WIP: Node role RPC call (#3719)

* Add a Node Role RPC call

* Formatting

* Fix tests

* Change tests to use NodeRole::Authority so I don't forget to update the test

* Improve role checking

* return a vec instead

* fix tests

substrate/core/rpc/src/system/mod.rs

@@ -25,7 +25,7 @@ use sr_primitives::traits::{self, Header as HeaderT};
 use self::error::Result;
 
 pub use api::system::*;
-pub use self::helpers::{Properties, SystemInfo, Health, PeerInfo};
+pub use self::helpers::{Properties, SystemInfo, Health, PeerInfo, NodeRole};
 pub use self::gen_client::Client as SystemClient;
 
 /// System API implementation
@@ -42,6 +42,8 @@ pub enum Request<B: traits::Block> {
 	Peers(oneshot::Sender<Vec<PeerInfo<B::Hash, <B::Header as HeaderT>::Number>>>),
 	/// Must return the state of the network.
 	NetworkState(oneshot::Sender<rpc::Value>),
+	/// Must return the node role.
+	NodeRoles(oneshot::Sender<Vec<NodeRole>>)
 }
 
 impl<B: traits::Block> System<B> {
@@ -94,4 +96,10 @@ impl<B: traits::Block> SystemApi<B::Hash, <B::Header as HeaderT>::Number> for Sy
 		let _ = self.send_back.unbounded_send(Request::NetworkState(tx));
 		Receiver(Compat::new(rx))
 	}
+
+	fn system_node_roles(&self) -> Receiver<Vec<NodeRole>> {
+		let (tx, rx) = oneshot::channel();
+		let _ = self.send_back.unbounded_send(Request::NodeRoles(tx));
+		Receiver(Compat::new(rx))
+	}
 }

substrate/core/rpc/src/system/tests.rs

@@ -79,6 +79,9 @@ fn api<T: Into<Option<Status>>>(sync: T) -> System<Block> {
 						average_upload_per_sec: 0,
 						peerset: serde_json::Value::Null,
 					}).unwrap());
+				},
+				Request::NodeRoles(sender) => {
+					let _ = sender.send(vec![NodeRole::Authority]);
 				}
 			};
 
@@ -221,3 +224,11 @@ fn system_network_state() {
 		}
 	);
 }
+
+#[test]
+fn system_node_roles() {
+	assert_eq!(
+		wait_receiver(api(None).system_node_roles()),
+		vec![NodeRole::Authority]
+	);
+}