ChainSpec trait (#5185)

* ChainSpec trait

* Apply suggestions from code review

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Added docs

* Fixed build

* Fixed build

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

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

@@ -12,7 +12,7 @@ use sp_runtime::traits::{Verify, IdentifyAccount};
 //const STAGING_TELEMETRY_URL: &str = "wss://telemetry.polkadot.io/submit/";
 
 /// Specialized `ChainSpec`. This is a specialization of the general Substrate ChainSpec type.
-pub type ChainSpec = sc_service::ChainSpec<GenesisConfig>;
+pub type ChainSpec = sc_service::GenericChainSpec<GenesisConfig>;
 
 /// The chain specification option. This is expected to come in from the CLI and
 /// is little more than one of a number of alternatives which can easily be converted
@@ -142,9 +142,9 @@ fn testnet_genesis(initial_authorities: Vec<(AuraId, GrandpaId)>,
 	}
 }
 
-pub fn load_spec(id: &str) -> Result<Option<ChainSpec>, String> {
+pub fn load_spec(id: &str) -> Result<Box<dyn sc_service::ChainSpec>, String> {
 	Ok(match Alternative::from(id) {
-		Some(spec) => Some(spec.load()?),
-		None => None,
+		Some(spec) => Box::new(spec.load()?),
+		None => Box::new(ChainSpec::from_json_file(std::path::PathBuf::from(id))?),
 	})
 }

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

@@ -4,7 +4,7 @@ use std::sync::Arc;
 use std::time::Duration;
 use sc_client::LongestChain;
 use sc_client_api::ExecutorProvider;
-use node_template_runtime::{self, GenesisConfig, opaque::Block, RuntimeApi};
+use node_template_runtime::{self, opaque::Block, RuntimeApi};
 use sc_service::{error::{Error as ServiceError}, AbstractService, Configuration, ServiceBuilder};
 use sp_inherents::InherentDataProviders;
 use sc_executor::native_executor_instance;
@@ -69,7 +69,7 @@ macro_rules! new_full_start {
 }
 
 /// Builds a new service for a full client.
-pub fn new_full(config: Configuration<GenesisConfig>)
+pub fn new_full(config: Configuration)
 	-> Result<impl AbstractService, ServiceError>
 {
 	let is_authority = config.roles.is_authority();
@@ -181,7 +181,7 @@ pub fn new_full(config: Configuration<GenesisConfig>)
 }
 
 /// Builds a new service for a light client.
-pub fn new_light(config: Configuration<GenesisConfig>)
+pub fn new_light(config: Configuration)
 	-> Result<impl AbstractService, ServiceError>
 {
 	let inherent_data_providers = InherentDataProviders::new();

substrate/bin/node/cli/src/chain_spec.rs

@@ -56,7 +56,7 @@ pub struct Extensions {
 }
 
 /// Specialized `ChainSpec`.
-pub type ChainSpec = sc_service::ChainSpec<
+pub type ChainSpec = sc_service::GenericChainSpec<
 	GenesisConfig,
 	Extensions,
 >;

substrate/bin/node/cli/src/command.rs

@@ -46,7 +46,7 @@ where
 			cmd.update_config(&mut config, load_spec, &version)?;
 
 			let client = sc_service::new_full_client::<
-				node_runtime::Block, node_runtime::RuntimeApi, node_executor::Executor, _, _,
+				node_runtime::Block, node_runtime::RuntimeApi, node_executor::Executor,
 			>(&config)?;
 			let inspect = node_inspect::Inspector::<node_runtime::Block>::new(client);
 
@@ -56,7 +56,7 @@ where
 			cmd.init(&version)?;
 			cmd.update_config(&mut config, load_spec, &version)?;
 
-			cmd.run::<_, _, node_runtime::Block, node_executor::Executor>(config)
+			cmd.run::<node_runtime::Block, node_executor::Executor>(config)
 		},
 		Some(Subcommand::Factory(cli_args)) => {
 			cli_args.shared_params.init(&version)?;
@@ -108,7 +108,7 @@ where
 			subcommand.update_config(&mut config, load_spec, &version)?;
 			subcommand.run(
 				config,
-				|config: service::NodeConfiguration| Ok(new_full_start!(config).0),
+				|config: sc_service::Configuration| Ok(new_full_start!(config).0),
 			)
 		},
 	}

substrate/bin/node/cli/src/lib.rs

@@ -83,9 +83,9 @@ impl ChainSpec {
 	}
 }
 
-fn load_spec(id: &str) -> Result<Option<chain_spec::ChainSpec>, String> {
+fn load_spec(id: &str) -> Result<Box<dyn sc_service::ChainSpec>, String> {
 	Ok(match ChainSpec::from(id) {
-		Some(spec) => Some(spec.load()?),
-		None => None,
+		Some(spec) => Box::new(spec.load()?),
+		None => Box::new(chain_spec::ChainSpec::from_json_file(std::path::PathBuf::from(id))?),
 	})
 }

substrate/bin/node/cli/src/service.rs

@@ -25,7 +25,7 @@ use sc_client::{self, LongestChain};
 use grandpa::{self, FinalityProofProvider as GrandpaFinalityProofProvider, StorageAndProofProvider};
 use node_executor;
 use node_primitives::Block;
-use node_runtime::{GenesisConfig, RuntimeApi};
+use node_runtime::RuntimeApi;
 use sc_service::{
 	AbstractService, ServiceBuilder, config::Configuration, error::{Error as ServiceError},
 };
@@ -270,11 +270,8 @@ type ConcreteTransactionPool = sc_transaction_pool::BasicPool<
 	ConcreteBlock
 >;
 
-/// A specialized configuration object for setting up the node..
-pub type NodeConfiguration = Configuration<GenesisConfig, crate::chain_spec::Extensions>;
-
 /// Builds a new service for a full client.
-pub fn new_full(config: NodeConfiguration)
+pub fn new_full(config: Configuration)
 -> Result<
 	Service<
 		ConcreteBlock,
@@ -296,7 +293,7 @@ pub fn new_full(config: NodeConfiguration)
 }
 
 /// Builds a new service for a light client.
-pub fn new_light(config: NodeConfiguration)
+pub fn new_light(config: Configuration)
 -> Result<impl AbstractService, ServiceError> {
 	type RpcExtension = jsonrpc_core::IoHandler<sc_rpc::Metadata>;
 	let inherent_data_providers = InherentDataProviders::new();

substrate/bin/node/inspect/src/command.rs

@@ -31,15 +31,12 @@ impl InspectCmd {
 	}
 
 	/// Parse CLI arguments and initialize given config.
-	pub fn update_config<G, E>(
+	pub fn update_config(
 		&self,
-		mut config: &mut sc_service::config::Configuration<G, E>,
-		spec_factory: impl FnOnce(&str) -> Result<Option<sc_service::ChainSpec<G, E>>, String>,
+		mut config: &mut sc_service::config::Configuration,
+		spec_factory: impl FnOnce(&str) -> Result<Box<dyn sc_service::ChainSpec>, String>,
 		version: &sc_cli::VersionInfo,
-	) -> sc_cli::Result<()> where
-		G: sc_service::RuntimeGenesis,
-		E: sc_service::ChainSpecExtension,
-	{
+	) -> sc_cli::Result<()> {
 		self.shared_params.update_config(config, spec_factory, version)?;
 
 		// make sure to configure keystore

substrate/bin/utils/chain-spec-builder/src/main.rs

@@ -128,7 +128,7 @@ fn generate_chain_spec(
 		Default::default(),
 	);
 
-	chain_spec.to_json(false).map_err(|err| err.to_string())
+	chain_spec.as_json(false).map_err(|err| err.to_string())
 }
 
 fn generate_authority_keys_and_store(