From fc84c69b7e6284a47a096cdf331d75c4ab97a893 Mon Sep 17 00:00:00 2001
From: Gleb Natapov <gleb@scylladb.com>
Date: Tue, 31 May 2022 10:33:52 +0300
Subject: [PATCH] service: raft: add support for topology_change command into
 raft_group0_client

Extend raft_group0_client::prepare_command with support of
topology_change type of command.
---
 service/raft/raft_group0_client.cc | 7 ++++++-
 service/raft/raft_group0_client.hh | 4 +++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/service/raft/raft_group0_client.cc b/service/raft/raft_group0_client.cc
index 7c4bc25e8e..a7b36b58c6 100644
--- a/service/raft/raft_group0_client.cc
+++ b/service/raft/raft_group0_client.cc
@@ -283,7 +283,9 @@ future<group0_guard> raft_group0_client::start_operation(seastar::abort_source*
     }
 }
 
-group0_command raft_group0_client::prepare_command(schema_change change, group0_guard& guard, std::string_view description) {
+template<typename Command>
+requires std::same_as<Command, schema_change> || std::same_as<Command, topology_change>
+group0_command raft_group0_client::prepare_command(Command change, group0_guard& guard, std::string_view description) {
     group0_command group0_cmd {
         .change{std::move(change)},
         .history_append{db::system_keyspace::make_group0_history_state_id_mutation(
@@ -411,4 +413,7 @@ void raft_group0_client::set_query_result(utils::UUID query_id, service::broadca
     }
 }
 
+template group0_command raft_group0_client::prepare_command(schema_change change, group0_guard& guard, std::string_view description);
+template group0_command raft_group0_client::prepare_command(topology_change change, group0_guard& guard, std::string_view description);
+
 }
diff --git a/service/raft/raft_group0_client.hh b/service/raft/raft_group0_client.hh
index 08cfac71fb..c369635126 100644
--- a/service/raft/raft_group0_client.hh
+++ b/service/raft/raft_group0_client.hh
@@ -127,8 +127,10 @@ public:
     // and add_entry would again forward to shard 0.
     future<group0_guard> start_operation(seastar::abort_source* as = nullptr);
 
-    group0_command prepare_command(schema_change change, group0_guard& guard, std::string_view description);
     group0_command prepare_command(broadcast_table_query query);
+    template<typename Command>
+    requires std::same_as<Command, schema_change> || std::same_as<Command, topology_change>
+    group0_command prepare_command(Command change, group0_guard& guard, std::string_view description);
 
     // Returns the current group 0 upgrade state.
     //