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

… fails (#2682)

Co-authored-by: Dario Castañé <[email protected]>

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