client: helper to create standalone client without service (#4536)

substrate/client/service/src/builder.rs

@@ -139,28 +139,32 @@ pub type TLightCallExecutor<TBl, TExecDisp> = sc_client::light::call_executor::G
 	>,
 >;
 
-impl<TCfg, TGen, TCSExt> ServiceBuilder<(), (), TCfg, TGen, TCSExt, (), (), (), (), (), (), (), (), (), ()>
+type TFullParts<TBl, TRtApi, TExecDisp> = (
-where TGen: RuntimeGenesis, TCSExt: Extension {
-	/// Start the service builder with a configuration.
-	pub fn new_full<TBl: BlockT<Hash=H256>, TRtApi, TExecDisp: NativeExecutionDispatch>(
-		config: Configuration<TCfg, TGen, TCSExt>
-	) -> Result<ServiceBuilder<
-		TBl,
-		TRtApi,
-		TCfg,
-		TGen,
-		TCSExt,
 	TFullClient<TBl, TRtApi, TExecDisp>,
-		Arc<OnDemand<TBl>>,
+	Arc<TFullBackend<TBl>>,
-		(),
+	Arc<RwLock<sc_keystore::Store>>,
-		(),
+);
-		BoxFinalityProofRequestBuilder<TBl>,
+
-		Arc<dyn FinalityProofProvider<TBl>>,
+/// Creates a new full client for the given config.
-		(),
+pub fn new_full_client<TBl, TRtApi, TExecDisp, TCfg, TGen, TCSExt>(
-		(),
+	config: &Configuration<TCfg, TGen, TCSExt>,
-		(),
+) -> Result<TFullClient<TBl, TRtApi, TExecDisp>, Error> where
-		TFullBackend<TBl>,
+	TBl: BlockT<Hash=H256>,
-	>, Error> {
+	TExecDisp: NativeExecutionDispatch,
+	TGen: sp_runtime::BuildStorage + serde::Serialize + for<'de> serde::Deserialize<'de>,
+	TCSExt: Extension,
+{
+	new_full_parts(config).map(|parts| parts.0)
+}
+
+fn new_full_parts<TBl, TRtApi, TExecDisp, TCfg, TGen, TCSExt>(
+	config: &Configuration<TCfg, TGen, TCSExt>,
+) -> Result<TFullParts<TBl, TRtApi, TExecDisp>,	Error> where
+	TBl: BlockT<Hash=H256>,
+	TExecDisp: NativeExecutionDispatch,
+	TGen: sp_runtime::BuildStorage + serde::Serialize + for<'de> serde::Deserialize<'de>,
+	TCSExt: Extension,
+{
 	let keystore = Keystore::open(
 		config.keystore_path.clone().ok_or("No basepath configured")?,
 		config.keystore_password.clone()
@@ -208,6 +212,33 @@ where TGen: RuntimeGenesis, TCSExt: Extension {
 		)?
 	};
 
+	Ok((client, backend, keystore))
+}
+
+impl<TCfg, TGen, TCSExt> ServiceBuilder<(), (), TCfg, TGen, TCSExt, (), (), (), (), (), (), (), (), (), ()>
+where TGen: RuntimeGenesis, TCSExt: Extension {
+	/// Start the service builder with a configuration.
+	pub fn new_full<TBl: BlockT<Hash=H256>, TRtApi, TExecDisp: NativeExecutionDispatch>(
+		config: Configuration<TCfg, TGen, TCSExt>
+	) -> Result<ServiceBuilder<
+		TBl,
+		TRtApi,
+		TCfg,
+		TGen,
+		TCSExt,
+		TFullClient<TBl, TRtApi, TExecDisp>,
+		Arc<OnDemand<TBl>>,
+		(),
+		(),
+		BoxFinalityProofRequestBuilder<TBl>,
+		Arc<dyn FinalityProofProvider<TBl>>,
+		(),
+		(),
+		(),
+		TFullBackend<TBl>,
+	>, Error> {
+		let (client, backend, keystore) = new_full_parts(&config)?;
+
 		let client = Arc::new(client);
 
 		Ok(ServiceBuilder {

substrate/client/service/src/lib.rs

@@ -54,6 +54,7 @@ use sp_runtime::traits::{NumberFor, Block as BlockT};
 
 pub use self::error::Error;
 pub use self::builder::{
+	new_full_client,
 	ServiceBuilder, ServiceBuilderCommand, TFullClient, TLightClient, TFullBackend, TLightBackend,
 	TFullCallExecutor, TLightCallExecutor,
 };