feature(rpc): add real data to `getinfo` method (#3660)

* feature(rpc): add getinfo subversion field and getinfo docs

* feature(rpc): add getinfo build field

* refactor(rpc): replace the lazy_static

* docs(rpc): fic typo, add link to zcashd ticket

* tests(rpc): add getinfo unit test

* docs(rpc): complete comment

Cargo.lock

@@ -5708,6 +5708,8 @@ dependencies = [
  "tokio",
  "tracing",
  "tracing-futures",
+ "zebra-network",
+ "zebra-test",
 ]
 
 [[package]]

zebra-rpc/Cargo.toml

@@ -9,6 +9,8 @@ edition = "2021"
 
 [dependencies]
 
+zebra-network = { path = "../zebra-network" }
+
 futures = "0.3"
 
 # lightwalletd sends JSON-RPC requests over HTTP 1.1
@@ -24,3 +26,7 @@ tracing = "0.1"
 tracing-futures = "0.2"
 
 serde = { version = "1", features = ["serde_derive"] }
+
+[dev-dependencies]
+
+zebra-test = { path = "../zebra-test/" }

zebra-rpc/src/methods.rs

@@ -9,15 +9,34 @@
 use jsonrpc_core::{self, Result};
 use jsonrpc_derive::rpc;
 
+use zebra_network::constants::USER_AGENT;
+
+#[cfg(test)]
+mod tests;
+
 #[rpc(server)]
 /// RPC method signatures.
 pub trait Rpc {
     /// getinfo
     ///
-    /// TODO: explain what the method does
-    ///       link to the zcashd RPC reference
-    ///       list the arguments and fields that lightwalletd uses
-    ///       note any other lightwalletd changes
+    /// Returns software information from the RPC server running Zebra.
+    ///
+    /// zcashd reference: <https://zcash.github.io/rpc/getinfo.html>
+    ///
+    /// Result:
+    /// {
+    ///      "build": String, // Full application version
+    ///      "subversion", String, // Zebra user agent
+    /// }
+    ///
+    /// Note 1: We only expose 2 fields as they are the only ones needed for
+    /// lightwalletd: <https://github.com/zcash/lightwalletd/blob/v0.4.9/common/common.go#L91-L95>
+    ///
+    /// Note 2: <https://zcash.github.io/rpc/getinfo.html> is outdated so it does not
+    /// show the fields we are exposing. However, this fields are part of the output
+    /// as shown in the following zcashd code:
+    /// <https://github.com/zcash/zcash/blob/v4.6.0-1/src/rpc/misc.cpp#L86-L87>
+    /// Zcash open ticket to add this fields to the docs: <https://github.com/zcash/zcash/issues/5606>
     #[rpc(name = "getinfo")]
     fn get_info(&self) -> Result<GetInfo>;
 
@@ -32,13 +51,16 @@ pub trait Rpc {
 }
 
 /// RPC method implementations.
-pub struct RpcImpl;
+
+pub struct RpcImpl {
+    /// Zebra's application version.
+    pub app_version: String,
+}
 impl Rpc for RpcImpl {
     fn get_info(&self) -> Result<GetInfo> {
-        // TODO: dummy output data, fix in the context of #3142
         let response = GetInfo {
-            build: "TODO: Zebra v1.0.0 ...".into(),
-            subversion: "TODO: /Zebra:1.0.0-beta.../".into(),
+            build: self.app_version.clone(),
+            subversion: USER_AGENT.into(),
         };
 
         Ok(response)

zebra-rpc/src/methods/tests.rs

@@ -0,0 +1,2 @@
+//! Test code for RPC methods
+mod vectors;

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

@@ -0,0 +1,23 @@
+//! Fixed test vectors for RPC methods.
+
+use super::super::*;
+use zebra_network::constants::USER_AGENT;
+
+#[test]
+fn rpc_getinfo() {
+    zebra_test::init();
+
+    let rpc = RpcImpl {
+        app_version: "Zebra version test".to_string(),
+    };
+
+    let get_info = rpc.get_info().expect("We should have a GetInfo struct");
+
+    // make sure there is a `build` field in the response,
+    // and that is equal to the provided string.
+    assert_eq!(get_info.build, "Zebra version test");
+
+    // make sure there is a `subversion` field,
+    // and that is equal to the Zebra user agent.
+    assert_eq!(get_info.subversion, USER_AGENT);
+}

zebra-rpc/src/server.rs

@@ -24,14 +24,17 @@ pub struct RpcServer;
 
 impl RpcServer {
     /// Start a new RPC server endpoint
-    pub fn spawn(config: Config) -> tokio::task::JoinHandle<()> {
+    pub fn spawn(config: Config, app_version: String) -> tokio::task::JoinHandle<()> {
         if let Some(listen_addr) = config.listen_addr {
             info!("Trying to open RPC endpoint at {}...", listen_addr,);
 
+            // Initialize the rpc methods with the zebra version
+            let rpc_impl = RpcImpl { app_version };
+
             // Create handler compatible with V1 and V2 RPC protocols
             let mut io =
                 jsonrpc_core::IoHandler::with_compatibility(jsonrpc_core::Compatibility::Both);
-            io.extend_with(RpcImpl.to_delegate());
+            io.extend_with(rpc_impl.to_delegate());
 
             let server = ServerBuilder::new(io)
                 // use the same tokio executor as the rest of Zebra
@@ -54,6 +57,7 @@ impl RpcServer {
                     info!("Stopping RPC endpoint");
                 })
             };
+
             tokio::task::spawn_blocking(server)
         } else {
             // There is no RPC port, so the RPC task does nothing.

zebrad/src/commands/start.rs

@@ -75,6 +75,7 @@ use zebra_consensus::CheckpointList;
 use zebra_rpc::server::RpcServer;
 
 use crate::{
+    application::app_version,
     components::{
         inbound::{self, InboundSetupData},
         mempool::{self, Mempool},
@@ -196,7 +197,7 @@ impl StartCmd {
                 .in_current_span(),
         );
 
-        let rpc_task_handle = RpcServer::spawn(config.rpc);
+        let rpc_task_handle = RpcServer::spawn(config.rpc, app_version().to_string());
 
         info!("spawned initial Zebra tasks");