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/api/src/system/helpers.rs

@@ -50,6 +50,14 @@ pub struct Health {
 	pub should_have_peers: bool,
 }
 
+impl fmt::Display for Health {
+	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+		write!(fmt, "{} peers ({})", self.peers, if self.is_syncing {
+			"syncing"
+		} else { "idle" })
+	}
+}
+
 /// Network Peer information
 #[derive(Debug, PartialEq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -66,12 +74,17 @@ pub struct PeerInfo<Hash, Number> {
 	pub best_number: Number,
 }
 
-impl fmt::Display for Health {
-	fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-		write!(fmt, "{} peers ({})", self.peers, if self.is_syncing {
-			"syncing"
-		} else { "idle" })
-	}
+/// The role the node is running as
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
+pub enum NodeRole {
+	/// The node is a full node
+	Full,
+	/// The node is a light client
+	LightClient,
+	/// The node is an authority
+	Authority,
+	/// An unknown role with a bit number
+	UnknownRole(u8)
 }
 
 #[cfg(test)]

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

@@ -24,7 +24,7 @@ use jsonrpc_derive::rpc;
 
 use self::error::Result;
 
-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;
 
 /// Substrate system RPC API
@@ -64,4 +64,8 @@ pub trait SystemApi<Hash, Number> {
 	// TODO: make this stable and move structs https://github.com/paritytech/substrate/issues/1890
 	#[rpc(name = "system_networkState", returns = "jsonrpc_core::Value")]
 	fn system_network_state(&self) -> Receiver<jsonrpc_core::Value>;
+
+	/// Returns the roles the node is running as.
+	#[rpc(name = "system_nodeRoles", returns = "Vec<NodeRole>")]
+	fn system_node_roles(&self) -> Receiver<Vec<NodeRole>>;
 }

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]
+	);
+}

substrate/core/service/src/lib.rs

@@ -368,6 +368,7 @@ macro_rules! new_impl {
 
 
 		let _ = to_spawn_tx.unbounded_send(Box::new(build_network_future(
+			$config.roles,
 			network_mut,
 			client.clone(),
 			network_status_sinks.clone(),
@@ -662,6 +663,7 @@ fn build_network_future<
 	S: network::specialization::NetworkSpecialization<B>,
 	H: network::ExHashT
 > (
+	roles: Roles,
 	mut network: network::NetworkWorker<B, S, H>,
 	client: Arc<C>,
 	status_sinks: Arc<Mutex<Vec<mpsc::UnboundedSender<(NetworkStatus<B>, NetworkState)>>>>,
@@ -669,7 +671,7 @@ fn build_network_future<
 	should_have_peers: bool,
 	dht_event_tx: Option<mpsc::Sender<DhtEvent>>,
 ) -> impl Future<Item = (), Error = ()> {
-	// Compatibility shim while we're transitionning to stable Futures.
+	// Compatibility shim while we're transitioning to stable Futures.
 	// See https://github.com/paritytech/substrate/issues/3099
 	let mut rpc_rx = futures03::compat::Compat::new(rpc_rx.map(|v| Ok::<_, ()>(v)));
 
@@ -725,6 +727,21 @@ fn build_network_future<
 						let _ = sender.send(network_state);
 					}
 				}
+				rpc::system::Request::NodeRoles(sender) => {
+					use rpc::system::NodeRole;
+
+					let node_roles = (0 .. 8)
+						.filter(|&bit_number| (roles.bits() >> bit_number) & 1 == 1)
+						.map(|bit_number| match Roles::from_bits(1 << bit_number) {
+							Some(Roles::AUTHORITY) => NodeRole::Authority,
+							Some(Roles::LIGHT) => NodeRole::LightClient,
+							Some(Roles::FULL) => NodeRole::Full,
+							_ => NodeRole::UnknownRole(bit_number),
+						})
+						.collect();
+
+					let _ = sender.send(node_roles);
+				}
 			};
 		}