Fix(log): default level may race

Rename global variables in uber’s style.

log/event.go

@@ -8,8 +8,8 @@ import (
 )
 
 var (
-	logCh  = make(chan interface{})
-	source = observable.NewObservable(logCh)
+	_logCh  = make(chan interface{})
+	_source = observable.NewObservable(_logCh)
 )
 
 type Event struct {
@@ -24,16 +24,16 @@ func newEvent(level Level, format string, args ...interface{}) *Event {
 		Time:    time.Now(),
 		Message: fmt.Sprintf(format, args...),
 	}
-	logCh <- event /* send all events to logCh */
+	_logCh <- event /* send all events to logCh */
 
 	return event
 }
 
 func Subscribe() observable.Subscription {
-	sub, _ := source.Subscribe()
+	sub, _ := _source.Subscribe()
 	return sub
 }
 
 func UnSubscribe(sub observable.Subscription) {
-	source.UnSubscribe(sub)
+	_source.UnSubscribe(sub)
 }

log/log.go

@@ -2,14 +2,14 @@ package log
 
 import (
 	"os"
-	"sync/atomic"
 
 	"github.com/sirupsen/logrus"
+	"go.uber.org/atomic"
 )
 
 var (
-	// defaultLevel is package default logging level.
-	defaultLevel = InfoLevel
+	// _defaultLevel is package default logging level.
+	_defaultLevel = atomic.NewUint32(uint32(InfoLevel))
 )
 
 func init() {
@@ -18,7 +18,7 @@ func init() {
 }
 
 func SetLevel(level Level) {
-	atomic.StoreUint32((*uint32)(&defaultLevel), uint32(level))
+	_defaultLevel.Store(uint32(level))
 }
 
 func Debugf(format string, args ...interface{}) {
@@ -43,7 +43,7 @@ func Fatalf(format string, args ...interface{}) {
 
 func logf(level Level, format string, args ...interface{}) {
 	event := newEvent(level, format, args...)
-	if event.Level > defaultLevel {
+	if uint32(event.Level) > _defaultLevel.Load() {
 		return
 	}