From c72b9cac4f6d97c1069ebf02ead661f2974a4121 Mon Sep 17 00:00:00 2001
From: IAvecilla <iavecilla@fi.uba.ar>
Date: Tue, 20 Feb 2024 18:53:49 -0300
Subject: [PATCH] Create new endpoint to check last view of the node

---
 .../roles/src/validator/messages/consensus.rs |  3 +-
 node/tools/src/rpc/methods/last_view.rs       | 50 +++++++++++++++++++
 node/tools/src/rpc/methods/mod.rs             |  1 +
 node/tools/src/rpc/server.rs                  |  9 ++++
 4 files changed, 62 insertions(+), 1 deletion(-)
 create mode 100644 node/tools/src/rpc/methods/last_view.rs

diff --git a/node/libs/roles/src/validator/messages/consensus.rs b/node/libs/roles/src/validator/messages/consensus.rs
index d7a1d9ba..927f26f9 100644
--- a/node/libs/roles/src/validator/messages/consensus.rs
+++ b/node/libs/roles/src/validator/messages/consensus.rs
@@ -4,6 +4,7 @@ use super::{BlockHeader, Msg, Payload, Signed};
 use crate::{validator, validator::Signature};
 use anyhow::bail;
 use bit_vec::BitVec;
+use serde::Serialize;
 use std::collections::{BTreeMap, BTreeSet};
 use zksync_consensus_utils::enum_util::{BadVariantError, Variant};
 
@@ -417,7 +418,7 @@ impl ValidatorSet {
 }
 
 /// A struct that represents a view number.
-#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize)]
 pub struct ViewNumber(pub u64);
 
 impl ViewNumber {
diff --git a/node/tools/src/rpc/methods/last_view.rs b/node/tools/src/rpc/methods/last_view.rs
new file mode 100644
index 00000000..2f86631c
--- /dev/null
+++ b/node/tools/src/rpc/methods/last_view.rs
@@ -0,0 +1,50 @@
+//! Peers method for RPC server.
+use crate::{config::encode_json, decode_json, AppConfig};
+
+use super::RPCMethod;
+use jsonrpsee::types::{error::ErrorCode, Params};
+use std::{fs, sync::Arc};
+use zksync_consensus_storage::{BlockStore, ReplicaState};
+use zksync_protobuf::serde::Serde;
+
+/// Config method for RPC server.
+pub(crate) struct LastView;
+
+impl LastView {
+    /// Provide the node's config information
+    pub(crate) fn info(node_storage: Arc<BlockStore>) -> Result<serde_json::Value, ErrorCode> {
+        let block = node_storage;
+        let sub = &mut block.subscribe();
+        let state = sub.borrow().clone();
+        let replica_state = ReplicaState::from(state.last).view;
+        let replica_state =
+            serde_json::to_value(replica_state).map_err(|_e| ErrorCode::InternalError);
+        replica_state
+    }
+}
+
+impl RPCMethod for LastView {
+    /// Config response for /config endpoint.
+    fn callback(_params: Params) -> Result<serde_json::Value, ErrorCode> {
+        // This may change in the future since we are assuming that the executor binary is being run inside the config directory.
+        let node_config =
+            fs::read_to_string("config.json").map_err(|_e| ErrorCode::InternalError)?;
+        let node_config = decode_json::<Serde<AppConfig>>(&node_config)
+            .map_err(|_e| ErrorCode::InternalError)?
+            .0;
+        let config = encode_json(&Serde(node_config));
+        Ok(serde_json::json!({
+            "config": config
+        }))
+    }
+
+    /// Config method name.
+    fn method() -> &'static str {
+        "last_view"
+    }
+
+    /// Method path for GET requests.
+    fn path() -> &'static str {
+        "/last_view"
+    }
+}
diff --git a/node/tools/src/rpc/methods/mod.rs b/node/tools/src/rpc/methods/mod.rs
index 8c104ae5..bcdf6a98 100644
--- a/node/tools/src/rpc/methods/mod.rs
+++ b/node/tools/src/rpc/methods/mod.rs
@@ -12,4 +12,5 @@ pub trait RPCMethod {
 
 pub(crate) mod config;
 pub mod health_check;
+pub mod last_view;
 pub(crate) mod peers;
diff --git a/node/tools/src/rpc/server.rs b/node/tools/src/rpc/server.rs
index dc420f16..2d68bc5e 100644
--- a/node/tools/src/rpc/server.rs
+++ b/node/tools/src/rpc/server.rs
@@ -42,6 +42,10 @@ impl RPCServer {
             .layer(ProxyGetRequestLayer::new(
                 ConfigInfo::path(),
                 ConfigInfo::method(),
+            )?)
+            .layer(ProxyGetRequestLayer::new(
+                LastView::path(),
+                LastView::method(),
             )?);
 
         let server = Server::builder()
@@ -61,6 +65,11 @@ impl RPCServer {
             ConfigInfo::info(config.clone())
         })?;
 
+        let node_storage = self.node_storage.clone();
+        module.register_method(LastView::method(), move |_params, _| {
+            LastView::info(node_storage.clone())
+        })?;
+
         let handle = server.start(module);
         scope::run!(ctx, |ctx, s| async {
             s.spawn_bg(async {