perf(filter): Allow stale reads in filter

Allow reading from slave replicas when fetching all patterns for
patterns index. Add dialer test case.

cmd/config.go

@@ -28,8 +28,9 @@ type RedisConfig struct {
 	// Redis node port
 	Port string `yaml:"port"`
 	// Redis database
-	DB              int `yaml:"dbid"`
-	ConnectionLimit int `yaml:"connection_limit"`
+	DB              int  `yaml:"dbid"`
+	ConnectionLimit int  `yaml:"connection_limit"`
+	AllowSlaveReads bool `yaml:"allow_slave_reads"`
 }
 
 // GetSettings returns redis config parsed from moira config files
@@ -41,6 +42,7 @@ func (config *RedisConfig) GetSettings() redis.Config {
 		Port:              config.Port,
 		DB:                config.DB,
 		ConnectionLimit:   config.ConnectionLimit,
+		AllowSlaveReads:   config.AllowSlaveReads,
 	}
 }
 

database/redis/database.go

@@ -46,8 +46,7 @@ type DbConnector struct {
 	metricsCache         *cache.Cache
 	sync                 *redsync.Redsync
 	source               DBSource
-
-	slaveConnector *DbConnector
+	slaveConnector       *DbConnector
 }
 
 // NewDatabase creates Redis pool based on config
@@ -144,7 +143,7 @@ func createPoolDialers(logger moira.Logger, config Config) (mainDialer, slaveDia
 		db:            config.DB,
 		dialTimeout:   dialTimeout,
 	}
-	return
+	return mainDialer, nil
 }
 
 func (connector *DbConnector) makePubSubConnection(channel string) (*redis.PubSubConn, error) {

database/redis/database_test.go

@@ -41,6 +41,20 @@ func TestAllowStale(t *testing.T) {
 			So(staleDatabase, ShouldPointTo, database)
 		})
 
+		Convey("When using sentinel with slave reads disabled, returns same db", func() {
+			sentinelConfig := Config{
+				MasterName:        "mstr",
+				SentinelAddresses: []string{"addr.ru"},
+				DB:                0,
+				AllowSlaveReads:   false,
+			}
+			database := newTestDatabase(logger, sentinelConfig)
+
+			staleDatabase := database.AllowStale()
+
+			So(staleDatabase, ShouldPointTo, database)
+		})
+
 		Convey("When using sentinel, returns slave db instance, retains references", func() {
 			sentinelConfig := Config{
 				MasterName:        "mstr",

filter/patterns_storage.go

@@ -30,7 +30,7 @@ func NewPatternStorage(database moira.Database, metrics *metrics.FilterMetrics,
 
 // Refresh builds pattern's indexes from redis data
 func (storage *PatternStorage) Refresh() error {
-	newPatterns, err := storage.database.GetPatterns()
+	newPatterns, err := storage.database.AllowStale().GetPatterns()
 	if err != nil {
 		return err
 	}

filter/patterns_storage_test.go

@@ -19,6 +19,7 @@ func TestProcessIncomingMetric(t *testing.T) {
 
 	mockCtrl := gomock.NewController(t)
 	database := mock_moira_alert.NewMockDatabase(mockCtrl)
+	database.EXPECT().AllowStale().AnyTimes().Return(database)
 	logger, _ := logging.GetLogger("Scheduler")
 
 	Convey("Create new pattern storage, GetPatterns returns error, should error", t, func() {

perfomance_tests/filter/filter_test.go

@@ -39,6 +39,7 @@ func BenchmarkProcessIncomingMetric(b *testing.B) {
 
 	mockCtrl := gomock.NewController(b)
 	database := mock_moira_alert.NewMockDatabase(mockCtrl)
+	database.EXPECT().AllowStale().AnyTimes().Return(database)
 	logger, _ := logging.GetLogger("Benchmark")
 
 	database.EXPECT().GetPatterns().Return(patterns, nil)