feat redis: add common statistic of states for instances at cluster level

Tests: протестировано в тестинге

Author: leonidlazarev

redis/functional_tests/metrics/tests/static/metrics_values.txt

@@ -286,6 +286,19 @@ redis.state: redis_database=metrics_test, redis_instance=127.0.0.1:00000, redis_
 redis.state: redis_database=metrics_test, redis_instance=127.0.0.1:00000, redis_instance_state=init_error, redis_instance_type=masters, redis_shard=test_master0	GAUGE	0
 redis.state: redis_database=metrics_test, redis_instance=127.0.0.1:00000, redis_instance_state=init_error, redis_instance_type=sentinels	GAUGE	0
 
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=connected, redis_instance_type=masters	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=connected, redis_instance_type=sentinels	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=disconnect_error, redis_instance_type=masters	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=disconnect_error, redis_instance_type=sentinels	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=disconnected, redis_instance_type=masters	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=disconnected, redis_instance_type=sentinels	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=disconnecting, redis_instance_type=masters	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=disconnecting, redis_instance_type=sentinels	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=init, redis_instance_type=masters	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=init, redis_instance_type=sentinels	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=init_error, redis_instance_type=masters	GAUGE	0
+redis.cluster_states: redis_database=metrics_test, redis_instance_state=init_error, redis_instance_type=sentinels	GAUGE	0
+
 redis.timings: percentile=p0, redis_database=metrics_test	GAUGE	0
 redis.timings: percentile=p0, redis_database=metrics_test, redis_instance=127.0.0.1:00000, redis_instance_type=masters, redis_shard=test_master0	GAUGE	0
 redis.timings: percentile=p0, redis_database=metrics_test, redis_instance=127.0.0.1:00000, redis_instance_type=sentinels	GAUGE	0

redis/src/storages/redis/impl/redis_stats.cpp

@@ -1,5 +1,7 @@
 #include <storages/redis/impl/redis_stats.hpp>
 
+#include <array>
+
 #include <storages/redis/impl/command.hpp>
 #include <storages/redis/impl/redis.hpp>
 #include <userver/logging/log.hpp>
@@ -102,6 +104,34 @@ const std::string_view kCommandTypes[] = {
     "zscore",
 };
 
+struct ConnStateStatistic {
+  std::array<size_t, static_cast<size_t>(Redis::State::kDisconnectError) + 1>
+      statistic{};
+
+  void Add(const ShardStatistics& shard_stats) {
+    for (const auto& [_, stats] : shard_stats.instances) {
+      UASSERT(stats.state <= Redis::State::kDisconnectError);
+      statistic.at(static_cast<size_t>(stats.state))++;
+    }
+  }
+
+  size_t Get(Redis::State state) const {
+    UASSERT(state <= Redis::State::kDisconnectError);
+    return statistic.at(static_cast<size_t>(state));
+  }
+};
+
+void DumpMetric(utils::statistics::Writer& writer,
+                const ConnStateStatistic& stats) {
+  for (size_t i = 0; i <= static_cast<int>(Redis::State::kDisconnectError);
+       ++i) {
+    const auto state = static_cast<Redis::State>(i);
+    writer["cluster_states"].ValueWithLabels(
+        stats.Get(state),
+        {"redis_instance_state", redis::Redis::StateToString(state)});
+  }
+}
+
 }  // namespace
 
 std::chrono::milliseconds MillisecondsSinceEpoch() {
@@ -239,19 +269,34 @@ void DumpMetric(utils::statistics::Writer& writer,
   DumpMetric(writer, stats.shard_group_total, false);
   writer["errors"].ValueWithLabels(stats.internal.redis_not_ready.load(),
                                    {"redis_error", "redis_not_ready"});
-  if (settings.GetMetricsLevel() >= MetricsSettings::Level::kShard) {
-    for (const auto& [shard_name, shard_stats] : stats.masters) {
+
+  ConnStateStatistic conn_stat_masters;
+  for (const auto& [shard_name, shard_stats] : stats.masters) {
+    if (settings.GetMetricsLevel() >= MetricsSettings::Level::kShard) {
       writer.ValueWithLabels(shard_stats, {{"redis_instance_type", "masters"},
                                            {"redis_shard", shard_name}});
     }
-    for (const auto& [shard_name, shard_stats] : stats.slaves) {
+    conn_stat_masters.Add(shard_stats);
+  }
+  writer.ValueWithLabels(conn_stat_masters,
+                         {{"redis_instance_type", "masters"}});
+
+  ConnStateStatistic conn_stat_slaves;
+  for (const auto& [shard_name, shard_stats] : stats.slaves) {
+    if (settings.GetMetricsLevel() >= MetricsSettings::Level::kShard) {
       writer.ValueWithLabels(shard_stats, {{"redis_instance_type", "slaves"},
                                            {"redis_shard", shard_name}});
     }
+    conn_stat_slaves.Add(shard_stats);
   }
+  writer.ValueWithLabels(conn_stat_slaves, {{"redis_instance_type", "slaves"}});
+
   if (stats.sentinel) {
     writer.ValueWithLabels(*stats.sentinel,
                            {"redis_instance_type", "sentinels"});
+    ConnStateStatistic conn_stat;
+    conn_stat.Add(stats.sentinel.value());
+    writer.ValueWithLabels(conn_stat, {{"redis_instance_type", "sentinels"}});
   }
 }