draft(rpc): add scaffolding for ping RPC and getpeerinfo latency metrics

Author: syszery

zebra-rpc/src/methods.rs

@@ -544,6 +544,17 @@ pub trait Rpc {
     #[method(name = "getpeerinfo")]
     async fn get_peer_info(&self) -> Result<Vec<PeerInfo>>;
 
+    /// Requests that a ping be sent to all other nodes, to measure ping time.
+    ///
+    /// Results provided in getpeerinfo, pingtime and pingwait fields are decimal seconds.
+    /// Ping command is handled in queue with all other commands, so it measures processing backlog, not just network ping.
+    ///
+    /// zcashd reference: [`ping`](https://zcash.github.io/rpc/ping.html)
+    /// method: post
+    /// tags: network
+    #[method(name = "ping")]
+    async fn ping(&self) -> Result<()>;
+
     /// Checks if a zcash transparent address of type P2PKH, P2SH or TEX is valid.
     /// Returns information about the given address if valid.
     ///
@@ -2645,6 +2656,15 @@ where
             .collect())
     }
 
+    async fn ping(&self) -> Result<()> {
+        tracing::debug!("Receiving ping request via RPC");
+
+        // TODO: Send Message::Ping(nonce) to all connected peers,
+        // and track response round-trip time for getpeerinfo's pingtime/pingwait fields.
+
+        Ok(())
+    }
+
     async fn validate_address(&self, raw_address: String) -> Result<ValidateAddressResponse> {
         let network = self.network.clone();
 

zebra-rpc/src/methods/tests/vectors.rs

@@ -2895,6 +2895,8 @@ async fn rpc_addnode() {
         [PeerInfo {
             addr,
             inbound: false,
+            pingtime: None,
+            pingwait: None,
         }]
     );
 

zebra-rpc/src/methods/types/peer_info.rs

@@ -5,14 +5,22 @@ use derive_new::new;
 use zebra_network::{types::MetaAddr, PeerSocketAddr};
 
 /// Item of the `getpeerinfo` response
-#[derive(Clone, Debug, PartialEq, Eq, serde::Serialize, serde::Deserialize, Getters, new)]
+#[derive(Clone, Debug, PartialEq, serde::Serialize, serde::Deserialize, Getters, new)]
 pub struct PeerInfo {
     /// The IP address and port of the peer
     #[getter(copy)]
     pub(crate) addr: PeerSocketAddr,
 
     /// Inbound (true) or Outbound (false)
     pub(crate) inbound: bool,
+
+    /// The round-trip ping time in seconds.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(crate) pingtime: Option<f64>,
+
+    /// The wait time on a ping response in seconds.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub(crate) pingwait: Option<f64>,
 }
 
 /// Response type for the `getpeerinfo` RPC method.
@@ -23,6 +31,9 @@ impl From<MetaAddr> for PeerInfo {
         Self {
             addr: meta_addr.addr(),
             inbound: meta_addr.is_inbound(),
+            // TODO: Fill in pingtime and pingwait once live ping tracking is implemented.
+            pingtime: None,
+            pingwait: None,
         }
     }
 }
@@ -32,6 +43,8 @@ impl Default for PeerInfo {
         Self {
             addr: PeerSocketAddr::unspecified(),
             inbound: false,
+            pingtime: None,
+            pingwait: None,
         }
     }
 }

zebra-rpc/tests/serialization_tests.rs

@@ -1133,8 +1133,47 @@ fn test_get_peer_info() -> Result<(), Box<dyn std::error::Error>> {
     let inbound1 = obj[1].inbound();
 
     let new_obj = vec![
-        PeerInfo::new(addr0.into(), inbound0),
-        PeerInfo::new(addr1.into(), inbound1),
+        PeerInfo::new(addr0.into(), inbound0, None, None),
+        PeerInfo::new(addr1.into(), inbound1, None, None),
+    ];
+    assert_eq!(obj, new_obj);
+
+    Ok(())
+}
+
+#[test]
+fn test_get_peer_info_with_ping_values_serialization() -> Result<(), Box<dyn std::error::Error>> {
+    let json = r#"
+[
+  {
+    "addr": "192.168.0.1:8233",
+    "inbound": false,
+    "pingtime": 123,
+    "pingwait": 45
+  },
+  {
+    "addr": "[2000:2000:2000:0000::]:8233",
+    "inbound": false,
+    "pingtime": 67,
+    "pingwait": 89
+  }
+]
+"#;
+    let obj: GetPeerInfoResponse = serde_json::from_str(json)?;
+
+    let addr0 = *obj[0].addr().deref();
+    let inbound0 = obj[0].inbound();
+    let pingtime0 = obj[0].pingtime();
+    let pingwait0 = obj[0].pingwait();
+
+    let addr1 = *obj[1].addr().deref();
+    let inbound1 = obj[1].inbound();
+    let pingtime1 = obj[1].pingtime();
+    let pingwait1 = obj[1].pingwait();
+
+    let new_obj = vec![
+        PeerInfo::new(addr0.into(), inbound0, *pingtime0, *pingwait0),
+        PeerInfo::new(addr1.into(), inbound1, *pingtime1, *pingwait1),
     ];
     assert_eq!(obj, new_obj);