expose peer information via rpc (#1362)

* expose peer information via rpc

* fixes tests

* cleanup

Co-Authored-By: xlc <xlchen1291@gmail.com>

* Update docs

Co-Authored-By: xlc <xlchen1291@gmail.com>

* Add missing docs

* keep original type for PeerInfo best_hash/best_number

* cleanup

* Update mod.rs

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

@@ -45,6 +45,23 @@ pub struct Health {
 	pub is_syncing: bool,
 }
 
+/// Network Peer information
+#[derive(Debug, PartialEq, Serialize)]
+pub struct PeerInfo<Hash, Number> {
+	/// Peer Node Index
+	pub index: usize,
+	/// Peer ID
+	pub peer_id: String,
+	/// Roles
+	pub roles: String,
+	/// Protocol version
+	pub protocol_version: u32,
+	/// Peer best block hash
+	pub best_hash: Hash,
+	/// Peer best block 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 {

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

@@ -24,14 +24,14 @@ mod tests;
 
 use std::sync::Arc;
 use network;
-use runtime_primitives::traits;
+use runtime_primitives::traits::{self, Header as HeaderT};
 
 use self::error::Result;
-pub use self::helpers::{Properties, SystemInfo, Health};
+pub use self::helpers::{Properties, SystemInfo, Health, PeerInfo};
 
 build_rpc_trait! {
 	/// Substrate system RPC API
-	pub trait SystemApi {
+	pub trait SystemApi<Hash, Number> {
 		/// Get the node's implementation name. Plain old string.
 		#[rpc(name = "system_name")]
 		fn system_name(&self) -> Result<String>;
@@ -55,6 +55,10 @@ build_rpc_trait! {
 		/// - not performing a major sync
 		#[rpc(name = "system_health")]
 		fn system_health(&self) -> Result<Health>;
+
+		/// Returns currently connected peers
+		#[rpc(name = "system_peers")]
+		fn system_peers(&self) -> Result<Vec<PeerInfo<Hash, Number>>>;
 	}
 }
 
@@ -80,7 +84,7 @@ impl<B: traits::Block> System<B> {
 	}
 }
 
-impl<B: traits::Block> SystemApi for System<B> {
+impl<B: traits::Block> SystemApi<B::Hash, <B::Header as HeaderT>::Number> for System<B> {
 	fn system_name(&self) -> Result<String> {
 		Ok(self.info.impl_name.clone())
 	}
@@ -115,4 +119,15 @@ impl<B: traits::Block> SystemApi for System<B> {
 			Ok(health)
 		}
 	}
+
+	fn system_peers(&self) -> Result<Vec<PeerInfo<B::Hash, <B::Header as HeaderT>::Number>>> {
+		Ok(self.sync.peers().into_iter().map(|(idx, peer_id, p)| PeerInfo {
+			index: idx,
+			peer_id: peer_id.map_or_else(Default::default, |p| p.to_base58()),
+			roles: format!("{:?}", p.roles),
+			protocol_version: p.protocol_version,
+			best_hash: p.best_hash,
+			best_number: p.best_number,
+		}).collect())
+	}
 }

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

@@ -16,8 +16,10 @@
 
 use super::*;
 
-use network::{self, SyncState, SyncStatus, ProtocolStatus};
+use network::{self, SyncState, SyncStatus, ProtocolStatus, NodeIndex, PeerId, PeerInfo as NetworkPeerInfo, PublicKey};
+use network::config::Roles;
 use test_client::runtime::Block;
+use primitives::H256;
 
 #[derive(Default)]
 struct Status {
@@ -37,6 +39,15 @@ impl network::SyncProvider<Block> for Status {
 			num_active_peers: 0,
 		}
 	}
+
+	fn peers(&self) -> Vec<(NodeIndex, Option<PeerId>, NetworkPeerInfo<Block>)> {
+		vec![(1, Some(PublicKey::Ed25519((0 .. 32).collect::<Vec<u8>>()).into()), NetworkPeerInfo {
+			roles: Roles::FULL,
+			protocol_version: 1,
+			best_hash: Default::default(),
+			best_number: 1
+		})]
+	}
 }
 
 
@@ -129,3 +140,18 @@ fn system_health() {
 		}
 	);
 }
+
+#[test]
+fn system_peers() {
+	assert_eq!(
+		api(None).system_peers().unwrap(),
+		vec![PeerInfo {
+			index: 1,
+			peer_id: "QmS5oyTmdjwBowwAH1D9YQnoe2HyWpVemH8qHiU5RqWPh4".into(),
+			roles: "FULL".into(),
+			protocol_version: 1,
+			best_hash: Default::default(),
+			best_number: 1u64,
+		}]
+	);
+}