Treat --key as private key of pkcs8 (paritytech#7)

* Treat --key as private key of pkcs8

* Fix mismatched formatter

core/service/Cargo.toml

@@ -12,6 +12,7 @@ lazy_static = "1.0"
 log = "0.4"
 slog = "^2"
 tokio = "0.1.7"
+hex = "0.3"
 exit-future = "0.1"
 serde = "1.0"
 serde_json = "1.0"

core/service/src/lib.rs

@@ -41,6 +41,7 @@ use exit_future::Signal;
 pub use tokio::runtime::TaskExecutor;
 use substrate_executor::NativeExecutor;
 use parity_codec::{Encode, Decode};
+use primitives::ed25519::Pair;
 use tel::telemetry;
 
 pub use self::error::{ErrorKind, Error};
@@ -71,6 +72,7 @@ pub struct Service<Components: components::Components> {
 	pub network: Option<Arc<components::NetworkService<Components::Factory>>>,
 	pub transaction_pool: Arc<TransactionPool<Components::TransactionPoolApi>>,
 	keystore: Keystore,
+	private_key: Option<String>,
 	exit: ::exit_future::Exit,
 	signal: Option<Signal>,
 	/// Configuration of this Service
@@ -123,6 +125,8 @@ impl<Components: components::Components> Service<Components> {
 			}
 		};
 
+		let private_key = config.keys.get(0).map(|x| x.to_owned());
+
 		let (client, on_demand) = Components::build_client(&config, executor)?;
 		let import_queue = Arc::new(Components::build_import_queue(&mut config, client.clone())?);
 		let best_header = client.best_block_header()?;
@@ -299,6 +303,7 @@ impl<Components: components::Components> Service<Components> {
 			transaction_pool,
 			signal: Some(signal),
 			keystore,
+            private_key,
 			config,
 			exit,
 			//_rpc: Box::new(rpc),
@@ -309,6 +314,17 @@ impl<Components: components::Components> Service<Components> {
 	/// give the authority key, if we are an authority and have a key
 	pub fn authority_key(&self) -> Option<primitives::ed25519::Pair> {
 		if self.config.roles != Roles::AUTHORITY { return None }
+		if let Some(ref private_key) = self.private_key {
+            let pkcs8_bytes: Vec<u8> = hex::decode(&private_key[2..]).unwrap();
+                if let Ok(pair) = Pair::from_pkcs8(&pkcs8_bytes) {
+					Some(pair)
+				} else {
+					panic!("Fail to generate pair from pkcs8 bytes")
+				}
+		} else {
+            panic!("AUTHORITY must provide private key")
+		}
+		/*
 		let keystore = &self.keystore;
 		if let Ok(Some(Ok(key))) =  keystore.contents().map(|keys| keys.get(0)
 				.map(|k| keystore.load(k, "")))
@@ -317,6 +333,7 @@ impl<Components: components::Components> Service<Components> {
 		} else {
 			None
 		}
+		*/
 	}
 
 	pub fn telemetry(&self) -> Option<Arc<tel::Telemetry>> {