 @@
 
 //! Substrate service tasks management module.
 
-use std::{panic, pin::Pin, result::Result, sync::Arc};
+use std::{panic, result::Result};
 use exit_future::Signal;
 use log::debug;
 use futures::{
@@ -29,18 +29,15 @@ use prometheus_endpoint::{
 };
 use sc_client_api::CloneableSpawn;
 use sp_utils::mpsc::TracingUnboundedSender;
-use crate::config::TaskType;
+use crate::config::{TaskExecutor, TaskType};
 
 mod prometheus_future;
 
-/// Type alias for service task executor (usually runtime).
-pub type ServiceTaskExecutor = Arc<dyn Fn(Pin<Box<dyn Future<Output = ()> + Send>>, TaskType) + Send + Sync>;
-
 /// An handle for spawning tasks in the service.
 #[derive(Clone)]
 pub struct SpawnTaskHandle {
 	on_exit: exit_future::Exit,
-	executor: ServiceTaskExecutor,
+	executor: TaskExecutor,
 	metrics: Option<Metrics>,
 }
 
@@ -113,7 +110,7 @@ impl SpawnTaskHandle {
 			}
 		};
 
-		(self.executor)(Box::pin(future), task_type);
+		self.executor.spawn(Box::pin(future), task_type);
 	}
 }
 
@@ -216,7 +213,7 @@ pub struct TaskManager {
 	/// A signal that makes the exit future above resolve, fired on service drop.
 	signal: Option<Signal>,
 	/// How to spawn background tasks.
-	executor: ServiceTaskExecutor,
+	executor: TaskExecutor,
 	/// Prometheus metric where to report the polling times.
 	metrics: Option<Metrics>,
 }
@@ -225,7 +222,7 @@ impl TaskManager {
  	/// If a Prometheus registry is passed, it will be used to report statistics about the
  	/// service tasks.
 	pub(super) fn new(
-		executor: ServiceTaskExecutor,
+		executor: TaskExecutor,
 		prometheus_registry: Option<&Registry>
 	) -> Result<Self, PrometheusError> {
 		let (signal, on_exit) = exit_future::signal();

client/service/test/src/lib.rs

@@ -38,7 +38,7 @@ use sc_service::{
 	RuntimeGenesis,
 	Role,
 	Error,
-	TaskType,
+	TaskExecutor,
 };
 use sp_blockchain::HeaderBackend;
 use sc_network::{multiaddr, Multiaddr};
@@ -142,7 +142,7 @@ fn node_config<G: RuntimeGenesis + 'static, E: ChainSpecExtension + Clone + 'sta
 	index: usize,
 	spec: &GenericChainSpec<G, E>,
 	role: Role,
-	task_executor: Arc<dyn Fn(Pin<Box<dyn futures::Future<Output = ()> + Send>>, TaskType) + Send + Sync>,
+	task_executor: TaskExecutor,
 	key_seed: Option<String>,
 	base_port: u16,
 	root: &TempDir,
@@ -256,17 +256,19 @@ impl<G, E, F, L, U> TestNet<G, E, F, L, U> where
 		authorities: impl Iterator<Item = (String, impl FnOnce(Configuration) -> Result<(F, U), Error>)>
 	) {
 		let executor = self.runtime.executor();
+		let task_executor: TaskExecutor = {
+			let executor = executor.clone();
+			(move |fut: Pin<Box<dyn futures::Future<Output = ()> + Send>>, _| {
+				executor.spawn(fut.unit_error().compat());
+			}).into()
+		};
 
 		for (key, authority) in authorities {
-			let task_executor = {
-				let executor = executor.clone();
-				Arc::new(move |fut: Pin<Box<dyn futures::Future<Output = ()> + Send>>, _| executor.spawn(fut.unit_error().compat()))
-			};
 			let node_config = node_config(
 				self.nodes,
 				&self.chain_spec,
 				Role::Authority { sentry_nodes: Vec::new() },
-				task_executor,
+				task_executor.clone(),
 				Some(key),
 				self.base_port,
 				&temp,
@@ -282,11 +284,15 @@ impl<G, E, F, L, U> TestNet<G, E, F, L, U> where
 		}
 
 		for full in full {
-			let task_executor = {
-				let executor = executor.clone();
-				Arc::new(move |fut: Pin<Box<dyn futures::Future<Output = ()> + Send>>, _| executor.spawn(fut.unit_error().compat()))
-			};
-			let node_config = node_config(self.nodes, &self.chain_spec, Role::Full, task_executor, None, self.base_port, &temp);
+			let node_config = node_config(
+				self.nodes,
+				&self.chain_spec,
+				Role::Full,
+				task_executor.clone(),
+				None,
+				self.base_port,
+				&temp,
+			);
 			let addr = node_config.network.listen_addresses.iter().next().unwrap().clone();
 			let (service, user_data) = full(node_config).expect("Error creating test node service");
 			let service = SyncService::from(service);
@@ -298,11 +304,15 @@ impl<G, E, F, L, U> TestNet<G, E, F, L, U> where
 		}
 
 		for light in light {
-			let task_executor = {
-				let executor = executor.clone();
-				Arc::new(move |fut: Pin<Box<dyn futures::Future<Output = ()> + Send>>, _| executor.spawn(fut.unit_error().compat()))
-			};
-			let node_config = node_config(self.nodes, &self.chain_spec, Role::Light, task_executor, None, self.base_port, &temp);
+			let node_config = node_config(
+				self.nodes,
+				&self.chain_spec,
+				Role::Light,
+				task_executor.clone(),
+				None,
+				self.base_port,
+				&temp,
+			);
 			let addr = node_config.network.listen_addresses.iter().next().unwrap().clone();
 			let service = SyncService::from(light(node_config).expect("Error creating test node service"));
 

primitives/database/src/lib.rs

@@ -165,6 +165,12 @@ pub trait Database<H: Clone>: Send + Sync {
 	}
 }
 
+impl<H> std::fmt::Debug for dyn Database<H> {
+	fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+		write!(f, "Database")
+	}
+}
+
 /// Call `f` with the value previously stored against `key` and return the result, or `None` if
 /// `key` is not currently in the database.
 ///