From e24bee545bdd815dcca1e1714ddf24620f21339f Mon Sep 17 00:00:00 2001
From: Petr Gusev <petr.gusev@scylladb.com>
Date: Wed, 10 Jan 2024 21:09:31 +0400
Subject: [PATCH] raft ips: rename gossiper_state_change_subscriber_proxy ->
 raft_ip_address_updater

---
 service/storage_service.cc | 18 +++++++++---------
 service/storage_service.hh | 10 ++++++----
 2 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/service/storage_service.cc b/service/storage_service.cc
index 6b6130d773..06d4b76bca 100644
--- a/service/storage_service.cc
+++ b/service/storage_service.cc
@@ -650,9 +650,9 @@ future<> storage_service::merge_topology_snapshot(raft_topology_snapshot snp) {
    co_await _db.local().apply(freeze(muts), db::no_timeout);
 }
 
-// {{{ gossiper_state_change_subscriber_proxy
+// {{{ raft_ip_address_updater
 
-class storage_service::gossiper_state_change_subscriber_proxy: public gms::i_endpoint_state_change_subscriber {
+class storage_service::raft_ip_address_updater: public gms::i_endpoint_state_change_subscriber {
     raft_address_map& _address_map;
     storage_service& _ss;
 
@@ -663,14 +663,14 @@ class storage_service::gossiper_state_change_subscriber_proxy: public gms::i_end
             co_return;
         }
         raft::server_id id(utils::UUID(app_state_ptr->value()));
-        rslog.debug("gossiper_state_change_subscriber_proxy::on_endpoint_change() {} {}", endpoint, id);
+        rslog.debug("raft_ip_address_updater::on_endpoint_change() {} {}", endpoint, id);
 
         const auto prev_ip = _address_map.find(id);
         _address_map.add_or_update_entry(id, endpoint, ep_state->get_heart_beat_state().get_generation());
 
         // If the host_id <-> IP mapping has changed, we need to update system tables, token_metadat and erm.
         if (_ss._raft_topology_change_enabled && prev_ip != endpoint && _address_map.find(id) == endpoint) {
-            rslog.debug("gossiper_state_change_subscriber_proxy::on_endpoint_change(), host_id {}, "
+            rslog.debug("raft_ip_address_updater::on_endpoint_change(), host_id {}, "
                         "ip changed from [{}] to [{}], "
                         "waiting for group 0 read/apply mutex before reloading Raft topology state...",
                 id, prev_ip, endpoint);
@@ -694,7 +694,7 @@ class storage_service::gossiper_state_change_subscriber_proxy: public gms::i_end
     }
 
 public:
-    gossiper_state_change_subscriber_proxy(raft_address_map& address_map, storage_service& ss)
+    raft_ip_address_updater(raft_address_map& address_map, storage_service& ss)
         : _address_map(address_map)
         , _ss(ss)
     {}
@@ -734,7 +734,7 @@ public:
     }
 };
 
-// }}} gossiper_state_change_subscriber_proxy
+// }}} raft_ip_address_updater
 
 template<typename Builder>
 class topology_mutation_builder_base {
@@ -4446,12 +4446,12 @@ future<> storage_service::init_address_map(raft_address_map& address_map) {
     for (auto [ip, host] : co_await _sys_ks.local().load_host_ids()) {
         address_map.add_or_update_entry(raft::server_id(host.uuid()), ip);
     }
-    _gossiper_proxy = make_shared<gossiper_state_change_subscriber_proxy>(address_map, *this);
-    _gossiper.register_(_gossiper_proxy);
+    _raft_ip_address_updater = make_shared<raft_ip_address_updater>(address_map, *this);
+    _gossiper.register_(_raft_ip_address_updater);
 }
 
 future<> storage_service::uninit_address_map() {
-    return _gossiper.unregister_(_gossiper_proxy);
+    return _gossiper.unregister_(_raft_ip_address_updater);
 }
 
 future<> storage_service::join_cluster(sharded<db::system_distributed_keyspace>& sys_dist_ks, sharded<service::storage_proxy>& proxy) {
diff --git a/service/storage_service.hh b/service/storage_service.hh
index 682e891d00..105f8afd8b 100644
--- a/service/storage_service.hh
+++ b/service/storage_service.hh
@@ -763,10 +763,12 @@ private:
         raft::term_t term{0};
         uint64_t last_index{0};
     } _raft_topology_cmd_handler_state;
-    class gossiper_state_change_subscriber_proxy;
-    // A proxy class representing subscription to on_change
-    // events, and updating the address map on this events.
-    shared_ptr<gossiper_state_change_subscriber_proxy> _gossiper_proxy;
+    class raft_ip_address_updater;
+    // Represents a subscription to gossiper on_change events,
+    // updating the raft data structures that depend on
+    // IP addresses (raft_address_map, token_metadata.topology, erm-s),
+    // as well as the system.peers table.
+    shared_ptr<raft_ip_address_updater> _raft_ip_address_updater;
 
     std::unordered_set<raft::server_id> find_raft_nodes_from_hoeps(const std::list<locator::host_id_or_endpoint>& hoeps);