From e9ffdaf4ed5dd8cadc167713dc9481932ea965c8 Mon Sep 17 00:00:00 2001
From: Kishore Nallan <kishorenc@gmail.com>
Date: Sat, 21 Jan 2023 18:17:50 +0530
Subject: [PATCH] Update caught up only when leader status is available.

---
 src/raft_server.cpp | 38 +++++++++++++++++---------------------
 1 file changed, 17 insertions(+), 21 deletions(-)

diff --git a/src/raft_server.cpp b/src/raft_server.cpp
index 0f332bd6..91393b56 100644
--- a/src/raft_server.cpp
+++ b/src/raft_server.cpp
@@ -660,29 +660,24 @@ void ReplicationState::refresh_catchup_status(bool log_msg) {
     std::string api_res;
     std::map<std::string, std::string> res_headers;
     long status_code = HttpClient::get_response(url, api_res, res_headers);
-    if(status_code == 404) {
-        // earlier versions don't have this end-point, so we just ignore
-        return ;
-    }
-
-    if(status_code != 200) {
-        this->read_caught_up = false;
-        return ;
-    }
-
-    // compare leader's applied log with local applied to see if we are lagging
-    nlohmann::json leader_status = nlohmann::json::parse(api_res);
-    if(leader_status.contains("committed_index")) {
-        int64_t leader_committed_index = leader_status["committed_index"].get<int64_t>();
-        if(leader_committed_index <= n_status.committed_index) {
-            // this can happen due to network latency in making the /status call
+    if(status_code == 200) {
+        // compare leader's applied log with local applied to see if we are lagging
+        nlohmann::json leader_status = nlohmann::json::parse(api_res);
+        if(leader_status.contains("committed_index")) {
+            int64_t leader_committed_index = leader_status["committed_index"].get<int64_t>();
+            if(leader_committed_index <= n_status.committed_index) {
+                // this can happen due to network latency in making the /status call
+                // we will refrain from changing current status
+                return ;
+            }
+            this->read_caught_up = ((leader_committed_index - n_status.committed_index) < healthy_read_lag);
+        } else {
             // we will refrain from changing current status
-            return ;
+            LOG(ERROR) << "Error, `committed_index` key not found in /status response from leader.";
         }
-        this->read_caught_up = ((leader_committed_index - n_status.committed_index) < healthy_read_lag);
     } else {
-        // we will refrain from changing current status
-        LOG(ERROR) << "Error, `committed_index` key not found in /status response from leader.";
+        // we will again refrain from changing current status
+        LOG(ERROR) << "Error, /status end-point returned bad status code " << status_code;
     }
 }
 
@@ -697,6 +692,7 @@ ReplicationState::ReplicationState(HttpServer* server, BatchedIndexer* batched_i
         config(config),
         num_collections_parallel_load(num_collections_parallel_load),
         num_documents_parallel_load(num_documents_parallel_load),
+        read_caught_up(false), write_caught_up(false),
         ready(false), shutting_down(false), pending_writes(0),
         last_snapshot_ts(std::time(nullptr)), snapshot_interval_s(config->get_snapshot_interval_seconds()) {
 
@@ -743,7 +739,7 @@ const std::string &ReplicationState::get_ext_snapshot_path() const {
 void ReplicationState::do_dummy_write() {
     std::shared_lock lock(node_mutex);
 
-    if(node->leader_id().is_empty()) {
+    if(!node || node->leader_id().is_empty()) {
         LOG(ERROR) << "Could not do a dummy write, as node does not have a leader";
         return ;
     }