system_keyspace: persistence for Raft Group 0 id and Raft Server Id

Implement system_keyspace helpers to persist Raft Group 0 id and Raft Server id. Do not use coroutines in a template function to work around https://bugs.llvm.org/show_bug.cgi?id=50345
nawenqiang · Nov 25, 2021 · fd29585 · fd29585
1 parent 65e5499
commit fd29585
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Showing 2 changed files with 53 additions and 9 deletions.
diff --git a/db/system_keyspace.cc b/db/system_keyspace.cc
@@ -1595,19 +1595,33 @@ template future<> system_keyspace::update_peer_info<sstring>(gms::inet_address e
 template future<> system_keyspace::update_peer_info<utils::UUID>(gms::inet_address ep, sstring column_name, utils::UUID);
 template future<> system_keyspace::update_peer_info<net::inet_address>(gms::inet_address ep, sstring column_name, net::inet_address);
 
+template <typename T>
+future<> set_scylla_local_param_as(const sstring& key, const T& value) {
+    sstring req = format("UPDATE system.{} SET value = ? WHERE key = ?", system_keyspace::SCYLLA_LOCAL);
+    auto type = data_type_for<T>();
+    return qctx->execute_cql(req, type->to_string_impl(data_value(value)), key).discard_result();
+}
+
+template <typename T>
+future<std::optional<T>> get_scylla_local_param_as(const sstring& key) {
+    sstring req = format("SELECT value FROM system.{} WHERE key = ?", system_keyspace::SCYLLA_LOCAL);
+    return qctx->execute_cql(req, key).then([] (::shared_ptr<cql3::untyped_result_set> res)
+            -> future<std::optional<T>> {
+        if (res->empty() || !res->one().has("value")) {
+            return make_ready_future<std::optional<T>>(std::optional<T>());
+        }
+        auto type = data_type_for<T>();
+        return make_ready_future<std::optional<T>>(value_cast<T>(type->deserialize(
+                    type->from_string(res->one().get_as<sstring>("value")))));
+    });
+}
+
 future<> system_keyspace::set_scylla_local_param(const sstring& key, const sstring& value) {
-    sstring req = format("UPDATE system.{} SET value = ? WHERE key = ?", SCYLLA_LOCAL);
-    return qctx->execute_cql(req, value, key).discard_result();
+    return set_scylla_local_param_as<sstring>(key, value);
 }
 
 future<std::optional<sstring>> system_keyspace::get_scylla_local_param(const sstring& key){
-    sstring req = format("SELECT value FROM system.{} WHERE key = ?", SCYLLA_LOCAL);
-    return qctx->execute_cql(req, key).then([] (::shared_ptr<cql3::untyped_result_set> res) {
-        if (res->empty() || !res->one().has("value")) {
-            return std::optional<sstring>();
-        }
-        return std::optional<sstring>(res->one().get_as<sstring>("value"));
-    });
+    return get_scylla_local_param_as<sstring>(key);
 }
 
 future<> system_keyspace::update_schema_version(utils::UUID version) {
@@ -2932,6 +2946,24 @@ future<> system_keyspace::delete_paxos_decision(const schema& s, const partition
         ).discard_result();
 }
 
+future<utils::UUID> system_keyspace::get_raft_group0_id() {
+    auto opt = co_await get_scylla_local_param_as<utils::UUID>("raft_group0_id");
+    co_return opt.value_or<utils::UUID>({});
+}
+
+future<utils::UUID> system_keyspace::get_raft_server_id() {
+    auto opt = co_await get_scylla_local_param_as<utils::UUID>("raft_server_id");
+    co_return opt.value_or<utils::UUID>({});
+}
+
+future<> system_keyspace::set_raft_group0_id(utils::UUID uuid) {
+    return set_scylla_local_param_as<utils::UUID>("raft_group0_id", uuid);
+}
+
+future<> system_keyspace::set_raft_server_id(utils::UUID uuid) {
+    return set_scylla_local_param_as<utils::UUID>("raft_server_id", uuid);
+}
+
 sstring system_keyspace_name() {
     return system_keyspace::NAME;
 }

diff --git a/db/system_keyspace.hh b/db/system_keyspace.hh
@@ -415,6 +415,18 @@ public:
     static future<bool> cdc_is_rewritten();
     static future<> cdc_set_rewritten(std::optional<cdc::generation_id_v1>);
 
+    // Load Raft Group 0 id from scylla.local
+    static future<utils::UUID> get_raft_group0_id();
+
+    // Load this server id from scylla.local
+    static future<utils::UUID> get_raft_server_id();
+
+    // Persist Raft Group 0 id. Should be a TIMEUUID.
+    static future<> set_raft_group0_id(utils::UUID id);
+
+    // Called once at fresh server startup to make sure every server
+    // has a Raft ID
+    static future<> set_raft_server_id(utils::UUID id);
 }; // class system_keyspace
 
 future<> system_keyspace_make(distributed<database>& db, distributed<service::storage_service>& ss);