contrib/database/sql: Disable DBStats if statsd client initialization fails

contrib/database/sql/metrics.go

@@ -32,12 +32,9 @@ const (
 var interval = 10 * time.Second
 
 // pollDBStats calls (*DB).Stats on the db at a predetermined interval. It pushes the DBStats off to the statsd client.
+// the caller should always ensure that db & statsd are non-nil
 func pollDBStats(statsd internal.StatsdClient, db *sql.DB) {
-	if db == nil {
-		log.Debug("No traced DB connection found; cannot pull DB stats.")
-		return
-	}
-	log.Debug("Traced DB connection found: DB stats will be gathered and sent every %v.", interval)
+	log.Debug("DB stats will be gathered and sent every %v.", interval)
 	for range time.NewTicker(interval).C {
 		log.Debug("Reporting DB.Stats metrics...")
 		stat := db.Stats()

contrib/database/sql/option.go

@@ -43,8 +43,10 @@ func (c *config) checkStatsdRequired() {
 		sc, err := internal.NewStatsdClient(globalconfig.DogstatsdAddr(), statsTags(c))
 		if err == nil {
 			c.statsdClient = sc
+			log.Debug("Metrics from the database/sql contrib will be sent to %v", globalconfig.DogstatsdAddr())
 		} else {
-			log.Warn("Error creating statsd client for database/sql contrib package; DB Stats will be dropped: %v", err)
+			log.Warn("Error creating statsd client for database/sql contrib; DB Stats disabled: %v", err)
+			c.dbStats = false
 		}
 	}
 }

contrib/database/sql/option_test.go

@@ -72,4 +72,12 @@ func TestCheckStatsdRequired(t *testing.T) {
 		_, ok := cfg.statsdClient.(*statsd.Client)
 		assert.True(t, ok)
 	})
+	t.Run("invalid address", func(t *testing.T) {
+		globalconfig.SetDogstatsdAddr("unreachable/socket/path/dsd.socket")
+		cfg := new(config)
+		cfg.dbStats = true
+		cfg.checkStatsdRequired()
+		assert.Nil(t, cfg.statsdClient)
+		assert.False(t, cfg.dbStats)
+	})
 }

contrib/database/sql/sql.go

@@ -210,7 +210,7 @@ func OpenDB(c driver.Connector, opts ...Option) *sql.DB {
 		cfg:        cfg,
 	}
 	db := sql.OpenDB(tc)
-	if cfg.dbStats {
+	if cfg.dbStats && cfg.statsdClient != nil {
 		go pollDBStats(cfg.statsdClient, db)
 	}
 	return db