Add a JSON-RPC layer for reserved nodes (#8704)

* Add boilerplate for JSON-RPC layer for reserved nodes

* Add more boilerplate for JSON-RPC layer for reserved nodes

* Make JSON-RPC layer for reserved nodes async

* Use more realistic data in reserver_peers tests

* Make JSON-RPC layer for reserved nodes blocking

* Apply tomaka's suggestion to reduce .into_iter() for an iter

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>

Co-authored-by: Pierre Krieger <pierre.krieger1708@gmail.com>

substrate/client/network/src/protocol.rs

@@ -1014,6 +1014,11 @@ impl<B: BlockT> Protocol<B> {
 		self.peerset_handle.remove_reserved_peer(HARDCODED_PEERSETS_SYNC, peer.clone());
 	}
 
+	/// Returns the list of reserved peers.
+	pub fn reserved_peers(&self) -> impl Iterator<Item = &PeerId> {
+		self.behaviour.reserved_peers(HARDCODED_PEERSETS_SYNC)
+	}
+
 	/// Adds a `PeerId` to the list of reserved peers for syncing purposes.
 	pub fn add_reserved_peer(&self, peer: PeerId) {
 		self.peerset_handle.add_reserved_peer(HARDCODED_PEERSETS_SYNC, peer.clone());

substrate/client/network/src/protocol/notifications/behaviour.rs

@@ -555,6 +555,11 @@ impl Notifications {
 			.map(|((id, _), _)| id)
 	}
 
+	/// Returns the list of reserved peers.
+	pub fn reserved_peers<'a>(&'a self, set_id: sc_peerset::SetId) -> impl Iterator<Item = &'a PeerId> + 'a {
+		self.peerset.reserved_peers(set_id)
+	}
+
 	/// Sends a notification to a peer.
 	///
 	/// Has no effect if the custom protocol is not open with the given peer.

substrate/client/network/src/service.rs

@@ -619,6 +619,11 @@ impl<B: BlockT + 'static, H: ExHashT> NetworkWorker<B, H> {
 	pub fn add_reserved_peer(&self, peer: String) -> Result<(), String> {
 		self.service.add_reserved_peer(peer)
 	}
+
+	/// Returns the list of reserved peers.
+	pub fn reserved_peers(&self) -> impl Iterator<Item = &PeerId> {
+		self.network_service.behaviour().user_protocol().reserved_peers()
+	}
 }
 
 impl<B: BlockT + 'static, H: ExHashT> NetworkService<B, H> {

substrate/client/peerset/src/lib.rs

@@ -379,6 +379,11 @@ impl Peerset {
 		}
 	}
 
+	/// Returns the list of reserved peers.
+	pub fn reserved_peers(&self, set_id: SetId) -> impl Iterator<Item = &PeerId> {
+		self.reserved_nodes[set_id.0].0.iter()
+	}
+
 	/// Adds a node to the given set. The peerset will, if possible and not already the case,
 	/// try to connect to it.
 	///

substrate/client/rpc-api/src/system/mod.rs

@@ -102,6 +102,10 @@ pub trait SystemApi<Hash, Number> {
 	fn system_remove_reserved_peer(&self, peer_id: String)
 		-> Compat<BoxFuture<'static, Result<(), jsonrpc_core::Error>>>;
 
+	/// Returns the list of reserved peers
+	#[rpc(name = "system_reservedPeers", returns = "Vec<String>")]
+	fn system_reserved_peers(&self) -> Receiver<Vec<String>>;
+
 	/// Returns the roles the node is running as.
 	#[rpc(name = "system_nodeRoles", returns = "Vec<NodeRole>")]
 	fn system_node_roles(&self) -> Receiver<Vec<NodeRole>>;

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

@@ -66,6 +66,8 @@ pub enum Request<B: traits::Block> {
 	NetworkAddReservedPeer(String, oneshot::Sender<Result<()>>),
 	/// Must return any potential parse error.
 	NetworkRemoveReservedPeer(String, oneshot::Sender<Result<()>>),
+	/// Must return the list of reserved peers
+	NetworkReservedPeers(oneshot::Sender<Vec<String>>),
 	/// Must return the node role.
 	NodeRoles(oneshot::Sender<Vec<NodeRole>>),
 	/// Must return the state of the node syncing.
@@ -187,6 +189,12 @@ impl<B: traits::Block> SystemApi<B::Hash, <B::Header as HeaderT>::Number> for Sy
 		}.boxed().compat()
 	}
 
+	fn system_reserved_peers(&self) -> Receiver<Vec<String>> {
+		let (tx, rx) = oneshot::channel();
+		let _ = self.send_back.unbounded_send(Request::NetworkReservedPeers(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));

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

@@ -104,6 +104,9 @@ fn api<T: Into<Option<Status>>>(sync: T) -> System<Block> {
 						Err(s) => sender.send(Err(error::Error::MalformattedPeerArg(s.to_string()))),
 					};
 				}
+				Request::NetworkReservedPeers(sender) => {
+					let _ = sender.send(vec!["QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV".to_string()]);
+				}
 				Request::NodeRoles(sender) => {
 					let _ = sender.send(vec![NodeRole::Authority]);
 				}
@@ -337,6 +340,14 @@ fn system_network_remove_reserved() {
 	assert!(runtime.block_on(bad_fut).is_err());
 }
 
+#[test]
+fn system_network_reserved_peers() {
+	assert_eq!(
+		wait_receiver(api(None).system_reserved_peers()),
+		vec!["QmSk5HQbn6LhUwDiNMseVUjuRYhEtYj4aUZ6WfWoGURpdV".to_string()]
+	);
+}
+
 #[test]
 fn test_add_reset_log_filter() {
 	const EXPECTED_BEFORE_ADD: &'static str = "EXPECTED_BEFORE_ADD";

substrate/client/service/src/lib.rs

@@ -302,6 +302,14 @@ async fn build_network_future<
 							))),
 						};
 					}
+					sc_rpc::system::Request::NetworkReservedPeers(sender) => {
+						let reserved_peers = network.reserved_peers();
+						let reserved_peers = reserved_peers
+							.map(|peer_id| peer_id.to_base58())
+							.collect();
+
+						let _ = sender.send(reserved_peers);
+					}
 					sc_rpc::system::Request::NodeRoles(sender) => {
 						use sc_rpc::system::NodeRole;